[Biologic individuality between genetics and environment. On the formation of the biologic ego]

Histocompatibility antigens represent the biological basis of individuality. They make men different from one another and represent the essence of "self" which is continuously protected from "non self" by the immune system. Both fecundation and the evolution of pregnancy are favoured by a marked difference in histocompatibility antigens of the mother and father as well as of the mother and the fetus. The biology of pregnancy also find expression in the neonate: different percentages of the subclasses of T lymphocytes and low levels of NK cells and function. On the whole these data and the correlation between histocompatibility antigens and diseases allow life to be interpreted as an immune phenomenon and human individuality as an essentially immunological "biological Ego". Analogies may be found between the "biological" and the "psychological Ego". Many alterations may affect the protective immune network giving rise to primary or acquired immunodeficiencies. They may be expressed slowly and progressively or suddenly. The immune alterations of Down's syndrome and those of infantile AIDS may be taken as heuristic examples in this sense.