U1RNP antibody-positive neonatal lupus. A report of two cases with immunogenetic studies.
BACKGROUND
Neonatal lupus erythematosus (NLE) is a distinct subset of lupus characterized by cutaneous findings (50%), cardiac conduction defects (50%), and autoantibodies to Ro (SS-A) antigen. HLA typing studies of Ro (SS-A) antibody-positive mothers of infants with NLE have shown an association with the HLA-DR3 phenotype. We report the clinical and serologic features of two infant-mother pairs who are U1RNP antibody positive and Ro (SS-A) antibody negative. HLA typing is reported on these infants, their mothers, and two additional infant-mother pairs with U1RNP antibody-positive lupus whose clinical features have been reported previously.


METHODS
Cutaneous findings included malar erythema, annular and polycyclic plaques, and scales that resolved with residual telangiectasia and hyperpigmentation 6 months after birth. Systemic abnormalities, including complete heart block, were absent. HLA typing revealed HLA-DR3 in two of four mothers, HLA-DR4 and HLA-DRw53 in two of four mothers, and either HLA-DQ1 or HLA-DQ3 in four of four mothers. No distinct HLA associations were seen in the three infants examined.


CONCLUSIONS
The spectrum of cutaneous disease in U1RNP antibody-positive infants is similar to Ro (SS-A) antibody-positive infants with NLE. Complete heart block was not a feature of U1RNP antibody-positive NLE. HLA typing studies show a more diverse immunogenetic pattern in U1RNP antibody-positive mothers of infants with NLE compared with Ro (SS-A) antibody-positive mothers.
Dugan
E M
EM
Department of Dermatology, Johns Hopkins Medical Institutions, Baltimore, Md.
Tunnessen
W W
WW
Honig
P J
PJ
Watson
R M
RM
D000328:Adult; D000974:Antibodies, Antinuclear / Q000032:analysis* / Q000235:genetics; D001323:Autoantibodies / Q000032:analysis* / Q000235:genetics; D001324:Autoantigens / Q000032:analysis / Q000235:genetics; D005260:Female; D006680:HLA Antigens / Q000032:analysis* / Q000235:genetics; D015788:HLA-A1 Antigen / Q000032:analysis; D015795:HLA-B8 Antigen / Q000032:analysis; D006683:HLA-DQ Antigens / Q000032:analysis; D006684:HLA-DR Antigens / Q000032:analysis; D015802:HLA-DR2 Antigen / Q000032:analysis; D015803:HLA-DR3 Antigen / Q000032:analysis; D015804:HLA-DR4 Antigen / Q000032:analysis; D059845:HLA-DRB4 Chains; D006801:Humans; D007125:Immunogenetics; D007223:Infant; D008180:Lupus Erythematosus, Systemic / Q000235:genetics / Q000276:immunology*; D008297:Male; D020733:RNA, Small Cytoplasmic; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000235:genetics / Q000276:immunology*; D012261:Ribonucleoproteins / Q000032:analysis / Q000235:genetics; D017411:Ribonucleoproteins, Small Nuclear; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics; D055517:snRNP Core Proteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D001324:Autoantigens; D006680:HLA Antigens; D015788:HLA-A1 Antigen; D015795:HLA-B8 Antigen; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D015802:HLA-DR2 Antigen; D015803:HLA-DR3 Antigen; D015804:HLA-DR4 Antigen; D059845:HLA-DRB4 Chains; D020733:RNA, Small Cytoplasmic; D017412:Ribonucleoprotein, U1 Small Nuclear; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D014157:Transcription Factors; D055517:snRNP Core Proteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C051568:HLA-DQ1 antigen; C051569:HLA-DQ3 antigen; C050610:HLA-DR53; C116006:RO60 protein, human