CD4 and type 2 diabetes mellitus: Increased levels of several proinflammatory cytokines and receptors, including IL-2R, IL-6, IL-8, IL-10, and TNF-α, and reduction in the peripheral total T lymphocytes, CD4+ T cells, CD8+ T cells, and NK cells have been found to be associated with high risk of mortality in COVID-19 patients with type 2 diabetes (26).