We also report a significant positive correlation between the frequency of central memory CD8+ T cells (CD8+ TCM) and BMI in young patients only; and increased proliferation of central memory CD4+ T cells (CD4+ TCM) in aged patients only, these differences may be independent of COVID-19 since obesity has been reported to greatly increase memory T cell frequencies (93). Here, CD8A is linked to obesity due to melanocortin 4 receptor deficiency.