CD8A and COVID-19: In addition, serum IL-27 levels also negatively correlated with Tc17 cells’ frequency within CM (r = –0.346, p = 0.020), EM (r = –0.356, p = 0.016), and TEMRA (r = –0.378, p = 0.011) CD8+ T cells from patients with acute COVID-19 (Figure 8D–F, respectively), but not in COVID-19 convalescents and healthy controls.