Correlation of synovial fluid HMGB-1 levels with radiographic severity of knee osteoarthritis

Purpose: This study measured high-mobility group box 1 (HMGB-1) levels in serum and synovial fluid (SF) in patients with primary knee osteoarthritis (OA) and correlated these levels with radiographic disease severity. Methods: Seventy-eight OA patients and 30 controls were enrolled in this study. All OA patients were scored according to the Kellgren-Lawrence (KL) grading system. HMGB-1 levels were measured by enzyme-linked immunosorbent assay (ELISA). Results: SF HMGB-1 levels were significantly higher in knee OA patients, compared with controls (P < 0.01). Moreover, SF HMGB-1 levels were positively associated with KL scores (P < 0.01). Multinomial logistic regression demonstrated that the SF HMGB-1 level was an independent factor for radiographic severity of OA (P = 0.002); however, serum HMGB-1 levels did not differ significantly between OA patients and controls and did not correlate with KL scores (P > 0.05). Conclusion: These results demonstrate that HMGB-1 levels in SF of knee OA patients are independently associated with radiographic disease severity.