CD8A and COVID-19: COVID‐19 also leads to a decrease in the number of T lymphocytes (mostly CD4 and CD8), while the level of interleukin (IL)‐6, IL‐2‐R, IL‐10, and tumor necrosis factor‐α increases.[67] A reduction in the percentage of blood T lymphocytes is also a predictor of COVID‐19 severity.[68] A closer look at the T‐cell compartment revealed that their activation and exhaustion may be a lymphopenia source.[69]