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Bronchoalveolar Lavage (BAL) for Research; Obtaining Adequate Sample Yield
Published on: March 24, 2014
Lipid-laden macrophages in bronchoalveolar lavage fluid as a marker for pulmonary aspiration
1Children's Hospital, University of Essen, Germany.
Abstract:
An increased lipid content in alveolar macrophages of bronchoalveolar lavage (BAL) fluid is thought to be a useful indicator for recurrent pulmonary aspiration. To assess whether pulmonary diseases unrelated to aspiration can raise the lipid content in alveolar macrophages, we evaluated Oil-Red-O-stained smears of BAL fluid in 18 children aged 3-15 years undergoing elective surgery for nonpulmonary illnesses under general anesthesia and in 18 children 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 published for healthy adults. In children with pulmonary diseases but without evidence of aspiration, a significantly higher LLM index was observed compared to controls. The LLM indices of children with pulmonary diseases were similar to those published by other authors for children with pulmonary aspiration. We conclude that an elevated LLM index in alveolar macrophages of BAL can be found in a variety of pulmonary diseases in which there is no clinical evidence of aspiration and is therefore unlikely to be a specific parameter for silent pulmonary aspiration.
Insights
Elevated lipid content in alveolar macrophages (LLM index) may not specifically indicate pulmonary aspiration. Various lung diseases can increase this indicator, suggesting it is not a definitive marker for silent aspiration.
Area of Science:
- Pulmonology
- Cell Biology
- Diagnostic Pathology
Background:
- Increased lipid content in alveolar macrophages from bronchoalveolar lavage (BAL) fluid is a potential indicator for recurrent pulmonary aspiration.
- The specificity of this finding for aspiration, particularly in pediatric populations, requires further investigation.
Purpose of the Study:
- To determine if pulmonary diseases unrelated to aspiration can elevate lipid content in alveolar macrophages.
- To assess the diagnostic utility of the lipid-laden macrophage (LLM) index in children with and without pulmonary disease.
Main Methods:
- Evaluated Oil-Red-O-stained BAL fluid smears from pediatric patients.
- Determined a semiquantitative lipid-laden macrophage (LLM) index.
- Compared LLM indices in children with pulmonary diseases (pneumonia, exogenous allergic alveolitis, cystic fibrosis) versus controls without pulmonary illness.
Main Results:
- LLM indices in children without pulmonary disease were higher than reported for healthy adults.
- Children with pulmonary diseases (without aspiration) showed significantly higher LLM indices compared to controls.
- LLM indices in children with pulmonary diseases were comparable to those previously reported for children with pulmonary aspiration.
Conclusions:
- An elevated LLM index in alveolar macrophages is not specific to pulmonary aspiration.
- Various pulmonary diseases can lead to increased LLM indices, challenging its role as a sole indicator for silent aspiration.
