[Etiology and pathogenesis of multiple sclerosis: current aspects of causative factors in the disease course].

The components of pathogenesis of multiple sclerosis are presented. (I.) Genetic and metabolic factors were found to be fundamental for cellular immune reaction; the association with class 2 MHC (HLA-DR; IR) antigens is more relevant than that of class 1 MHC (HLA-ABC) antigens. (II.) A reaction to several viruses may be significant for the induction and the heterogenous course of disease; some mechanisms of an immune-dysbalance--induced by viruses--are exposed. (III.) Disturbances of cellular immunoregulation, a reduced activity of T-suppressor-lymphocytes, a break of immune tolerance and cytotoxic effector mechanisms are decisive for the autoimmune processes. In all, on the basis of multi-genetic anomalies a multi-phase pathogenesis may be assumed, developing in manner of a cascade in several steps and phases.