Ultrastructure and function of alveolar macrophages from cystic fibrosis patients

Abstract

Alveolar macrophages were isolated from three cystic fibrosis patients, and the structure and function of these cells were compared to that of normal alveolar macrophages. The cystic fibrosis (CF) and normal alveolar macrophages were able to phagocytize Pseudomonas in the presence of normal serum, but cells from both sources had decreased phagocytosis of Pseudomonas in the presence of CF serum. Phagocytosis of Staphylococcus was not inhibited. Ultrastructural studies showed CF macrophages to be morphologically normal, however, in contrast to CF polymorphonuclear cells, they had not been heavily engaged in phagocytosis. The similarities between CF and normal macrophages suggest that the chronic pulmonary infection of CF may be due to an extrinsic factor in an altered lung environment rather than to any intrinsic cellular defect of the alveolar macrophage. Speculation: Functional and morphologic observations indicate that cystic fibrosis alveolar macrophages are not providing an adequate phagocytic defense against Pseudomonas. This defective phagocytosis does not appear to arise from an intrinsic problem with the macrophages, but rather appears to be due to extrinsic factors, i.e., an altered lung environment together with a substance(s) present in cystic fibrosis serum which selectively inhibit Pseudomonas phagocytosis. © 1980 International Pediatric Research Foundation, Inc.