Pulmonary corpora amylacea contain surfactant apoprotein

The case of a 53-year-old female with interstitial pneumonitis is described with special regard to biochemical characterization of pulmonary corpora amylacea which were found in the lung specimen obtained by bronchial biopsy from the patient. The main protein component in bronchoalveolar lavage (BAL) fluid of the patient was albumin, but proteins in the precipitate fraction of BAL fluid, where the corpora amylacea were recovered, predominantly consisted of 36 kD protein which was stained with the monoclonal antibody PE 10 to human pulmonary surfactant apoprotein by immunoblot. Histologically the pulmonary corpora amylacea were stained with eosin and PAS. The particles were stained immunohistochemically by immunoperoxidase reaction using PE 10, but not by antibodies to human albumin. The pulmonary surfactant apoprotein seems, therefore, to be not simply adsorbed in the particles, but to be contained in them. Thus, the surfactant apoprotein may, at least in this case, be involved in the formation of pulmonary corpora amylacea.