Immune regulation of interleukin-23 on peripheral blood natural killer cell in patients with inflammatory bowel disease

Abstract

Objective To study the potential role of interleukin-23(IL-23)in induction of peripheral blood natural killer(NK)cell activation and cytotoxicity in patients with inflammatory bowel disease(IBD),and to investigate its clinical relevance to the pathogenesis.Methods Peripheral blood was collected from 12 healthy subjects,16 patients with Crohn's disease(CD)and 25 patients with ulcerative colitis(UC).NK cells isolated from peripheral blood using immunomagnetie beads were cultured in vitro and stimulated with IL-23 or IgG,or combination of two.Concentrations of tumor necrosis factor α(TNF-α)and interferon-γ(IFN-γ)were determined by enzyme linked immunosorbent assay.NK eytotoxicity to K562 cell was detected by flow cytometry.Results The levels of TNF-α and IFN-γ were not increased in healthy controls under stimulation with IgG or IL-23 (P＞0.05),but they were elevated under stimulation with IgG plus IL-23(P＜0.05).IL-23,not IgG,was found tO enhance TNF-α and IFN-γ secretion in IBD patients(P＜0.05).The levels of TNF-α and IFN-γ were significantly increased in IBD patients under the stimulation of IL-23 plus lgG (P＜0.01).The cytotoxicity of NK cells in healthy controls was not observed under stimulation with IL-23 alone or IL-23 plus IgG,whereas it could be enhanced by stimulation with IL-23 in CD patients (62.4%±5.5%)and UC patients(65.3%±6.6%,P＜0.05)or with IL-23 plus IgG in CD patients (50.2%±8.7%)and UC patients(51.5%±7.1%,P＜0.01).ConclusionIL-23 plays an important role in induction of NK cell activation and cytotoxicity in IBD patients,and may be involved in development of IBD. Key words: Inflammatory bowel diseases; Interleukin-23; Killer cells,natural