NADPH oxidase activity in the monocytes and neutrophils of patients with rheumatic fever.

The enzyme NADPH oxidase is involved in the production of oxygen free radicals. We measured its activity in neutrophils and monocytes obtained from patients with acute rheumatic fever, chronic rheumatic heart disease, acute streptococcal pharyngitis and normal controls. Follow up studies were made at 15 days, 3 months and 6 months. Streptococcal membrane antigen, carbohydrate antigens and latex were used to stimulate the oxidative activity in the neutrophils and monocytes. These three agents caused a significant increase in the enzyme activity of the phagocytes of patients with acute rheumatic fever and chronic rheumatic heart disease (p less than 0.001) but not in acute pharyngitis. Maximal NADPH oxidase enzyme activity was observed in patients with acute rheumatic fever. During the follow-up, there was a significant decline in the enzymatic activity in patients with acute rheumatic fever but not in those with chronic rheumatic heart disease. Enzymatic activity was greater when the phagocytic cells were triggered with membrane as compared to carbohydrate antigen and latex in all the groups and at all intervals. The enzymatic response of neutrophils and monocytes was similar although the magnitude of the NADPH oxidase activity was significantly higher in neutrophils than in monocytes.