IFN-γ inducible protein-10 (IP-10) concentrations in synovial fluid (SF). SF was obtained from patients with rheumatoid arthritis (RA; n = 32) or osteoarthritis (OA; n = 10). IP-10 in SF was assayed using enzyme-linked immunosorbent assay. Each point represents an individual patient. Data are expressed as the mean (ng/ml) ± SEM. *P < 0.01, versus OA SF.