Anti-Ro/SS-A antibodies in the pathophysiology of congenital heart block in neonatal lupus syndrome, an experimental model. In vitro electrophysiologic and immunocytochemical studies.
OBJECTIVE
To determine whether anti-Ro/SS-A antibodies selectively bind to neonatal cardiac cells and alter membrane repolarization.


METHODS
An in vitro electrophysiologic and immunocytochemical experimental model contrasting neonatal and rabbit cardiac tissue was employed.


RESULTS
Sera and IgG-enriched fractions from anti-Ro/SS-A antibody-positive mothers of infants with neonatal lupus erythematosus and congenital heart block bind to neonatal, rather than adult, rabbit cardiac tissue and alter the transmembrane action potential (i.e., inhibit repolarization). The additional presence of anti-La/SS-B antibodies was not additive or synergistic for these immunocytochemical and electrophysiologic features. Sera containing other antibody specificities (i.e., anti-native DNA, cardiolipin, Sm, and nuclear RNP) failed to stain the neonatal cardiac tissue or produced alterations in membrane repolarization.


CONCLUSIONS
Anti-Ro/SS-A antibodies may play a pathophysiologic role in the development of congenital heart block in neonatal lupus.
Alexander
E
E
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Buyon
J P
JP
Provost
T T
TT
Guarnieri
T
T
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology* / Q000502:physiology; D001323:Autoantibodies / Q000276:immunology; D001324:Autoantigens / Q000276:immunology; D002308:Cardiolipins / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006327:Heart Block / Q000151:congenital* / Q000276:immunology* / Q000503:physiopathology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D066298:In Vitro Techniques; D007231:Infant, Newborn; D008178:Lupus Erythematosus, Cutaneous / Q000276:immunology* / Q000503:physiopathology; D008297:Male; D009206:Myocardium / Q000276:immunology; D011247:Pregnancy; D020733:RNA, Small Cytoplasmic; D011817:Rabbits; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D000888:Antibodies, Anti-Idiotypic; D001323:Autoantibodies; D001324:Autoantigens; D002308:Cardiolipins; D007074:Immunoglobulin G; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human