Inflammatory and immunologic analysis of bronchoalveolar lavage from patients with post-COVID-19 lung disease
5 affiliations
- 1Department of Medicine, Indiana University
- 2Department of Microbiology and Immunology, Indiana University
- 3Translational Genomics Research Institute
- 4Department of Radiology, Indiana University
- 5Department of Biostatistics and Health Data Science, Indiana University
Abstract
Rationale: Infection with SARS-CoV-2 frequently leads to persistent pulmonary symptoms and radiographic abnormalities, of which several clinical phenotypes have been described. The etiology and inflammatory milieu of these processes is unknown.
Objectives: To study the alveolar milieu in subjects with suspected post-COVID-19 lung disease up to 2 years after acute infection.
Methods: Clinical bronchoalveolar lavage (BAL) samples were processed for analysis of cell differential, presence of spike protein, and SARS-CoV-2 antibody responses. Findings were linked to chest CT findings and clinical outcome.
Results: Clinical BAL fluid samples from patients with suspected post-COVID-19 lung disease can be separated into three inflammatory phenotypes: a lymphocytic predominant pattern, a neutrophilic predominant pattern, and a normal cellular differential. Spike protein is found in BAL many subjects at the time of study. Robust antibody responses to SARS-CoV-2 are seen in many subjects. No clear association was observed between chest CT scan patterns and the type of inflammatory milieu in the lung. BAL inflammatory pattern was unable to predict long term outcome, though early bad outcomes were not seen in subjects with a normal BAL differential.
Conclusion: Suspected post-COVID-19 lung disease exists in several forms, each with characteristic inflammatory milieus. Persistent viral protein may contribute to these responses. These findings highlight the potential difficulty of performing studies of post-COVID-19 lung disease predicated solely on clinical presentation due to patient variability.
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BibTeX
@article{twigg2026inflammatory,
title = {{Inflammatory and immunologic analysis of bronchoalveolar lavage from patients with post-COVID-19 lung disease}},
author = {Homer L. Twigg and Rachel Wilson and Andy Q. Yu and Wei Li and John A. Altin and Robert D. Tarver and Isabel Knight and Patricia A. Smith and Mark E. Fraser and Peter Castelluccio and Jen Rie},
journal = {Frontiers in Microbiology},
year = {2026},
month = oct,
doi = {10.3389/fmicb.2026.1923299},
url = {https://www.frontiersin.org/articles/10.3389/fmicb.2026.1923299/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Inflammatory and immunologic analysis of bronchoalveolar lavage from patients with post-COVID-19 lung disease
AU - Homer L. Twigg
AU - Rachel Wilson
AU - Andy Q. Yu
AU - Wei Li
AU - John A. Altin
AU - Robert D. Tarver
AU - Isabel Knight
AU - Patricia A. Smith
AU - Mark E. Fraser
AU - Peter Castelluccio
AU - Jen Rie
PY - 2026
DA - 2026/10/19
JO - Frontiers in Microbiology
DO - 10.3389/fmicb.2026.1923299
UR - https://www.frontiersin.org/articles/10.3389/fmicb.2026.1923299/full
AB - Rationale: Infection with SARS-CoV-2 frequently leads to persistent pulmonary symptoms and radiographic abnormalities, of which several clinical phenotypes have been described. The etiology and inflammatory milieu of these processes is unknown. Objectives: To study the alveolar milieu in subjects with suspected post-COVID-19 lung disease up to 2 years after acute infection. Methods: Clinical bronchoalveolar lavage (BAL) samples were processed for analysis of cell differential, presence of spike protein, and SARS-CoV-2 antibody responses. Findings were linked to chest CT findings and clinical outcome. Results: Clinical BAL fluid samples from patients with suspected post-COVID-19 lung disease can be separated into three inflammatory phenotypes: a lymphocytic predominant pattern, a neutrophilic predominant pattern, and a normal cellular differential. Spike protein is found in BAL many subjects at the time of study. Robust antibody responses to SARS-CoV-2 are seen in many subjects. No clear association was observed between chest CT scan patterns and the type of inflammatory milieu in the lung. BAL inflammatory pattern was unable to predict long term outcome, though early bad outcomes were not seen in subjects with a normal BAL differential. Conclusion: Suspected post-COVID-19 lung disease exists in several forms, each with characteristic inflammatory milieus. Persistent viral protein may contribute to these responses. These findings highlight the potential difficulty of performing studies of post-COVID-19 lung disease predicated solely on clinical presentation due to patient variability.
SN - 1664-302X
ER -