High Resolution Melting Curve Assay for Detecting rs12979860 IL28B Polymorphisms Involved in Response of Iranian Patients to Chronic Hepatitis C Treatment

Background: A recent genome-wide association study (GWAS) on patients with chronic hepatitis C (CHC)treated with peginterferon and ribavirin (pegIFN-α/RBV) identified a single nucleotide polymorphism (SNP)on chromosome 19 (rs12979860) which was strongly associated with a sustained virological response (SVR). Theaim of this study was twofold: to study the relationship between IL28B rs12979860 and sustained virologicalresponse (SVR) to pegIFN-α/RVB therapy among CHC patients and to detect the rs12979860 polymorphism byhigh resolution melting curve (HRM) assay as a simple, fast, sensitive, and inexpensive method. Materials and
Methods: The study examined outcomes in 100 patients with chronic hepatitis C in 2 provinces of Iran fromDecember 2011 to June 2013. Two methods were applied to detect IL28B polymorphisms: PCR-sequencing as agold standard method and HRM as a simple, fast, sensitive, and inexpensive method.
Results: The frequencies ofIL28B rs12979860 CC, CT, and TT alleles in chronic hepatitis C genotype 1a patients were 10% (10/100), 35%(35/100), and 6% (6/100) and in genotype 3a were 13% (13/100), 31% (31/100), and 5% (5/100), respectively.In genotype 3a infected patients, rs12979860 (CC and CT alleles) and in genotype 1a infected patients (CCallele) were significantly associated with a sustained virological response (SVR). The SVR rates for CC, CT andTT (IL28B rs12979860) were 18%, 34% and 4%, respectively. Multiple logistic regression analysis identifiedtwo independent factors that were significantly associated with SVR: IL-28B genotype (rs 12979860 CC vs TTand CT; odds ratio [ORs], 7.86 and 4.084, respectively), and HCV subtype 1a (OR, 7.46). In the present study,an association between SVR rates and IL28B polymorphisms was observed.
Conclusions: The HRM assaydescribed herein is rapid, inexpensive, sensitive and accurate for detecting rs12979860 alleles in CHC patients.This method can be readily adopted by any molecular diagnostic laboratory with HRM capability and will beclinically beneficial in predicting treatment response in HCV genotype 1 and 3 infected patients. In addition, itwas demonstrated that CC and CT alleles in HCV-3a and the CC allele in HCV-1a were significantly associatedwith response to pegIFN-α/RBV treatment. The present results may help identify subjects for whom the therapymight be successful.