Development and Validation of a Simple, Rapid and Inexpensive PCR-RFLP Method for Genotyping of Common IL28B Polymorphisms: A Useful Pharmacogenetic Tool for Prediction of Hepatitis C Treatment Response

BACKGROUND: In 2009, 3 genome-wide association studies implicated IL28B single-nucleotide polymorphisms (SNPs) as the strongest genetic pretreatment predictor of sustained virological response (SVR) in hepatitis C infection. Recently, the American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL) included IL28B testing in their guidelines. OBJECTIVES: The main aim of this study was to develop and validate a simple, rapid, and inexpensive polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for genotyping of common IL28B polymorphisms (rs12979860 and rs8099917). PATIENTS AND METHODS: Two methods were developed to genotype common IL28B polymorphisms: 1) PCR-sequencing as a reference method and 2) PCR-RFLP as a rapid and inexpensive method. Both polymorphisms were genotyped in 104 Iranian hepatitis C patients by both methods simultaneously. To validate the PCR-RFLP method, the PCR-RFLP genotyping results should be 100% concordant with the PCR-sequencing results. RESULTS: Genotyping of rs12979860 and rs8099917 by PCR-RFLP was concordant with PCR-sequencing in 104 (100%) individuals. The analytical sensitivity and specificity of the PCR-RFLP method for genotyping of both SNPs are 100%. Among these 104 patients with chronic hepatitis C, the frequency of the rs12979860 CC, CT and TT genotypes were 40.4%, 47.1% and 12.5% and the frequency of the rs8099917 TT, GT and GG genotypes were 59.6%, 35.6% and 4.8%, respectively. Also, three IL28B haplotypes (rs12979860-rs8099917) were found among our patients including C-T, T-G and T-T with 63.9%, 22.6% and 13.5% frequency, respectively. C-G haplotype was absent in all of our patients. CONCLUSIONS: We have developed a validated, fast, and simple PCR-RFLP method for genotyping of common IL28B SNPs that is more cost-effective than sequencing.