The action of aspirin on plasma kininogen and other plasma proteins in rheumatoid patients: relationship to disease activity.

Abstract

1. When six female seropositive rheumatoid patients were given placebo therapy for 48 h, their plasma kininogen level, 9.2 +/- 0.7 microgram bradykinin equivalents (bk eq) per ml, was found to be 59% greater than that of a group of eight healthy female volunteers (5.8 +/- 0.5 microgram/ml). 2. When the rheumatoid patients received aspirin therapy for 1 week, their mean plasma kininogen concentration fell by 31% to 6.3 +/- 0.8 microgram Bk eq/ml. This was accompanied by a 20.4% fall in mean plasma alpha 2-globulin level. Haematocrit and total plasma protein were not significantly altered (P > 0.05). 3. The fall in kininogen was very rapid, the main reduction occurring within the first hour. 4..