Maternal Antibodies against Fetal Cardiac Antigens in Congenital Complete Heart Block

Abstract
An immunologic basis for congenital heart block has been proposed previously. To investigate the association between congenital heart block and maternal antibodies capable of crossing the placenta, we used immunofluorescence to examine serum samples from 41 mothers and 8 affected children, together with serum from controls, for antibodies to fetal cardiac tissue. Twenty-one mothers (51 percent) had IgG antibody reactive with fetal heart tissue, as compared with only 9 of 94 controls (10 percent; P<0.001). Three of 8 affected babies, but none of 50 healthy babies, had similar antibodies. The antibodies reacted with all myocardial tissue and were not directed specifically to the conduction system. They also reacted with other fetal tissues and could be distinguished from nuclear and smooth-muscle autoantibodies.