Cord blood eosinophils and Type 2 Innate lymphoid cells are correlated in infants born to mothers with asthma during pregnancy

Introduction: Maternal asthma has been linked to detectable alterations in cord blood immune cell populations. Innate lymphoid cells (ILCs) have been implicated in the development of allergic diseases. ILC subsets have potential roles in the early development of asthma but this remains poorly understood. Aim: To evaluate the cord blood immunophenotype in infants born to mothers with asthma during pregnancy taking part in the Breathing for Life Trial (BLT). Methods: Cord blood from 32 BLT participants was collected into EDTA tubes and processed within 6 hours of birth. Cells were stained in whole cord blood: Eosinophils (CD45+CD16-CD193+), ILC1(Lin–CD127+CD161+CD117–CD294–), ILC2(Lin–CD127+CD161+CD294+), ILC3 natural cytotoxic receptor (NCR)– (Lin–CD127+CD161+CD294–CD117+NKp44–), ILC3 NCR+ (Lin– CD127+CD161+CD294–CD117+NKp44+). After being fixed, cells were acquired on a BD LSRFortessa X-20 flow cytometer and analysed using FlowJo software. Tidal breathing flow-volume loop (TBFVL) measurements during quiet sleep were performed in infants at 6 weeks of age. Results: This preliminary analysis has shown correlations between ILC1 and ILC2 (n=32) and ILC3s NCR- (r=0.64-0.68). Eosinophils correlated with ILC2 (r=0.40) and were inversely correlated with lung function (tPTEF/tE%) at 6 weeks (r=−0.58, n=13). Conclusion: The study of ILC subtypes in cord blood is feasible and ILC1, ILC2 and ILC3 NCR+ numbers in cord blood show strong correlations. The correlation between ILC2s and eosinophils in cord blood and the potential association with lung function at 6 weeks of age warrants further investigation in this ongoing study.