CD4 and infection: We also examined the expression of mtTFA—another mitochondrial master regulator that is significantly inhibited in CD4+ T cells derived from individuals with chronic HIV (Zhao et al., 2021) or HCV (unpublished observations) infection—and no significant differences were observed in mtTFA levels in either group of cells after the treatment with MG2I and 10~20 min/day light exposure for 3 days (Figure 5a,c).