[The thymus in the development of immunocompetence, Physiological and clinical aspects (author's transl)].

The central role of the thymus in the development of immunocompetence is demonstrated in a comprehensive survey. The origin and maturation of the thymocytes, clonal expansion, and the induction of tolerance are discussed in detail. It appears that the major-histocompatibility-antigens play an important role in the maturation processes of the thymocytes. They are probably made available to the developing cells by thymic macrophages. Dysfunction of the thymus leads to immunodeficiencies as well as autoimmune diseases. The heterogeneity of these diseases as well as various therapeutic possibilities for achieving immunologic reconstitution are discussed.