Superoxide dismutases in polymorphonuclear leukocytes from patients with ankylosing spondylitis or rheumatoid arthritis.

The activity of cyanide-sensitive and cyanide-insensitive superoxide dismutase (CNs- and CNi-SOD) was measured in polymorphonuclear neutrophils isolated from the blood of patients with ankylosing spondylitis (A.S.) or adults with rheumatoid arthritis (R.A.). Our purpose was to detect alterations in the protecting activity of these enzymes that might cause rheumatic lesions secondary to superoxide anion generation in the inflammatory loci. There was no difference in total SOD activity (CNs + CNi) in either A.S. or R.A. when compared to the control group. In contrast, CNi-SOD activity decreased in R.A. and A.S. and CNs-SOD activity rose significantly in A.S. only. None of the changes observed in SOD activity correlated with patient's age, erythrocyte sedimentation rate, clinical evolution of the disease or the drug doses administered. It is concluded that the reduced activity of CNi-SOD might be partly responsible for the reduced protection of the joints against oxygen-free radicals in patients with A.S. or R.A. Other factors however appear to have greater effects on the clinical evolution of these diseases.