Association of plasma and synovial fluid interferon-γ inducible protein-10 with radiographic severity in knee osteoarthritis.

OBJECTIVES

The objective of this study was to investigate interferon-γ inducible protein-10 (IP-10) concentrations in plasma and synovial fluid of patients with knee osteoarthritis (OA) and to analyze their relationship with disease severity.

DESIGN AND METHODS

Forty OA patients and 15 healthy controls were enrolled in this study. OA grading was performed according to the Kellgren-Lawrence criteria. IP-10 levels in plasma and synovial fluid were assessed using enzyme-linked immunosorbent assay.

RESULTS

Plasma IP-10 levels in the knee OA patients were significantly lower than those of controls (P=0.006). IP-10 levels in plasma were markedly higher with regard to paired synovial fluid (P<0.001). Furthermore, IP-10 concentrations in plasma and synovial fluid displayed significant inverse correlation with radiographic severity (r=-0.713, P<0.001 and r=-0.561, P<0.001, respectively). Subsequent analysis revealed that plasma IP-10 levels were positively correlated with synovial fluid IP-10 levels (r=0.424, P=0.006).

CONCLUSIONS

IP-10 levels in both plasma and synovial fluid were inversely associated with the severity of knee OA. Accordingly, IP-10 could serve as a biomarker for determining disease severity and might play a possible role in the pathophysiology of osteoarthritis.