Bronchoalveolar neutrophilia inversely correlates with DLCO at diagnosis in asbestosis but not lung function decline at 1 year

Our plain-English summary of Bronchoalveolar neutrophilia inversely correlates with DLCO at diagnosis in asbestosis but not lung function decline at 1 year, by G. Walters, S. Agarwal, K. Singh, et al (Journal of Thoracic Disease, 2013).

The study

• Authors: G. Walters, S. Agarwal, K. Singh, P.S. Burge, E.E. McGrath
• Journal: Journal of Thoracic Disease
• Published: 2013;5(3):314-6
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The role of bronchoalveolar lavage (BAL) in the assessment of interstitial lung disease (ILD) remains controversial. Previous studies have demonstrated that BAL cell differential is useful in predicting disease progression in many forms of ILD. We wished to investigate whether BAL had a similar use in predicting disease progression in asbestosis. 21 patients who had significant asbestos exposure, findings of UIP radiologically and BAL performed as part of their investigation were reviewed. There was a significant inverse correlation between percentage BAL neutrophils and percentage predicted DLCO at diagnosis (n=21; P=0.02; r(2)=(-)0.25; CI, (-)0.77(-)0.08), but not with DLCO decline over 1 year. Unlike previous reports in IPF, BAL cell differential is not predictive of decline in classic asbestosis with a UIP pattern and its routine use in this cohort of patients provides little if any additional benefit.

In plain English

This brief report was a retrospective review of patients diagnosed with asbestosis showing a UIP pattern (a type of lung scarring seen on scans) at an occupational lung disease unit in Birmingham, UK, between June 2000 and March 2012. The authors reviewed 43 patients, all male, with a mean age of 74.5 and significant asbestos exposure from various occupations. Of these, 21 had bronchoalveolar lavage (BAL), a procedure that washes part of the lung with fluid and counts the cells recovered. Seventeen of the 21 had raised neutrophils, a type of white blood cell. Higher BAL neutrophil percentages were significantly associated with lower DLCO at diagnosis (n=21; P=0.02). DLCO is a measure of how well the lungs pass gas into the blood. Neutrophils were not associated with DLCO decline over one year. Lymphocytes and eosinophils showed no association with lung function. The authors concluded that, unlike in idiopathic pulmonary fibrosis, BAL neutrophilia did not predict decline in this form of asbestosis, and that routine BAL offered little if any additional benefit. They noted the study was small, retrospective and clinic-based, and so subject to selection bias.

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 review of clinic patients (brief report)
• Who was studied: 43 patients diagnosed with asbestosis with a UIP pattern at the Birmingham Chest Clinic Occupational Lung Disease Unit, UK, between June 2000 and March 2012. All were male, mean age 74.5 (SD 7). 21 of them had BAL at presentation, and 21 had lung function data for at least one year after diagnosis.
• Exposure: Significant asbestos exposure from various occupations, with a mean exposure of 16.3 years (SD 10). Fiber types were not specified.
• Main results:
  • Among all 43 patients, mean percentage predicted values at diagnosis were FEV1 82.5% (SD 19), FVC 84.5% (SD 18) and DLCO 52% (SD 15).
  • Among the 21 patients with at least one year of follow-up lung function data, mean annual decline in percentage predicted values in the first year was FEV1 1.4% (SD 7), FVC 2.1% (SD 7) and DLCO 4.2% (SD 8).
  • Of the 21 patients who had BAL, 3 had normal differential cell counts and 17 had raised neutrophil differentials (range 6-80%). The median neutrophil count was 14% (IQR 7-28).
  • In the 21 patients with BAL, there was a significant inverse correlation between percentage BAL neutrophils and percentage predicted DLCO at diagnosis (P=0.02), but not with DLCO decline over 1 year.
  • BAL lymphocytes and eosinophils were not associated with lung function at diagnosis or with its decline over 12 months.
  • Of the 43 patients, 39 (91%) had benign asbestos pleural disease on radiological examination.
  • Of the 43 patients, 13 had died since diagnosis: 5 from ischaemic heart disease, 3 from unknown causes, 2 from community acquired pneumonia, 2 from squamous cell lung cancer and 1 from gastric adenocarcinoma.
• The authors' conclusion: The authors concluded that, unlike in IPF, BAL neutrophilia is not predictive of decline in classic asbestosis with a UIP pattern, and that its routine use in this cohort provides little if any additional benefit.
• Limitations the authors state:
  • The study was small, retrospective and clinic-based, and therefore subject to selection bias.
  • The sample included no cases of asymptomatic asbestosis with significant CT findings.
  • Only three cases had biopsy-proven UIP; the other cases were defined radiologically.
  • The study covered only asbestosis with a UIP pattern, not asbestosis with other interstitial radiology findings that are often features of early asbestosis.
  • Asbestos bodies, a marker of asbestos exposure, were not quantified.

Topics

Medical terms in this study, explained in our Lexicon: Diffusing Capacity (DLCO), Bronchoalveolar Lavage (BAL), Interstitial Lung Disease, Disease Progression, Asbestos Exposure.

Related studies

• Bronchoalveolar cell differential count and the number of asbestos bodies correlate with survival in patients with asbestosis — E. Keskitalo, L. Varis, et al. (2019)
• The natural course of lung function decline in asbestos exposed subjects with pleural plaques and asbestosis — M. Barnikel, P.M. Million, et al. (2019)
• Assessment of progression of asbestosis in the sheep model by bronchoalveolar lavage and pulmonary function tests — R. Bégin, M. Rola-Pleszczynski, et al. (1983)
• Mineralogical analysis of bronchoalveolar lavage fluid as an aid to diagnosis of "imported" pleural asbestosis — P. De Vuyst, M. Mairesse, et al. (1983)
• Asbestosis occurring after brief inhalational exposure: usefulness of bronchoalveolar lavage in diagnosis — R.G. Barbers, J.L. Abraham (1989)
• Decline in annual lung function in workers exposed to asbestos with and without pre-existing fibrotic changes on chest radiography — T. Nakadate (1995)

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