Th-17 cells and serum IL-17 in rheumatoid arthritis patients: Correlation with disease activity and severity

Aim of the work: To investigate the role of T-helper 17 (Th17) cells in peripheral blood and serum interleukin-17 (IL-17) in rheumatoid arthritis (RA) patients, and their correlation with disease activity and joint destruction. Patients and methods: This study included forty RA patients and twenty matched healthy controls. Disease activity score in 28 joints (DAS-28), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-CCP, tumor necrosis factor alpha (TNF-α), serum IL-17 and Th17 cells in peripheral blood were measured. Radiological assessment using modified Sharp/van der Heijde (mSvH) score for hand and feet in addition to MRI score for the wrist and metacarpophalangeal (MCP) joints were performed for detection of synovitis and bone erosion. Results: The patients were 38 females and 2 males with a mean of 41.15 ± 5.85 years and disease duration of 15.6 ± 4.62 years. Serum IL-17 and Th17 cells in peripheral blood were found to be significantly increased in RA patients (204.1 ± 33.8 pg/ml and 4.62 ± 1.13%) than in controls (25.36 ± 5.39 pg/ml and 0.7 ± 0.021%) (p < 0.001). Th17 cells significantly correlated with serum IL-17 (r 0.88, p < 0.001). Both Th17 cells and serum IL-17 significantly correlated with DAS-28, ESR, CRP, TNF-α, Van der Heijde modification score and MRI scores for wrist and MCP joints for synovitis and bone erosion (all with a p < 0.001). Conclusion: This study demonstrates an important role for Th-17 cells and serum IL-17 in the pathogenesis of the inflammatory and destructive pattern characteristic of RA.