The role of probiotics and postbiotics in modulating the gut microbiome-immune system axis in the pediatric age.

The complex microbial community of the gut microbiome plays a fundamental role in driving development and function of the human immune system. This phenomenon is named the gut microbiome-immune system axis. When operating optimally, this axis influences both innate and adaptive immunity, which orchestrates the maintenance of crucial elements of host-microorganisms symbiosis, in a dialogue that modulates responses in the most beneficial way. Growing evidence reveals some environmental factors which can positively and negatively modulate the gut microbiome-immune system axis with consequences on the body health status. Several conditions which increasingly affect the pediatric age, such as allergies, autoimmune and inflammatory disorders, arise from a failure of the gut microbiome-immune system axis. Prenatal or postnatal modulation of this axis through some interventional strategies (including diet, probiotics and postbiotics), may lead to a positive gene-environment interaction with improvement of immune-modulatory effects and final positive effect on human health. In particular probiotics and postbiotics exerting pleiotropic regulatory actions on the gut-microbiome-immune system axis provide an innovative preventive and therapeutic strategy for many pediatric conditions.