Background: In children with gastroesophageal reflux (GER) both acid refluxes (AR) and weakly acidic refluxes (WAR) can induce respiratory symptoms (RS).
Methods: To characterize the airway inflammation in children with more prevalent WAR or AR (defined according a ROC curve analysis), we performed a 3 year-retrospective review of the medical records of patients who underwent fiberoptic bronchoscopy for difficult-to-treat chronic/recurrent respiratory symptoms and who had a positive multiple intraluminal esophageal impedance (pH/MII) monitoring.
Results: In the 13 WAR and 11 AR children, the number of cells recovered by bronchoalveolar lavage (BAL) was similar [0.78 (0.29-1.28) x 106 cells, and 1.05 (0.68-1.64) x 106 cells, respectively] (P = 0.22). A neutrophilic alveolitis and an elevated lipid-laden-macrophage (LLM) index were detected in both groups: no differences were found in neutrophils and lymphocyte percentages or in LLM index between WAR and AR children. In contrast, higher BAL epithelial cell proportions were seen in WAR [10.4 (4.85-23.45) %], as compared to AR [2.5 (1.25-7.25) %] children (P = 0.0045), suggesting greater airway damage in the formers. In the whole patient population a significant correlation was found between the proportions of BAL epithelial cells and the number of WAR events (r = 0.43; P = 0.037). Finally, elevated BAL concentrations of substance P and of pepsin were observed, not statistically different in the WAR and AR groups.
Conclusions: In this patient population, WAR events can be associated with a significant airway inflammation and injury that, because of the biochemical mechanisms involved, are likely not completely preventable and/or counteracted by anti-acid treatments.
Keywords: Bronchoalveolar lavage; Epithelial cells; Lipid laden macrophages; Pepsin; Substance P.
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