Humoral immunity in cardiomyopathy

Sera from patients with heart disease were examined by single sandwich indirect immunofluorescence for the presence of antibodies to human heart muscle. Endocardial biopsy specimens were also examined by direct immunofluorescence for deposition of antibodies in vivo. No consistent or specific abnormality was found in the biopsy specimens or sera of patients with congestive cardiomyopathy. The presence of anti-heart antibodies in cardiac disease appears to reflect damage to cardiac muscle whatever the cause. Immunofluorescence is an insensitive test for anti-heart antibodies.