[Secondary immunopathogenesis in myocarditis, diseases of the heart muscles and infarct-associated arrhythmia in childhood and adulthood].

In histologically proven or clinically diagnosed perimyocarditis in children and adults alterations in cellular and humoral effector mechanisms are demonstrable: OKIaI-positive B- or activated T-lymphocytes are increased in the peripheral blood, whereas natural killer cell activity is reduced. Antibodies are directed to the membranes of isolated human atrial myocytes and, to a lesser extent with lesser specificity, to endothelial cells and to the extracellular matrix. AMLAs are of diagnostic relevance if they belong to the IgM class, indicating a recent humoral immune stimulation and, if they fix complement, indicating a functional property which is complement associated lysis of target cells. Immunohistological studies demonstrate fixation of immunoglobulins to the autologous biopsy specimens, which are diagnostic only if they also belong to the IgM class and fix complement. In acute rhythm disturbances in the context of a recent "common cold", similar humoral immune reactions can be found in children, which are compatible with a secondary immunopathogenesis after viral illness involving the myocardium.