Kallikreins and kininogens in saliva and plasma of patients presenting with rheumatoid arthritis.

We evaluated the activities of salivary kallikrein and tissue/plasma kallikreins, and the plasma levels of high-molecular (HKg) and low-molecular (LKg) weight kininogens in patients with rheumatoid arthritis. The patients exhibited higher levels of the active salivary kallikrein compared to the controls. In contrast, the total salivary kallikrein activity of patients was not different from controls. In plasma from the patients, tissue kallikrein activity or plasma prekallikrein activity was not significantly different from the controls. Plasma HKg levels observed in patients were higher than in controls, whereas plasma LKg levels did not differ significantly from controls. Our results showed that most of the salivary kallikrein seen in patients is in its active form, suggesting the presence of systemic or local factors with the ability to activate salivary pro-kallikrein.