Manganese-containing superoxide-dismutase deficiency in polymorphonuclear leukocytes of adults with rheumatoid arthritis.

Superoxide dismutase (SOD) is known to regulate the level of superoxide radicals inside cells. The purpose of this work was to investigate the role of SOD activity in tissue damage produced by superoxide radicals. SOD was measured in polymorphonuclear cells of patients with rheumatoid arthritis and controls. The distinct SOD activities, including manganese-containing and copper-zinc-containing enzymes, were evaluated in cytoplasma and mitochondria of human granulocytes. Except for the comparison between total SOD and cytoplasmic copper-zinc SOD, no correlation was found among the different SOD levels. Moreover, a significant decrease was observed only for cytoplasmic manganese-containing enzyme in granulocytes of adults with rheumatoid arthritis. These data confirm the necessity of evaluation of various SOD classes and suggest the interest of biochemical tests in granulocytes for early diagnosis and better comprehension of tissue damage due to inflammation.