Association of −319 C/T and +49 A/G polymorphisms of CTLA-4 gene in patients with hepatitis C virus infection

Abstract Introduction and objective Molecular changes in the CTLA-4 gene can modify the ability to control T lymphocyte proliferation, and promote the persistence or elimination of the hepatitis C virus (HCV). We aimed to investigate the frequency and association of −319 C/T and +49 A/G polymorphism in the CTLA-4 gene in patients infected with HCV. Methods The CTLA-4 gene polymorphisms (−319 C/T in the promoter region, and +49 A/G in exon 1) were analyzed by T-ARMS-PCR in 420 individuals, including 205 chronic HCV infected patients and 215 healthy subjects. Results We found a positive association of +49G allele with HCV infection (OR 1.48; 95% CI: 1.09–2.02; p = 0.02), and with males (OR 1.80; 95% CI: 1.16–2.79; p  = 0.02), both in chronic disease (without cirrhosis). Also, significant differences in +49 A/G genotypes distribution between HCV infected patients and healthy subjects were shown in a dominant genetic model (GG + GA versus AA; OR 1.57; 95% CI: 1.05–2.33; p  = 0.04). No significant differences were observed in the −319 C/T polymorphism between HCV infected patients and healthy subjects. Moreover, −319C/+49G haplotype confers susceptibility to HCV genotype 3 infection (OR 10.68; 95% CI: 1.17–96.97; p  = 0.04). Conclusions The +49G allele confers susceptibility to HCV infection and with male gender, both in chronic disease. In addition, the −319C/+49G haplotype confers susceptibility to HCV genotype 3 infection. Our results support an important role of the −319 C/T and +49 A/G polymorphisms in HCV infection.