Evidence map›Paper›PMID 42846042›Full record

SynthesisFrontiers in medicine2026

Bronchoalveolar lavage lymphocyte patterns in hypersensitivity pneumonitis and nonspecific interstitial pneumonia: a systematic review.

Hatice Elmas, Lutz Welker

Abstract readSystematic Review
In one paragraph

Synthesis in Frontiers in medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

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2 · The registry

The trial behind it

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3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

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4 · The record

Corrections and comments

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5 · Who and what money

Authors and funding

2 authors.

Hatice ElmasSection Cytopathology, Institute of Pathology, University Medical Center Hamburg-Eppendorf UKE, Hamburg, Germany.
Lutz WelkerSection Cytopathology, Institute of Pathology, University Medical Center Hamburg-Eppendorf UKE, Hamburg, Germany.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Background: Bronchoalveolar lavage (BAL) is an important adjunctive tool in the multidisciplinary evaluation of interstitial lung diseases (ILDs), particularly hypersensitivity pneumonitis (HP) and nonspecific interstitial pneumonia (NSIP). However, considerable overlap in BAL cellular profiles and inconsistent lymphocyte thresholds limit its independent diagnostic value. This systematic review summarizes current evidence regarding the diagnostic and prognostic utility of BAL cellular analysis in differentiating HP from NSIP. Methods: A systematic literature search of PubMed/MEDLINE, Embase, CENTRAL identified studies evaluating BAL cellular, immunophenotypic, and biomarker findings in HP and NSIP. Study selection followed PRISMA recommendations. Owing to methodological heterogeneity, the evidence was synthesized narratively. Results: Twenty-one studies met the inclusion criteria. BAL lymphocytosis consistently supported the diagnosis of HP, particularly at thresholds above 30%, although higher cut-offs improved specificity at the expense of sensitivity. Considerable overlap between HP and NSIP was observed, especially in fibrotic disease, limiting the diagnostic performance of isolated lymphocyte percentages. Emerging BAL biomarkers, including CD4/CD8 ratio, NK/NKT-cell subsets, IL-9 signaling, KL-6, and flow cytometric immunophenotyping, showed potential to improve differential diagnosis. In addition, higher BAL lymphocyte counts were associated with favorable treatment response and improved prognosis in selected HP and NSIP populations. Conclusion: BAL cellular analysis remains a valuable complementary diagnostic tool rather than a standalone test for distinguishing HP from NSIP. Accurate interpretation requires integration with exposure history, high-resolution computed tomography, histopathology when available, and multidisciplinary discussion. Standardized BAL protocols and prospective validation of advanced immunophenotypic biomarkers are needed to improve diagnostic precision and clinical decision-making in fibrotic ILDs. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261397405, identifier PROSPERO (CRD420261397405).

Indexed as

BAL (bronchoalveolar lavage)diagnostic accuracyILDnonspecific interstitial pneumoniaNSIPpneumological disease

Identifiers

PMID42846042
PMCPMC13642831

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.