Leucocyte superoxide dismutase in rheumatoid arthritis.

Superoxide dismutase (SOD) activity was measured in polymorphonuclear leucocytes (PMNLs) and mononuclear cells (MNCs) from 60 patients with rheumatoid arthritis (RA) and in 15 controls. In all patients and controls SOD activity (U/mg protein) in MNCs was twice that in PMNLs. SOD activity in PMNLs and in MNCs from patients with RA was significantly higher than that in controls. SOD activity in PMNLs (but not in MNCs) from patients treated with corticosteroids was significantly higher than that from patients treated with nonsteroidal anti-inflammatory drugs. There was no relation between SOD activity in both PMNLs and MNCs and either the patients' age, sex, duration of disease, serum immunoglobulin concentration, IgM rheumatoid factor, and copper level, or the degree of disease activity.