The neonate's immunity gap, breast feeding and cot death.

In many mammals infant behaviour imposes a period during which the young will only take the mother's milk. It is suggested that the immunological components of the milk serve in this period to augment the baby's immune system while he traverses from the antigenic isolation of a fetus to his independent defence. In humans almost all cot deaths occur during this phase. Diverse statistics relating to factors associated with greater risk of cot death are drawn on, suggesting that a number of seemingly unconnected factors can all (including lack of breast-feeding) be interpreted as potential immunity defaults. This interpretation lends support to the idea of an immune mechanism underlying cot death which in some way is an abnormal response resulting from the default and which, with at least one other precipitating mechanism, leads to death.