The role of microvascular injury in the evolution of idiopathic pulmonary fibrosis.

Interstitial lung disease compatible with idiopathic pulmonary fibrosis (IPF) developed in 19 previously healthy patients. Although interstitial and/or honeycomb parenchymal fibrosis was present in all, there were patchy areas of paucicellular septal capillary injury along with corroborative direct immunofluorescent evidence of a humorally mediated microvascular injury syndrome. Significantly elevated factor VIII levels were seen in 17 of 18 patients tested.

Direct and indirect immunofluorescence as a diagnostic adjunct in the interpretation of nonneoplastic medical lung disease.

Fresh open lung biopsy material from 57 patients was incubated with fluoresceinated complement and immunoglobulin antisera. An indirect immunofluorescent assay using neonatal lung as substrate was conducted as well. Direct immunofluorescent patterns could be categorized into interalveolar septal capillary deposition, large vessel wall localization, alveolar basement membrane localization, or a pauci-immune immunofluorescence pattern.