[Immunological background of patients with dilated cardiomyopathy and myocarditis: clinical and experimental studies]

Immunogenetic mechanism may be involved in the pathogenesis of idiopathic cardiomyopathy. Viral myocarditis is considered a cause of dilated cardiomyopathy. In this study, we examined the major histocompatibility complexes (human leukocyte antigens: HLA) by microdroplet cytotoxicity test, lymphocyte subsets by laser flow cytometry, and the activity of lymphocyte blastoformation induced by phytohemagglutinin (PHA) and concanavalin A (Con A) in patients with cardiomyopathies (DCM) and myocarditis (MC). We also examined the incidence and histopathology of encephalomyocarditis (EMC) virus myocarditis in inbred strains of mice, and serial changes of T- and B-lymphocytes in the peripheral blood of DBA/2 mice inoculated with EMC virus by immunofluorescence techniques. The results were as follows: Major histocompatibility complex (HLA and H-2); HLA-B12 in patients with DCM and HLA-DR8 in patients with MC were more frequent than in controls. In EMC virus infection, differences were found in the frequency of occurrence of MC in inbred strains of A/J (H-2a), C57BL/6 (H-2b), BALB/c (H-2d), DBA/2 (H-2d) and C3H/He (H-2k) mice. Genetic mechanism may play a role heart similar to lesions in patients with DCM were seen in DBA/2 mice in the chronic stage of MC. in susceptibility to virus infection. Lymphocyte population study; OKT 8 (suppressor T-cell) was significantly lower in patients with DCM and hypertrophic cardiomyopathy (HCM) than in controls. There were no significant changes of lymphocyte subsets in patients with MC as compared with the controls.(ABSTRACT TRUNCATED AT 250 WORDS)