Increased interleukin-23 is associated with increased disease activity in patients with rheumatoid arthritis

Background Interleukin-23 (IL-23) is a pro-inflammatory cytokine that is thought to be central to the development of autoimmune diseases.This study was conducted to determine whether or not the serum concentration of IL-23 is elevated in patients with rheumatoid arthritis (RA),and to determine the relationship between the IL-23 level and disease activity in RA patients.Methods Serum samples were obtained from 59 patients with RA and 30 healthy controls.The clinical parameters of disease activity were determined,including the 28-joint disease activity score (DAS28),C-reactive protein (CRP),rheumatoid factor (RF) levels,and the degree of bony erosions based on X-rays.The levels of IL-23 and IL-17 were determined by enzyme-linked immunosorbent assay (ELISA).The correlations between the serum levels of IL-23 and disease activity parameters of patients with RA were determined.Results The serum IL-23 level was significantly elevated in patients with RA compared to healthy controls.The serum IL-23 levels in the RA patients correlated with IL-17 and CRP levels,and the DAS28.The levels of IL-23 based on X-ray classification phase Ⅰ,Ⅱ,Ⅲ,and Ⅳ were gradually elevated in RA patients.Conclusions The levels of serum IL-23 in RA patients were higher than in healthy controls.Thus,elevated serum IL-23 levels may be useful markers to detect active RA.In addition,IL-23 is involved in disease progression and bony erosions in patients with RA.