Bronchoalveolar lavage cell differential count is associated with survival and radiological UIP pattern in familial pulmonary fibrosis

Our plain-English summary of Bronchoalveolar lavage cell differential count is associated with survival and radiological UIP pattern in familial pulmonary fibrosis, by H. Jaula, J. Leppänen, L. Mattila, et al (BMC Pulmonary Medicine, 2026).

The study

• Authors: H. Jaula, J. Leppänen, L. Mattila, L. Ahvenjärvi, E. Nurkkala, H. Lampela, E. Lappi-Blanco, H. Vähänikkilä, T. Harju, R. Kaarteenaho
• Journal: BMC Pulmonary Medicine
• Published: 2026;26(1):84
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

BACKGROUND: Bronchoalveolar lavage fluid (BAL) cell differential count analysis is a common diagnostic tool in interstitial lung diseases (ILD), but studies of the BAL cell profile in familial pulmonary fibrosis (FPF) are sparse. In this retrospective cohort study, we aimed to determine BAL cell profile in patients with FPF and to compare findings to those with idiopathic pulmonary fibrosis (IPF) or asbestosis. We also investigated BAL cell profile according to clinical features, radiological usual interstitial pneumonia (UIP) patterns, survival and additionally in the subgroups of the patients with pathogenic gene variants and histological investigations. METHODS: Data were collected from medical records between 1 January 2000 and 30 September 2024. The inclusion criterion was pulmonary fibrosis (PF) (ICD 10-code J84.X), with at least one self-reported relative with PF and BAL data available. High-resolution computer tomography (HRCT) scans and histology were re-evaluated. RESULTS: The BAL results of 49 FPF patients were compared with 72 IPF and 90 asbestosis cases. Differences in BAL cell profile were revealed between groups of FPF, IPF, and asbestosis. Furthermore, we found differences in BAL cell profile between smoking habits and radiological UIP patterns. The BAL results of the patients with pathogenic gene variants were variable. Moreover, BAL eosinophils associated with survival in FPF and familial IPF. CONCLUSIONS: As a novel finding, a high proportion of BAL eosinophils is associated with shortened survival of patients with FPF, thus emphasising the need to further investigate the role of eosinophils in the pathogenesis of FPF.

In plain English

This retrospective Finnish cohort study examined lung-washing fluid (bronchoalveolar lavage, BAL) cells from 49 patients with familial pulmonary fibrosis, identified from 2000 to 2024 records. These were compared with 72 patients with sporadic idiopathic pulmonary fibrosis (IPF) and 90 with asbestosis from earlier reports. The familial group had lower total cell counts than both comparison groups, more neutrophils than the asbestosis group, and fewer eosinophils and basophils than the IPF group. Familial patients with CT scans classed as usual or probable usual interstitial pneumonia had fewer macrophages and more lymphocytes than those with indeterminate or other-diagnosis scans. In the familial group, a higher absolute eosinophil number was associated with shorter survival (multivariate hazard ratio 1.2, 95% confidence interval 1.04 to 1.27). Patients with eosinophils of 2.0% or less had an estimated median survival of 139.3 months, versus 56.2 months for the rest (p = 0.017), with intervals printed as 36.2 to 242.4 and 35.3 to 772 months. The authors concluded that the role of eosinophils needs further investigation. They named the retrospective design and small numbers as limitations.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective cohort study based on medical records
• Who was studied: 49 patients with familial pulmonary fibrosis (FPF) who had BAL data available. FPF here means pulmonary fibrosis with at least one self-reported relative with pulmonary fibrosis. They came from a cohort of 68 identified from medical records between 1 January 2000 and 30 September 2024. They were compared with 72 patients with sporadic idiopathic pulmonary fibrosis (IPF) and 90 patients with asbestosis. The study was conducted under Finnish legislation and approved by a Finnish hospital-district ethics committee.
• Exposure: The study did not examine asbestos exposure, fiber types or doses. It compared bronchoalveolar lavage cell counts (macrophages, lymphocytes, neutrophils, eosinophils, basophils). Patients with asbestosis served only as a comparison group, and their characteristics were described in earlier publications.
• Main results:
  • Total BAL cell count was lower in the FPF group than in the IPF group (p = 0.043) and the asbestosis group (p = 0.025). Medians were 144, 186.0 and 192.0 ×10⁶/L respectively.
  • Compared with the asbestosis group, the FPF group had more neutrophils (p = 0.012). Compared with the IPF group, it had fewer eosinophils (p = 0.028) and fewer basophils (p = 0.038).
  • Within the FPF group, current smokers (n = 5) had a higher total cell count than non-smokers (n = 27): 268 ± 98.7 versus 146.8 ± 71.1 ×10⁶/L, p = 0.002. Smokers also had fewer lymphocytes: 3.3 ± 2.1% versus 16.5 ± 11.1%, p = 0.004.
  • FPF patients in the radiological UIP group were compared with the non-UIP group. The UIP group (n = 38) combined usual interstitial pneumonia and probable usual interstitial pneumonia. The non-UIP group (n = 11) combined scans indeterminate for UIP and alternative diagnosis. The UIP group had fewer macrophages (median 73.8% versus 85.0%, p = 0.021) and more lymphocytes (median 14.0% versus 6.0%, p = 0.013).
  • In the FPF group, estimated median survival was 76.1 months. A higher absolute eosinophil number was associated with survival: hazard ratio 1.1 (95% CI 1.01 to 1.21) in univariate analysis and 1.2 (95% CI 1.04 to 1.27) in multivariate analysis.
  • FPF patients with an eosinophil percentage of 2.0% or less had better survival than those above it (p = 0.017). Estimated median survival was 139.3 months versus 56.2 months. The intervals are printed as 36.2 to 242.4 and 35.3 to 772 months respectively.
  • In the familial IPF subgroup (estimated median survival 71.6 months), the absolute neutrophil and eosinophil numbers remained associated with survival in multivariate analysis. The hazard ratios were 1.2 (95% CI 1.05 to 1.36) for neutrophils and 1.2 (95% CI 1.07 to 1.36) for eosinophils. Survival was better with eosinophils of 2.0% or less: 78.6 versus 54.3 months, p = 0.040.
  • Familial IPF patients had fewer basophils than sporadic IPF patients (p = 0.031). There were no significant differences between FPF patients with pathogenic gene variants (n = 9) and those who tested negative (n = 9).
  • Estimated survival was better in GAP stage I (76.2 months) than GAP stage II (23.7 months, p = 0.008). No association was found between GAP stage and BAL cell counts.
• The authors' conclusion: The authors concluded that a high proportion of BAL eosinophils is associated with shortened survival in patients with familial pulmonary fibrosis. In their view, this calls for further investigation of the role of eosinophils in the disease.
• Limitations the authors state:
  • Retrospective design and small number of patients
  • Surgical lung biopsies and genetic testing were done in only about one-third of cases

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Bronchoalveolar Lavage (BAL), Pulmonary Fibrosis, Interstitial Lung Disease, Cohort Study, Idiopathic, Interstitial, High-Resolution CT (HRCT), Histology.

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• Clinical and radiological criteria for the differential diagnosis between asbestosis and idiopathic pulmonary fibrosis: Application in two cases — A. Stufano, A. Scardapane, et al. (2021)
• Radiological characteristics, histological features and clinical outcomes of lung cancer patients with coexistent idiopathic pulmonary fibrosis — K.A. Khan, M.P. Kennedy, et al. (2015)
• Bronchoalveolar lavage in pulmonary fibrosis: comparison of cells obtained with lung biopsy and clinical features — P.L. Haslam, C.W. Turton, et al. (1980)
• Influence of cigarette smoking on bronchoalveolar lavage cellularity in asbestos-induced lung disease — D.A. Schwartz, J.R. Galvin, et al. (1992)
• Bronchoalveolar lavage cell and lymphocyte phenotype profiles in healthy asbestos-exposed shipyard workers — J.M. Wallace, J.S. Oishi, et al. (1989)

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