IL28B CC-genotype association with HLA-DQB1*0301 allele increases the prediction of spontaneous HCV RNA clearance in thalassaemic HCV-infected patients

Background: A single nucleotide polymorphism (SNP), upstream of the IL28B gene has been recently associated with natural clearance of HCV. In a well-characterized cohort of patients with thalassaemia major exposed to the risk of acquiring HCV infection by blood transfusions, we aimed to replicate this finding and to evaluate whether combining the IL28B genotype and HLA class II alleles allow viral clearance to be accurately predicted. Methods: Of 168 patients, 130 with complete clinical history were included in the analysis. According with their HCV antibodies status 13 were defined HCV resistant, and 117 infected. Infected patients were subdivided, giving 49 with self-limiting and 68 with ongoing infection. Results: IL28B CC-genotype was observed in 32 patients with self-limiting and in 23 with ongoing infection (64% versus 34%; P=0.004). HLA DQB1*0301 allele was associated with viral clearance in 36 cases (73%; P<0.0001). Both DQB1*0301 and IL28B CC-genotype were found to be independent predictors of HCV clearance (OR=5.64, 95% CI 1.52-20.9 and OR=5.76, 95% CI 2.16-15.33, respectively). With the addition of DQB1*0301, the accuracy of the prediction increased from 63% to 69%. Conclusions: In addition to IL28B CC-genotype, HLA DQB1*0301 helps in predicting natural clearance of HCV after acute infection.