Lipid-laden alveolar macrophage index in sputum is not useful in the differential diagnosis of pulmonary symptoms secondary to gastroesophageal reflux.

Background: Gastroesophageal reflux (GER) is frequently associated with pulmonary diseases. Esophageal acid-induced bronchoconstriction and recurrent microaspirations of gastric content are the proposed mechanisms. At present there is not a sensitive test available to prove a causal relationship between pulmonary symptoms and GER. In this study we aimed to investigate the value of a marker of aspiration: lipid-laden alveolar macrophage index (LLAM) in induced sputum, in the diagnosis of pulmonary symptoms highly suspected to be due to GER.
Methods: Twenty-two patients with the endoscopic diagnosis of erosive esophagitis who had various pulmonary symptoms that could not be attributed to any apparent etiology constituted the study group. Fifteen healthy volunteers with no prior diagnosis of gastroesophageal and lung disease constituted the control group. Subjects were questioned for pulmonary and abdominal symptoms and underwent physical examination, chest radiography, pulmonary function tests, and sputum induction. Prepared cytospins were stained with oil red-O to detect cytoplasmic lipid droplets and LLAM index was calculated.
Results: There was no statistically significant difference between the LLAM indexes of the study (1.9 +/- 3.3) and control group (4.2 +/- 4.5). LLAM index had a significant positive correlation with the duration of reflux symptoms (p=0.01, r=0.5).
Conclusions: LLAM index is not found to be a valuable method in the differential diagnosis of pulmonary symptoms suspected to be due to GER.