TY - JOUR T1 - Normal values for bronchoalveolar lavage (BAL) differential cell count and lymphocyte subpopulations JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.congress-2021.PA684 VL - 58 IS - suppl 65 SP - PA684 AU - Daniel Soriano AU - Sebastian Fähndrich AU - Thomas Köhler AU - Wolfram Meschede AU - Joachim Müller-Quernheim AU - Gernot Zissel AU - Björn Christian Frye Y1 - 2021/09/05 UR - http://erj.ersjournals.com/content/58/suppl_65/PA684.abstract N2 - Bronchoalveolar lavage (BAL) cytology is frequently used in diagnostic work-up but normal values for differential cell count derive only from small cohorts.We analysed lymphocyte differentiation from BAL of 83 healthy individuals to establish normal values. Female and male (w:m=1:1,1), smokers and non-smokers (s:ns=1:3) in the age of 15-74 years were analysed. The role of smoking, age, gender, recovery and BAL volume was tested for correlation with BAL differential cell count and lymphocyte immunophenotyping employing CD3, CD4, CD8, and the CD4/CD8-ratio. Immunophenotyping for CD57, CD1a, CD25 and CD20 was available for 34 individuals.In the herein analyzed healthy cohort, immunophenotyping identified 55% of CD3+ lymphocytes as CD4+ (IQR 44,5-68,5), 29% as CD8+ (IQR 19.3-39.0%) and a CD4/CD8 ratio of 1.9 (IQR 1.2-3.3). 1% of cells were CD20+ (IQR 0-2), 9% were CD57+ (IQR 4-13) and 3% CD25 positive (IQR 2-5). CD1a was 1% (IQR 0-1). Smokers tend to have a lower CD4/CD8 ratio (Median=1,9, IQR 1,1-2,3) than non-smokers (Median=2, IQR 1,2-3,9, p=0,36). Age and gender did not influence immunophenotyping in our cohort, however we observed a higher CD4/CD8 obtained by BAL with higher volume (Median=2,95 IQR:1,9-4,8 for lavage volume >300 ml, Median=1,6, IQR:1,1-2,2 for lavage volume <=300 ml, p=0,0009).In summary, we provide normal values for differential cell count in one of the largest cohorts of healthy individuals. Smoking status and lavage volume may influence normal values. The next step is the investigation of their clinical usefulness.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA684.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only). ER -