CD4 and COVID-19: All CD8+ and CD4+ T cells (including naive, CM, TM, EM, and EMRA) in patients with COVID-19 demonstrated an increase in the expression of LAG-3.2 Multi-omic single-cell analysis has also found up-regulation of LAG-3 on most T/NK cells, with the exception of Tregs, in samples from advanced COVID-19 patients.39 In addition, it was also found that LAG-3+CD4+ T cells are negatively correlated with activated monocytes.