CD4 and infection: The response of intracellular IFN-γ, IL-17A, and IL-21 expressing CD4+ or CD8+ effector T cells in HBV resolved infection was significantly higher than observed in OBI or CHB (P < 0.05, Figures 3B,E,F, 4B,E), while the concentration of circulating IL-17A was higher in OBI and CHB (P < 0.01, Figure 6D).