Lee et al. in study of 198 COVID-19 patients with single cell multi-nomics and analysis of plasma metabolite found that increasing disease severity correlated with division of monocytes into two metabolically and functionally distinct subsets, metabolically hyperactive CD8+ T cell subpopulation, marked metabolic heterogeneity with CD4+ cells and metabolically dominant NK cell subpopulation [47]. Here, CD4 is linked to COVID-19.