Childhood immune maturation and allergy development: regulation by maternal immunity and microbial exposure.

PROBLEM The increasing allergy prevalence in affluent countries may be caused by reduced microbial stimulation, resulting in an abnormal post-natal immune maturation. Most studies investigating the underlying mechanisms have focused on post-natal microbial exposure. Also, the maternal microbial environment during pregnancy may program the immune development of the child, however. METHOD OF STUDY This review focuses on how maternal immunity and microbial exposures regulate childhood immune and allergy development. RESULTS Prenatal environmental exposures may alter gene expression via epigenetic mechanisms, aiming to induce physiological adaptations to the anticipated post-natal environment, but potentially also increasing disease susceptibility in the offspring. Although the importance of fetal programming mostly has been studied in cardiovascular and metabolic disease, this hypothesis is also very attractive in the context of environmentally influenced immune-mediated diseases. CONCLUSION Efficacious preventive measures, required to combat the allergy epidemic, may be identified by determining how the immune interaction between mother and child is influenced by microbial factors.