PT - JOURNAL ARTICLE AU - Bilal Malik AU - Rebecca Mckerrow AU - John Harrington AU - John W. Upham AU - Nathan Bartlett AU - Peter Ab Wark TI - ILC2 cells from severe allergic and eosinophilic asthma demonstrate increased expression of TSLP receptor (TSLPR) and enhanced proliferative capacity AID - 10.1183/13993003.congress-2021.PA823 DP - 2021 Sep 05 TA - European Respiratory Journal PG - PA823 VI - 58 IP - suppl 65 4099 - http://erj.ersjournals.com/content/58/suppl_65/PA823.short 4100 - http://erj.ersjournals.com/content/58/suppl_65/PA823.full SO - Eur Respir J2021 Sep 05; 58 AB - Background: It is evident that group 2 innate lymphoid cells (ILC2s) play an important role in asthma by promoting type 2 inflammation.Aims: To compare ILC2s proliferation and cytokine secretion between severe allergic and eosinophilic asthma (SA), mild asthma (MA), healthy controls (HC) and allergic controls without asthma (AC).Methods: HC and AC subjects had normal lung function and no history of asthma. MA subjects had GINA step 1 or 2 asthma. SA subjects had GINA step 5 severe eosinophilic and allergic asthma. All SA subjects were on high dose of inhaled corticosteroids median (Q1, Q3) 1440 (800, 2200) (mcg/d). Peripheral blood mononuclear cells (PBMCs) were obtained from HC n=10, AC n=10, MA n=10 and SA n=10. ILC2s were identified and sorted by flow cytometer, cultured for 14 days with IL-2, IL-33, IL-25 and TSLP. ILC2s proliferative capacity was assessed by Ki-67 expression, surface receptors and secretion of IL-5 and IL-13 by flow cytometer on day 14 of culture. Significance was calculated using 1-way ANOVA while correlation analysis was done using Pearson test.Results: At day 14 of culture, ILC2s from SA demonstrated increased TSLPR expression (p=<0.0001), Ki-67 expression (p=<0.0001) and cytokine release of IL-5 (p=<0.0001) and IL-13 (p=<0.0001) compared to ILC2s from HC, AC and MA. Increased TSLPR expression in SA positively correlated with Ki-67 expression (R2 = 0.75; p=<0.0001), IL-5 release (R2 = 0.63; p=<0.0001) and IL-13 release (R2 = 0.59; p=<0.0001).Conclusion: ILC2s from SA subjects demonstrate increased TSLPR expression that significantly correlated with increased proliferative capacity and secretion of IL-5 & IL-13FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA823.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).