Childhood Immune Maturation and Allergy Development: Regulation by Maternal Immunity and Microbial Exposure

Abstract

Citation Jenmalm MC. Childhood Immune Maturation and Allergy Development: Regulation by Maternal Immunity and Microbial Exposure. Am J Reprod Immunol 2011; 66 (Suppl. 1): 75–80Problem 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.

Immunological interactions between mother and child during pregnancy in relation to the development of allergic diseases in the offspring

“…The observation of maternal allergy as a more significant risk factor for allergy development in the offspring as compared with paternal allergy [159][160][161] has shed more light on the pregnancy as an important time period for fetal immune development [162]. The immunological mechanisms behind this phenomenon are not known, but indicate an influence of the maternal immunity on allergy development, besides the contribution of the genes.…”

GATA binding protein 3+ group 2 innate lymphoid cells are present in cord blood and in higher proportions in male than in female neonates

“…The mean ILC2 proportions were very similar in children developing allergy or staying healthy according to our strict criteria, however. Previously, it has been shown that children who later develop allergic disease have a more pronounced T H 2 deviation already at birth, 4 with enhanced circulating T H 2-associated chemokine levels, 5 which would suggest a role for increased ILC2 proportions in neonates later developing allergies. However, the involvement of ILC2 in allergic disease has primarily been observed at effector sites, that is, at mucosal surfaces.…”

“…However, previous studies have demonstrated the crucial function of GATA-3 in ILC2 since ectopic expression of GATA-3 in human Lin(2)CD127(1)CRTH2(2) cells resulted in induction of CRTH2 and the capacity to produce high amounts of type 2 cytokines in response to thymic stromal lymphopoietin plus IL-33. Because a more pronounced T H 2 deviation is suggested to precede the development of allergic disease 4 and ILC2 have been implicated to be involved in allergic responses, 1,2 we investigated whether high ILC2 proportions in cord blood could predict the development of allergic disease. However, no differences were detected in cord blood between children who later developed allergic diseases and those who remained nonallergic up to the age of 6 years (Table I) (percentages of ILC2 among lymphocytes: mean, 0.10 6 0.03, n 5 7, and mean 0.09 6 0.02, n 5 7, respectively).…”

“…Early life events occurring during critical windows of immune development can have a longterm impact on immune-mediated diseases, and immune status at birth, in part influenced by maternal immunity, may be an intrinsic factor predisposing to allergy development. 4 The aim of this study was to assess whether ILC2 are present in cord blood and whether their proportions are associated with allergy development and sex.…”

Lactobacillus reuteri, Infant Allergy Prevention and Childhood Immune Maturation

“…The intestine provides a unique environment for the development of both immunity and tolerance, and the initiated immune response is dependent on DC type and state of activation. The probiotic supplementation during pregnancy and early childhood could possibly provide microbial stimulation needed for normal development of immunoregulatory capacity, providing a source of TLR-ligand exposure [37,38].…”