T‐Cell Populations in Infancy After Maternal Probiotic Supplementation to Prevent Atopic Dermatitis

BACKGROUND: In the randomised, controlled study Probiotics in the Prevention of Allergy amongst Children in Trondheim (ProPACT), maternal probiotics given from 36 weeks pregnancy until 3 months post-delivery while breastfeeding reduced atopic dermatitis (AD) in the offspring. Previous analysis of T helper (Th) subsets indicated that the preventive effect may be partially mediated through reduced Th22 percentage at 3 months of age. OBJECTIVE: To examine the longitudinal effects of maternal probiotics on Th1, Th2, Th17, Th22, and regulatory T cells (Treg) in offspring at 10 days and 2 years of age compared to the previously published 3 months results. METHODS: Pregnant women (n = 415) were randomised to take probiotic milk (Lacticaseibacillus rhamnosus GG, Bifidobacterium animalis subsp. lactis Bb-12 and Lactobacillus acidophilus La-5) or placebo, and their offspring were assessed for AD at 2 years. We analysed the children's blood collected at 10 days (n = 112) and 2 years (n = 156) for Treg and Th subsets using flow cytometry and included the results from the previously analysed 3 months samples (n = 76) in the same study to compare the three timepoints using linear mixed models. RESULTS: There were no statistically significant differences between T cell populations of the children in the probiotics and placebo groups at 10 days and 2 years. CONCLUSION: We previously observed reduced Th22 percentage in the probiotics group at 3 months. However, since the effect was not seen earlier and did not last, it may not be the main reason for AD prevention.