Biochemical characterization of pulmonary washings of patients with alveolar proteinosis, interstitial pneumonitis and alveolar cell carcinoma.

Abstract

Biochemical compositions were studied of 15 pulmonary washings from 7 patients with alveolar proteinosis, and 2 washings from 2 patients with interstitial pneumonitis and 2 from 2 patients with alveolar cell carcinoma. The pulmonary washing was separated into the supernatant and precipitate fractions by a brief centrifugation. Analytical results revealed that the pulmonary washings from patients with alveolar proteinosis contained much more protein and lipids and a higher percentage of phospholipid than did the pulmonary washings from other patients. With regards to alveolar proteinosis, the precipitate fraction, i.e., water-insoluble material, contained lipids as the major component, the majority of which was dipalmitoyl phosphatidylcholine. Protein in the sedimental material was small in amount but was composed of proteins mainly of MW of 62,000, 36,000, 28,000 and 15,000 as measured by SDS[sodium dodecyl sulfate]-gel electrophoresis. The supernatant fraction, i.e., water-soluble material, was composed predominantly of serum proteins, with the lipid content being lower than those in the precipitate fraction. Apparently, material normally existing in the alveoli are excessively accumulated as alveolar-filling materials in alveolar proteinosis. There were marked differences in the lipid profiles between pulmonary washings from patients with alveolar proteinosis and those from patients with other diseases, indicating that the biochemical composition of pulmonary washings tends to reflect the nature of an underlying disease. The cause of the alveolar-filling materials in alveolar proteinosis was discussed.