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

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. ]]>
Allergic Asthmatics (AA) Inclusion Criteria: 1. Baseline forced expiratory volume in 1 second (FEV1) determined at the initial visit no less than 75% of the predicted value after bronchodilator administration. 2. Clinical history of allergic symptoms to cat or dust mite allergen and demonstrated skin reactivity (a positive allergen skin prick test). 3. Positive methacholine challenge, defined as a provocative concentration inducing a 20% reduction in FEV1 (PC20) <16 mg/ml. 4. Life-long absence of cigarette smoking (defined as a lifetime total of less than 5 pack-years and none in 5 years). 5. Willing and able to give informed consent. 6. Expressed the desire to participate in an interview with the principal investigator. 7. Age between 18 and 50 years. Exclusion Criteria: 1. Women of childbearing potential who are documented to be pregnant (based on urine beta-HCG testing), are sexually active and not using contraception, are seeking to become pregnant, or who are breast feeding. 2. Spontaneous asthmatic episode or clinical evidence of upper respiratory tract infection within the previous 6 weeks. 3. Participation in a research study involving a drug or biologic during the 30 days prior to the study. 4. Intolerance to albuterol, atropine, lidocaine, fentanyl, or midazolam. 5. Antihistamines within 7 days of the screening visit. 6. Presence of diabetes mellitus, congestive heart failure, ventricular arrhythmias, history of a cerebrovascular accident, renal failure, history of anaphylaxis, or cirrhosis. 7. Use of systemic steroids, increased use of inhaled steroids, beta blockers or monoamine oxidase inhibitors within 6 weeks of the initial visit. 8. Antibiotic use for respiratory disease within 1 month of the initial visit or a respiratory tract infection within 6 weeks of the bronchoscopy visits. 9. A history of asthma-related respiratory failure requiring intubation. 10. Quantitative skin-prick test positive reaction down to an allergen concentration of 0.056 bioequivalent allergy units (BAU) or allergy units (AU)/ml. 11. Participants with a high possibility of poor compliance with the study. 12. Cigarette smoking within the past 5 years or > 5 pack years total. 13. Having second-hand cigarette smoke exposure or indoor furry pets except in the case of dog, if the subject is not allergic to the dog and the subject has a negative skin test to dog. 14. Other lung diseases, such as sarcoidosis, bronchiectasis, or active lung infection. 15. Use of targeted biological therapy for asthma or allergic disorders including but not limited to benralizumab, dupilumab, mepolizumab, omalizumab, or reslizumab currently or within the last year. 16. Immunotherapy with cat or dust mite extract now or in the past. 17. Non-English speakers. 18. History of coagulopathy, thrombocytopenia, pulmonary hypertension, and/or use of anti-coagulants/anti-platelet drugs.Healthy Controls (HC) Inclusion Criteria: 1. No history of allergy and negative allergen skin prick testing. 2. Baseline FEV1 and forced vital capacity (FVC) determined at the initial visit no less than 80% of the predicted value.3. Life-long absence of cigarette smoking (defined as a lifetime total of less than 5 pack-years and none in 5 years). 4. Willing and able to give informed consent.5. Expressed the desire to participate in an interview with the principal investigator.6. Age between 18 and 50 years.Exclusion Criteria: 1. A history of asthma.2. Women of childbearing potential who are documented to be pregnant (based on urine beta-HCG testing), are sexually active and not using contraception, are seeking to become pregnant, or who are breast feeding.3. Participation in a research study involving a drug or biologic during the 30 days prior to the study. 4. Intolerance to albuterol, atropine, lidocaine, fentanyl, or midazolam. 5. Antihistamines within 7 days of the screening visit. 6. Presence of diabetes mellitus, congestive heart failure, ventricular arrhythmias, history of a cerebrovascular accident, renal failure, history of anaphylaxis, or cirrhosis. 7. Use of systemic steroids, increased use of inhaled steroids, beta blockers or monoamine oxidase inhibitors within 6 weeks of the initial visit. 8. Antibiotic use for respiratory disease within 1 month of the initial visit or a respiratory tract infection within 6 weeks of the bronchoscopy visits. 9. Quantitative skin-prick test positive reaction down to an allergen concentration of 0.056 bioequivalent allergy units (BAU) or allergy units (AU)/ml. 10. Participants with a high possibility of poor compliance with the study. 11. Cigarette smoking within the past 5 years or > 5 pack years total. 12. Having second-hand cigarette smoke exposure or indoor furry pets except in the case of dog, if the subject is not allergic to the dog and the subject has a negative skin test to dog. 13. Other lung diseases, such as sarcoidosis, bronchiectasis, or active lung infection. 14. Use of targeted biological therapy for asthma or allergic disorders including but not limited to benralizumab, dupilumab, mepolizumab, omalizumab, or reslizumab currently or within the last year. 15. Immunotherapy with cat or dust mite extract now or in the past. 16. Non-English speakers. 17. History of coagulopathy, thrombocytopenia, pulmonary hypertension, and/or use of anti-coagulants/anti-platelet drugs. ]]>