Gender-dependent association of CTLA4 polymorphisms with resolution of hepatitis C virus infection

Background/Aims: A vigorous T-cell response is essential for the resolution of HCV infection. It is modified by co-stimulatory molecules that attenuate T-lymphocyte responses by binding to CTLA4. We investigated whether CTLA4 single nucleotide polymorphisms are associated with the resolution of infection or with the course of disease. Methods: We enrolled 127 individuals with self-limited and 947 patients with chronic HCV infection, of whom 560 were treated with interferon-α-based therapies, and 200 healthy controls. We analyzed CTLA4 polymorphisms -318C > T and +49A > G by melting curve analysis and reconstructed haplotypes. Results: CTLA4 haplotypes were distributed differently between men but not women with self-limited and chronic infection (p = 0.043) but were not predictive of the stage of fibrosis in chronic carriers. Haplotypes were distributed differently between male but not female end-of-treatment responders and non-responders (p = 0.025). The influence of CTLA4 haplotypes was more pronounced in "hard-to-treat" situations, i.e., treatment with interferon-α monotherapy or infection with HCV genotypes 1/4. Logistic regression analysis confirmed gender-specific risk factors for a virological non-response. Conclusions: CTLA4 polymorphisms are associated with the resolution of HCV infection. This study underlines the role of an efficient T-cell response in the clearance of HCV and sheds light on a gender-dependent difference of immune regulation.