Immuno-reactive human epidermal growth factor (h-EGF) in rheumatoid synovial fluids

The immuno-reactive human epidermal growth factor (h-EGF) level, measured by a sensitive enzyme immunoassay, was significantly higher in synovial fluids or synovial tissue extracts from 89 patients with rheumatoid arthritis (RA) than in those from 53 patients with osteoarthritis. RA synovial immuno-reactive h-EGF was predominantly of a low molecular weight form (LMW h-EGF) on gel filtration chromatography. Furthermore, in the RA group, the synovial immuno-reactive h-EGF correlated positively with C-reactive protein, an acute-phase reactant, in the blood examination and with synovial immunoglobulin M. These results suggest that synovial h-EGF is specifically produced by RA synovium from the initial stage of arthritis, and that the measurement of synovial h-EGF serves as an early indicator to appraise the RA activity. A pathogenesis of RA including growth factors and growth inhibitory factors are discussed.