Abstract
Background: A subset of B cells that negatively regulates immune responses has been termed regulatory B cells (Breg), which can be characterized by IL-10 production. Breg cells are decreased and/or impaired in several inflammatory conditions.
Objectives: We determined IL-10 positive (IL-10+) Breg cell percentages in blood of Chronic Obstructive Pulmonary Disease (COPD) patients.
Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from never smokers, smokers without airflow limitation and patients with COPD. The percentage of IL-10+ Breg cells in PBMCs and cigarette-smoke extract (CSE) exposed magnetically sorted (MACS) B cells was determined by flowcytometry within the total B cell population and within specific B cell subsets. In addition, protein levels of IL-10 in cell culture supernatant were determined by ELISA.
Results: We observed a significantly lower percentage of IL-10+ Breg cells within memory B cells from smokers and patients with COPD, compared to never smokers. IL-10 protein levels were reduced in culture supernatant of smokers and COPD patients and correlated significantly with the total percentage of IL-10+ Breg cells. Furthermore, the addition of CSE significantly reduced the percentage and fluorescent intensity of IL-10+ B cells in a concentration-dependent manner.
Conclusion: We demonstrate decreased numbers of IL10+ memory Breg cells in blood of smokers and COPD patients ex vivo, and decreased percentages and impaired Breg function, upon CSE exposure in vitro. Further research is needed to elucidate whether Breg cell numbers are decreased and/or impaired in lung tissue of smokers or COPD patients in vivo and whether this contributes to COPD pathogenesis.
Footnotes
Cite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA833.
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).
- Copyright ©the authors 2021