Relationship between alpha 1-antitrypsin inactivation and tumor necrosis factor alpha concentration in the synovial fluid of patients with rheumatoid arthritis

To examine the relationship between alpha 1-antitrypsin (alpha 1AT) specific activity and tumor necrosis factor alpha (TNF alpha) concentration in synovial fluid from 48 patients with rheumatoid arthritis. The specific activity of alpha 1AT was calculated from the measurement of alpha 1AT concentration (by rocket immunoelectrophoresis) and elastase inhibitory capacity. TNF alpha was detected by enzyme-linked immunosorbent assay. TNF alpha concentrations correlated with the extent of alpha 1AT inactivation. Our findings are consistent with a role of elastase in TNF alpha release within the inflamed joint.