Role of oxygen free radicals generated by blood monocytes and neutrophils in the pathogenesis of rheumatic fever and rheumatic heart disease

The generation of oxygen free radicals by peripheral blood monocytes and neutrophils of patients with rheumatic fever and rheumatic heart disease has been studied using luminol enhanced chemiluminescence technique. Five groups of patients; acute rheumatic fever, recurrence of rheumatic activity, chronic rheumatic heart disease, acute pharyngitis and normal controls were studied. In all groups except the controls, measurements were made on 0, 15, 90 and 180 days. The chemiluminescence was measured in response to streptococcal membrane antigen, carbohydrate antigen and latex as triggering agents. Chemiluminescent response of monocytes, as well as, neutrophils was significantly higher (P < 0.01) in acute rheumatic fever and recurrence of rheumatic heart disease as compared to patients with acute pharyngitis and chronic rheumatic heart disease through the study period and with all the triggering agents. A significant decline (P < 0.001) in chemiluminescence was observed from day 0 to day 180 in the acute rheumatic fever, recurrence of rheumatic heart disease and pharyngitis patients while no such change, was observed in the chronic rheumatic heart disease group. This study raises the possibility that these phagocytic cells, which infiltrate the myocardium, may have a role in the pathogenesis of cardiac disease seen in patients with rheumatic heart disease, through the generation of oxygen free radicals.