Pervasive developmental disorders and immunological tolerance.

A wide range of studies in man and other species suggest that early compromise of immunological tolerance (both maternal-fetal and self) may lead to severe and varied cognitive deficits. This article briefly reviews what is known of the genesis and maintenance of normal tolerance and current ideas on pathological deviances in tolerance. These ideas are discussed in relation to risk factor, family, twin, biochemical, anatomical, and immunological studies of pervasive developmental disorders (particularly infantile autism). A range of immunological injury hypotheses for the genesis of the pervasive developmental disorders are considered and technical problems in deciding among them are presented.