CD4 and COVID-19: Irrespective of the antihypertensive treatment use, including ACEi or ARB, our cohort showed significantly (bonferroni corrected P significance) reduced levels of naïve CD8 + and CD4 + T cells (Fig. 5A and B) compared to healthy donors, which is consistent with the severe T cell depletion in COVID-19 patients [21, 30].