[Quantitative and qualitative changes in the fibronectin level in rheumatoid arthritis]

Blood plasma and synovial fluid (SF) of 48 patients with rheumatoid arthritis (RA) were studied. Plasma fibronectin (FN) concentration measured by rocket immunoelectrophoresis was found to be almost the same in patients and in healthy donors (348.6 +/- 16.4 micrograms/ml and 354.3 +/- 10.2 micrograms/ml, respectively. The level of SL FN was shown to rise in RA patients up to 1069.7 +/- 157.2 micrograms/ml, whereas in healthy persons and in posttraumatic synovitis it was equal to 420.0 +/- 112.6 micrograms/ml (p less than 0.05). Using cross-immunoelectrophoresis, the heterogeneity of synovial FN was revealed which was determined by complex formation with hyaluronic acid. It was found that both plasma and synovial fluid possessed higher gelatin-binding activity when compared with control samples as studied by the ability to agglutinate gelatinized particles. Direct correlation was shown between disease development rate and bioassayable plasma and synovial fibronectin.