Airway inflammation and injury in children with prevalent weakly acidic gastroesophageal refluxes.

Abstract

In children with gastroesophageal reflux (GER) both acid refluxes (AR) and weakly acidic refluxes (WAR) can induce respiratory symptoms (RS). 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. 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. 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.