IFNG and infection: Moreover, the percentage of IFN-γ+ NK cells associated with the ADCC response during years 1–2 was significantly increased compared with that during acute (within 3 months, p = 0.0009) or early (3–6 months, p = 0.0013, Figure 4B) infection, and did not elevate further, showing a tendency to reduce from 2 years after infection.