[Catalase activity of synovial fluid leukocytes in rheumatoid arthritis]

Catalase activity of rheumatoid synovial fluid measured by a gasometry was higher than that of osteoarthritic fluids, suggesting a possible origin of the catalase activity from synovial fluid leukocytes. Isoelectric focusing polyacrylamide gel electrophoresis of the extract from polymorphonuclear leukocytes (PMN) of rheumatoid synovial fluid exhibited two to four achromatic bands and one dark band of catalase activity. Catalase staining of synovial fluid cells with diaminobenzidine revealed a marked activity in PMN, no or weak activity in monocytes and negative activity in lymphocytes. Catalase scores of the PMN in rheumatoid synovial fluid were lower than those of osteoarthritic fluid and of normal peripheral blood PMN. Ultrastructural localization of catalase activity in leukocytes of rheumatoid synovial fluid was examined by diaminobenzidine staining. Electron dense deposits were observed in granules, probably peroxisomes and in cytoplasm of the PMN and also in microperoxisomes of the monocyte.