# Linking Gastroesophageal Reflux Characteristics to Airway Inflammation: Insights from Bronchoalveolar Lavage Cytology in Severe Preschool Wheeze

## TL;DR

This study finds that gastroesophageal reflux in preschool children with wheezing is linked to airway inflammation, which can be detected using bronchoalveolar lavage and improved reflux monitoring.

## Contribution

The study introduces bronchoalveolar lavage lipid-laden macrophages as a potential marker for reflux-related microaspiration in preschool children with wheeze.

## Key findings

- Children with GERD had significantly higher lipid-laden macrophages in bronchoalveolar lavage samples.
- Antireflux therapy led to a substantial reduction in wheezing episodes.
- Weakly acidic and proximal reflux episodes were most strongly associated with airway inflammation.

## Abstract

Background: Gastroesophageal reflux disease (GERD) has been implicated in recurrent wheezing, but mechanisms and diagnostic markers remain debated. Multichannel intraluminal impedance-pH (MII-pH) monitoring improves reflux detection compared to pH-metry, while bronchoalveolar lavage (BAL) cytology may provide evidence of aspiration-related airway inflammation. Objectives: This study aims to examine the relationship between reflux characteristics, BAL cytology and clinical outcomes in preschool children with severe recurrent wheeze. Methods: Preschool-aged children undergoing combined MII-pH and bronchoscopy for severe recurrent wheeze were included. BAL samples were assessed for lipid-laden macrophages (LLM). Associations between reflux parameters, BAL cytology and response to antireflux treatment were analysed. Results: GERD was identified in 70% of participants, with weakly acidic and proximal reflux episodes predominating. Children with GERD exhibited significantly higher percentages of LLM compared with those without GERD (12% vs. 1%, p < 0.001). LLM percentage correlated with multiple reflux characteristics, including weakly acidic, liquid and proximal reflux (p < 0.047; p < 0.047 and p < 0.047, respectively), as well as symptom indices (p < 0.001). Following antireflux therapy, wheezing episodes were substantially reduced. Conclusions: GERD, particularly weakly acidic and proximal reflux, is associated with airway inflammation and recurrent wheeze in preschool children. BAL LLM percentage may serve as a surrogate marker of reflux-related microaspiration. MII-pH monitoring enhances diagnostic accuracy beyond pH-metry and may help guide targeted antireflux interventions.