Endocardial fibroelastosis associated with maternal anti-Ro and anti-La antibodies in the absence of atrioventricular block.
OBJECTIVE
This study was designed to document the association of endocardial fibroelastosis (EFE) and maternal autoantibodies.


BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Division of Cardiology, The Hospital for Sick Children and the Research Institute, Toronto, Ontario, Canada.
Lynne E
LE
Nield
Earl D
ED
Silverman
Jeffrey F
JF
Smallhorn
Glenn P
GP
Taylor
J Brendan M
JB
Mullen
Leland N
LN
Benson
Lisa K
LK
Hornberger
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D001324:Autoantigens / Q000276:immunology*; D004695:Endocardial Fibroelastosis / Q000276:immunology* / Q000473:pathology; D005260:Female; D005333:Fetus / Q000276:immunology*; D006801:Humans; D007223:Infant; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008431:Maternal-Fetal Exchange; D009206:Myocardium / Q000276:immunology* / Q000473:pathology; D011247:Pregnancy; D012261:Ribonucleoproteins / Q000276:immunology*; D000097585:SS-B Antigen
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D001324:Autoantigens; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; C035356:SS-A antibodies