Polymorphism of Interleukin 28 and HCV: Implementation of a method

HCV infection represents a global health problem. Only 20-30% of patients affected by HCV infection recovers spontaneously, while the remaining patients develop a chronic infection with risk of evolution to cirrhosis and hepatocarcinoma. Nowadays, approximately 50% of individuals with hepatitis C infection is not responding to therapy with pegylated alphainterferon and ribavirin. Polymorphisms (SNPs) of the gene coding for the interleukin 28 (IL28) have recently been described and they are in strong relationship with the outcome of HCV infected patients. In particular, the polymorphism rs12979860 (C/T), located 3 kb upstream of the gene, is associated to a rapid and early response to therapy (genotype C/C). Consequently we have developed a method in high resolution melting (HRM), which allows a simple and rapid screening of polymorphism rs12979860. The validation of the method was carried out by analyzing the IL28 genotype of 50 patients already determined by sequencing. Sensitivity and specificity of the method were found to be equal to 100%.Accuracy, precision within and between series were equal to 100%. Compared to other methods described for the analysis of polymorphisms the HRM has the advantage of being faster and safe, relatively cheap and very simple in the optimization phase, therefore, applicable to a large throughput. Up till now we have analyzed 329 patients of which 46 co-infected HCV-HIV. The distribution of the polymorphism obtained is the following: 37% C/C, 51% C/T, 12% T/T.The distribution in the co-infected patients does not differ from that of the total HCV positive patients.We suggest a careful follow up of the therapeutic response of these patients to confirm the clinical usefulness of the test and to determine its true predictive value.