These findings come alongside our observations that the patients without respiratory failure had more baseline CD4+ and CD8+ T-lymphocytes (compared to those with severe COVID-19) and a pronounced increase in activated and memory CD4+ T-cells and total and activated CD8+ T-cells over time was observed in the patients treated with dexamethasone who reached convalescence, but not in those who failed to recover. This evidence concerns the gene CD4 and COVID-19.