Roles of ITPA and IL28B genotypes in chronic Hepatitis C patients treated with peginterferon plus ribavirin in Tunisian population

Despite considerable progress in the treatment of chronic hepatitis C, many countries do not have access to these new treatments.Predictive markers of response to treatment are therefore necessary before initiating with historical combination therapy (PEG-IFN+ribavirin) for these populations.We therefore evaluated the influence of IL28B polymorphisms on treatment response and Inosine Triphosphate (ITPA) polymorphisms on the incidence of anaemia in a population of 120 Tunisian patients infected with HCV genotype 1b and treated.The frequencies of favourable IL28B genotypes were 47% (CC for rs12979860) and 63% (TT for rs8099117). Patients in whom favourable IL28B alleles were identified had a higher chance of successful therapy: 82% for CC (rs12979860) and 75% for TT (rs8099117). Viral load decline during the first twelve weeks of treatment was more pronounced in patients with a favourable genotype (p0.0001). For patients with an unfavourable genotype, the second phase of viral decline was more pronounced in patients with SVR. A viral load decline cut-off of 2.68logIU/mL at week 12 was best suited to discriminate responders from non-responders with an odds ratio of 40 (95% CI:11.53-170.3). Analysis of ITPA polymorphisms revealed that 16% of Tunisian patients presented ITPase deficiency. None of these patients experienced a decline of ribavirin doses during treatment versus 67% for patients without ITPase deficiency (p0.001).These data obtained in a Tunisian population should optimize before and during treatment the chances of success for treatments currently available in Tunisia for chronic HCV infection.