Kidney international Vol 28 1985 pp 569583NEPHROLOGY FORUMMecha - PDF document

Kidney international, Vol. 28 (1985), pp. 569—583NEPHROLOGY FORUMMechanisms of glomerular injury in immune-complex diseasePrincipal discussant: WILLIAM G. COUSERUniversity of Washington, Seattle, Washington, USACase presentationA 27-year-old black woman was admitted to Harborview MedicalCenter, a component of the Warren G. Magnuson Health ServicesCenter at the University of Washington, complaining of midepigastricpain, chills, and sweats for the previous two days. She had beenhospitalized several times previously for similar complaints, Each timethe pain resolved spontaneously and no cause was found. The patientalso had a history of intravenous drug abuse including heroin andamphetamines over a period of 7 years, but she denied drug use in the 2 brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Elsevier - Publisher Connector 570Nephrology Forumular immune-complex deposits at mesangial, subendothelial,and subepithelial sites. Similar deposits are seen in otherpostinfectious nephropathies, such as subacute bacterial endo-carditis and shunt nephritis as well as in diseases such as lupusnephritis, type-I membranoproliferative glomerulonephritis(MPGN), and severe IgA nephropathy or Henoch-SchOnleinpurpura [6]. The pyogenic gingival infection that initiated thispatient's illness probably arose from mixed flora containingaerobic and anaerobic streptococci and other organisms. Al-though postinfectious nephntis usually is associated withgroup-A beta-hemolytic streptococci of so-called nephritogenicserotypes, it also has been reported with non-group-A strepto-cocci as well as with a variety of other organisms [7—9].The association between bacterial infection and glomerulone-phritis was first identified by Lohlein in 1907 [10]. Schick firstsuggested an immune basis for glomerulonephritis after observ-ing that nephritis following scarlet fever or tonsillitis occursafter a time interval consistent with that seen in hypersensitivityreactions [ii], Von Pirquet came to similar conclusions afterobserving the similarity between the time course of poststrepto-coccal nephritis and that of serum sickness in humans [12].Support for this hypothesis was provided in the late 1950s bythe first immunofluorescence studies of human kidney tissue,which demonstrated granular immune deposits in diseasedgiomeruli in poststreptococcal glomerulonephritis and otherdiseases [13]. Experimental verification of the immune basis ofnephritis following exposure to a foreign protein antigen wasprovided by the pioneering studies of Germuth and Dixon in the1950s and 1960s in acute and chronic BSA-serum sickness inrabbits [14—17]. These investigators noted that clinical andhistologic manifestations of glomerulonephritis could be in-duced in most rabbits ito 2 weeks following a single injection ofBSA, and that immune deposits of antigen and antibody devel-oped at mesangial, subendothelial, and subepithelial sites justas in the patient we are discussing [14—161 (Fig. 1). It wasfurther noted that the glomerular deposits developed coincidentwith the appearance of circulating, soluble immune complexesof the same antigen and antibody, and that the site of depositformation was related to the immune response and consequentratio of antigen to antibody present in the circulation [17, 18].Thus animals with high antibody levels formed large, lattice-like, insoluble immune complexes that were cleared rapidly bythe mononuclear phagocyte system (MPS) or were deposited insmall amounts in the giomerular mesangium [15,161.A lessvigorous antibody response led to smaller, more soluble com-plexes, with more deposits in the mesangium and along thecapillary wall at subendothelial sites [15—18].Poorantibodyresponders, or animals repeatedly re-injected with antigen tomaintain persistent antigen excess, developed predominantlysubepithelial deposits [16—18], Because the deposits formedonly in the presence of circulating immune complexes, andbecause antigen and antibody could not be detected alone inglomeruli by conventional immunofluorescence techniques, itwas concluded that the granular deposits and glomerulonephri-tis resulted from the glomerular trapping of soluble immunecomplexes formed in the circulation. The site of complexlocalization was believed to be determined largely by the ratioof antigen to antibody and hence the size of the lattice of theimmune complexes formed [16—18]. The giomerulus was seenas only a passive filter in this process. This view of thepathogenesis of immune-complex nephritis, prevalent for near-ly two decades, was supported by a number of studies of thefate of preformed immune complexes infused into animals(reviewed in 19). These studies demonstrated that mesangial aswell as subendothelial deposits could be produced by circulat-ing complex trapping. The origin of subepithelial deposits wasnot clarified by these studies, however. Moreover, short-terminfusion of preformed immune complexes did not induceglomerular disease sufficient to permit studies of how thisprocess caused glomerular injury, although inflammatory cellinfiltrates were sometimes seen [19]. Concepts of the mediationof immune-complex—induced tissue damage therefore werederived primarily from studies in experimental models of neph-rotoxic, or anti-GBM, nephritis and were then extrapolated toglomerular injury due to preformed immune-complex trapping[20].Interest in the pathogenesis of immune-complex glomerulo-nephntis was rekindled in the late 1970s. In Heymann nephritis,a rat model of membranous nephropathy induced by active orpassive immunization against a proximal tubular brush-borderantigen (FxlA), pretreatment with the aminonucleoside ofpuromycin, an epithelial cell toxin that interferes with glycopro-23LRELDLRIHS-PGSENFig. 1.Schematic depiction of intraglomerular sites of immune-complexformation.Subepithelial deposits such as those in postinfectious gb-merulonephritis (1) or membranous nephropathy (2) apparently form bylocal, or in-situ, mechanisms. Subendothelial (3) and mesangial (4)deposits are usually seen together and may form locally or result fromthe passive trapping of preformed immune complexes from the circula-tion. Anti-GBM antibody deposits are in a lin

ear pattern within thecapillary wall itself (5). The mechanism of formation, composition,quantity, and relative accessibility of each of these deposits to circulat-ing inflammatory cells are the major determinants of the type of lesionproduced.The inset illustrates the three layers of the normal glomerularcapillary wall, endothelial cells (EN), GBM, and epithelial cells (EP).The negative charge on the capillary wall results from the siaboproteins(S) coating the endothelial and epithelial cell surfaces and the heparan-sulfate proteoglycan (HS-PG) anionic sites in the lamina ram interna(LRI) and externa (LRE) of the GBM. (From Ref. 44). Glomerular injury in immune-complex disease571tein turnover on the cell membrane, prevented the formation ofsubepithelial immune-complex deposits [2 1—231. This findingfirst implicated a property of the glomerulus itself in immune-complex formation. It was then found that the deposits in theHeymann models, previously believed to result from trappingof circulating immune complexes containing brush-border anti-gens [24], could be produced by antibody binding directly to anintrinsic glomerular antigen [25, 26]. Subsequent studies haveextensively reevaluated the nature of glomerular immune-com-plex deposits at mesangial, subendothelial, and subepithelialsites [27, 28] (Fig. 1), and have considerably revised andextended our understanding of how these deposits form. Anoutline of the mechanisms of glomerular immune deposit forma-tion in the order! will discuss them here is presented in Tables 1and 2. Figure 2 illustrates the mechanisms that mediate immuneglomerular injury.Table 1. Mechanisms of subepithelial immune-complex formationI. In-situ immune-complex formationA. Antibody binding to glomerular antigens1. Heymann Antigen [25, 26, 3012. Epithelial cell foot process antigen [38]B. Planted nonglomerular antigens1. Charge-dependent mechanismsa. Cationic antigens [47—49, 62]b. Anionic antigens [66, 8012. Charge-independent mechanismsa. Direct binding of antigens to capillary wall by underfinedmechanisms [36, 83]b. IgG binding to capillary wall by immune mechanisms [84,85]II. Circulating immune-complex trappingA. ? Cationic or low avidity immune complexes [65, 87, 89]Mechanisms of subepithelial glomerularimmune-complex formationIn-situ immune-complex formationFixed glomerular antigens. Subepithelial immune-complexdeposits are now believed to form primarily on a local, or in-situ, basis rather than from circulating immune-complex trap-ping, but this mechanism may involve either insoluble fixedrenal antigens or soluble exogenous antigens. Table I lists themechanisms involved. The in-situ mechanism has been beststudied in the rat, where it was first shown to be responsible forinitiating subepithelial deposits in the passive Heymann nephri-tis model [25, 26], The antigen responsible for this lesion, whichbears a striking resemblance to human idiopathic membranousnephropathy, is now believed to be a glycoprotein with amolecular weight of about 330 Kd (GP330) [29, 301. The antigenis distributed along the glomerular epithelial cell membrane,where it is localized in endoplasmic reticulum and in coated pits[30]. Unlike deposition of anti-GBM antibody, which occursalmost immediately [31], antibody to the epithelial cell antigendeposits slowly for reasons that are unclear [32]. Studies ofantibodies combining with similar plasma-membrane antigens(such as angiotensin converting enzyme) on pulmonary endo-thelial cells or in the oolemma of rabbit oocytes [33, 34], andstudies utilizing antibody to GP330 and cultured rat glomerularepithelial cells [35] have suggested that the interaction ofdivalent antibody with such plasma membrane antigens inducesantigen redistribution and capping on the cell surface. Immunecomplexes are then shed into the adjacent lamina rara externaof the GBM and into slit pores. This distribution probablyresults in the discontinuous, finely granular appearance of thesedeposits. Other mechanisms may contribute to immune-com-plex formation in Heymann nephritis. For example, Abrass andCohen have identified a component of the nephritogenic tubularbrush-border antigen that can localize directly in glomeruli fromthe circulation and which may serve as a "planted" antigen[36]. These workers also have described the development laterin the course of passive Heymann nephritis of a secondantibody that reacts with glomeruli but not with brush borders[37]. Another example of a spontaneous nephropathy due toantibody reacting with an apparently different epithelial cellantigen has been reported in rabbits [38].Table 2. Mechanisms of mesangial and subendothelialimmune-complex formationIn-situ i,nmune-complex formationGlomerular antigensEndothelial cell-membrane antigens [90]Planted nonglomerular antigensCharge-related localization of large cationic antigens [63]Biochemical affinity of antigen for GBM glycoprotein [93]Mesangial uptake of macromolecular antigens [97]Immune-complex deposit interaction with:I. Rheumatoid factors [103]2. Antiidiotypic antibodies [104]3. Circulating immune complexes 1105]Circulating immune-complex trappingDeterminants of:Systemic factorsI. Renal blood flow [110]2.Mononuclear phagocytesystem function [107, 108]3. Erythrocyte CR1 receptors [109]Glomerular factors1. Hemodynamic changes [11112. Charge and permeability [78, 79]3. Mesangial afferent and efferent limb function [61, 112]Properties of immune complexes1.Size [113]2. Charge [89, 114]3. Complement-fixing ability [109]4. Biodegradability [99, 101].aNumeralsin brackets are reference numbers.Sincethe immunogen usually utilized to elicit Heymannnephritisis derivedfrom a crude proximal tubular brush-bordermembranefraction, many laboratorieshave searched for evi-dence of brush-border antigen or antibody to the immunogen inhuman membranous nephropathy. With rare exceptions [39,40], these studies have been negative [41, 42]. However, studiesdesigned to evaluate the possibility that the antibody in humanmembranous nephropathy may be directed against a glomerularepithelial cell antigen rather than against a tubular brush-borderantigen have not yet been carried out despite increasing suspi-cion that such an autoimmune mechanism is probably operative

in this disease [43, 44].Except for anti-GBM disease, no human equivalent of im-mune-complex glomerulonephritis due to antibody reactingwith a fixed glomerular antigen has so far been identified. 572NephrologyForum0Fig.2.Defined mechanismsby which glomerular im,nune-co,nplexdeposits mediate tissue injury as evidenced by increased glomerularpermeability and proreinuria are shown in solid lines. Proteinuria mayresult from antibody binding to some fixed glomerular antigens (1), orfrom the direct effect of complement activation (2). Complementactivation by subendothelial and mesangial deposits may attract neutro-phils by chemotactic (C5a) or immune adherence (C3b) mechanisms (3).Macrophages may also be attracted by immune adherence mechanismsinvolving Fc receptors (4). The capacity of sensitized T cells to causeglomerular injury by macrophage recruitment, or perhaps directly (5), isnot yet fully established and is therefore shown in dotted lines.Similarly, the role of mesangial cells in producing glomerular injuryremains hypothetical. Activated inflammatory cells cause basementmembrane damage by release of proteases and/or reactive oxygenspecies.However, antibodies to DNA are known to be polyspecific andreactive with shared antigenic epitopes on several structuresincluding polynucleotides, phospholipids, cell membranes, cy-toskeletons, and bacteria [45]. Monoclonal anti-DNA antibod-ies have been shown by Madaio et a! to bind directly toglomerular structures in mice [461. Such studies support thehypothesis that antibody binding to fixed non-GBM glomerularantigens may contribute to some types of human immune-complex nephritis.Planted non-glomerular antigens. Subepithelial immune-complex deposits also can occur in nephritis induced by exoge-nous antigens as they do in the chronic BSA serum-sicknessmodels. Multiple mechanisms have now been identified that canlead to such "planted" antigen deposits (Table 1); severalinvolve electrical interactions between glomerular anionic sites,principally the negatively charged heparan-sulfate proteogly-cans in the laminae rarae of the capillary wall (Fig. 1), andcationic, or positively charged, immune reactants.If chronic serum sickness is induced with BSA chemicallymodified to increase the p1 from 4.5 to greater than 9.0, rabbitsdevelop predominantly subepithelial deposits, independent ofthe immune response or of the quantity and size of circulatingimmune complexes [47]. Initial localization of cationic antigenprior to antibody binding has been demonstrated by bothimmunofluorescence and radiolabeling techniques, although theantigen does not persist and disease does not develop unlessantibody binding produces immune complexes [47—49]. More-over, a similar lesion can be produced if one perfuses anisolated kidney with cationic antigen followed by antibody to it,thus establishing that the deposits are formed locally [48, 49].The granular nature of these deposits probably results from thetendency of anionic structures to coalesce after interaction withcationic molecules [501, as well as from the capacity of immunecomplexes formed of multivalent antigens and precipitatingantibodies to rearrange and condense into larger latticed struc-tures visible by electron microscopy [51].LikeHeymann nephritis, the cationic BSA serum sicknessmodel has been suggested as a model of human membranousnephropathy [47, 52]. Thus therapy with polycations, whichneutralize anionic sites and therefore reduce deposit formationin cationic BSA serum sickness, has been advocated for studyin membranous nephropathy in humans 1521. As in all exoge-nous antigen-induced nephropathies, however, some depositsin serum sickness occur in subendothelial and mesangial sites aswell [47, 53]. Deposits in these locations are atypical of idio-pathic membranous nephropathy, which morphologically moreclosely resembles the lesion induced by the fixed-antigen mech-anism. This distinction could have therapeutic relevance, be-cause studies of polycation therapy in fixed antigen models ofmembranous nephropathy have shown no detectable effect onantibody deposition or on proteinuria 154].This mechanism of cationic antigen-induced immune-com-plex nephritis recently has been applied to studies of postinfec-tious nephritis in humans. Vogt and colleagues have isolatedseveral anionic and cationic extracellular proteins from nephri-togenic streptococci and used specific antibodies to them todemonstrate glomerular localization of only cationic antigens inglomerular immune deposits in 8 of 18 patients with earlypoststreptococcal glomerulonephntis [55]. Evidence also hasbeen provided for the participation of a streptococcal cellmembrane antigen, endostreptosin, in immune deposits in pa-tients with early poststreptococcal glomerulonephritis [56]. Thedeposits also may contain antibody to an abnormal IgG, desia-lated by the action of streptococcal neuraminidase, therebymaking it more cationic [57, 581. However, various inertmacromolecules, such as streptococcal M proteins, may belocalized in glomeruli without necessarily causing disease [59,60]. Nonspecific uptake of circulating macromolecules is in-creased in damaged glomeruli [61]. Immunofluorescence stud-ies that identify putative pathogenetic agents in human glomeru-lar immune deposits therefore must be interpreted with consid-erable caution [62].A second mechanism of in-situ subepithelial immune-com-plex formation related to charge involves large cationic antigenssuch as ferritin, which may first localize along the subendo-thelial surface of capillary walls. Secondary fixation of antibodyleads to formation of large latticed subendothelial deposits [63,64]. These complexes subsequently can dissolve and individualreactants (or perhaps small immune complexes) can cross thecapillary wall to reform as larger immune complex aggregates inthe subepithelial space [63]. This mechanism may be operativein diseases in which subepithelial and subendothelial depositscoexist, as in the patient discussed here, or in patients withsevere lupus nephritis.Although most attention has been directed at glomerularlocalization of cationic antigens, anionic antigens such as nativeIncreased glomerular permeability Glomerular injury in immune-co,

nplex disease573BSA and DNA clearly are important in producing both experi-mental and clinical immune-complex nephritis. Two additionalcharge-related mechanisms may account for the local formationof immune-complex deposits containing anionic antigens. Forexample, cationized IgG molecules can localize in glomerulijust as other cationic proteins do [65], and antibody IgG thencan bind anionic antigen and thus initiate immune-complexformation locally [661. The capacity of naturally occurringcationic IgG to localize in this way is suggested by studiesdemonstrating local formation of immune complexes of nativeBSA (p1 4.5) and anti-BSA antibody following several alternateperfusions of separated solutions of antigen and antibody in ratkidneys [67]. Subsequent studies demonstrating that immunedeposits in this system form largely when the cationic antibodyfraction is used support that hypothesis (FLEUREN 0, et al,personal communication). Anionic antigens perhaps facilitatesynthesis of such cationic antibody [68]. Experimental studieshave demonstrated facilitated deposition of cationic antibody toboth fixed and planted subepithelial antigens [69, 70], andelution studies have suggested a predominance of cationicantibodies in some naturally occurring models of glomerulone-phritis [71, 72]. But elution studies must be interpreted withparticular caution, as only a fraction of the deposited antibodyis eluted, and that fraction has not been shown to be repre-sentative of the total antibody deposited.A second mechanism of considerable potential importancewith respect to anionic antigen localization involves initialinteraction between nonimmune cationic proteins derived frominflammatory cells and platelets and glomerular anionic sites.Anionic antigens may then bind electrical y to deposited cation-ic proteins and initiate in-situ immune-complex formation.Several cationic proteins might participate in this process,including neutrophil cationic proteins [73], cationic products ofcomplement activation [74], and platelet factor IV [75]. Acetylglyceryl ether of phosphoryicholine (platelet activating factor,PAF), released from several inflammatory cells during immune-complex disease, may have similar effects by inducing releaseof platelet cationic proteins and vasoactive amines, whichincrease glomerular permeability and favor anionic antigenlocalization [76]. Immune-complex formation within the renalmicrovasculature can result in glomerular localization of plate-let factor IV and platelet cationic proteins [77]. Enhancedglomerular immune-complex formation with anionic antigens inthe presence of reduced capillary wall negative charge has beendemonstrated with the polycation polyethyleneimmine (PEI).This polycation increases formation of mesangial, subendo-thelial and subepithelial immune-complex deposits induced byinjection of anionic ferritin followed by antibody to it or byinjection of native BSA-containing immune complexes [78, 79].Subepithelial immune-complex deposits have been producedexperimentally by the injection of cationized non-antibody IgGfollowed by anionic BSA and then anti-BSA antibody [80].Evidence for a loss of glomerular anionic sites prior to thedevelopment of detectable glomerular immune-complex depos-its in murine lupus nephritis suggests that such a process alsomight be operative in vivo [81, 82].Two anionic antigens, DNA (p1 4.5) and a purified tubularbrush-border antigen (p1 5.4), have been shown to bind directlyto glomeruli, apparently by charge-independent mechanismsthat have not been well defined [36, 83]. Antigen also may belocalized in a subepithelial distribution by immunologic mecha-nisms in the form of IgG antibody to Heymann antigen (84, 851.Finally, for immune-complex deposits formed by any of thesemechanisms to persist and cause disease at any site, thedeposits must be composed of precipitating antigen-antibodysystems and be capable of undergoing rearrangement or con-densation into large lattice-like aggregates that can be visual-ized by conventional immunofluorescence or electron micros-copy [51, 86].Circulating immune-complex trappingThe issue of whether preformed immune complexes can bepassively trapped in a subepithelial site remains controversial,although I believe that this has not been convincingly shown tooccur. In studies reporting subepithelial localization of com-plexes made of low-avidity antibodies [87] or non-covalentlylinked immune complexes made with cationic antigens [65],intravascular dissociation of antigen and antibody with subse-quent in-situ immune-complex formation are likely to haveoccurred [88]. Subepithelial localization of covalently linkedcationic immune complexes has been achieved in only onestudy, which did not define the size of the complexes depositedor carefully exclude small amounts of free cationic antigen.Again, local complex formation is a possible explanation for theresults observed [89]. Charge neutralization has been suggestedto facilitate subepithelial localization of preformed immunecomplexes [79].Mesangial and subendothelial immune-complex depositsSubendothelial deposits are not seen in the absence ofmesangial deposits, and deposits at the two sites presumablydevelop by very similar mechanisms (Table 2). Diseases due tomesangial and subendothelial immune-complex deposits in-clude lupus and type-I MPGN as well as a variety of postinfec-tious processes such as bacterial endocarditis, shunt nephritis,and diseases such as that of today's patient [6]. Deposits atmesangial and subendothelial sites can develop by in-situmechanisms and from circulating immune-complex trapping.In-situ immune-complex formationAntibody binding to fixed glomerular antigens. Little clinicalor experimental evidence currently exists for a fixed-antigenmechanism in the development of glomerulonephritis associat-ed with mesangial deposits. However, glomerulonephritis hasbeen produced with antibody to angiotensin converting en-zyme, an antigen induced experimentally on the plasma mem-brane of endothelial cells [90]. Antibodies to endothelial cell-surface and Ia antigens have been reported in lupus and couldcontribute to the production of subendothelial deposits andglomerulonephritis by this mechanism [91, 92].Plant

ed non-glomerular antigens (Table 2). Antigen localiza-tion in a subendothelial distribution induces in-situ immune-complex formation and glomerulonephritis by two mechanisms.Large cationic antigens such as ferritin, which cannot readilypenetrate the GBM, may localize by charge interaction withanionic sites on the inner surface of the capillary wall andproduce subendothelial deposits [631. The affinity of certainplant lectins, such as concanavalin A, for glucose and mannoseresidues in capillary wall glycoproteins also can result inglomerular localization of antigen. Injection of antibody to 574Nephrology Forum"planted" concanavalin A results in a linear-granular pattern ofsubendothelial immune-complex deposits and glomerulonephri-tis [931.Lectin-likecomponents in some viruses may have thepotential for producing deposits by such a mechanism inhumans [43].The mesangium is an intracapillary network of mesangialcells and matrix which, like the subendothelial space, is contig-uous with the circulation through a layer of endothelial cellswith fenestrae of about 44 nm [94]. It is therefore a readyrepository for a variety of circulating macromolecules includingpotential antigens and preformed immune complexes. Thesemolecules enter the mesangial matrix and are degraded locallyby infiltrating monocytes or intrinsic mesangial cells, or theyexit via the glomerular hilus into the cortical interstitium andrenal lymph [95, 96]. This capacity of the mesangium to localizeantigens, and the nephritogenicity of in-situ immune-complexformation within the mesangium, are well illustrated by thestudies of Mauer and coworkers [61, 97]. Like many macromol-ecules, heat-aggregated human IgG administered intravenouslyinto rabbits localizes within the mesangium. To exclude thepresence of circulating antigen, rabbit kidneys containing theIgG mesangial deposits then were transplanted into normalrabbits before antibody to human IgG was administered. Theresultant production of IgG—anti-IgG immune complexes withinthe mesangial matrix induced a focal proliferative glomerulone-phntis much like that seen in several human renal diseasesassociated with mesangial immune-complex deposits, such asclass Il-Ill lupus nephritis, IgA nephropathy, and Henoch-Schönlein purpura [97]. In human IgA nephropathy, the IgAdeposits appear to represent polymeric IgA antibodies of muco-sal origin directed against some as yet unidentified antigen [98,99]. Anionic charge sites have been identified in the mesangium[100, 101] and may play a role in the localization and persistenceof cationic antigens, although this effect is much less evidentthan it is with capillary wall deposits [102].Because subendothelial and mesangial deposits, whetherformed locally or from circulating complex trapping, are indirect contact with immune reactants in the circulation, accre-tion of deposits with further glomerular injury may continue byother in-situ mechanisms, including the binding of rheumatoidfactors [1031 or antiidiotypic antibodies [104] to deposited IgG.Immune interaction also continues between reactive antigen orantibody binding sites in the deposits and their counterparts inimmune complexes formed in the circulation [105].Circulating immune-complex trappingNumerous studies have demonstrated the capacity of pre-formed immune complexes injected intravenously to be pas-sively trapped at mesangial and subendothelial sites (reviewedin Ref. 19). In contrast to the nephritis produced consistentlywhen immune-complex deposits form in situ, however, thepassive trapping of preformed complexes produces an influx ofscavenging mononuclear cells [106] but little other histologic orfunctional evidence of glomerular disease [19]. More prolongeddeposition of preformed complexes could be more productiveof tissue damage. Until this phenomenon is demonstrated,however, the contention that glomerulonephritis can resultfrom the passive trapping of preformed immune complexesmust remain a hypothesis.The factors regulating the glomerular deposition of preformedcomplexes from the circulation have been extensively studiedand defined and are summarized in Table 2. They includesystemic factors, glomerular factors, and properties of theimmune complexes themselves. Systemic factors include renalblood flow, MPS function, and erythrocyte CR1 receptors,which collectively determine the plasma level, disappearancekinetics, and renal delivery of immune complexes [107—110].Glomerular factors include hydrostatic pressure and filtrationfraction, which determine the driving forces by which immunecomplexes enter the capillary wall or mesangium from thecirculation [1111, charge and permeability characteristics of theglomerulus itself [78, 79], and mesangial afferent and efferentlimb or clearing function [61, 96, 112]. Properties of the immunecomplexes themselves are also important, particularly size andthe determinants of size such as concentration of antigen andantibody, and antigen:antibody ratio, antigen valence, andantibody class and avidity [113]. Other properties of immunecomplexes such as charge, complement-fixing ability, and rela-tive biodegradability also influence immune-complex deposi-tion and persistence in glomeruli [89, 95, 109, 113, 114].These same factors also influence the passive trapping ofimmune complexes in a subendothelial distribution. Subendo-thelial as well as mesangial deposits are seen when increasedquantities of large immune complexes are delivered to theglomerulus, as can occur with a reduction in MPS capacity ormesangial clearing function [107, 108] or, in primates, perhapsby saturation of erythrocyte C3b (CR1) receptor function [109].The largest and most persistent subendothelial deposits inexperimental systems have been produced with large latticedpreformed complexes made with cationized antibodies [1141.Alterations in capillary wall charge and permeability not onlyincrease deposition but alter the pattern of immune-complexdeposits and may facilitate subendothelial localization of pre-formed complexes [78, 79]. This finding may reflect changes inthe size-selective glomerular filtration barrier that accompanycharge reduction [115] or the increase in circulating immunecomplex size that results from loss of free an

tigen in the urine.Finally, with respect to the mechanisms of glomerular im-mune-complex formation seen in response to exogenous anti-gens such as infectious agents, I must reemphasize the dynamicrelationship always operative between antigen and antibody infree and immune-complex form (Ag + AbAgAb).The statusof this equilibrium is determined by the quantities of antigenand antibody available for immune-complex formation, antigenvalence, the relative avidity of antibody for antigen, and therate of clearance of the immune complexes formed. Thus,factors that reduce circulating immune-complex levels, such asenhanced MPS function or plasma-exchange therapy, alsoreduce levels of free antigen and antibody that may initiate in-situ immune-complex formation. Conversely, factors that in-crease circulating immune-complex levels, such as MPS block-ade, also increase free circulating antigen and antibody levels.This increment in available reactants would enhance bothcirculating immune-complex deposition and, if appropriate con-ditions existed, in-situ immune-complex formation [116]. Thus,circulating immune complexes must be present, as they were inthe patient we are discussing, for deposits to form fromexogenous antigens by either immune-complex trapping or in-situ mechanisms. Circulating complexes provide a reservoir forthe reactants that produce in-situ immune-complex deposits. Gloinerular injury in immune-complexdisease575Measurement of serum levels or glomerular deposits of antigen,antibody, and immune complexes therefore cannot distinguishbetween these two mechanisms of deposit formation in eitherhuman or animal models such as serum sickness [62, 1161.Mediation of immune-complex-induced glomerular injuryThe formation of antigen-antibody complexes within theglomerulus does not directly induce tissue injury. Rather,damage occurs as a consequence of activation of other cellularand humoral mediator systems. Because of the difficulty inproducing experimental glomerular injury by deposition ofpreformed immune complexes, most studies of the mediation ofimmune renal injury have been carried out in models of in-situimmune-complex formation [281. As I have mentioned, themechanism by which immune-complex deposits form largelydetermines the intraglomerular site of deposit formation (Fig.1). In turn, the type of inflammatory mediators activated (Fig.2), and consequently the lesion produced, are importantlydependent on the site as well as on the composition of theimmune deposits [1171. Four mechanisms have been estab-lished by which glomerular immune-complex deposits caninitiate tissue injury; evidence is accumulating for a fifth. Thesemechanisms are illustrated schematically in Figure 2.Direct effect of antibody deposition alone. The reaction ofIgG antibody with GBM antigens can markedly increaseglomerular permeability to protein independently of comple-ment or inflammatory cells [1181. A similar effect has beendemonstrated with univalent and divalent fragments of IgGantibody to the Heymann antigen on epithelial cell surfaces[1191. This effect occurs only with antibody to certain antigeniccomponents of the glomerular capillary wall but not with others[120, 121]. The effect presumably reflects an internal alterationor distortion of the geometry of the filtration barrier and resultsin altered permselectivity. It has not been demonstrated withexogenous antigen-induced immune-complex formation inglomeruli.Direct effect of complement. This newly recognized form ofimmune glomerular injury was first demonstrated in the passiveHeymann nephritis model of membranous nephropathy inducedby antibody reacting with a fixed subepithelial antigen. Protein-una induced by in-situ subepithelial immune-complex forma-tion was complement-dependent but did not involve inflamma-tory cells [122]. A similar mechanism is operative when thesubepithelial deposits form in situ with planted exogenousantigens [84]. Studies of passive Heymann nephritis in ratsmade C6 deficient demonstrate a requirement for the CSb-9, ormembrane attack complex (MAC), portion of the complementsystem for full development of proteinuria [123]. A similarrequirement for C6 also has been demonstrated in cationicBSA-induced serum sickness [53] and in complement-depen-dent anti-GBM nephritis in the rabbit [124]. Further support forthe membranolytic role of complement in immune glomerularinjury is provided by the observation that neoantigens of thecomplement MAC are present, along with terminal complementcomponents, in glomerular lesions induced by complement-dependent mechanisms but are absent in lesions in the genesisof which complement does not participate [125, 126]. Thepresence of neoantigens of the MAC in glomerular immunedeposits in human renal diseases, including lupus nephritis andidiopathic membranous nephropathy [127, 128], suggests that asimilar mechanism may be operative in humans. The molecularmechanism by which MAC formation and insertion into lipidbilayers of cell membranes—or perhaps into basement mem-branes [129]—alters the size-selective glomerular filtration bar-rier has not yet been defined.Complement-neutrophil—mediated glomerular injury. Themajor mechanism of complement-mediated immune-complex—induced tissue injury has long been thought to be generation ofchemotactic peptides, primarily CSa, by complement activation[130]. The generation of C5a results in neutrophil attraction tothe site of immune deposits and, as a consequence, tissue injuryis produced by release of toxic products of neutrophil activationadjacent to the GBM [20, 131, 132]. However, this mechanismhas been demonstrated only in certain models of anti-GBMdisease. Several observations document the importance ofneutrophils in these models. Neutrophils invade glomeruli 4 to24 hours following anti-GBM antibody deposition in quantitiesproportional to the amount of antibody deposited [131]. Theonset of nonselective proteinuna correlates with the appear-ance of neutrophils, and the amount of proteinuna with theirnumber [132, 133]. Proteinuna can be diminished or abolishedby both complement and neutrophil depletion in some models[131, 132], and it can be produced by infusing neutrophils intoneutrophil-depleted animals with antibody an

d complementdeposits [134]. The importance of complement and C5a genera-tion in neutrophil-mediated disease has been inferred from thebeneficial effects of complement depletion and from the in-vitrochemotactic properties of CSa [135]. But as I have alreadymentioned, it now appears that a substantial portion of thecomplement effect may involve the terminal complement sys-tem [53,123—126].As shown in Figure 2, neutrophils also mightbe attracted through immune-adherence mechanisms involvingC3b receptors [136] or might be attracted independently ofcomplement via Fc receptor interaction with deposited immu-noglobulins [137, 138].The mechanism of neutrophil-mediated injury has been pre-sumed to involve proteolytic digestion of GBM by enzymesreleased locally by invading neutrophils. This hypothesis issupported by (1) the ability of neutrophil-denved proteases todigest GBM in vitro [139, 140]; (2) the appearance of neutrophil-derived enzymes and GBM fragments in the urine in comple-ment-dependent glomerular injury [139—141]; and (3) the pres-ence of neutrophil cationic proteins in glomerular deposits [73].More recent studies have suggested a role for reactive oxygenspecies (ROS) in neutrophil-mediated tissue injury [142, 143].These ROS include hydrogen peroxide (H202), superoxideanion (02),hydroxylradical (OH), and singlet oxygen('02)released during the respiratory burst by activated phagocyticcells such as neutrophils and macrophages. Intrarenal infusionof stimulants to ROS generation produces a glomerular neutro-phil infiltrate and proteinuna, which can be prevented byneutrophil depletion or by catalase, which destroys H202 [144].Proteinuria in complement-neutrophil—dependent anti-GBMnephntis also can be reduced by catalase [145].Presumablysimilar mechanisms are operative in macrophage-mediatedglomerular injury.Complement-independent, cell-mediated glomerular injury.Again, neutrophils appear to be able to mediate glomerularinjury independently of complement when Pc portions of im-mune deposits are accessible for initiating immune adherence 576Nephrology Forum[137, 138]. This action probably would apply with subendo-thelial and mesangial immune-complex deposits but is not seenwith subepithelial deposits, which are separated from circulat-ing inflammatory cells by a layer of GBM [84, 122]. Macro-phages also participate in immune-complex disease throughcomplement-independent mechanisms (Fig. 2). They are promi-nent in glomeruli in several models of immune-complex nephri-tis [146, 147] as well as in human disease [148, 149]. In additionto immune-adherence mechanisms, several platelet-derived cat-ionic proteins that can localize in glomeruli and facilitateimmune-complex formation also have chemotactic propertiesfor inflammatory cells (reviewed in Ref. 150). When immunecomplexes form locally within the GBM, macrophage infiltratesand proteinuna can be much reduced by prior irradiation or byselective macrophage depletion [151, 1521, and can be inducedin cell-depleted animals by macrophages [1531. Macrophagedepletion also reduces proteinuria in accelerated, acute BSAserum sickness [1521. The fact that this form of glomerularinjury is ameliorated when induced by antibody lacking the Fcportion suggests that macrophages are recruited primarily byimmune-adherence mechanisms [1541. Other studies have sug-gested, however, that macrophages follow an earlier T-cellinfiltrate in glomeruli and that macrophage accumulation isreduced by T-cell depletion. The possibility thus exists of asensitized cell-mediated phenomenon [1551. One study hassuggested a role for non-sensitized lymphocytes, perhaps Fc-receptor—bearing natural killer cells, in mediating a focal loss ofglomerular polyanion and proteinuria in early anti-GBM nephri-tis [1561. This observation may represent an antibody-depen-dent, cell-mediated cytotoxicity mechanism, which has beenwell documented in experimental antitubular basement mem-brane antibody-induced interstitial nephritis [1571.Finally, resident glomerular mesangial cells may participatein some types of immune glomerular disease [95, 158]. Mesangi-al cells thus can produce a variety of potential inflammatorymediators, including prostaglandins [159], acidic and neutralproteases [160, 161], ROS [162], and an interleukin 1-likecytokine [163]. Stimulants for such mesangial reactivity caninclude exposure to, or endocytosis of, several circulating ordeposited immune reactants, including immune complexes,complement components, and platelet activating factor [164,165]. The identification of a subpopulation of mesangial cellsthat bear Ia antigens, and which thus may present foreignantigens in a genetically restricted fashion to sensitized T cells,suggests that local cell-mediated immune reactors may occur inthe mesangium [166]. Whether these various properties of themesangial cell are pathogenetic in glomerular disease is not yetestablished.Specifically sensitized cells. The role of antibody-indepen-dent cellular hypersensitivity to fixed or planted antigeniccomponents of glomerular immune complexes in human diseasehas long been speculated on [167, 1681 but usually has beendiscounted [169]. Experimental support for this mechanism isnow mounting, however. Infusion of cells sensitized to anantigen planted in the glomerulus can induce glomerular hyper-cellularity [170] and sometimes proteinuria [171]. Bolton andcoworkers induced glomerulonephritis by using GBM to immu-nize bursectomized chickens unable to mount an antibodyresponse [1721. The authors reported transfer of this lesion withcells alone [173], and thus provided strong evidence for thecapacity of sensitized cells to cause glomerular disease in thatspecies. Thus, the cellular arm of the immune response toantigens that induce immune-complex nephritis may play apreviously unappreciated role in producing these lesions.SummaryThe patient we are discussing here had an acute glomerulone-phritis induced by immune-complex formation in glomeruli.The lesion apparently was related to a chronic bacterial infec-tion. Glomerulonephritis resulted from immune-complex de-posits formed at mesangial, subendothelial, and subepithelialsites. Removal of the offending antigenic stimulus resulted inclinical improv

ement and presumably resolution of the immune-complex deposits. It should be apparent that the type andseverity of her glomerular disease were determined by at leastfour factors: (1): The mechanism of glomerular immune-com-plex formation. For example, formation of immune complexesin situ in the mesangium results in a severe focal proliferativeglomerulonephritis, whereas deposition of apparently similarquantities of the same reactants as preformed immune complex-es induces little evidence of glomerular disease [19, 97]. (2) Theintraglomerular site of immune-complex formation. Immunecomplexes formed in situ in the subepithelial space produce anoninflammatory, complement-dependent, cell-independentmembranous glomerular lesion [84, 122], whereas the formationof the same quantity of the same complexes within the capillarywall, and therefore more accessible to circulating inflammatorycells, induces a proliferative inflammatory lesion that is comple-ment and neutrophil or macrophage mediated [117, 137, 152].(3) The biologic properties of the deposited antibody. Subepi-thelial deposits of complement-fixing IgG result in a markedcomplement-dependent increase in glomerular capillary perme-ability, whereas deposition of the same quantity of non—comple-ment-fixing antibody at the same site produces no detectableglomerular injury [1221. (4) Finally, if other factors are equal,the greater the quantity of deposits formed, the more severe thedisease produced [32, 131].Obviously, considerable progress has been made recently inour understanding of the pathogenesis of immune-complexglomerulonephritis like this patient's. But only by further studyof these mechanisms can we hope to continue to advance ourunderstanding of human immune-complex nephritis and there-by acquire the capacity to modify it in a way that will bebeneficial to patients such as the one discussed here.Questions and answersDa. CHRISTINE ABRASS (Associate Professor of Medicine,Division of Nephrology, University of Washington, SeattleVeterans Administration Hospital): You have reviewed thor-oughly the data that support the in-situ mechanism, and I thinkthere is little doubt that this mechanism plays an important rolein immune-complex nephritis. On the other hand, over the lastseveral years it has become a bandwagon that many investiga-tors have jumped on, and experiments have been contrived toprove its importance. Few investigators have designed experi-ments using modern techniques to support the circulatingimmune-complex mechanism. We were relatively narrow-mind-ed for many years, accepting only the circulating immune-complex theory. More recently, we are told to believe only thein-situ theory. It may be more appropriate to consider that both Glomerular injury in immune-complex disease577of these mechanisms are operative in immune-complexnephritis.Da. CousEa: This is a very important point. Bandwagonsclearly develop in medicine. The relatively uncritical accept-ance of the circulating immune-complex trapping mechanism isan example that lasted for more than two decades. Now we riska similar phenomenon with respect to in-situ complex forma-tion. Obviously, it is important that we avoid overinterpretationof these recent studies as well. However, I also think that theexperimental evidence that in-situ immune complex formationcan reproduce the clinical and histologic features of most formsof immune-complex nephritis in humans has now become verystrong [28, 174]. The contention that similar lesions can resultfrom circulating complex trapping remains unproved, althoughit was suggested more than 25 years ago [16, 17]. 1 agree,however, that more studies in this area are needed and that it iscritical that objectivity be retained when we interpret the datathat emerge.DR. REx 0cm (Nephrology Fellow, University of Washing-ton): In patients with glomerulonephritis, what is the clinicalrole for measuring circulating immune complexes?DR. COUSER: That is a good question. Obviously develop-ment of techniques for measuring circulating immune complex-es was stimulated by the thesis that they were the causativeagents in these diseases and from expectations that suchmeasurements would be of diagnostic and prognostic value,With the exception of one study in lupus by Abrass et al [1751,these expectations have generally not been fulfilled [176, 177].In my view, the measurement of circulating immune complexesis of no particular value in any renal disease that I am aware of.I include lupus unless the measurements can be done with thesame frequency and intensity as they were done by Dr. Abrassin her study [175]. However, as I discussed earlier, that doesnot mean that the reactants that form glomerular deposits arenot present in circulating immune-complex form, but only thatthe variables that lead to immune-deposit formation in glomeru-Ii are not reflected in a clinically useful way by measurements oftotal circulating immune-complex levels.DR. STEVEN ADLER (Assistant Professor of Medicine, Divi-sion of Nephrology, University of Washington, UniversityHospital): Immunologic mechanisms obviously are important inmost of the acute glomerular diseases we see, but do thesemechanisms have a role in the progression of renal disease?DR. COUSER: For several decades investigators have soughtimmunologic processes such as cellular immunity to renalantigens to account for progressive glomerulonephritis. I thinkall this work can be summarized simply by saying that nonehave been reproducibly found. As you point out, the immuno-logic mechanisms I have discussed do account well for theinitiation of most forms of glomerulonephritis and, if severeenough, lead to progressive disease. But they do not explainprogression. Although the thesis has not been proved in hu-mans, I think the studies by Brenner and colleagues in rats haveestablished adaptive hemodynamic factors, particularly in-creased intraglomerular pressures, as the most likely mecha-nisms responsible for progressive glomerular disease [178].Presumably these adaptive changes in glomerular pressures andflows must exceed a threshold level to cause progressivedisease, and in turn a critical amount of filtering surface areamust be irreversibly lost during the acute phase of the d

iseasefor this to occur. Humans might be less susceptible to thesechanges than are rats, and other factors are likely to beimportant as well. However, there is little evidence at presentto implicate immune mechanisms in this process.DR. JEROME P. KASSIRER: It always has been puzzling to methat some forms of immune-complex disease are spontaneouslyreversible and others are not. For example, in poststreptococ-cal glomerulonephritis the patient has a severe immune reactionaccompanied by a severe reduction in GFR, yet recovery isoften rapid and complete. By contrast, the patient with lupuswho also has severe immunologic damage usually doesn't getbetter even with aggressive therapy. What is the explanation forthis difference?DR. CousER: I think lupus is probably not a good examplebecause in lupus there is an ongoing autoimmune process,whereas in poststreptococcal nephritis the disease is usuallyself-limited even without therapy. Recovery depends on howmuch the initial decrease in renal function reflects reversible, orfunctional, factors rather than irreversible structural changessuch as necrosis, sclerosis, and fibrosis. Postinfectious glomer-ulonephritis may be quite analogous to models of acute nephri-tis studied experimentally, in which the decreased GFR isconsequent to changes in glomerular plasma flow and ultrafll-tration coefficient (IU) apparently reflecting hemodynamic con-sequences of complement activation and loss of surface areadue to inflammatory cell infiltrates [179, 180]. Because these arelargely functional changes, they may be reversed spontaneouslyor by appropriate therapy before structural damage occurs. Inother forms of acute glomerulonephritis, the initial process maybe severe enough to produce irreversible structural damage sothat recovery is not possible, or it occurs only accompanied byadaptive hemodynamic changes sufficient to result in progres-sive disease [181]. Reversibility depends on the type andseverity of the initial lesion rather than on the mechanism thatproduced it.DR. RICHARD JOHNSON (Nephrology Fellow, University ofWashington): Are there any factors that might predisposecertain individuals over others to the development of postinfec-tious glomerulonephritis?DR. C0usER: Yes, there clearly are. For example, in largepopulations of patients exposed to the same nephritogenicstreptococcus, some patients have no disease, some havesubclinical disease, and some have severe glomerulonephritis[182]. Some of this variation must relate to the amount andduration of antigenic exposure. However, much of the variationis also related to host genetic factors that determine the immuneresponse to a particular antigen [183]. The influence of immuno-genetic factors on severity and prognosis has been well estab-lished by familial and genetic studies for several glomerulardiseases [183—185]. In poststreptococcal glomerulonephritis,associations have been noted with HLA-D and -DR antigens insome studies [186, 187]. Although it may be difficult andexpensive to carry out, the importance of immunogeneticfactors to the severity and outcome of glomerulonephritis isnow sufficiently well established, so this variable should beaccounted for in designing randomized prospective treatmentstudies.DR. MICHAEL R. KELLY (Clinical Professor of Medicine,University of Washington, Swedish Hospital): In clinicalnephrology, we usually regard the C3 level as important in 578Nephrology Forumhelping to make a diagnosis of postinfectious glomerulonephri-tis. In this patient, complement levels were normal. Would youcomment on the value of C3 measurements in these kinds ofpatients?Da. COUSER: In classic poststreptococcal glomerulonephri-tis, levels of complement as measured by C3, or total hemolyticcomplement, are reduced acutely in approximately 90% ofpatients, so these measurements are relatively sensitive inmaking a diagnosis [188—190]. However, cases of apparentlyclinically typical acute poststreptococcal nephritis with normalcomplement levels have been described [191, 192]. The pres-ence of hypocomplementemia is obviously not specific forpoststreptococcal nephritis, because it also can be seen in otherpostinfectious nephritides, shunt nephritis, membranoprolifera-tive glomerulonephritis, lupus, and certain inherited comple-ment deficiencies associated with nephritis [190]. In glomerulo-nephritis following nonstreptococcal bacterial infections suchas that probably in this patient, hypocomplementemia is lesscommon. It is present in only approximately 50% of patientswith nephritis due to bacterial endocarditis [193], and often isabsent in nephritis associated with visceral abscesses [194].Serum complement levels must be interpreted in the context ofthe rest of the clinical and laboratory findings.DR. DAVID LOVETT (Assistant Professor of Medicine, Divi-sion of Nephrology, University of Washington, Seattle Veter-ans Administration Hospital): You have emphasized the role ofimmune complexes formed in situ in initiating complementactivation. Is there evidence for nonimmune local complementactivation in the absence of immune deposits, and what rolemight such a process play in glomerular disease?DR. COUSER: Yes, there are examples of glomerular diseasesuch as type-TI membranoproliferative glumerulonephritis, latestages of postinfectious nephritis, and others in which depositsof complement components can be seen in the absence ofimmune deposits [5, 196]. Furthermore, complement compo-nents and membrane attack complex neoantigens are oftenassociated with structural glomerular lesions such as sclerosis,fibnn caps, and PAS-positive deposits in diabetes, etc. [128].Some of these deposits might be epiphenomena reflectingcomplement activation by damaged kidney cells, as we haveshown in vitro [197]. However, there is now substantial evi-dence that the C5b-9 portion of complement can have a non-lytic effect on cell membranes and can result in increasedproduction of several inflammatory mediators [198]. Your ownstudies and those of Dr. Adler have shown increased produc-tion of proteases, prostanoids, interleukin 1-like cytokines, andreactive oxygen species by mesangial cells in response to C5b-9without immune deposits [165, 199]. The potential role ofresident glomerula

r cells in mediating glomerular disease and ofcomplement in stimulating that process is obviously a fruitfularea for future research.DR. KASSIRER: Do you think it will be possible to tailor ourtreatment to the specific immunologic mechanism responsiblefor glomerular injury?DR. COUSER: Yes, I do. Unfortunately, patients do not cometo our attention until they already have significant disease, soprevention is difficult, although much progress is being made inreducing the incidence of poststreptococcal glomerulonephritisin this country. However, as I mentioned earlier, a criticaldeterminant of outcome in these diseases is how successful wecan be in preventing irreversible tissue damage during the acutephase of the disease. Clarification of the mechanisms involvedin mediating specific types of glomerular immune injury such asterminal complement components, macrophages, sensitizedcells, reactive oxygen species, etc. does afford the potential fordirected therapeutic interventions that may minimize or preventfurther tissue damage once an accurate diagnosis has beenmade.DR. THERESA RATTAZZI (Clinical Assistant Professor ofMedicine, University of Washington, Valley General Hospital):If immunologic mechanisms play a role in the initiation ofglomerulonephritis but not in the progression of the disease,what is the role of steroids in treating glomerular disease andwhy do we use them?DR. CousEa: The answer to why we use steroids probablyderives largely from their dramatic effect in minimal-changenephrotic syndrome and the hope, which has largely beenunfulfilled, that they would be similarly beneficial in otherglomerular diseases, which are now known to be mediated byentirely different mechanisms. However, steroids do appear tobe of benefit in several acute inflammatory forms of glomerulo-nephritis such as lupus nephritis [200] and idiopathic, rapidlyprogressive glomerulonephritis [201]. The mechanism for theirbeneficial effects in these diseases is unknown, although theaccumulating evidence for a role for cell-mediated immunity inglomerulonephritis, which I have already reviewed, is oneattractive possibility. A short-term course of steroids alsoappears to be beneficial in slowing the rate of progression ofcertain chronic glomerular diseases such as membranousnephropathy [202] and perhaps focal glomerular sclerosis (Un-published data, Collaborative study of adult glomerular dis-ease, C. H. Coggins, Director). In these diseases the mecha-nism of the steroid effect is even less clear but may be onnonimmune factors that influence progression rather than onimmune factors that initiated the diseases.Reprint requests to Dr. W. Couser, Division of Nephrology, RM-11,School of Medicine, University of Washington, Seattle, Washington98195, USAReferences1. CUNNINGHAM BE, BRENTJENS JR. ZIELEZNY MA, ANDRES GA,VENUTO RC: Heroin nephropathy. A clinicopathologic and epide-miologic study. Am J Med 68:47—53, 19802. P.Ao TKS, NICASTRI AD, FRIEDMAN EA: Renal consequences ofnarcotic abuse. Adv Nephrol 7:261—290, 19783. CITRON PB, HALPERN M, MCCARRON M, LUNDBERG GD, Mc-CORMICK R, PINCUS IJ, TATTER D, HAVERSACK BJ: Necrotizingangiitis associated with drug abuse. NEnglJMed 283: 1001—lOll,19704. STEINMULLER DR, BOLTON WK, STILMANT MM, COUSER WG:Chronic interstitial nephritis and mixed cryoglobulinemia associat-ed with drug abuse. Arch Pathol Lab Med 103:63—66, 19795. MENSCHEL S, COHEN D, GRoss B, FRANGIONE B, GALLO G: AAprotein-related renal amyloidosis in drug addicts. Am J Pathol112:195—199, 19836. COUSER WG: Glomerular diseases (chapter 62), in Cecil's Text-book of Medicine (17th ed), edited by WYNGAARDEN JB, SMITHLH JR, Philadelphia, Saunders, 1985, pp 568—5897. BARNHAM M, THORNTON TJ, LANGE K: Nephritis caused byStreptococcus zooepidemicus (Lancefield group C). Lancet1:945—948, 19838. SATO M, NAKAZORA H, OFUJI T: The pathogenetic role ofStaphylococcus aureus in primary human glomerulonephritis. ClinNephrol 11:190—195, 1979 Glomerular injury in immune-complex disease5799. BOLTONWK,SANDE AM, NORMANSELL DE, STURGILL BC,WESTERVELT FB JR:Ventriculojugularshunt nephritis with Gory-nebacierium bovis. Successful therapy with antibiotics. AmJ Med59:417—424,197510. LOHLEIN M: Uber die entzundlichen Veranderungen der Glomer-uli der menschlichen Nieren und ihre Bedeutung fur die Nephritis.Arbeiten aus dem Pathologischen Institut zu Leipzig. Leipzig, S.Hirzel, 190711. SCHICK B: Die Nachkrankheiten des Scharlachs. JahrbKinderheil65:132—173,190712. VON PIRQUET CE: Allergy. Arch In fern Med 7:259—288, 383—436,191113. MELLORS RC, ORTEGA LG: Analytical pathology: Ill. New obser-vations on the pathogenesis of glomerulonephritis, lipoid nephro-sis, polyarteritis nodosa and secondary amyloidosis in man. Am JPathol32:455—499,195614. GERMUTH OF Ja, PACE MG, TIPPETT JC: Comparative histologicand immunologic studies in rabbits of induced hypersensitivity ofthe serum sickness type: II. The effect of sensitization to homolo-gous and cross-reactive antigens on the rate of antigen eliminationand the development of allergic lesions. JExp Med 101:135—150,195515. GERMUTH FG JR, FLANAGAN C, MONTIENEGRO MR: The rela-tionships between the chemical nature of the antigen, antigendosage, rate of antibody synthesis and the occurrence of arteritisand glomerulonephritis in experimental hypersensitivity. JohnsHopkins MedJ 101:149—169,195716. DIXON FJ, VAZQUEZ JJ, WEIGEL WO, COCHRANE CG: Pathogen-esis of serum sickness. Arch Pathol 68:18—28, 195817. DixoN FJ, FELDMAN JD, VAZQUEZ JJ: Experimental glomerulo-nephritis: The pathogenesis of a laboratory model resembling thespectrum of human glomerulonephritis. JExp Med 113:899—920,196118. GERMUTH FG JR, RODRIGUEZ E: in immunopathology of theRenalGlomerulus: Immune Complex Deposit and Anti-basementMembraneDisease. Boston, Little, Brown, 197319. COUSER WG, SALANT DJ: In-situ immune complex formation andglomerular injury (editorialreview). Kidney mt17:1—13, 198020. COCHRANE CG: Mediation of immunologic glomerular injury.Transplant Proc 1:949—958, 196921. Cousaa WG, HOYER JR, JERMANOVICH NB, BELOK S, STILMANTMM: Effect of aminonucleoside nephrosis on immune complexlocalization in autologous immune complex nephropathy in rats. JClinInvest 61:561—572, 197822. COUSER WG,

SALANT DJ, STILMANT MM, ARBEIT LA, DARBY C,SLIOGERIS VS: The effects of aminonucleoside of puromycin andnephrotoxic serum on subepithelial immune-deposit formation inpassive Heymann nephritis. J Lab Clin Med 94:917—932, 197923. SALANT DJ, BELOK S, DARIIY C, STILMANT MM, COUSER WG:Determinants of glomerular localization of subepithelial immunedeposits: Effects of altered antigen:antibody ratio, steroids, vaso-active amine antagonists and aminonucleoside of puromycin onpassive Heymann nephritis in rats. Lab Invest 41:89—99, 197924. EDINGTON TS, GLASSOCK RJ, DIXON FJ: Autologous immunecomplex pathogenesis of experimental allergic glomerulonephritis.Science 155:1432—1434, 196725. VAN DAMME BJC, FLEUREN GJ, BAKKER WW, VERNIER RL,HOEDEMAEKER PJ: Experimental glomerulonephritis in the ratinduced by antibodies directed against tubular antigens: IV. Fixedglomerular antigens in the pathogenesis of heterologous immunecomplex glomerulonephritis. Lab Invest 38:502—510, 197826. COUSER WG, STEINMULLER DR, STILMANT MM, SALANT DJ,LOWENSTEIN LM: Experimental glomerulonephritis in the isolat-ed perfused rat kidney. J Clin Invest 62:1275—1287, 197827. COUSER WG, ADLER SA, BAKER PJ, JOHNSON RJ, PERKINSONDA: Mechanisms of immune complex formation and deposition inglomeruli. Nephrology Today: Proc 9th mt Cong Nephrol. NewYork, Springer-Verlag, pp 508—52628. COUSER WG, SALANT DJ: Immunopathogenesis of glomerularcapillary wall injury in nephrotic states. ContempIssues Nephrol9:47—83,198229. KERJASCHKI D, FARQUHAR MG: The pathogenic antigen of Hey-mann nephritis is a membrane glycoprotein of the renal proximaltubule brush border. Proc NatlAcad Sci USA 79:5557—5561, 198230. KERJASCHKI D, FARQUHAR MG: Immunocytochemical localiza-tion of the Heymann nephritis antigen (GP330) in glomerularepithelial cells of normal Lewis rats. J Exp Med 157:667—685, 198331. UNANUE ER, DIXON FJ: Experimental glomerulonephritis. V.Studies on the interaction of nephrotoxic antibodies with tissues ofthe rat. JExp Med121:697—714, 196532. SALANT DJ, DARBY C, C0USER WG: Experimental membranousglomerulonephritis in rats. Quantitative studies of glomerularimmune deposit formation in isolated glomeruli and whole ani-mals. JGlitz Invest 66:71—81,198033. BARBA LM, CALDWELL PRB, DOWNIE GH, CAMUSSI G, BRENT-JENS JR, ANDRES GA: Lung injury mediated by antibodies toendothelium: I. In the rabbit repeated interaction of heterologousanti-angiotensin-converting enzyme antibodies with alveolar en-dothelium results in resistance to immune injury through antigenicmodulation. JExp Med 158:2141—2158, 198334. MATSUO S, CALDWELL PRB, BRENTJENS JR, ANDRES GA: "Invivo" interaction of antibodies with cell surface antigens: Amechanism responsible for "in situ" formation of immune depos-its in the zona peltucida of rabbit oocytes. J Clin Invest 75:1369—1380, 198535. CAMUSSI G, BRENTJENS JR, KERIASCHICI D, MALAVASI F, NOBLED, ROHOLT OA, FARQUHAR MG, ANDRES G: Antibody-inducedredistribution of Heymann's antigen on the surface of visceralglomerular epithelial cells in Lewis rats (abstract).Kidney mt27:207, 198536. ABRASS CK: Direct binding of renal tubular antigen to the subepi-thelial space of the glomerulus (abstract).Abstr 9th mtGongNephrol,Los Angeles, 1984, p 231a37. ABRASS CK, MCVAY J, GLASSOCK RJ: Evaluation of homologousand isologous passive Heymann nephritis: Influence on endoge-nous antibody production. JImmunol 130:195—202,198338. NEALE Ti, W000ROFFE AJ, WILSON CB: Spontaneous glomeru-lonephritis in rabbits. Role of a glomerular capillary antigen.Kidney Int26:701—711,198439. DOUGLAS MFS, RABIDEAU DP, SCHWARTZ MM, LEWIS EJ:Evidence of autologous immune-complex nephritis. N EnglJ Med305:1326—1329,198140. ZANETTI M, MANDET C, DUBOUST A, BEDROSSIAN J, BARIETY i:Demonstration of a passive Heymann nephritis-like mechanism ina human kidney transplant. ClinNephrol 15:272—277,198141. ZAGER RA, COUSER WG, ANDREWS BS, BOLTON WK, POHL MA:Radioimmunologic search for anti-tubular epithelial antibodiesand circulating immune complexes in patients with membranousnephropathy. Nephron 24:10—16, 197942. CoLLINS AD, ANDRES GA, MCCLUSKEY RT: Lack of evidence fora role of renal tubular antigen in human membranous glomerulone-phritis. Nephron 27:297—301, 198143. NEALE TJ, WILSON CB: Glomerular antigens and glomerulone-phritis. SpringerSemin Immunopathol 5:221—249,198244. ADLER S, COUSER WG: Immunologic mechanisms of renal disease(edit rev). Am J Med Sci 289:55—60, 198545. SHOENFELD Y, RAUCH J, MA55IC0TTE H, DATTA SK, ANDRED-SCHWARTZ J, STOLLAR BD, SCHWARTZ RS: Polyspecificity ofmonoclonal lupus autoantibodies produced by human-human hy-bridomas. N Engi JMed308:414—420, 198346. MADAIO MP, CARLSON JA, HODDER 5: Monoclonal anti-DNAantibodies bind directly to intrinsic glomerular antigens and formimmune deposits (abstract). Kidney mt 27:216a, 198547. BORDER WA, WARD HJ, KAMIL ES, COHEN AH: Induction ofmembranous nephropathy in rabbits by administration of anexogenous cationic antigen: Demonstration of a pathogenic rolefor electrical charge. J Glitz Invest 69:451—461, 198248. OITE T, BATSFORD SR, MIHATSCH MJ, TAKAMIYA H, VOGT A:Quantitative studies of in situ immune complex glomerulonephritisin the rat induced by planted cationized antigen. JExp Med155:460—474,198249. WARD Hi, COHEN AH, BORDER WA: In situ formation of subepi-thelial immune complexes in the rabbit glomerulus: Requirementof a cationic antigen. Nephron 36:257—264, 198450.TANAKAT: Gels. SciAm 224:124—138, 198151. AGODOA LYC, GAUTHIER VJ, MANNIK M: Precipitating antigen 580NephrologyForumantibody systems are required for the formation of subepithelialelectron dense immune deposits in rat glomeruli. JExp Med158:1259—1271,198352. ADLER SG, WANG H, WARD HJ, COHEN AH, BORDER WA:Electrical charge: Its role in the pathogenesis and prevention ofexperimental membranous nephropathy in the rabbit. JC/in invest71:487—499,198353. GROGGEL GC, ADLER S, RENNKE HG, COUSER WG, SALANT DJ:Role of the terminal complement pathway in experimental mem-branous nephropathy in the rabbit. JC/in Invest 72:1948—1957,198354. ADLER S, BAKER P, PRITZL P, COUSER WG: Effect of alterationsin glomerular charge on deposition of cationic and anionic antibod-ies to fixed glomerular antigens in the rat. f

LabC/in Med,in press55. VOGT A, BATSFORD S, RODRIGUEZ-ITURBE B, GARCIA R: Cation-Ic antigens in poststreptococcal glomerulonephritis. C/inNephrol20:271—279,198356. LANGE K, SELIGSON G, CRONIN W: Evidence for the in situ originof poststreptococcal glomerulonephritis: glomerular localizationof endostreptosin and the clinical significance of the subsequentantibody response. Clin Nephrol 19:3—10, 198357. MCINTOSH RM, GARCIA R, RABIDEAU D, R0DRIGuEz-ITrnum B:Evidence for an autologous immune complex pathogenic mecha-nism in acute poststreptococcal glomerulonephritis. Kidney In!14:501—510, 197858. RODRIGUEZ-ITURBE B, RABIDEAU D, GARCIA R, RUBI0 L, MCIN-TOSH RM: Characterization of the glomerular antibody in acutepoststreptococcal glomerulonephritis. Ann intern Med 92:478—481, 198059. KAPLAN MH: Localization of streptococcal antigens in tissues. I.Histologic distribution and persistence of M protein types 1, 5, 12and 19 in the tissues of the mouse. J Exp Med 107:341, 195860. MILLER F: Renal localization and persistence of type 12 strepto-coccal M-protein. ProcSoc Exp Biol Med 108:539—543,196161. MAUER SM, FISH AJ, BLAU EB, MICHAEL AF: The glomerularmesangium: I. Kinetic studies of macromolecular uptake in nor-mal and nephrotic rats. J Clin invest 51:1092—1099, 197262. COUSER WG: What are circulating immune complexes doing inglomerulonephritis? (editorial) N EngI J Med 300:1230—1232, 198163. VOOT A, ROHRBACH R, SHIMIzu F, TAKAMIYA H, BATSFORD S:Interaction of cationized antigen with rat glomerular basementmembrane: In situ immune complex formation. Kidney in! 22:27—35, 198264. VOGT A: New aspects of the pathogenesis of immune complexglomerulonephritis: Formation of subepithelial deposits. ClinNephrol21:15—20, 198465. GALLO GR, CAULIN-GLASER T, LAMM ME: Charge of circulatingimmune complexes as a factor in glomerular basement membranelocalization in mice. J Clin Invest 67:1305—1313, 198166. AGODOA LYC, GAUTHIER Vi, MANNIK M: Antibody localizationin the glomerular basement membrane may precede in situ im-mune deposit formation in rat glomeruli. J Immuno/, 134:880—884,198567. FLEUREN G, GROND J, HOEDEMAEKER PJ: In situ formation ofsubepithelial glomerular immune complexes in passive serumsickness. Kidneymt17:631—637, 198068. SELA M, MOZES E: Dependence of the chemical nature ofantibodies on the net electrical charge of antigens. ProcNatlAcadSci USA 55:445—452, 196669. MADAIO MP, SALANT DJ, ADLER 5, DARBY C, COUSER WG:Effect of antibody charge and concentration on glomerular deposi-tion of anti-GBM antibody. Kidney In! 26:397—403, 198470. FEINTZEIG ID, DITTMER JE, SALANT DJ: The charge of antibody,antigen and the glomerular capillary wall and the location ofantigen influence antibody deposition in experimental glomerulo-nephritis. Kidney In!, in press71. EBLING F, HAHN BH: Restricted subpopulations of DNA antibod-ies in kidneys of mice with systemic lupus. Comparison ofantibodies in serum and renal eluates. Arth Rheum 23:392—403,198072. DANa H, HARBECKRJ:A comparison of anti-DNA antibodiesfrom serum and kidney eluates of NZB x NZW F1 mice. J GunLabImmunol 9:139—145, 198273. CAMUSSIG,TETTA C, SEGOLONI G, KODA R, VERCELLONE A:Localization of neutrophil cationic proteins and loss of anioniccharges in glomeruli of patients with systemic lupus erythemato-sus. C/inImmunol Immunopathol 24:299—314,198274. FERNANDEZ HM, HUGLI TE: Partial characterization of humanC5a anaphylatoxin. I. Chemical description of the carbohydrateand polypeptide portion of C5a. JImmunol117:1688—1694, 197675. BARNES JL, LEVINE PS, VENKATACHALAM MA: Binding ofplatelet factor four (PF4) to glomerular polyanion. Kidney In!25:759—765, 198476. CAMussi G, TETTA C, CODA R, S0G0L0NI GP, VERCELLONE A:Platelet-activating factor-induced loss of glomerular anioniccharges. Kidney In! 25:73—81, 198477. BARNES JL, CAMUSSI G, TETTA C, VENKATACHALAM MA:Glomerular localization of platelet cationic proteins followingimmune complex induced platelet activation(abstract).Kidney In!27:206, 198578.BARNESJL,VENKATACHALAM MA: Glomerular interactions ofexogenous and endogenous polycations, in The Pathogenicity ofCationic Proteins, editedbyLAMBERT PP, BERGMANN P,BEAUWENS R, New York, Raven Press, 1983, pp 281—29379.BARNES JL, VENKATACHALAM MA: Enhancementofglomerularimmune complex deposition by circulating polycation. f Exp Med160:286—293, 198480. CHANEKL,BOYD ND, FRITZLER M: In vivo anionic immunecomplex deposition in the murine glomerulus (abstract). C/in Res31:448, 198381.MELNICK GF, LADOULIS CT, CAVALLO T: Decreased anionicgroups and increased permeability precedes deposition of immunecomplexes in the glomerular capillary wall. Am f Pathol 105:114—120,198182.CAVALLO T, GOLDMAN M, GRAVES K, LAMBERT P-H: Alteredglomerular permeability in the early phase of immune complexnephritis. Kidney In!24:632—637,198383. CARLSON JA, MADAIO MP: Low molecular weight DNA binds tonormal mouse glomeruli in vivo (abstract). Kidney mt 25:210,198484. VAN Es LA, BLOK APR, SCHOENFELD L, GLASSOCK RJ: Chronicnephritis induced by antibodies reacting with glomerular boundimmune complexes. Kidney In! 11:106—115, 197785. ADLER 5, SALANT DJ, DITTMER JE, RENNKE HG, MADAIO MP,Cousa WG: Mediation of proteinuria in membranous nephrop-athy due to a planted glomerular antigen. Kidney mt 23:807—815,198386. MANNIK M, AGODOA LYC, DAVID KA: Rearrangement of im-mune complexes in glomeruli leads to persistence and develop-ment of electron dense deposits. f Exp Med 157:1516—1528, 198387. GERMUTH FG JR. RODRIGUEZ E, LORELLE CA, TRUMP El,MILANO L, WISE O'L: Passive immune complex glomerulonephri-tis in mice: Models for various lesions found in human disease. II.Low avidity complexes and diffuse proliferative glomerulonephn-tiswith subepithelial deposits. Lab Invest 41:366—371,197988. GERMUTH FG JR, RODRIGUEZ E, WISE O'L: Passive immunecomplexglomerulonephritis in mice. III. Clearance kinetics andproperties of circulating complexes. LabInvest 46:515—519, 198289. CAULIN-GLASSERT, GALLO GR,LAMMME: Nondissociatingcationic immune complexes can deposit in glomerular basementmembrane. J Exp Med 158:1561—1572, 198390. MATSUO S,CALDWELLP, BRENTJENS J, ANDRES G:Nephrotoxicserum glomerulonephritis inducedin the rabbit by anti-endothelialantibodies(abstract)

.Kidney In!27:217, 198591. CINE5 DB,LYSSAP,REEBERMB, DEHORATIUS Ri:Presenceofcomplement-fixing anti-endothelial cell antibodies in systemiclupus erythematosus. J C/in Invest 73:611—625,198492. OKUDAIRAK, SEARLES RP, CEUPPENS JL,GOODWINJS,WIL-LIAMS RCJR: Anti-Iareactivity in sera from patientswith system-ic lupus erythematosus. JC/in invest 69:17—24,198293.GOLBUS SM, WILSONCB:Experimental glomerulonephritis in-duced by in situ formation of immune complexes in the glomerularcapillarywall.Kidney In! 16:148—157, 197994. KANWAR YS: Biology of disease. Biophysiology of glomerularfiltration and proteinuria. LabInvest51:7—21, 198495. STERZEL RB,LOVETTDH, STEINHD,KASHGARIAN M: The Glomerular injury in immune-complexdisease581mesangium and glomerulonephritis. Kim Wochenschr 60:1077—1094, 198296. MICHAEL AF, KEANE WF, RAil L, VERNIER RL, MAUER SM:The glomerular mesangium (editorial review). Kidney mt 17:141—154, 198097. MAUERSM,SUTHERLAND DER, HOWARD RJ, FISH AJ, NAJAR-IAN JS, MICHAEL AF: The glomerular mesangium: HI. Acuteimmune mesangial injury: A new model of glomerulonephritis. JExpMed 137:553—570, 197398. TOMINO Y, ENDOH M, NoMoTo Y, SAKAI H: Specificity of elutedantibody from renal tissues of patients with IgA nephropathy. AmJ Kidney Dis 1:276—280, 198299. COUSER WG: Mesangial IgA nephropathies: Steady progress(editorial). West J Med 140:89—91, 1984100. KANWAR YS, JAKuBowsK! ML, ROSENZWEIG U: Distribution ofsulfated glycosaminoglycans in the glomerular basement mem-brane and mesangial matrix. Eur J Cell Biol 31:290—295, 1983101. COHEN S, VERNIER RL, MICHAEL AF: The effect of charge on therenal distribution of ferritin. Am J Pathol 110:170—181, 1983102. GAUTHIER VJ, STRIKER GE, MANNIK M: Glomerular localizationof immune complexes prepared with anionic antibodies or withcationic antigen. Lab invest50:125—137,1984103. FORD PM, KOSATKA 1: In situ immune complex formation in themouse glomerulus: Reactivity with human 1gM rheumatoid factorand the effect of subsequent immune complex deposition. Clin Expimmunol 5 1:285—291, 1983104. ZANETTI M, WILSON CB: Participation of auto-anti-idiotypes inimmune complex glomerulonephritis in rabbits. J Immunol131:2781—2783, 1983105. FORD PM, KOSATKA I: A mechanism of enhancement of immunecomplex deposition following in situ immune complex formationin the mouse glomerulus. Immunology 43:433—438, 1981106. STRIKER GE, MANNIKM,TUNGMY:Role of marrow-derivedmonocytes and mesangial cells in removal of immune complexesfrom renal glomeruli. J Exp Med 149:127—136, 1979107. BARCELLI U, RABBMACHER R, 00! YM, 001 BS: Modification ofglomerular immune complex deposition in mice by activation ofthe reticuloendothelial system. J Clin Invest 67:20—27, 1981108. HAAKENSTAD A0, STRIKER GE, MANNIK M: The glomerulardeposition of soluble immune complexes prepared with reducedand alkylated antibodies and with intact antibodies in mice. Labinvest 35:293—301, 1976109. CORNACOFFJB,HEBERT LA, SMEAD WL, VANAMANME,BIRMINGHAM Di: The primate erythrocyte-immune complexclearing mechanism. J Clin Invest 71:236—247, 1983110. HEBERT LA, ALLHISER CL, KOETHE SM: Some hemodynamicdeterminants of immune complex trapping by the kidney. Kidneymt 14:452—465, 1978111. WARD DM, BLANTZ RC: Uptake of macromolecules by theglomerular mesangium is increased by angiotensin II (abstract).C/inRes 29:479, 1981112. RAu L, KEANEWF,OSSWALDH,MICHAEL A: Mesangial func-tion in ureteral obstruction in the rat. Blockade of the efferentlimb. J C/in invest64:1204—1212,1979113. MANNIK M: Pathophysiology of circulating immune complexes.Arth Rheum 25:783—787, 1982114. GAUTHIER Vi, MANNIK M, STRIKER GE: Effect of cationizedantibodies in preformed immune complexes on deposition andpersistence in renal glomeruli. J Exp Med 156:766—777, 1982115. BARNES JL, RADNIK RA, GILCHRIST EP, VENKATACHALAM MA:Size and charge selective permeability defects induced in glomeru-lar basement membrane by a polycation. Kidney Int 25:11—19,1984116. COUsER WG, SALANT DJ, MADAIO MP, ADLER 5, GROGGEL GC:Factors influencing glomerular and tubulointerstitial patterns ofinjury in systemic lupus erythematosus. Am J Kidney Dis 2 (suppll):126—134, 1982117. SALANT DJ, ADLER S, DARBY C, GROGGEL GC, RENNKE HG,DITTMER iE: Influence of antigen distribution on the mediation ofimmunologic glomerular injury. Kidney mt 27:938—950, 1985118. COUSER WG, DARBY C, SALANT Di, ADLER 5, STEELE KM,STILMANTMM,LOWENSTEIN LM: Effect of antibody to glomeru-lar basement membrane on protein excretion in the isolatedperfused rat kidney. Am J Physiol, in press119. SALANT Di, CAPPARELL N, MADAIO MP, DARBY CM, STILMANTMM,COUSER WG: Altered glomenilar permeability induced byF(ab)2 and Fab' antibodies to rat renal tubular epithelial antigen.Kidneymt 21:36—43, 1981120.YAARM, FOIDARTJM,BROWNKS,RENNARDSI,MARTINGR,LIOTTA L:The Goodpasture-like syndrome in mice induced byintravenousinjections of anti-type IV collagen and anti-lamininantibody.Am J Pathol 107:79—91, 1982121. ROTHBARD 5, WATSONRF:Comparison of reactions of antibodiesto rat collagen and to rat kidney in the basement membranes of ratrenal glomeruli. JExp Med 129:1145—1 161, 1969122. SALANT Di, BELOK S, MADAIO MP, COUSER WG: A new role forcomplement in experimental membranous nephropathy in rats. JC/in Invest66:1339—1350,1980123. BAKER PJ, OCHI R, ADLER 5, JOHNSON Ri, COUSER WG: C6depletion abolishes proteinuria in experimental membranousnephropathy (abstract).C/in Res33:475A, 1985124. GROGGEL GC, SALANT DJ, DARBY C, RENNKE HG, COUSER WG:Role of the terminal complement pathway in the heterologousphase of anti-glomerular basement membrane nephritis in therabbit. Kidney Int 27:643—651, 1985125. ADLER 5, BAKER PJ, PRITZL PM, CousER WG: Presence ofterminal complement components in complement-dependent ex-perimental glomerulonephritis. Kidney mt 26:830—837, 1984126. PERKINSON DT, BAKER PJ, COUSER WG, JOHNSONRi, ADLER5:Membrane attack complex deposition in experimental glomerularinjury. Am J Pathol, in press127. BIE5ECKER G, KATZ 5, KOFFLER D: Renal localization of themembrane attack complex in systemic lupus erythematosus ne-phritis. JExp Med 151:1779—1794, 1981128. FALK RJ,DALMASSOAP, KIM Y,T5AICH,SCHEINMANii,GEWURZH, MICHAEL AF: Neoantigen of the polymerized ninthcomponent of complem

ent. Characterization of a monoclonalantibody and immunohistochemical localization in renal disease. JClin Invest 72:560—573, 1983129. Ko WC, BURRELLR:Evidence for antibody-dependent bindingof the terminal complement component to alveolar basementmembrane.C/inlmmuno/ Immunopatho/ 23:10—21, 1982130. SCHREIBER RD,MULLER-EBERHARDHJ: Complement and renaldisease. Contemp Issues Nephrol3:67—105,1978131. COCHRANE CG,UNANUEE, DixoN Fi: A role of polymorphoneu-clear leukocytes and complement in nephrotoxic nephritis. J ExpMed 122:99—110, 1965132. COCHRANECG,MULLER-EBERHARD Hi, AIKEN BS: Depletion ofplasma complement in vivo by a protein of cobra venom, its effecton various immunologic reactions. J Im,nunol105:55—65,1970133. GANGNF,MAUTNERW, KALANT N:Nephrotoxic serum nephri-tis.II.Chemical, morphologic and functional correlates of glomer-ular basement membrane at the onset of proteinuria. Lab Invest23:150—157, 1970134. HENSON PM: Pathologic mechanisms in neutrophil-mediated inju-ry. Am J Pathol 68:593—612, 1972135. GOETZL E JR. AUSTIN KF: Active site chemotactic factors and theregulation of the human neutrophil chemotactic response, inAntibiotics and Chemotherapy(vol19), edited by SoluuN E,Basel,Karger, 1974, pp 218—232136. Ross GD: Analysis of the different types of leukocyte membranecomplement receptors and their interaction with the complementsystem. J Immunoi Methods 37:197—211, 1980137. NAISH PF, THOMSON NM, SIMPSONIi,PETERS DK: The role ofpolymorphonuclear leukocytes in the autologous phase of nephro-toxic nephritis. C/in Exp Immunol 22:102—109, 1975138. SINDREY M,NAISHP: The mediation of the localization ofpolymorphonuclear leukocytes in glomeruli during the autologousphase of nephrotoxic nephritis. C/in Exp Immuno/ 35:350—355,1979139. HAWKINSD,COCHRANE CG: Glomerular basement membranedamage in immunological glomerulonephritis. Immuno/ogy14:556—681, 1968140. DAVIES M, BARRETT AJ, Tit.vIs J, SANDERS E, COLESGA:Thedegradation of human glomerular basement membrane with puri-fied lysosomal proteinases. Evidence for the pathogenic role of the 582NephrologyForumpolymorphonuclear leukocyte in glomeruonephritis. Clin Sci Mo!Med 54:233—240, 1978141. COCHEANE CG, AIKIN BS: Polymorphonuclear leukocytes inimmunologic reactions. The destruction of vascular basementmembrane in vivo and in vitro, J Exp Med 124:733—752, 1966142. FANTONE JC, WARD PA: Role of oxygen-derived free radicals andmetabolites in leukocyte-dependent inflammatory reactions. Am JPathol107:397—418,1982143. FREEMAN BA, Co JD: Biology of disease. Free radicals andtissue injury. Lab Invest 47:412—426, 1982144. RERAN A, WIGGINS RC, JOHNSON KJ: Hydrogen peroxide in-duced proteinuria in rats caused by injection of phorbol myristateacetate (PMA) into the renal artery (abstract). Kidney mt 25:217,1984145. REHAN A, JOHNSON KJ, WIGGINS RC, KUNKEL RG, WAIW PA:Evidence for the role of oxygen radicals in acute nephrotoxicnephritis. Lab Invest 51:396—403, 1984146. SANO M: Participation of monocytes in glomerulonephritis inacute serum sickness of rabbit. Acta Pathol Jpn 26:423—433, 1976147. THOMSON NM, HOLDSWORTH SR, GLASGOW EF, ATKINS RC:The macrophage in the development of experimental crescenticglomerulonephritis. Am J Pathol 94:223—236, 1979148. JONES DB: Inflammation and repair of the glomerulus. Am JPathol 27:991-1009, 1951149. MONGA G, MAZZUCCO G, BARBIANO DIBELGIOJOSO G,BUSNACH0: The presence and possible role of monocyte infiltration inhuman chronic proliferative glomerulonephritis. Am J Pathol94:271—281, 1979150. BARNES JL, VENKATACHALAM MA: Role of platelets and polyca-tionic mediators in glomerular vascular injury. Semin Nephrol, inpress151. SCHREINER GF, COTRAN RS, PARDO V, UNANUE ER: A mononu-clear cell component in experimental immunological glomerulone-phritis. JExp Med 147:369—384,1978152. HOLDSWORTH SR, NEALE TJ, WILSON C: Abrogation of macro-phage-dependent injury in experimental glomerulonephritis in therabbit. Use of anti-macrophage serum. JClin Invest 68:686—696,1981153. HOLDSWORTI-I SR, NEALE TJ: Macrophage-induced glomerularinjury. Cell transfer studies in passive autologous antiglomerularbasement membrane antibody-initiated experimental glomerulo-nephritis. LabInvest 51:172—180,1984154. HOLDSWORTH SR: Fc dependence of macrophage accumulationand subsequent injury in experimental glomerulonephritis. JIm-muno!130:735—739, 1983155. TIPPING PG, NEALE TJ, HOLDSWORTH SR: T cell-macrophageinteraction in antibody induced experimental glomerulonephritis(abstract). Abst 9th liii Cong Nephrol, 1984, p 264A156. KREISBERG JI, WAYNE DB, KARNOVSKY MJ: Rapid focal loss ofnegative charge associated with mononuclear cell infiltration earlyin nephrotoxic serum nephritis. Kidney mt 16:290—300, 1979157. NEILSON EG, PHILLIPS SM: Cell-mediated immunity in interstitialnephritis. IV. Anti-tubular basement membrane antibodies canfunction in antibody-dependent cellular cytotoxicity reactions:Observations on a nephntogenic effector mechanism acting as aninformational bridge between the humoral and cellular immuneresponse. Jlmmunol126:1990—1993,1981158. SCHREINER GF,COTRANRS, UNANUE ER: Macrophages andcellular immunity in experimental glomerulonephritis. SpringerSeminImmunopathol 5:251—267, 1982159.SCHARSCHMIDTLA, DUNN Mi: Prostaglandin synthesis by ratglomerular mesangial cells in culture. Effects of angiotensin II andarginine vasopressin. JClin lnvest71:1756—1764, 1983160. LOVETT DH, RYAN JL, KASHGARIAN M, STERZEL RB: Lysosom-al enzymes in glomerular cells of the rat. AmJ Pathol 107:161—166, 1982161. LOVETT DH, STERZEL RB,RYANJL, KASHGARIAN M: Neutralprotease activity produced in vitro by cells of the glomerularmesangium. Kidney mt 23:342—349, 1983162. BAUD L, HAGEGE J, SRAER I, RONDEAU E, PEREZ i, ARDAILLOUR: Reactive oxygen production by cultured rat glomerular mesan-gial cells during phagocytosis is associated with stimulation oflipoxygenase activity. JExp Med 158:1836-1852,1983163. LOVETT DH, RYAN IL, STERZEL RB: A thymocyte-activatingfactor derived from glomerular mesangial cells. J Immunol130:1796—1801, 1983164. SED0R iR, ABBOUD HE: Platelet activating factor stimulatesoxygen radical release by cultured rat mesangial cells (abstract).Kidney mt 27:222, 1985165. ADLER S, BAKER PJ, JOHNSON RJ,

0cm R, COUSER WG: Mem-brane attack complex (C5b-9) stimulates production of reactiveoxygen species by rat mesangial cells (abstract). Clin Res33:474A, 1985166. SCHREINER GF, KIELY J-M, COTRAN RS, UNANUE ER: Charac-terization of resident glomerular cells in the rat expressing La-determinants and manifesting genetically restricted interactionswith lymphocytes. J Clin Invest 68:920—931, 1981167. ROCKLIN RE, LEwIS EJ, DAVID JR: In vitro evidence for cellularhypersensitivity to glomerular basement membrane antigens inhuman glomerulonephritis. N Engi J Med283:497—501,1970168. FILLIT HM, READE SE, SHERMAN RL, ZABRISKI iB, VAN DERLJNI: Cellular reactivity to altered glomerular basement membrane inglomerulonephritis. N Engi J Med 298:861—868, 1978169. DixoN FJ: What are sensitized cells doing in glomerulonephritis?(editorial),N Engi J Med 283:536—537,1970170. BAHN AK, COLLINS A, SCHNEEBERGER E,MCCLUSKEYR:Acell-mediated reaction against glomerular-bound immune complexes. JExp Med 150:1410—1417,1979171. UNANUE ER, SCHREINER GF, COTRAN RS: A role of mononuclearphagocytes in immunologically induced glomerulonephritis, inImmune Mechanisms in Renal Disease, edited by CUMMINGS NB,MICHAEL AF, WILSON CB, New York, Plenum, 1983, pp 443—452172. BOLTON WK, TUCKER FL, STURGILL BC: New avian model ofexperimental glomerulonephritis consistent with mediation bycellular immunity. JGlitz Invest 73:1263—1276,1984173. CHANDRA M, TYSON T, STURGILL B, BOLTON K: Transfer ofexperimental autoimmune glomerulonephritis in chickens by sen-sitized cells (abstract).Kidney mt27:208, 1985174. COUSER WG, ADLER SA, BAKER PJ, JOHNSON RI, PERKINSONDA: Mechanisms of immune complex formation and deposition inglomeruli. Nephrology.Proc 9th mtCongNephrol, editedbyROBINSON RR, Springer-Verlag, New York, 1984, pp 508—526175. ABRASS CK, NIES KM. Louis IS, BORDER WA, GLASSOCK RJ:Correlation and predictive accuracy of circulating immune com-plexes with disease activity in patients with systemic lupuserythematosus. ArthrRheum 23:273—282,1980176. CAIRNS SA, LONDON RA, MALLICK NP: Circulating immunecomplexes in idiopathic glomerular disease. Kidney mt 21:507—512, 1982177. SOLLING I, OLSEN S: Circulating immune complexes in glomeru-lonephritis. Glitz Nephrol 16:63—74, 1981178. BRENNER BM: Nephrology Forum: Hemodynamically mediatedglomerular injury and the progressive nature of kidney disease.Kidney mt 23:647—655, 1983179. BLANTZ RC, WILSON CB: Acute effects of anti-glomerular base-ment membrane antibody on the process of glomerular filtration inthe rat. JClin Invest 58:899—911,1976180. BLANTZ RC: Physiologic approaches to the mechanisms ofglomerular immune injury (chapter 5), in Immune Mechanisms inRenalDisease,edited by CUMMINGS NB, MICHAEL AF, WILSONCB, Plenum, New York, 1983, pp 83—94181. BALDWIN DS, GLUCK MC, SHACT RG, GALLO G: The long-termcourse of poststreptococcal glomerulonephritis. Ann lntern Med80:342—358, 1974182. KAPLAN EL, ANTHONY BF, CHAPMAN SS, WANNAMAKER LW:Epidemic acute glumerulonephritis associated with Type 49 strep-tococcal pyoderma. I. Clinical and laboratory findings. AmJ Med48:9—27,1970183. REES AJ: The HLA complex and susceptibility to glomerulone-phritis. Plasma Ther Transfus Technol 5:455—470, 1984184. REES AJ, PETERS DK, AMOS N, WELSH KJ, BATCHELOR JR: Theinfluence of HLA-linked genes on the severity of anti-GBMantibody-mediated nephritis. Kidney mt 26:444—450, 1984185. BERTHOUX FC, LAURENT B, LE PETIT i-C, GENIN C, BROUTIN F,TOURAINE F,HASSANAA, CHAMPAILLER A: Immunogeneticsand immunopathology of human primary membranous glomerulo- Glomerular injury in immune-complex disease583nephritis: HLA-A, B, DR antigens; functional activity of splenicmacrophage Fc-receptors and peripheral blood T-lymphocytesubpopulations. C/in Nephrol 22:15—20, 1984186. SASAGUKI 1, HAYASE R, IWANOTO I, TSUCHIDA H: HLA andacute poststreptococcal glomerulonephritis. N Engi J Med301:1184—1185, 1979187. LAYRISSE Z, R0DRIGuEz-ITuaaE B, GARCIA-RAMIREZ R, RODRI-GUEz A, TIwARI J: Family studies of the HLA system in acutepost-streptococcal nephritis. Hum Immunol 7:177—185, 1983188. JORDAN SC,LEMIREJM: Acute glomerulonephritis. Diagnosisand treatment. Pediatr Clin North Am 29:857—873, 1982189. CAMERON JS, Vici RM, OGG CS, SEYMOUR WM, CHANTLER C,TURNER DR: Plasma C3 and C4 concentrations in the managementof glomerulonephritis. Br Med J 3:668—672, 1973190. LEWIS EJ: Patterns of circulating complement in renal diseases.Annu RevMed30:445—455, 1979191. TINA LV, D'ALBORA JB, ANTONOVYCH TT, BELLANTI JA, CAL-CHENO PL: Acute glomerulonephritis associated with normalserum /31C-globulin. Am J Dis Child 115:29—36, 1968192. MCLEAN RH, SCHEAGER MA, ROTHFIELD NF, BERMAN MM:Normal complement in early poststreptococcal glomerulonephn-tis. BrMedJ 1:1326—1328, 1977193. NEWGARTEN J, GALLO GR, BALDWIN DS: Glomerulonephritis inbacterial endocarditis. Am J Kidney Dis 3:371—379, 1984194. BEAUFILS M: Nephrology Forum: Glomerular disease complicat-ing abdominal sepsis. Kidney mt 19:609—618, 1981195. WILSON CB: Immunopathologic evaluation of renal disease, inRenal Disease (4th ed), edited by BLACK AK, JONES NF, Oxford,Blackwell, 1979, p 1581%. GREKAS D, MORLEY AR, WILKINSON R, KERR DNS: Isolated C3deposition in patients without systemic disease. Clin Nephrol21:270—274, 1984197. BAKER PJ, ADLER S, YANG Y, COUSER WG: Complement activa-tion by heat-killed human kidney cells: formation, activity andstabilization of cell bound C3 convertases. J Immunol 133:877—881, 1984198. HANSCH GM, SEITZ M, MARTINOTTI G, BETZ M, RAUTEBERGEW, GEMSA D: Macrophages release arachidonic acid, prosta-glandin E2 and thromboxane in response to late complementcomponents. J Immunol 133:2145—2150, 1984199. LOVETT D, HANSCH 0, RESCH K, GEMSA D: Activation ofglomerular mesangial cells (MC) by terminal complement compo-nents: Immunobiology 168:34—35, 1984200. POLLAK YE, DOSEKUN AK: Evaluation of treatment in lupusnephritis: effects of prednisone. Am J Kidney Dis 2(Suppl 1): 170—177, 1982201. CousEk WG: Rapidly progressive glomerulonephritis (edit rev).Am J Nephrol 2:57—69, 1982202. Collaborative Study of the Adult Idiopathic Nephrotic Syndrome:A controlled study of short-term prednisone treatment in adultswith membranous nephropathy. N Engi J Med 301:130