Impaired function of regulatory T cells in cord blood of children of allergic mothers

Allergy is one of the most common diseases with constantly increasing incidence. The identification of prognostic markers pointing to increased risk of allergy development is of importance. Cord blood represents a suitable source of cells for searching for such prognostic markers. In our previous work, we described the increased reactivity of cord blood cells of newborns of allergic mothers in comparison to newborns of healthy mothers, which raised the question of whether or not this was due to the impaired function of regulatory T cells (Tregs) in high-risk children. Therefore, the proportion and functional properties of Tregs in cord blood of children of healthy and allergic mothers were estimated by flow cytometry. The proportion of Tregs[CD4+CD25highCD127lowforkhead box protein 3 (FoxP3+)] in cord blood of children of allergic mothers tends to be higher while, in contrast, the median of fluorescence intensity of FoxP3 was increased significantly in the healthy group. Intracellular presence of regulatory cytokines interleukin (IL)-10 and transforming growth factor (TGF)-beta was also higher in Tregs of children of healthy mothers. Although we detected an increased proportion of Tregs in cord blood of children of allergic mothers, the functional indicators (intracellular presence of regulatory cytokines IL-10 and TGF-beta, median of fluorescence intensity of FoxP3) of those Tregs were lower in comparison to the healthy group. We can conclude that impaired function of Tregs in cord blood of children of allergic mothers could be compensated partially by their increased number. Insufficient function of Tregs could facilitate allergen sensitization in high-risk individuals after subsequent allergen encounter.