Frequencies of IL-28B-rs12979860 and rs8099917 variants and the role of IL-28B-rs12979860 as predictors of response in HCV patients in case of direct acting antiviral therapy

Abstract

The treatment outcomes in Hepatitis C virus (HCV) are attributed to various factors like viral load, viral genotype, ethnicity, and host genome. Therefore, this study was carried out to determine the genetic frequencies of IL-28B-rs12979860 and rs8099917 variants and to explore the role IL-28B-rs12979860 as predictors of therapeutic response in direct acting antiviral therapy. Two study subjects, chronic HCV patients (182) and control individuals (59), were recruited in this project. The patients were initially diagnosed through ELISA (Biotech-USA); however, active, and non-active infection status of the patients was determined through Real Time PCR (Amplisense-HCV FRT, Russia). Genomic DNA was extracted from whole blood using silica spin column extraction kit (MN, Germany) followed by genotyping of two SNPs IL-28B-rs12979860 C/T and IL-28B-rs8099917 T/G using a real time PCR assay (Amplisense HCV FRT, Russia). The genotype frequency of IL-28B-rs12979860 was significant in co-dominant [χ2 =13.78; P=0.001], homozygous dominant (TT vs CC+CT) [OR=3.903 (0.123-0.519); P=0.0002], homozygous recessive (CC vs TT+CT) [OR=0.322 (0.160-0.625); P=0.0016], and additive C vs T) [OR=0.354 (0.22-0.572); P<0.0001] models. Similarly, a significant genotype distribution of IL-28B-rs8099917 was observed in co-dominant [χ² =16.53; P=0.0003], homozygous dominant (GG vs TT+GT) [OR= 2.304 (1.03- 5.11); P=0.04], homozygous recessive (TT vs GG+GT) [OR=0.222 (0.108-0.476); P=0.00], and additive (T vs G) [OR= 0.361 (0.221-0.591); P<0.0001] models. Furthermore, we found that out of the total 101 chronic HCV patients, 80 (79.2%) showed SVR while 21 (21.8%) did not achieve SVR and were called as relapsed patients’ group. Thus, evaluating response of certain genotype of IL-28B-rs12979860 to direct-acting antiviral (DAA), the TT genotype was observed 33 (71.7%) in SVR and 13 (28.3%) in relapsed patients. However, CC genotype was found 23 (95.8%) and 1 (4.2%) in SVR and relapsed patients, respectively. While CT genotype was 24 (77.4%) in SVR and 7 (22.6%) in relapsed patients.