High prevalence of autoantibodies neutralizing type I IFNs in Japanese patients with hepatitis C

Autoantibodies neutralizing type I IFNs (AAN-I-IFNs) are being identified as major, common, and global determinants of a growing range of severe viral diseases. We examined whether persistent hepatitis C virus (HCV) infection, with or without IFN-α therapy, could induce AAN-I-IFNs. We tested 2,573 HCV patients aged 1-95 years (1,115 treated with IFN-α, 1,458 untreated) and 1,000 healthy controls. AAN-INF-α2 prevalence was significantly higher in hepatitis C patients (2.7%) than in healthy controls (0.7%) and was higher still in those treated with IFN-α (3.9%) than in untreated patients (1.9%) (P = 0.0053). A longitudinal study of 15 IFN-α-treated patients with AAN-IFN-α2 revealed that only one had AAN-IFN-α2 before IFN-α therapy and that 12 patients developed AAN-IFN-α2 in the year following treatment. However, 80% eventually became AAN-IFN-α2 negative. These findings suggest that chronic HCV infection, perhaps due to the chronic production of endogenous IFN-α, and exogenous IFN-α treatment promote the development of AAN-IFN-α2.