title: Restoration of natural killer cell activity by pegylated interferon-alpha/ribavirin therapy in chronic hepatitis C patient.
abstract: OBJECTIVE
  The combination therapy of pegylated interferon-α and ribavirin (PEG IFN/RBV) is one of the effective treatments for chronic hepatitis C (CHC) patients. Natural killer (NK)-cell activity was reported to be impaired in patients with hepatitis C virus (HCV). The aim of this study was to examine whether PEG IFN/RBV therapy could restore NK activity in CHC patients.
  
  
  METHODS
  In 19 CHC patients, PEG IFN/RBV therapy was performed. Just before (0M), at 3 months of the therapy (3M) and at 6 months after completion of the therapy (6M), NK activity and the frequency of NK cells, CD56(dim) NK cells and CD56(bright) NK cells in peripheral blood was estimated by creatinine release assay and flow cytometry. Statistical analysis was performed by anova and Mann-Whitney U-test.
  
  
  RESULTS
  anova showed that NK activity significantly improved at 6M (vs 0M, P < 0.05) in the patients studied and in the patients with sustained virological response (SVR). It also showed that frequency of CD56(bright) NK cells was significantly increased at 6M (vs 0M, P < 0.05) in the patients studied and in the SVR group. However, no significant change in NK activity and frequency of CD56(bright) NK cells were detected in non-SVR group. Furthermore, NK activity ratio (6M/0M) in the SVR group was revealed to be higher compared with that in the non-SVR group by analysis using Mann-Whitney U-test (P < 0.05).
  
  
  CONCLUSIONS
  PEG IFN/RBV therapy in CHC patients could improve NK activity by increasing the frequency of CD56(bright) NK cells in SVR patients. Our study also revealed that eradication of HCV could restore NK-cell activity.
authors.affiliation: Department of Gastroenterology, Tokyo Medical University, Tokyo, Japan; Division of Gastroenterology, Saitama Medical Center, Jichi Medical University, Saitama, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Nakamura
authors.forename: Takeharu
authors.initials: T
authors.lastname: Asano
authors.forename: Shinichi
authors.initials: S
authors.lastname: Asabe
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ando
authors.forename: Takatomo
authors.initials: T
authors.lastname: Sano
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miyata
authors.forename: Junichi
authors.initials: J
authors.lastname: Taira
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Imai
authors.forename: Fuminori
authors.initials: F
authors.lastname: Moriyasu
authors.forename: Michio
authors.initials: M
authors.lastname: Imawari
keywords: CD56brightNK cell; CD56dimNK cell; natural killer cell; natural killer cell subset