Cellular sources of oxidants in the lung.

Reactive oxygen species (ROS) are important causative factors of many lung diseases, for instance pulmonary emphysema, adult respiratory distress syndrome (ARDS), lung fibrosis or rejection of transplanted lung. Moreover, recent data show that these molecules also play some physiological roles including signal transduction which regulates such important functions as cell growth and apoptosis. This review describes various cellular sources of ROS in the lung. Special attention was paid to neutrophils, eosinophils, alveolar macrophages and cells of alveolar epithelium. A possible contribution of ROS released by these cells to various lung diseases is discussed.