IL-8 and airway neutrophilia in children with gastroesophageal reflux and asthma-like symptoms

Summary

Gastroesophageal reflux (GER) may induce respiratory symptoms (RS) through inhalation of acid gastric contents.

To characterize the airway inflammation associated with this condition, 20 children [7.4 (0.9) yr old] with “difficult to treat” RS and a positive 24-h oesophageal pH monitoring (pHm) were studied and bronchoalveolar lavage (BAL) performed. The control group included 10 children [7.3 (1.3) yr], non-atopics, with a respiratory clinical history similar to the cases but no reflux, as demonstrated by a negative 24-h oesophageal pHm.

On BAL samples, in addition to inflammatory indexes, the lipid-laden macrophage (LLM) index was determined as index of gastric content inhalation.

As compared to controls, GER children had higher neutrophil proportion ($P=0.002$), higher LLM index ($P=0.004$) and higher concentrations of interleukin (IL)-8 ($P=0.005$), myeloperoxidase (MPO) ($P=0.001$) and elastase ($P=0.045$) in BAL fluid. In GER children, but not in controls, neutrophil proportion significantly correlated with LLM index ($r=0.65$, $P=0.002$), with IL-8 ($r=0.62$, $P=0.003$) and MPO levels ($r=0.54$, $P=0.014$) but not with elastase concentrations. These results suggest an active pathogenetic role of IL-8 in the recruitment and activation of neutrophils in the airways of children with GER, respiratory symptoms and BAL findings suggestive of gastric content aspiration.