Two cohort studies have demonstrated that subjects with higher naïve CD8+ T-cell populations had higher CD4+:CD8+ T-cell ratios on ART [9, 10], while higher CD4+:CD8+ T-cell ratios prior to infection or the presence of human leukocyte antigen (HLA)-A*74:01 in an African cohort [11] have also been reported to positively influence normalisation of CD4+:CD8+ T-cell ratios. The gene discussed is CD8A; the disease is infection.