Abstract
Background and Objective: The importance of extracellular traps (ETs) in chronic respiratory conditions is increasingly recognized but their role in paediatric bronchiectasis is poorly understood. The specialized techniques currently required to study ETs preclude routine clinical use. A simple and cost-effective ETs detection method is needed to support diagnostic applications. We aimed to determine whether ETs could be detected using light microscopy-based assessment of Romanowsky-stained bronchoalveolar lavage (BAL) slides from children with bronchiectasis, and whether the ETs cellular origin could be determined.
Methods: Archived Romanowsky-stained BAL slides from a cross-sectional study of children with bronchiectasis were examined for ETs using light microscopy. The cellular origin of individual ETs was determined based on morphology and physical contact with surrounding cell(s).
Results: ETs were observed in 78.7% (70/89) of BAL slides with neutrophil (NETs), macrophage (METs), eosinophil (EETs) and lymphocyte (LETs) ETs observed in 32.6%, 51.7%, 4.5% and 9%, respectively. ETs of indeterminate cellular origin were present in 59.6% of slides. Identifiable and indeterminate ETs were co-detected in 43.8% of slides.
Conclusion: BAL from children with bronchiectasis commonly contains multiple ET types that are detectable using Romanowsky-stained slides. While specialist techniques remain necessary to determining the cellular origin of all ETs, screening of Romanowsky-stained slides presents a cost-effective method that is well-suited to diagnostic settings. Our findings support further research to determine whether ETs can be used to define respiratory endotypes and to understand whether ETs-specific therapies may be required to resolve airway inflammation among children with bronchiectasis.
| Original language | English |
|---|---|
| Pages (from-to) | 1126-1135 |
| Number of pages | 10 |
| Journal | Respirology |
| Volume | 28 |
| Issue number | 12 |
| Early online date | 16 Aug 2023 |
| DOIs | |
| Publication status | Published - Dec 2023 |
Bibliographical note
Funding Information:We thank the participating children and their families. We thank the clinical and laboratory staff at Menzies School of Health Research, in particular, Lesley Versteegh for her contributions to participant recruitment, sample collection and processing. We also thank Heidi Smith-Vaughan, Kim Hare and the Child Health Division Laboratory Team for their contributions to sample processing and the bacterial culture work. We would also like to thank the staff of Royal Darwin Hospital for their critical support of our research. Research funding: This work was supported by a project grant from the Centre for Research Excellence in Respiratory Health for Aboriginal and Torres Strait Islander children (NHMRC GNT1040830). Robyn L. Marsh is supported by an Al and Val Rosenstrauss Fellowship from the Rebecca L Cooper Foundation. Amy S. Bleakley is supported by a Research Training Program scholarship from Charles Darwin University. Anne B. Chang is supported by a NHMRC Senior Practitioner Fellowship (APP1154302). Michael J. Binks and Steven Kho are supported by Menzies Future Leaders Fellowships. Open access publishing facilitated by Charles Darwin University, as part of the Wiley - Charles Darwin University agreement via the Council of Australian University Librarians.
Funding Information:
Our results are consistent with earlier studies describing NETs in sputum and BAL from patients with a range of respiratory conditions, including adults with bronchiectasis and children with cystic fibrosis or other causes of chronic cough. Results from our experiments with PBMCs and fresh BAL indicate that the high number of ETs‐positive specimens in our study is unlikely to be a specimen processing artefact. This interpretation is supported by the absence of ETs in 21% of the slides examined. Instead, our results support the findings of earlier studies suggesting ETs formation is an important component of the innate response to lower airway infection. Positive correlations between ETs absolute counts and markers of neutrophilic inflammation are consistent with the hypothesis that ETs contribute to airway inflammation among children with bronchiectasis; however, these observations require confirmation with leukocyte‐specific ETs tests. 16,21,34 8 10
Funding Information:
: This work was supported by a project grant from the Centre for Research Excellence in Respiratory Health for Aboriginal and Torres Strait Islander children (NHMRC GNT1040830). Robyn L. Marsh is supported by an Al and Val Rosenstrauss Fellowship from the Rebecca L Cooper Foundation. Amy S. Bleakley is supported by a Research Training Program scholarship from Charles Darwin University. Anne B. Chang is supported by a NHMRC Senior Practitioner Fellowship (APP1154302). Michael J. Binks and Steven Kho are supported by Menzies Future Leaders Fellowships. Open access publishing facilitated by Charles Darwin University, as part of the Wiley ‐ Charles Darwin University agreement via the Council of Australian University Librarians. Research funding
Publisher Copyright:
© 2023 The Authors. Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.