This study was designed to document the association of endocardial fibroelastosis
(EFE) and maternal autoantibodies.
Neonatal lupus erythematosus is associated with the transplacental passage of maternal
anti-Ro and anti-La antibodies, leading to complete atrioventricular block (CAVB).
In some cases, CAVB is associated with EFE. Isolated EFE may be independently related
to maternal anti-Ro and anti-La antibodies.
We identified three cases (one fetus and two infants, all female) of isolated EFE
in infants born to autoantibody-positive mothers in the absence of CAVB. Demographics,
echocardiograms, and pathology were reviewed. Immunohistochemical analyses for immunoglobulin
(Ig)G, IgM, IgA, T-cell, B-cell, and terminal deoxynucleoleotidyl transferase-mediated
dUTP-biotin nick end-labeling (TUNEL) (test for cell apoptosis) staining were performed
on multiple sections of the heart in each case and compared with negative controls.
Two cases died and one received a cardiac transplant. All three cases had histologically
confirmed EFE. All cases demonstrated significant diffuse IgG infiltration. To a lesser
extent, myocardial tissue was also positive for IgM, CD43, and Granzyme B. None of
the specimens were TUNEL positive.
These are the first reported cases of isolated EFE associated with maternal anti-Ro
and anti-La antibodies in the absence of CAVB. The diffuse deposition of IgG and the
presence of a T-cell infiltrate throughout the myocardium suggest that the transplacental
passage of maternal autoantibodies induces an immune reaction within the myocardium,
leading to isolated EFE. Autoantibody-mediated EFE may be an etiologic factor in cases
of fetal and neonatal "idiopathic" dilated cardiomyopathy.