T cells play a central role in host protection against respiratory pathogens, but maladaptive T cell responses can lead to pulmonary diseases. Defining the biology of protective versus pathogenic T cell responses in the lungs of humans will be critical to nominate novel approaches to improve respiratory health. Previous studies have examined T cells from the lungs captured via bronchoalveolar lavage (BAL), endobronchial brushings, or biopsies. However, whether these different approaches are capturing distinct T cell phenotypes and/or clonotypes remains unclear. We aimed to evaluate and compare the transcriptional signatures of T cells isolated via BAL versus endobronchial brushings in healthy controls (HCs) and allergic asthmatics (AAs). The most significant difference in T cell subsets abundance between AAs and HCs was the enrichment of CD4 T helper type 2 (Th2) cells when comparing endobronchial brush samples but not when examining BAL, indicating differences in the T cell subsets captured from the BAL versus airway mucosa specimen processing. TCR repertoire analysis revealed that the brush and BAL repertoires were largely distinct, with those expanded in the brush having a TRM phenotype. Data available through dbGaP include scRNAseq and TCRseq from CD3+ T cells of AA and HC endobronchial brushings.

Distinct Phenotypes and Repertoires of Bronchoalveolar and Airway Mucosal T Cells in Health and Allergic Asthma