Direct-acting antiviral (DAA)-induced downregulation of endogenous IFN-β response in peripheral blood mononuclear cells (PBMCs) isolated from HCV-infected patients. (A, B) PBMCs from HCV-infected patients were isolated before DAA (pre DAA) and at the end of DAA (post DAA) treatment. TaqMan real-time quantitative polymerase chain reaction (PCR) was performed to detect mRNA levels of IFN-β, IFI44, CXCL10, and GAPDH. (C, D) Serum and PBMC from two HCV-infected patients were isolated before and at the end of DAA treatment. TaqMan real-time quantitative PCR was performed to detect viral RNA level of HCV in the sera and mRNA levels of IFN-β, IFI44, CXCL10, and GAPDH in the PBMCs. GAPDH, glyceraldehyde 3-phosphate dehydrogenase; IFN, interferon; IFI44, interferon-induced protein 44; CXCL10, C-X-C motif chemokine ligand 10; HCV, hepatitis C virus; wks, weeks; Pt, patient. * P