Association of Transforming Growth Factor–β1 Functional Polymorphisms with Natural Clearance of Hepatitis C Virus

Transforming growth factor (TGF)-β1 suppresses the proliferation and cytotoxicity of natural killer (NK) cells, which play critical roles in resolving hepatitis C virus (HCV) infection, especially during the acute phase. We examined 230 anti-HCV antibody-positive subjects for HCV RNA and the -509T/C genotype in the TGF-β1 gene promoter. The -509CC genotype and the -509C allele were significantly associated with higher HCV clearance rates (P =.01) and with lower transcriptional activity. The genetic effect remained significant even after adjustment for a history of transfusion. Low TGF-β1 producers might have less suppression of NK cells and be more likely to resolve HCV infection.