Helicobacter pylori pediatric infection changes FcεRI expression in dendritic cells and Treg profile in vivo and in vitro

H. pylori infection shows an inverse relationship with allergies. Dendritic cells regulate mucosal immune responses including the induction of T regulatory cells which are fundamental in Helicobacter pylori-induced dampening of allergies. In this respect expression of high-affinity IgE receptor (Fc epsilon RI) has been associated with a regulatory dendritic cell profile. Therefore we aimed to evaluate possible mechanisms by which H. pylori infection might modify atopy in pediatric patients. Here we show that H. pylori-infected children exhibited both increased expression of Fc epsilon RI on peripheral myeloid and plasmacytoid dendritic cells and higher levels of Foxp3 and Latency Associated Peptide on T regulatory cells. Moreover, exposure to H. pylori drove increased Fc epsilon RI expression and IL 10 secretion by both pediatric H. pylori-exposed monocyte derived dendritic cells and T cells. Finally, we show a positive correlation between expression of Fc epsilon RI in circulating myeloid DCs and total Treg cells, suggesting that in children, H. pylori infection may have a modulating role in atopy, mediated by both altered surface expression of Fc epsilon RI on children's DC and an increased T regulatory cell profile. (C) 2019 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.