REVIEW article
Front. Immunol.
Sec. Cancer Immunity and Immunotherapy
This article is part of the Research TopicCommunity Series in Reducing Adverse Effects of Cancer Immunotherapy: Volume IIIView all 22 articles
Bronchoalveolar Lavage Fluid in Immune Checkpoint Inhibitor-Related Pneumonitis: From Pathophysiological Window to a Precision Diagnostic Tool
Provisionally accepted
- 1Army Medical University, Chongqing, China
- 2Chongqing University Cancer Hospital, Chongqing, China
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Immune checkpoint inhibitor related pneumonitis is a serious adverse reaction with diverse clinical and radiologic patterns, which make both diagnosis and treatment challenging. Therefore, understanding its underlying biology is crucial for improving clinical management. Bronchoalveolar lavage fluid provides a minimally invasive way to explore the lung immune environment, and it supports cytologic, molecular, and multi-omics analyses. In particular, BALF lymphocytosis serves as a key diagnostic sign. Furthermore, single-cell sequencing has revealed that abnormal T-cell activation and myeloid cell reprogramming play central roles in the development of CIP. These findings have, in turn, led to the identification of potential biomarkers such as CCL18, IL-6, and IP-10 for early detection and disease monitoring. However, the absence of standardized sampling and interpretation methods still limits the reproducibility of results and the broader application of BALF analysis in clinical practice. In the future, integrating BALF-derived data into artificial intelligence frameworks may enhance diagnostic precision and guide personalized therapy. Overall, BALF represents a valuable platform for refining CIP classification, clarifying disease mechanisms, and supporting the development of targeted treatments.
Keywords: BALF (Bronchoalveolar lavage fluid), biomarkers, CIP, ICIs - Immune check point inhibitors, Single cell sequence (scRNA-seq)
Received: 15 Jan 2026; Accepted: 02 Feb 2026.
Copyright: © 2026 Zheng, Yang, Qi, Lin, Chen and Sun. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Jianguo Sun
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