[Ultrastructure of blood-air barrier in primary pulmonary hypertension].

The respiratory section of lung biopsies from patients with primary pulmonary hypertension (PPH) was studied by electron transmission microscopy. The alterations found allow to suggest the presence of apoptotic degeneration of cells of the capillary endothelium and lung epithelium, this being confirmed also by an alveolar macrophages increase. The role of apoptosis in the PPH pathogenesis is discussed.