Correlation between the genetic variations in interleukin 28B and chronic hepatitis C virus genotypes in the Chinese population.

Genetic variations at the interleukin 28B (IL-28B) locus and chronic hepatitis C virus (HCV) genotypes are significant factors in predicting the therapeutic outcome for HCV infection. The present study aimed to determine the geographical distribution of HCV genotypes and single nucleotide polymorphisms (SNPs) associated with IL-28B in Chinese patients infected with HCV. The gene frequencies of 13 types of IL-28B SNPs and HCV genotypes were investigated in 1,014 patients infected with HCV, who were recruited from varying regions of China. The correlation between the SNPs of IL-28B, the HCV genotypes and age, gender and geographical location were investigated. The data revealed geographical differences in age, gender and HCV genotypes in the Chinese HCV patients. HCV genotype 1 was distributed extensively and had a higher incidence compared with other HCV genotypes in all regions, with the exception of South (38%) and Northwest China (45.6%). A gender differences also existed (P<0.01). The distribution of genotype 6 was lower compared with other HCV genotypes in the majority of the regions (P<0.01). In middle‑aged patients, the number of male patients was higher than the number of female patients in North and South China, which was the opposite of the results found in the other regions. There were no geographical differences in IL-28B SNPs in Chinese HCV‑infected populations. Notably, there were significant differences between HCV genotype 1 and 2 in the genotype percentages of the majority of SNPs (P<0.01). In conclusion, a geographical distribution in HCV genotypes and a correlation between HCV genotypes and IL-28B SNPs have been identified, and indicate that these variants may be associated with spontaneous and treatment-induced HCV clearance.