Association between severity of knee osteoarthritis and serum and synovial fluid interleukin 17 concentrations

OBJECTIVE: To determine interleukin (IL)-17 concentrations in serum and synovial fluid from patients with knee osteoarthritis, and evaluate their correlation with disease severity. METHODS: Serum and synovial fluid were collected from patients with primary knee osteoarthritis; age- and sex-matched healthy control subjects provided serum samples. This study was conducted retrospectively. IL-17 was quantified by enzyme-linked immunosorbent assay. Osteoarthritis severity and grade were assessed using the Lequesne index and Kellgren and Lawrence (KL) grading system, respectively. RESULTS: Serum IL-17 concentrations were significantly higher in patients (n = 98) than in controls (n = 50). In the patient group, the synovial fluid IL-17 concentration increased significantly with KL grade and was significantly positively correlated with Lequesne index (r = 0.6232). CONCLUSIONS: The synovial fluid IL-17 concentration could represent a useful biochemical marker to reflect knee osteoarthritis severity and progression.