Anti-p57: a novel association with neonatal lupus.
IgG antibodies to a 57-kD protein (p57) present in various human and bovine extracts were detected by immunoblotting in the serum of the mother of a baby with congenital heart block, but not in the corresponding cord blood, suggesting specific antibody consumption in the baby. Since this indicates a possible functional role for these antibodies, the antigen target was characterized and the association of the antibodies to heart block was further studied. A human K562 lambda gt11 cDNA library was screened and two clones were identified whose products reacted with the prototype serum. Antibody affinity-purified by use of the cloned gene products reacted on immunoblot with the 57-kD band. Partial sequences of both inserts were identical, but differed from DNA encoding the Ro(SSA) and La(SSB) antigens. Antibodies to the p57 were detected in 10% of systemic lupus erythematosus (SLE) sera, almost exclusively in association with anti-Ro(SSA). Furthermore, they were present in 38% (8/21) mothers of babies with neonatal lupus expressing either cardiac or cutaneous manifestations. Antibodies to this 57-kD protein may be an additional risk factor for neonatal lupus in anti-Ro-positive women. Moreover, disappearance of antibody from cord blood suggests that they may have a role in disease manifestations.
Maddison
P J
PJ
Royal National Hospital for Rheumatic Diseases, Bath, UK.
Lee
L
L
Reichlin
M
M
Sinclair
A
A
Wasson
C
C
Schemmer
G
G
Reichlin
M
M
D001323:Autoantibodies / Q000032:analysis* / Q000235:genetics; D001324:Autoantigens / Q000235:genetics; D018076:DNA, Complementary / Q000032:analysis; D005260:Female; D006327:Heart Block / Q000151:congenital / Q000235:genetics / Q000276:immunology; D006801:Humans; D007231:Infant, Newborn; D008178:Lupus Erythematosus, Cutaneous / Q000235:genetics / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D009035:Mothers; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000235:genetics; D014157:Transcription Factors; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D001323:Autoantibodies; D001324:Autoantigens; D018076:DNA, Complementary; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D014157:Transcription Factors; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human