title: Effects of IL-28B gene polymorphism on response to peginterferon plus ribavirin combination therapy for genotype 2 chronic hepatitis C.
abstract: OBJECTIVE
  Interleukin (IL)-28B gene polymorphism is closely linked with treatment response to peginterferon plus ribavirin combination therapy for hepatitis C virus genotype 1. However, few studies have reported its effects on therapy for genotype 2. We aimed to examine the effects of IL-28B gene polymorphism on treatment response in hepatitis C virus genotype 2 patients.
  
  
  METHODS
  In a retrospective study of 101 patients infected with either genotype 2a (n = 65) or 2b (n = 36) and treated with peginterferon plus ribavirin, we investigated predictive factors for a sustained virological response (SVR), including genetic variations near the IL-28B gene (rs8099917, rs11881222 and rs8103142) and clinical variables such as age, sex, body mass index, stage of fibrosis and drug adherence.
  
  
  RESULTS
  Ultra-rapid virological response, rapid virological response (RVR), end-of-treatment response, SVR and relapse rates were 22.2%, 61.4%, 95.0%, 87.1% and 7.9%, respectively. In univariate analysis, RVR and IL-28B single nucleotide polymorphisms (SNP) (rs8099917, rs11881222 and rs8103142) were significantly associated with SVR. In subgroup analysis, IL-28B SNP were significantly associated with SVR in genotype 2a patients but not in genotype 2b patients. In multiple logistic regression analysis, RVR and IL-28B SNP (rs8099917) were independently associated with SVR. Furthermore, IL-28B SNP was significantly associated with relapse but RVR was not.
  
  
  CONCLUSIONS
  In genotype 2 patients treated with peginterferon plus ribavirin combination therapy, IL-28B gene polymorphism was a significant independent predictor of SVR as well as RVR. IL-28B major allele may favor reduced relapse rates in patients with genotype 2 chronic hepatitis C.
authors.affiliation: Gastroenterological Center, Yokohama City University Medical Center.
authors.forename: Yu
authors.initials: Y
authors.lastname: Shimoyama
authors.forename: Akito
authors.initials: A
authors.lastname: Nozaki
authors.forename: Manabu
authors.initials: M
authors.lastname: Morimoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Moriya
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kondo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukuda
authors.forename: Kazushi
authors.initials: K
authors.lastname: Numata
authors.forename: Eiji
authors.initials: E
authors.lastname: Miyajima
authors.forename: Mari S
authors.initials: MS
authors.lastname: Oba
authors.forename: Masataka
authors.initials: M
authors.lastname: Taguri
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morita
authors.forename: Shin
authors.initials: S
authors.lastname: Maeda
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Tanaka
keywords: IL-28B gene polymorphism; chronic hepatitis C; genotype 2