[Transplantation antigens: biological function and role as disease determinants]

A summary of data is presented which illustrate that major transplantation antigens are named incorrectly for historical reasons. Their biological function is not really to promote rejection of foreign cells and organs but rather to guide cell-cell interactions of cells involved in immunological defense. Immunological recognition of self-transplantation antigens is determined in the thymus and influences the quality of the immune response, and therefore also disease susceptibility.