PD-1 expression was significantly higher on total Tregs (p < 0.0001) and all four Tregs subsets (Naïve, p < 0.0001; TCM, p < 0.0001; TEM, p < 0.0147; Effector, p < 0.0153) in CHC patients compared with HCs. The gene discussed is PDCD1; the disease is cryohydrocytosis.