Detection of kallikrein-like activity in inflamed synovial tissue.

The synovial tissue kallikrein of rheumatoid patients, arthritic dogs and normal dogs has been partially characterized and estimated. Both human and dog synovial tissue kinin-forming enzyme appears to be distinct from plasmin, plasma kallikrein and pancreatic kallikrein. In three rheumatoid arthritic patients, the mean synovial tissue kallikrein level was found to be 106 +/- 13.5 ng bradykinin equivalents (BK Equiv) per g per min. In nine arthritic dogs the mean synovial tissue kallikrein level, 60.5 +/- 4.5 ng BK Equiv per g per min, was found to be greater (p less than 0.05) than that of five normal dogs (21.6 +/- 5.3 ng BK Equiv per g per min). The possible significance of this finding is discussed.