CD4 and COVID-19: It was observed that BALF cell count analysis of hospitalized COVID-19 patients showed an accumulation of CD4+ and CD8+ T cells (81), similar to sarcoidosis patients, and most cell counts showed CD4/CD8 ratios higher than 1.5, which may explain the reason for the higher decrease in CD8+ T-cell number than CD4+ T-cell number (82).