In Vitro H_2O_2 Production by Neutrophils and Macrophages in Bronchoalveolar Lavage Fluids from Patients with Interstitial Pneumonia

Abstract

This study was designed to clarify role of H_2O_2 released by neutrophils and macrophages in the pathogenesis of interstitial pneumonia in terms of idiopathic interstitial pneumonia (IIP) and rheumatoid arthritis interstitial pneumonia (RA-IP). To accomplish this, H_2O_2 production by neutrophils and macrophages in bronchoalveolar lavage fluid (BALF) were measured in 8 patients with IIP or RA-IP and compared to 6 normal controls and 7 patients with sarcoidosis. Both spontaneous and PMA-induced H_2O_2 production by neutrophils from patients with IIP and RA-IP was higher than that from normal controls and sarcoidosis. However, H_2O_2 production by macrophages was not significantly different between IIP, RA-IP, normal controls and sarcoidosis. These results surggested that in IP, macrophages and neutrophils produced H_2O_2, the most important source of H_2O_2, in the development of fibrosis, was neutrophils.