Trafficking of Lymphocyte Subsets in Host Defense and Immunopathogenesis in COVID-19

National Institute Of Allergy And Infectious Diseases

Investigators

Abstract

Selective expansion in the blood of lymphocyte subsets as defined by chemokine receptor expression can be used to infer activities for these cells in defense and/or pathology, while selective depletion of subsets from blood in pneumonia and other disorders can be used to infer the migration of these cells and roles for their receptors in trafficking into tissue. In FY 2025 we have continued studies based on the analysis of chemokine receptor expression on T, NK, and dendritic cells and monocytes in the blood of individuals hospitalized due to COVID-19 as compared to healthy donors using multi-parameter flow cytometry. We have identified decreased expression of several chemokine receptors on the T and/or NK cells in patients hospitalized with COVID-19. We have conducted experiments with human cells and cell lines ex vivo and in SARS-CoV-2-infected mice to understand the mechanisms underlying these changes. Our data suggest that multiple mechanisms may be contributory, including cellular activation, chemokine-mediated extravasation and retention in tissue, and the inflammatory environment.