IL4 and allergic disease: The fetus develops in an environment in which the production of interleukin-4 and the immunosuppressive and anti-inflammatory interleukin-10 predominates over that of interferon-γ.12 This, by itself, does not determine the birth of a child prone to allergic disease (and, at any rate, allergic manifestations are rare at birth, even in children who will subsequently become allergic).