Pulmonary hemorrhage in systemic lupus erythematosus.

Pulmonary hemorrhage is a rare and often fatal manifestation of systemic lupus erythematosus (SLE), and enters the differential diagnosis of diffuse lung disease in patients with SLE. Pulmonary hemorrhage results from deposit of immune complexes in the alveolar basement membrane, which in turn damages capillary endothelium. Similar immune-complex deposition is present in the glomerular basement membrane of patients with systemic lupus erythematosus and pulmonary hemorrhage.