Cardiac immunoglobulin deposition in congenital heart block associated with maternal anti-Ro autoantibodies.

Isolated congenital complete heart block is frequently found in offspring of mothers who have IgG anti-Ro/SSA autoantibodies. IgG deposition was reported in the heart of a baby who died from heart block and heart failure. The pattern of antibody deposition observed was the same as that reproduced in animal models for anti-Ro/SSA binding. The IgG deposition was present in, but not limited to, the conduction system. Scattered small infiltrates of mononuclear cells and a limited, patchy deposition of complement were also observed. These findings support the possibility that isolated congenital heart block may be causally related to autoantibodies.