# Bronchoalveolar Results in Young Children with Chronic Lung Symptoms: Lessons Learned from an Allergy–Pulmonology Project Guided by an Updated Mini Review of the Current Literature of Bronchoalveolar Lavage Eosinophilia and Neutrophilia in Normal Children

## TL;DR

This study updates normal bronchoalveolar lavage (BAL) cell counts in children and finds that elevated eosinophils and neutrophils are common in symptomatic children, suggesting asthma or protracted bronchitis.

## Contribution

The study provides an updated reference for BAL cellularity in normal children and highlights new insights into interpreting abnormal results in symptomatic cases.

## Key findings

- Eosinophils >1 were found in up to 25% of children with asthma-like symptoms and a similar percentage in non-asthma cases.
- Neutrophilia >50% and high bacterial colony counts were common in over 50% of children undergoing BAL.
- Lipid-laden macrophages were not specific to aspiration-related diagnoses.

## Abstract

What are the main findings of this study?
The background of BAL cellularity in normal children has not been updated for more than 25 years, which can serve as a reference point for comparing results in symptomatic childrenBronchoalveolar lavage (BAL) in young children is usually done under circumstances of complex pulmonary symptomatology and comparing their results with normal children can be revealing.

The background of BAL cellularity in normal children has not been updated for more than 25 years, which can serve as a reference point for comparing results in symptomatic children

Bronchoalveolar lavage (BAL) in young children is usually done under circumstances of complex pulmonary symptomatology and comparing their results with normal children can be revealing.

What are the implications of the main findings?
Eosinophilia is not expected in the lavage fluid of normal children, so its presence in a pulmonary symptomatic child should increase the likelihood of asthma considerationElevated lavage neutrophils are not a finding in normal children, and their presence, when a majority percent of the total cells that exist, should increase the consideration for protracted bronchitis.

Eosinophilia is not expected in the lavage fluid of normal children, so its presence in a pulmonary symptomatic child should increase the likelihood of asthma consideration

Elevated lavage neutrophils are not a finding in normal children, and their presence, when a majority percent of the total cells that exist, should increase the consideration for protracted bronchitis.

Background: Pediatric bronchoscopy and bronchoalveolar lavage (BAL) are valuable procedures, used by pediatric pulmonologists in a wide variety of clinical scenarios. Reports of indications for BAL include investigations of infectious processes, for unusual or poorly responsive pneumonia, and non-infections reasons, including interstitial lung disease and aspiration syndromes. BAL in pediatric asthma is occasionally done in severe and uncontrolled asthma, to rule out co-morbid conditions or to investigate asthma phenotypes. We report here the results of BAL in young children with global pre-BAL diagnoses, with comprehensive analysis of the BAL cellularity and culture results, and with a post hoc review by an allergist. The results of BAL in children with enigmatic pulmonary processes were compared to the expected BAL cellularity in normal children, obtained by an expanded historical mini review. Methods: The initial objective was to perform a mini review of the collective published data for normal/control children with BAL differential cell counts with the purpose of using the results to compare normals to the information obtained on the symptomatic children with BAL results from pulmonologists in our combined allergy–pulmonary division. The exploratory study group was children 0–6 years of age who underwent a BAL from 2000 to 2024 at an academic pulmonary-allergy division. The children had presumptive diagnoses requiring investigation, including the most common diagnoses of asthma, chronic cough, aspiration, or refractory bronchitis, and in this post hoc protocol only the diagnoses provided on the pre- and/or post-operative summary by the divisional pulmonologist(s) performing the BAL were used in the post hoc analysis. Secondarily, the operative day pre- and/or post-lavage diagnoses were used to divide the children into groups (based on operative day diagnoses) to stratify their lavage results, based on eosinophils, neutrophils, culture positivity and lipid-laden macrophages. Normative data collected from the literature was used as the historically expected results for the BAL group(s) analysis. Results: A mini review of BAL cellularity across 25+ years of literature was performed to establish normative data for our subsequent analysis. Both eosinophils and neutrophils are low or absent in normal children based on the comprehensive literature review. As a part of a larger cohort of 500 children ages 0–20 years, 317 children ages 0–6 were selected for review. The protocol was approved by the University Institutional Review Board. Using the mini review as reference, we found that eosinophil counts of one or more were recovered in over 20% of all children, regardless of bronchoscopy indication. Neutrophilia > 50% of cells and/or bacteria colony counts > 100,000 organisms were also frequent findings (>50 percent of the children). As a separate observation, lipid-laden macrophages did not isolate to aspiration indications for the bronchoscopy and lavage. Conclusions: An updated mini review of the cellularity expected in control children provided a context to the findings in our studied exploratory sample population. There was a high recovery of neutrophils coupled with culture positivity found across all children undergoing BAL. Eosinophils > 1 were present in up to 25% with a pre-lavage asthmatic symptom indication, but almost an equal percentage in other children with non-asthma-like conditions was surprising. Lipid-laden macrophage data was unhelpful.