Anti-beta-receptor antibodies in familial cardiomyopathy: correlation with HLA-DR and HLA-DQ gene polymorphisms.

The presence of beta-receptor autoantibodies and their relationship to restriction fragment length polymorphisms of the human leukocyte antigen (HLA) class II genes were studied in 42 affected and unaffected members of a family with a heritable disorder of the conduction system and cardiac muscle. Antibodies were detected in 34% of all members (59% of affected and 22% of unaffected; p < 0.01). Significant differences between affected and unaffected individuals and between anti-beta-receptor antibody positive and negative individuals were noted in the prevalence of polymorphisms obtained with Taq I for the HLA-DR beta and HLA-DQ alpha genes. In affected individuals, there was a strong positive correlation between these polymorphisms and the presence of anti-beta-receptor antibodies. These results suggest that autoimmune mechanisms under the control of the class II genes play an important role in the pathogenesis of familial cardiomyopathy.