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

## TL;DR

A study found that maternal probiotics during pregnancy and breastfeeding did not significantly affect T-cell populations in infants at 10 days or 2 years, suggesting the earlier observed Th22 reduction at 3 months may not be the main reason for preventing atopic dermatitis.

## Contribution

The study extends the analysis of maternal probiotics' effects on T-cell subsets in offspring to 2 years of age, revealing that the earlier Th22 reduction may not be a lasting mechanism for AD prevention.

## Key findings

- Maternal probiotics did not significantly alter T-cell populations in offspring at 10 days or 2 years of age.
- The previously observed reduction in Th22 cells at 3 months did not persist at later timepoints.
- The lack of consistent T-cell changes suggests Th22 reduction may not be the primary mechanism for AD prevention.

## Abstract

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.

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.

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.

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.

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.