Presented by Scott Brakenridge MD Associate Professor of Surgery amp Anesthesiology UF Sepsis amp Critical Illness Research Center ScottBrakenridgesurgeryufledu Brakenridgemd The immune response to COVID19 is characterized by ID: 909914
Download Presentation The PPT/PDF document "Immunophenotyping the Hospitalized COVI..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Immunophenotyping
the Hospitalized COVID-19 Patient
Presented by:
Scott Brakenridge, MD
Associate Professor of Surgery & Anesthesiology
UF Sepsis & Critical Illness Research Center
Scott.Brakenridge@surgery.ufl.edu
@
Brakenridge_md
Slide2The immune response to COVID-19 is characterized by…(???)
Current pathophysiologic dogma and therapeutic approach to COVID-19 has focused on viral replication (
Remdesivir
) and blunting the initial host “cytokine storm” (
sarilumab
, tocilizumab).Emerging trial results →
Interacting on these mechanisms
Ø effective…
However, emerging data suggests after the initial inflammatory response, immune suppression predominates and predicts mortality.
Severe
lymphopenia
& T-cell exhaustion
Immunosuppression
co-exists with
and/or follows the initial inflammatory responseSignificant heterogeneity is present in other acute host innate immune responses (i.e., Sepsis, severe trauma)Understanding the immunologic trajectory and “endotypes” of COVID-19 infection is key for mechanistic selection and design of COVID clinical trials.
(Remy, Brakenridge et al; Commentary -
Lancet
Resp
Med
2020)
Slide3Innovation/Rationale
All current enrolling or proposed COVID-19 interventional trials utilizing
immunomodulating
agents focus on attempting to blunt the initial “cytokine storm” which in current dogma is thought to drive the severe pulmonary clinical manifestations of the disease. However,
both the immunologic trajectory of the host immune response remains incompletely defined
. We propose to characterize both the magnitude and trajectory of the host immune response, and define the impact of lymphopenia and immunosuppression on patient outcomes.
Most if
not all of the current biomarkers proposed are static phenotypic markers of either inflammatory or immune status. What we propose here is a
functional measure of the dynamic status of both cells of the innate and
adaptive
immune system In COVID-19 patients over time
. We believe that the phenotype of the cell, either from cell surface expression, proteomics or
transcriptomics
, will be less informative than measuring the ex vivo capability of cells to respond to exogenous ligand stimulation
.Enzyme-linked immune absorbent spot (ELISpot) is a highly sensitive immunoassay that measures the frequency of cytokine-secreting cells at the single-cell level 12. In addition to detecting the number of cytokine secreting cells, the relative amount of cytokine produced by each cell can be determined by quantitating the area of each spot. Importantly, ELISpot is technically easy to perform, more sensitive at revealing group differences in cell function compared to other methods, and can independently assess the functional status of both innate and adaptive immunity. ELISpot results are readily obtained overnight, and there are existing CAP-CLIA laboratories that are using this assay for testing adaptive immune responses to M. tuberculosis and Candida infections (e.g., Oxford LLP, Quest Diagnostics). Therefore, we can take advantage moving forward of an existing infrastructure to rapidly translate these results into CAP-CLIA-accredited, FDA-cleared diagnostic assays.
We
have shown that myeloid derived suppressor cells (MDSC) play a significant role in persistent immunosuppression in critically ill surgical patients with sepsis. COVID-19 patients exhibit profound and deadly immunosuppression, thought to be due mainly to T-cell exhaustion.
We propose that expansion of myeloid suppressor cell (MDSC) populations contribute significantly to this immune suppression and represent a valid therapeutic target
.
Slide4Project Aims
To characterize both the magnitude and trajectory of the host immune response, and define the impact of
lymphopenia
and immunosuppression on COVID-19 patient outcomes.
To determine the time course of adaptive immune suppression during disease progression and resolution or death, focusing on blood T cell production of
IFN-g
and stimulated monocyte production of
TNF-a
as quantitated by a novel functional bioassay (ELISpot).
To determine whether expansion of myeloid-derived suppressor cells (MDSC) contributes to the adaptive immune failure seen in COVID-19 infected patients..
Slide5Project Design
2-Center prospective observational cohort study (UF/
WashU
)
Established collaborators, 2 synergistic & independently (CTSI) funded studies
30 COVID-19, 30 bacterial sepsis, 15 healthy controls (same at WashU)
Serial biologic sample acquisition
Peripheral blood
Pulmonary aspirate/secretions (became logistically problematic…)
Analyses
Serial immune biomarkers (IL-6, IL-8, IL-10, sPD-L1)
Ex vivo
immune functional phenotyping (ELISpot)
T-cell/MDSC phenotyping and suppression analyses (Flow cytometry & functional assays)
Slide6Enzyme-Linked Immune absorbent Spot (ELISpot)
Practical, timely, dynamic and functional measure of both
innate and adaptive
immunity
A
ssessment of cellular response (spot count) and function (spot size)
Facilitates rapid testing of
ex vivo response to therapeutics
Existing CAP-CLIA laboratory application for tuberculosis and fungal infections
(S. Brakenridge
preliminary data
)
Slide7Progress/Preliminary Results
Severe/progressive adaptive immune
suppresion
Ex vivo
IL-7 ‘rescue’
Enrollment
26 COVID patients, 11 sepsis patients, 7 healthy controls
Samples banked for pooled biomarker/genomic analyses
Ongoing ELISpot analyses
ELISpot adaptive immunity accruing data
Slide8Progress/Preliminary Results
WashU
preliminary data
Consistent findings of profound adaptive immunosuppression
Slide9Summary
CTSI funded pilot project nearing completion
Preliminary data already accruing
There is evidence of profound adaptive immunosuppression in COVID-19 patients
ELISpot exhibits the potential for rapid translation to clinical relevant diagnostics
Immune stimulants may offer efficacy in restoring immunosuppression in COVID-19 patients
UF investigators (Brakenridge/Moldawer) are multi-center study leads in recently initiated international COVID-19 IL-7 clinical trial