[Activated C3 in the synovial fluid of patients with rheumatoid arthritis and arthrosis (correlations with C3, C4 and C3 proactivator/modification caused by storage)].

Cleavage products of C3 in synovial fluid were determined by the method of 2-dimensional electrophoresis (Laurell). Statistically significant differences were observed in rheumatoid synovial fluid compared with the osteoarthrosis group. Storage is of crucial importance for the in vitro activation of C3. In fresh synovial fluid there was a significant positive correlation between breakdown products of C3 and C3, C4 and C3-proactivator. After storage (even in -70 degrees C) this positive correlation in the rheumatoid synovial fluid changes into a negative one. This phenomenon is not observed in synovial fluid from patients with osteoarthrosis. There is evidence that in the rheumatoid synovial fluid C3-activating fractions in 40S, 19S and 2,5S are responsible for the generation of C3 cleavage products.