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Increased CD95 (Fas) and PD-1 expression in peripheral blood T lymphocytes in COVID-19 patients
Silvia Bellesi1, Elisabetta Metafuni1, Stefan Hohaus1,2
1Dipartimento di Diagnostica per Immagini, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Radioterapia Oncologica ed Ematologia, Rome, Italy.
Insights
COVID-19 infection is associated with increased expression of CD95 and PD-1 on T cells, indicating potential T cell exhaustion and apoptosis. This immune response may contribute to disease severity and altered T cell counts in patients.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Low CD4+ and CD8+ T lymphocyte counts are characteristic of COVID-19.
- T cell exhaustion and apoptosis are implicated in severe viral infections.
Purpose of the Study:
- To investigate the expression of CD95 (Fas) and PD-1 on T cells in COVID-19 patients.
- To correlate T cell marker expression with clinical parameters like lymphocyte counts.
Main Methods:
- Flow cytometry was used to analyze T cell surface markers.
- Comparison of marker expression between 42 COVID-19 patients and healthy controls.
Main Results:
- Significantly higher CD95 and PD-1 expression on CD4+ and CD8+ T cells in COVID-19 patients.
- Higher CD95 expression on CD4+ T cells correlated with lower CD4+ counts.
- Increased CD95 expression on T cells correlated with a reduced percentage of naive T cells.
Conclusions:
- COVID-19 infection induces T cell activation, characterized by increased expression of apoptosis- and exhaustion-related molecules.
- These findings suggest a mechanism for T cell depletion and dysfunction during SARS-CoV-2 infection.
Abstract:
A low count of CD4+ and CD8+ lymphocytes is a hallmark laboratory finding in the coronavirus disease 2019 (COVID-19). Using flow cytometry, we observed significantly higher CD95 (Fas) and PD-1 expression on both CD4+ T and CD8+ T cells in 42 COVID-19 patients when compared to controls. Higher CD95 expression in CD4+ cells correlated with lower CD4+ counts. A higher expression of CD95 in CD4+ and CD8+ lymphocytes correlated with a lower percentage of naive events. Our results might suggest a shift to antigen-activated T cells, expressing molecules increasing their propensity to apoptosis and exhaustion during COVID-19 infection.
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