Risk factors for developing allergy in children

Abstract

The factors which seem to influence or turn on the allergic response in children can be prenatal, perinatal and postnatal. In prenatals heredity takes the first place but environmental factors contribute as well as genetk ones. Of prenatal peristatic (environmental) factors highly allergenic food in allergic mothers and progesterone therapy may be important in turning on the allergic process in potentially allergic infants. The mother's progesterone therapy during pregnancy was shown to increase significantly the mean IgE levels and the mean percentage of detectable IgE in the cord blood. This hormone has been reported to be immuno-suppressive in vitro. As 20-alpha-hydroxy- steroid dehydrogenase was discovered in the mouse thymus, the hypothesis has been put forward that this enzyme, engaged in the progesterone metabolism, may have a protective role in reducing progesterone activity in the thymocytes. Thus, the progesterone administered to pregnant women might interact with fetal thymus maturation imd because a delayed thymic maturation was involved in th~ allergy onset, a hypothetical role of progesterone may be explained. According to another hypothesis progesterone may modify the placental biology including a placental transfer of IgE.