The Tregs frequency was higher in chronic hepatitis C patients than that in the controls (P = 0.031) (Fig. 2), which was significantly decreased at 12 weeks after treatment with IFNα-2b/RBV (P = 0.015) (Fig. 3A) or PegIFNα-2a/RBV (P = 0.034) (Fig. 3B). Here, IFNA2 is linked to chronic hepatitis C virus infection.