Association of a single nucleotide polymorphism near the interleukin-28B gene with response to hepatitis C therapy in Asian patients.

A single nucleotide polymorphism near the interleukin-28B (IL28B) gene has been shown to predict hepatitis C virus (HCV) treatment response. We aim to determine the role of the IL28B genotype in Asian patients. A total of 118 patients (all Korean, 55 patients with genotype 1 infection and 63 patients with genotype 2 infection) were consecutively enrolled and analyzed. The sustained virological response (SVR) rate was 74% (87/118), while 26 patients (22%) relapsed and five patients were non-responders (4%). For rs8099917, the frequencies of major homozygotes (TT), heterozygotes (GT), and minor homozygotes (GG) were 0.85, 0.14 and 0.01, respectively. Of the 55 patients with HCV genotype 1 infection, the SVR rate was 67% and 44% (P = 0.19) and the non-response rate was 2% and 22% (P = 0.015) for the major allele and minor or hetero allele, respectively. Of the 63 patients with HCV genotype 2 infection, the SVR rate was 80% and 100% (P = 0.13) and the non-response rate was 4% and 0% (P = 0.55) for major allele and hetero allele, respectively. The IL28B genotype may help identify non-responding patients in HCV genotype 1, but not in HCV genotype 2. Because of the high frequency of favorable alleles and the low frequency of non-response, the IL28B polymorphism may play a smaller role in Asian patients.