Optimising the yield from bronchoalveolar lavage on human participants in infectious disease immunology research

Abstract

Bronchoalveolar lavage (BAL) is becoming a common procedure for research into infectious disease immunology. Little is known about the clinical factors which influence the main outcomes of the procedure. In research participants who underwent BAL according to guidelines, the BAL volume yield, and cell yield, concentration, viability, pellet colour and differential count were analysed for association with important participant characteristics such as active tuberculosis (TB) disease, TB exposure, HIV infection and recent SARS-CoV-2 infection. In 337 participants, BAL volume and BAL cell count were correlated in those with active TB disease, and current smokers. The right middle lobe yielded the highest volume. BAL cell and volume yields were lower in older participants, who also had more neutrophils. Current smokers yielded lower volumes and higher numbers of all cell types, and usually had a black pellet. Active TB disease was associated with higher cell yields, but this declined at the end of treatment. HIV infection was associated with more bloody pellets, and recent SARS-CoV-2 infection with a higher proportion of lymphocytes. These results allow researchers to optimise their participant and end assay selection for projects involving lung immune cells.

Unveiling the Diagnostic Potential: A Comprehensive Review of Bronchoalveolar Lavage in Interstitial Lung Disease

“…An optimal yield from BAL is considered to be greater than 30% of the instilled volume, translating to more than 70 ml from a 240 ml BAL. This emphasis on achieving an optimal cell yield is crucial for obtaining meaningful diagnostic information, ensuring that the procedure provides valuable insights into the underlying lung pathology [ 33 ].…”

“…These collaborative efforts contribute to refining the diagnostic accuracy and efficacy of BAL in the broader context of pulmonary medicine [ 32 ]. The continuous refinement and integration of BAL techniques with other diagnostic modalities exemplify a multifaceted approach aimed at improving the safety, efficiency, and diagnostic precision of the procedure, underscoring its evolving role in the diagnostic landscape [ 5 , 7 , 32 , 33 ].…”

A novel aerosol collection method shows the cough aeromicrobiome of people with tuberculosis is phylogenetically distinct from respiratory tract specimens

“…However, the sputum microbiota more closely resembles the upper respiratory tract (URT) than the lower respiratory tract (LRT) 9,10 , which is the primary site-of-disease in TB. Sampling the LRT is di cult because it requires bronchoscopy 11 , which is invasive, ethically complex for research purposes only, and expensive, often rendering which unfeasible in large cohorts where TB is prevalent 12 . Aerosols, which are more accessible, could be a useful proxy for studying the LRT, as aerosols partly originate from the LRT 13 .…”