Abstract
Background: By the end of 2019, the COVID-19 pandemic spread all around the world with a wide spectrum of clinical presentations ranging from mild to moderate to severe or critical cases. T cell subtype dysregulation is mostly involved in the immunopathogenic mechanism. The present study aimed to highlight the role of monitoring T cell subtypes and their activation (expression of CD38) in COVID-19 patients compared to healthy subjects and their role in predicting severity and patients’ outcomes. Materials: The study involved 70 adult COVID-19 confirmed cases stratified into three groups: a mild/asymptomatic group, a clinically moderate group, and a clinically severe/critical group. Flow cytometry analysis was used for the assessment of CD3
+
cells for total T cell count, CD4
+
cells for helper T cells (Th), CD8
+
cells for cytotoxic T cells (Tc), CD4
+
CD25
+
cells for regulatory T cells (T reg), and CD38 expression in CD4
+
T cells and CD8
+
T cells for T cell activation. Results: A statistically significant difference was found between COVID-19 cases and healthy controls as regards low counts of all the targeted T cell subtypes, with the lowest counts detected among patients of the severe/critical group. Furthermore, CD38 overexpression was observed in both CD4
+
and CD8
+
T cells. Conclusion: Decreased T cell count, specifically CD8
+
T cell (Tc), with T cell overactivation which was indicated by CD38 overexpression on CD4
+
and CD8
+
T cells had a substantial prognostic role in predicting severity and mortality among COVID-19 patients. These findings can provide a preliminary tool for clinicians to identify high-risk patients requiring vigilant monitoring, customized supportive therapy, or ICU admission. Studies on larger patient groups are needed.