CD8A and cerebrovascular disorder: Du et al. [42] identified four risk factors: age ≥65 years, preexisting concurrent cardiovascular or cerebrovascular diseases, CD3+CD8+ T cells ≤ 75 cell/μL, and cardiac troponin I ≥ 0.05 ng/mL; these last two factors were predictors for mortality of COVID-19 pneumonia patients.