BAL Fluid Cellular Analysis and Radiologic Patterns in Patients With Fibrotic Interstitial Lung Disease

Amanda Grant-Orser¹, Michael Asmussen², Daniel-Costin Marinescu³, Cameron J Hague⁴, Nestor L Muller⁴, Darra T Murphy⁵, Andrew Churg⁶, Joanne L Wright⁶, Amna Al-Arnawoot⁷, Ana-Maria Bilawich⁸, Patrick Bourgouin⁹, Gerard Cox¹⁰, Celine Durand¹¹, Tracy Elliot¹², Jennifer Ellis⁴, Jolene H Fisher¹³, Derek Fladeland¹⁴, Gillian C Goobie¹⁵, Zachary Guenther¹², Ehsan Haider⁷, Nathan Hambly¹⁰, James Huynh¹², Geoffrey Karjala¹⁴, Nasreen Khalil⁸, Martin Kolb¹⁰, Jonathon Leipsic⁴, Stacey Lok¹⁶, Sarah MacIsaac¹⁰, Micheal McInnis¹⁷, Helene Manganas¹⁸, Veronica Marcoux¹⁶, John Mayo⁴, Julie Morisset¹⁸, Ciaran Scallan¹⁰, Tony Sedlic⁴, Shane Shapera¹³, Kelly Sun¹³, Victoria Tan¹⁰, Alyson W Wong³, Boyang Zheng¹⁹, Christopher J Ryerson³, Kerri A Johannson²⁰

Affiliations

¹ Department of Medicine, University of Calgary, Calgary, AB, Canada; Snyder Institute for Chronic Disease, University of Calgary, Calgary, AB, Canada. Electronic address: amanda.grant-orser@ahs.ca.
² Department of Kinesiology, Vancouver Island University, Vancouver, BC, Canada.
³ Department of Medicine, University of British Columbia, Vancouver, BC, Canada; Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.
⁴ Department of Radiology, Vancouver General Hospital and University of British Columbia, Vancouver, BC, Canada.
⁵ Department of Radiology, St James' Hospital, Dublin, Ireland.
⁶ Department of Pathology, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.
⁷ Department of Radiology, McMaster University, St. Joseph's Healthcare, Hamilton, ON, Canada.
⁸ Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
⁹ Department of Radiology, Radiation Oncology and Nuclear Medicine, University of Montreal, QC, Canada.
¹⁰ Department of Medicine, McMaster University, Hamilton, ON, Canada.
¹¹ Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada.
¹² Department of Radiology, University of Calgary, AB, Canada.
¹³ Department of Medicine, University of Toronto, Toronto, ON, Canada.
¹⁴ Department of Medical Imaging, University of Saskatchewan, Saskatoon, SK, Canada.
¹⁵ Department of Medicine, University of British Columbia, Vancouver, BC, Canada; Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada; Department of Medicine, University of Pittsburgh, Pittsburgh, PA.
¹⁶ Department of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
¹⁷ Department of Medical Imaging, University of Toronto, Toronto, ON, Canada; University Medical Imaging Toronto, Toronto General Hospital, Toronto, ON, Canada.
¹⁸ Department of Medicine, Université de Montréal, Montreal, QC, Canada.
¹⁹ Division of Rheumatology, McGill University, Montreal, QC, Canada.
²⁰ Department of Medicine, University of Calgary, Calgary, AB, Canada; Snyder Institute for Chronic Disease, University of Calgary, Calgary, AB, Canada.

PMID: 39179174
PMCID: PMC11752126 (available on 2026-01-01)
DOI: 10.1016/j.chest.2024.07.166

BAL Fluid Cellular Analysis and Radiologic Patterns in Patients With Fibrotic Interstitial Lung Disease

Amanda Grant-Orser et al. Chest. 2025 Jan.

. 2025 Jan;167(1):172-182.

doi: 10.1016/j.chest.2024.07.166. Epub 2024 Aug 22.

Authors

Affiliations

¹ Department of Medicine, University of Calgary, Calgary, AB, Canada; Snyder Institute for Chronic Disease, University of Calgary, Calgary, AB, Canada. Electronic address: amanda.grant-orser@ahs.ca.
² Department of Kinesiology, Vancouver Island University, Vancouver, BC, Canada.
³ Department of Medicine, University of British Columbia, Vancouver, BC, Canada; Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.
⁴ Department of Radiology, Vancouver General Hospital and University of British Columbia, Vancouver, BC, Canada.
⁵ Department of Radiology, St James' Hospital, Dublin, Ireland.
⁶ Department of Pathology, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.
⁷ Department of Radiology, McMaster University, St. Joseph's Healthcare, Hamilton, ON, Canada.
⁸ Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
⁹ Department of Radiology, Radiation Oncology and Nuclear Medicine, University of Montreal, QC, Canada.
¹⁰ Department of Medicine, McMaster University, Hamilton, ON, Canada.
¹¹ Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada.
¹² Department of Radiology, University of Calgary, AB, Canada.
¹³ Department of Medicine, University of Toronto, Toronto, ON, Canada.
¹⁴ Department of Medical Imaging, University of Saskatchewan, Saskatoon, SK, Canada.
¹⁵ Department of Medicine, University of British Columbia, Vancouver, BC, Canada; Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada; Department of Medicine, University of Pittsburgh, Pittsburgh, PA.
¹⁶ Department of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
¹⁷ Department of Medical Imaging, University of Toronto, Toronto, ON, Canada; University Medical Imaging Toronto, Toronto General Hospital, Toronto, ON, Canada.
¹⁸ Department of Medicine, Université de Montréal, Montreal, QC, Canada.
¹⁹ Division of Rheumatology, McGill University, Montreal, QC, Canada.
²⁰ Department of Medicine, University of Calgary, Calgary, AB, Canada; Snyder Institute for Chronic Disease, University of Calgary, Calgary, AB, Canada.

PMID: 39179174
PMCID: PMC11752126 (available on 2026-01-01)
DOI: 10.1016/j.chest.2024.07.166

Abstract

Background: BAL cellular analysis is often recommended during the initial diagnostic evaluation of fibrotic interstitial lung disease (ILD). Despite recommendation for its use, between-center heterogeneity exists and supportive data concerning the clinical utility and correlation of BAL findings with radiologic features or patterns remain sparse.

Research question: In patients with fibrotic ILD, are BAL findings associated with radiologic features, patterns, and clinical diagnoses?

Study design and methods: Patients with fibrotic ILD who underwent BAL for diagnostic evaluation and who were enrolled in the prospective Canadian Registry for Pulmonary Fibrosis were re-reviewed in a standardized multidisciplinary discussion (MDD). BAL was categorized according to guideline-recommended thresholds, and using thresholds of lymphocytosis > 20% and neutrophils > 4.5%. High-resolution CT (HRCT) scans were scored (anonymized to clinical data) for specific features and percentage lung involvement. Radiologists classified HRCT scans according to guideline-defined patterns for idiopathic pulmonary fibrosis and fibrotic hypersensitivity pneumonitis; then, MDD diagnoses were assigned, considering all available data.

Results: Bronchoscopy with cellular analysis was performed in 209 of 1,593 patients (13%). Lymphocyte % was weakly negatively correlated with total fibrosis % (r = -0.16, P = .023) but not statistically significantly correlated with ground glass opacity % (r = 0.01, P = .94). A mixed BAL pattern was the most frequent in all radiologic patterns (range, 45%-69%), with a minority classifiable according to BAL guidelines. BAL lymphocytosis appeared with similar frequency across HRCT patterns of fibrotic hypersensitivity pneumonitis (21%) and usual interstitial pneumonia (18%). Only 5% of patients with MDD-based fibrotic hypersensitivity pneumonitis had a guideline-defined isolated lymphocytosis > 15%.

Interpretation: BAL cellular analyses did not significantly correlate with radiologic features, guideline patterns, or MDD-based diagnoses. Ground glass opacities are often interpreted to represent pulmonary inflammation, but were not associated with BAL lymphocytosis in this cohort.

Keywords: BAL; bronchoscopy; guidelines; interstitial lung disease; radiologic patterns.

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Conflict of interest statement

Financial/Nonfinancial Disclosures None declared.

References

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BAL Fluid Cellular Analysis and Radiologic Patterns in Patients With Fibrotic Interstitial Lung Disease

Affiliations

BAL Fluid Cellular Analysis and Radiologic Patterns in Patients With Fibrotic Interstitial Lung Disease

Authors

Affiliations

Abstract

Conflict of interest statement

References

MeSH terms

LinkOut - more resources

Full Text Sources

Medical