Lipid-laden macrophages in bronchoalveolar lavage fluid as a marker for pulmonary aspiration

An increased lipid content in alveolar macrophages of bronchoalveolar lavag e (BAL) fluid is thought to be a useful indicator for recurrent pulmonary a spiration. To assess whether pulmonary diseases unrelated to aspiration can raise the lipid content in alveolar macrophages, we evaluated Oil-Red-O-st ained smears of BAL fluid in 18 children aged 3-15 years undergoing electiv e surgery for nonpulmonary illnesses under general anesthesia and in 18 chi ldren aged 1-16 years who had pulmonary diseases without clinical evidence of aspiration (pneumonia, exogenous allergic alveolitis, or cystic fibrosis ). A semiquantitative lipid-laden macrophage (LLM) index was determined for each patient. LLM indices in children without pulmonary disease were higher than those pu blished for healthy adults. In children with pulmonary diseases but without evidence of aspiration, a significantly higher LLM index was observed comp ared to controls. The LLM indices of children with pulmonary diseases were similar to those published by other authors for children with pulmonary asp iration. We conclude that an elevated LLM index in alveolar macrophages of BAL can b e found in a variety of pulmonary diseases in which there is no clinical ev idence of aspiration and is therefore unlikely to be a specific parameter f or silent pulmonary aspiration. Pediatr Pulmonol, 1999;27: 419-422. (C) 199 9 Wiley-Liss, Inc.