[Ectopic expression and the significance of HLA-class II antigens in the myocardium in patients with dilated cardiomyopathy].

Expression of HLA-class II antigens (DQ, DP) in the myocardium of patients with different heart diseases and normal controls was studied with indirect immunofluorescence (IIF). The positive rates in different groups were as follows: dilated cardiomyopathy (DCM, 12/13,+- ), rheumatic heart disease (2/4, +-+ + +), congenital heart diseases (1/14,+), left atrial myxoma (0/1) and normal controls (1/8,+). The immunofluorescent area was in the endocardium and endothelial cells of the blood vessels (VIII factor related antigen positive areas in dual staining of the myocardium). There were significant differences between the positive rates of DCM and those of other heart diseases including rheumatic heart disease, congenital heart diseases and left atrial myxoma (chi 2 cor = 15.3, P < 0.001), as well as between DCM and normal controls (chi 2 cor = 9.9, P < 0.01). The expression of HLA-class II antigens is highly selective. Ectopic expression has been postulated to be responsible for autoimmune diseases. So it can be used as a specific marker for autoimmunity in DCM.