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Human Cytomegalovirus Infection Recent Developments Human Cytomegalovirus Infection Recent Developments

Human Cytomegalovirus Infection Recent Developments - PDF document

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Human Cytomegalovirus Infection Recent Developments - PPT Presentation

detected by by 46 The classification of herpes viruses according to their morphology shows a structural similarity for all herpes viruses which are found in more than 50 different animal species T ID: 960730

infection cmv human igm cmv infection igm human antibodies antibody hcmv igg diagnosis table cid negative viruses 1984 herpes

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Human Cytomegalovirus Infection: Recent Developments detected by by 46]. The classification of herpes viruses according to their morphology shows a structural similarity for all herpes viruses, which are found in more than 50 different animal species. The DNA of herpes viruses is double-stranded (1.6 x 108 D for HCMV) and embedded in the centre of an iko- saeder-shaped nucleocapsid, consisting of 162 cap- somers as subunits. The capsid is surrounded by a lipo- and glycoprotein-containing envelope, which extends the virion diameter to 150-180 nm. Infection with causing the various cytomegalo-viruses show remarkable remarkable HCMV was first isolated in 1956/57 from pa- tient material [38, 47, 53]. Infection with be vertical or hori- ning with with Fi- nally, CMV is thought to inherit oncogenic proper- ties as shown in vitro [1 a] and as discussed for AIDS and M. Kaposi [49, 51]

. 51]. In general, a variety of methods as summarized in Table 2 are suitable for laboratory diagnosis. The histological and cytological exami- nation of tissue biopsies, as mentioned above, is nowadays almost exclusively used in pathology. Considerable improvement in the diagnosis of cy- tomegalovirus infection came from the introduc- tion of electron microscopy, which contain high high 46]. Virus isolation yields good results if cultures of human ° C C Thus, the virus may be transmitted by infected leucocytes and in this this This way the occasional occurrence of exogenous CMV re-int?ction besides its endogenous reactiva- tion was demonstrated [22]. More convenient, but less accurate, is the identification of viral isolates by immunological methods, by restriction [12, 17], procedure, trends 1. a salivary glands [7]. b presented in 1 : al. : (HCMV) Infection + + (M. Pfeiff

er), but without CNS and PNS (meningitis, encephalitis, (ulcus, colitis), clinical signs); rejection crisis); 2. Strategies Microscopic examination (inclusion bodies) reactions caused [55], e.g. e.g. 39]. Antigen demonstration in tissue biopsies should be especially taken into considera- tion, if CMV-specific antibody kinetics fail to dem- onstrate active CID. Furthermore, the direct detection and quantifi- cation of CMV CMV 49a]. After cloning of the complete human cytomegatovirus genome in cosmids, these techniques may be considerably im- proved [13a, 31 a]. Laboratory Diagnosis: Demonstration of Antibodies against HCMV The most convenient way to establish CMV diag- nosis is serology, i.e. the demonstration of specific antibodies. A variety of liquid- and solid-phase an- tibody assays have been developed, of which the techniques most commonly used are presented in 1. Conventi

onal methods a) Neutralization test (NT) b) Passive haemagglutination (PHA) c) Complement-fixation test (CFT) 2. Immunoassays a) Immunofluorescence test (IFT) b) Radioimmunoassay (RIA) c) Enzyme-linked immunosorbent assay (ELISA) Table 3. Besides CFT and PHA tests, immuno- fluorescence and ELISA are of particular laborato- ry importance at present. Sensitivity, specificity and antibody kinetics, however, are reaction). Primarily, in the the 36]. In the past, mainly the demonstration of com- plement-fixing antibodies has elucidated a variety of disease symptoms, e.g. neurological manifesta- tions [26]. Following primary infection, antibody titers persist for life, showing, however, individual deviations. CFT antibody titers in general allow only limited conclusion on the activity of CID [13, 52]. Significant antibody titer increases, which can be utilized to establish an unequiv

ocal applied in to envelope also screen lope antigens antigens Furthermore, this differential synthesis of CMV antibodies increases the possibil- ity of differentiation between to the used in the present the pro- i / i i 1 2 3 5 6 7 -b .... I I I I i 1 I 1 2 3 L 5 6 7 8 9 durable antigen-erythro- this test test One of the reasons for the never widespread. widespread. 44]. Selective inhibition of viral protein synthesis in different stages of the infectious cycle by various drugs or use of nonpermissive cell lines allows demonstration of (immediate) EA. Being relatively weak antigens during CID, these cause porary antibody [14, 21]. were also also The IgM-specific ELISA is performed either according to the conventional method, i.e. with solid-phase fixed antigens or according to the p- capture technique [41]. Both methods show com- parably satisfying results, if the most freque

nt problems, IgG competition and rheumatoid factor interference, are eliminated by immobilized anti- 7- antibodies [15]. A comparison of former and new methods in CMV IgM antibody testing in several cases of CID is given in Table significant titer titer Thus, for differentiation of primary and recurrent infec- tion, it was suggested that we calculate the IgM/ IgG ratio. This, however, will not allow reliable diagnosis in the relevant individual case, since high individual differences in results in in we have examined the generation of anti-CMV antibodies of specific IgG subclasses by using an extended conventional ELISA ob- tained from several patients suffering from CID and monospecific anti-human IgG subclass anti- bodies. The results confirm that primary CMV in- fections besides IgGt, predominantly stimulate an- tibodies of the IgG a subclass, while recurrent infec- tions sh

ow a weaker boost of the IgG 3 subclass antibodies (Fig. 3a, b) [28]. Finally, it has been suggested that examination examination Application and clinical relevance of the above methods for HCMV diagnosis are summarized in Table 5 in comparison to other viruses of the hu- man herpes virus group [20 a]. of Human tests in in )Case Blood sampling CFT CFT after PHA with IgM-IFT IgM- Clinical signs Age no. (days after onset IgG pre- the IgM ELISA (years) of disease) cipitation fraction 1 1. 7 days 2,048 40 2,048 40 12 32 1.17 days 2. 32 negative negative negative negative 24 64 2. 37 A A ) b , /~/ r , , , , , , 20 30 50 60 B B G - 3. a 1 = 2 = 3 = 4 = duced whole blood time-consuming procedure of lymphocyte separa- separa- Quantitative determination of ratios revealed during CID CID 48]. We could confirm of CMV aI. : of Human herpesvirus infections infections 247 Laboratory HSV 1

+ 2 Latent Active Latent Active Latent [g-class specific against early antigens nuclear antigen + + / + + + / + + + f/_+ patients with in cases of IM second epidem- epidem- As with HSV and EBV, transmission of CMV also needs close physical contact such as sexual inter- course or mother-baby relationships. CMV can be further transmitted or activated by blood transfu- sions [1]. Predisposed for CMV infection are im- munocompromised or immunosuppressed pa- tients. Such an immunoexposure or immunosup- pression may be physiological (e.g. newborns, pregnancy), pathological spot checks tests in [19, 20]. developed countries et al. : age n 90 22 42% (74%) 0 153 125 138% (90%) 21% (87%) 1 (67.6-97.3 % ) f hemodialysis ~ 38 23 23 % (61%) 0 (43.4-75.9%) f (82.9-94.6%) f (cumulative frequency sample before (or sub have been in later later 34, 50]. Perinatal CMV infection occasionally caus

es atypical pneumonia mostly combined with pneumocystis carinii infections sim- ilar to recent reports of AIDS cases (Table 7). Altogether, a broad variety of symptoms has been described, mostly involving the haemato- poetic system [26, 29]. 29]. We could already demonstrate enhanced CMV-IgM titers in in CMV-IgM tests in this this 35]. Positive CMV antibody titers are are Renal transplant recipients are partic- at risk for three Renal transplant in risk groups should should Especially in transfusions of newborns the use of such (fresh) blood should be avoided. Similar to vertical CMV transmission, primary infection is regarded to be much more dangerous than sec- ondary reactivation [29, 54]. 9 [30]. infection (CMV, CMV- CMV- - - - - 1 : - - 1:8 negative negative Thus, nowadays the use of CMV hyperimmunoglobulin hyperimmunoglobulin 31]. More important in our view is the routine

Table 8. Serologically demonstrated incidence of infections (re- currences) with human herpes viruses in patients (n = 153) VZV EBV 4 19 more than latent infection with with An important goal in the prevention and treatment of HCMV infec- tions is the further improvement of diagnostic lab- oratory procedures to allow rapid and valid viral diagnosis which also takes immunosuppressive therapy into consideration. Table 9. Frequency of herpes virus infections (CMV, HSV, VZV and = 153). f m +/ ++ ++/ +++ ++ ++ ~ 6 2 4 0 1 0 0 i 4 0 0 3 2 (40) 6 1 1 10 5 3 0 0 4 3 ~ 32 6 2 1 6 7 0 0 7 5 3 8 (42) 3 0 0 3 4 1 0 0 0 0 3 4 2 0 1 1 1 1 1 0 3 2 3 i 0 0 0 0 2 2 0 0 3 3 2 2 14 13 1 0 (HCMV) Infection SP (1983) F (1973) 8 + : 1166-1169 R (1984) virus infection of human tion. Birth 20, 1 : 327--344 den Sektions- 1 : Lab Med M (1984) [Ofig A] K (1978) H (1979) strain differentiation different

iation A] 238:149- t64 13a. Fleckenstein B, Mfiller I, Collins J (1982) I (1984) IgM antibodies diagnosing cytomegalovirus G (1979) serum samples Microbiol Immunol F (1977) Doerr HW, H (1977) Congenital cytomegalovirus : 555-561 Toronto, pp Immunoassays an F, Mlchelson S (1980) and II, and non-human Huschka U, U, A] 253 : 120-130 25. Kitpatrick BA, Huang ES, Pagano JS (1976) Analysis of cytomegalovirus genomes with restriction endonucleases HinD III and Eco R-1. J Virol 18:1095 1105 E (1971) R, Braun H (1985) A B (1983) J (1984) der Uni- 169. J O (1978) al.: Diagnosis 289 : M, Bosshard patients with B (1980) (CMV) using D, Vogt A (1977) M (1975) R (1972) IgM) by A (1977) G (1961) salivary gland Simmons RL, lethal cytomegalovirus Prog Med R (1984) Dis 150:I21-126 R (1983) Dtsch Med SV (1973) loviral complement-fixing 98: 281-287 P (1980) for measurement 24, 1984 15, 1985 Prof.