Drugs in autoimmune diseases.

Autoimmune diseases arise when autoimmunity or the loss of self tolerance results in tissue damages. Many mechanisms have been proposed for the origin of autoimmunity, including immunologic, viral, hormonal and genetic factors. All known parts of the immunological network are involved in causing immunopathologic symptoms. Therefore, more or less specific immunosuppressants are widely used in the treatment of autoimmune disorders which range from organ-specific, i.e. Hashimoto's thyroiditis, to non-organ-specific or systemic diseases, i.e. systemic lupus erythematosus. Unspecifically acting cytostatics do not only suppress autoimmune reactions but also create severe side-effects due to the impairment of immune responses against foreign antigens, leading, for example, to an increased risk of infections. Moreover, the genotoxic activity of cytostatics might induce malignancies. Corticosteroids are clinically well known and very active agents for the management of acute symptoms but different side-effects limit their use in the treatment of chronic diseases. Cyclosporin A has been an important step forward to a more specific prevention of organ transplant rejections and to the therapy of some autoimmune disorders. Modern approaches to immunosuppression include monoclonal antibodies directed against a variety of different determinants on immunocompetent cells. Ciamexone and Leflunomide which are in early clinical and preclinical development, respectively, might be interesting new drugs. Future immunopharmacologic drug research and development should lead to more specific, low molecular weight, orally active and chemically defined immunosuppressive compounds with good tolerability under long-term treatment of autoimmune diseases.