32 treatment-naive CHC patients and 20 healthy controls were recruited. Patients were examined before DAAs therapy (0w) and at weeks 4 (4w) and weeks 12 (12w) and weeks24 (24w) of the therapy. The percent age of myeloid-derived suppressor cells and NK cells of the peripheral blood were analyzed by flow cytometry. The investigators discuss the relationship between direct acting antiviral treatment effect and myeloid-derived suppressor cells and NK cells activity in chronic hepatitis C.