Raised Plasma Kininogen Levels in Rheumatoid Patients — Response to Therapy with Nonsteroidal Anti-Inflammatory Drugs

Abstract

In the aetiology of rheumatoid arthritis there is some evidence to implicate the formation of kinins in synovial fluid (Melmon, Webster, Goldfinger & Seegmiller, 1967; Keele & Eisen, 1970). The relationship between synovial kinin levels and clinical symptoms is, however, inconsistent (Keele & Eisen, 1970; Webster & Maling, 1970). In the systemic circulation no abnormalities in the kinin system have previously been described in this disease. We have recently reported some preliminary findings concerning changes in plasma kininogen levels in rheumatoid patients (Brooks, Dick, Sharma & Zeitlin, 1974; Zietlin, Sharma, Brooks & Dick, In Press). When patients with active rheumatoid arthritis received no treatment for 48 hours, their mean venous kininogen levels rose to more than twice the level found in eleven healthy volunteers or in five non-inflamed convalescent fracture patients. When the rheumatoid patients were put back on indomethacin therapy for one week, their mean plasma kininogen level fell to nearly half of the untreated value and lay within the healthy control range.