Pre-natal sensitization in humans

Allergy has a very strong hereditary component but even in identical twins, concordance for the development of allergic disease can be as low as 50%. This suggests that there is a very strong environmental influence on manife stations of sensitization. To what extent environment might have an influen ce on the ontogeny of sensitization antenatally has hitherto not been a foc us of much research. However, circumstantial evidence suggests that this ma y be important.