Abstract
The immune system comprises a highly integrated network of multiple tissues and cell types with complicated interactions and effects. It is modulated by the endocrine and nervous systems and there is growing realization of its multifunctionality. The session focusing on immunologic effects of dioxin and related compounds following prenatal exposure involved a review of the immunotoxic effects that have been reported for polyhalogenated aromatic hydrocarbons (PHAHs), a discussion of species differences in responses, and development of the immune system, and data from two ongoing epidemiological studies comparing the immune status of children exposed to higher-than-average concentrations of PHAHs both prenatally and lactationally.