[Significance of immunologic tolerance in dermatology]

The immunological tolerance processes enable the organism to distinguish between self and non-self and are, therefore, critical for an efficient immune system. Exogenous or endogenous factors that disturb tolerance mechanisms induce uncontrolled activation of the immune system and the development of autoimmune diseases. In the field of dermatology, the most relevant autoimmune diseases are connective tissue diseases and autoimmune bullous skin disorders. In contrast, increased activity of tolerance shuts down parts of the normal immune response and thus facilitates the development of neoplasia and microbial infections in the skin and other organs. Immunological mechanisms for the induction of tolerance have been studied with the help of experimental models of tolerance to contact allergens. T- and B-cells, as well as antigen presenting cells, in particular dendritic cells, are involved in the immunological mechanisms of tolerance. The modification of autologous immune cells of patients with malignant tumors, allergic and autoimmune diseases might have potential for the development of new therapies.