High frequencies of a favorable IL-28B rs8099917 polymorphism and the clinical implications in patients with HCV in one multiracial area of Taiwan

There is a strong association between hepatitis C virus (HCV) treatment efficacy and the interleukin (IL)-28B gene. However, the IL-28B variant's distribution and potential role in the therapeutic response are not well established in Taitung, a racially diverse county in Taiwan. Here, we investigated the distribution pattern of IL-28B rs8099917 and its influence on treatment efficacy. In this retrospective study, we enrolled 180 patients who had been treated with pegylated-interferon plus ribavirin. Patients' general information, virological characteristics, IL-28B status, laboratory results, treatment course, and outcome were analyzed. Of the patients enrolled, 56.7% were male, with a mean age of 54.11 years. A total of 24.4% of the population were indigenous people. The majority of patients had the favorable IL-28B polymorphism (rs8099917 TT/TG/GG: 94.4%/5.6%/0%). The proportion of patients with the TT genotype seemed to be higher in indigenous patients. The rate of sustained virological response (SVR) among included patients was 73.0%. Univariate analysis showed that genotype non-1, patients achieved rapid virological response (RVR), lower body mass index (BMI), and lower baseline HCV viral load were significantly associated with SVR. Multivariate analysis revealed that BMI <25 and RVR are the independent predictor of success treatment. In conclusion, the favorable IL-28B rs8099917 polymorphism occurs in high frequency in this multiracial area, which might be important to help guide physicians and patients in their future clinical decisions.