Objective: To determine the clinical implications of the over-expression of synovial and circulating interleukin (IL)-23p19 and the correlation between IL-23p19 and other cytokines such as IL-17, tumour necrosis factor (TNF)alpha, and IL-1beta in rheumatoid arthritis (RA).
Methods: Synovial fluid (SF) and sera of 22 patients with RA were obtained during knee arthrocentesis and stored at -20 degrees C. Tender/swollen joint counts, 100-mm visual analogue scale (VAS), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), and antibodies to cyclic citrullinated peptide (anti-CCP Ab) were measured. Bony erosions were determined by X-rays. Serum and SF IL-23p19, IL-17, TNFalpha, and IL-1beta concentrations were measured by sandwich enzyme-linked immunosorbent assay (ELISA).
Results: The concentration of IL-23p19 correlated with the concentration of IL-17 in SF and sera, and with the concentrations of TNFalpha and IL-1beta in sera. SF IL-23p19 concentration was higher in patients who had bony erosions than those who had not. However, there was no correlation between IL-23p19 concentrations and other clinical parameters of RA.
Conclusion: Upregulated IL-23p19 in SF might be involved in joint destruction in RA through interplay with other cytokines such as IL-17, TNFalpha, and IL-1beta.