ABSTRACT
The human immune system is highly developed at birth relative to other mammalian species, and the majority of key effector mechanisms appear almost adultequivalent in functional capacity. However, it is becoming increasingly clearer that subtle modification of a variety of cellular and molecular mechanisms is necessary to maintain immunological homeostasis in the intrauterine environment, and the persistence of these modifications into postnatal life has potential pathological implications in relation to a variety of diseases, including asthma and atopy. This review provides a broad summary of current understanding of immune ontogeny in humans, focusing in particular on issues of relevance to the etiology and pathogenesis of these latter two diseases.
