Bronchoalveolar lavage's role in diagnosis, management of interstitial lung disease (Review)

Is bronchoalveolar lavage useful in the diagnosis and management of interstitial lung disease? Meyer and Raghu believe so (although their manuscript title suggests they're not 100% sure). They explain why in the October ERJ. They argue that if interpreted in the right clinical context, certain bronchoalveolar lavage findings can help cinch the diagnosis of ILD:

• Lymphocytes >= 25%: granulomatous or lymphocytic disease likely present (sarcoidosis, BOOP/COP, lymphoproliferative disorder, drug reaction, cellular NSIP, hypersensitivity pneumonitis, chronic beryllium disease, or LIP)

• Eosinophils >=25%: eosinophilic pneumonia

• Neutrophils >=50%: infection, acute interstitial pneumonitis, diffuse alveolar damage, or acute exacerbation of idiopathic pulmonary fibrosis

• CD1a+ cells > 4% on flow cytometry: pulmonary Langerhans cell histocytosis

If there are >5% squamous cells, the sample may be contaminated by oral secretions (or the person aspirated some). If there are >5% bronchial epithelial cells, it may not be a true alveolar sample and may therefore be unsuitable. These authors argue against the routine use of flow cytometry in evaluating ILD; they feel the standard cited patterns (e.g. for CD4/CD8 ratio) are too insensitive and nonspecific to aid in diagnosis of sarcoidosis or HP. The joint ATS/ERS/JRS/ALAT 2011 expert statement on evaluation for possible IPF does not recommend routine BAL in that setting, instead recommending that BAL be considered on a case-by-case basis at expert centers that can perform accurate cell count & differentials and interpret the results.

Meyer KC, Raghu G. Bronchoalveolar lavage for the evaluation of interstitial lung disease: is it clinically useful? Eur Resp J 2011;38(4):761-769.