Anti-DNA, anti-phospholipid, and anti-Ro/SSA autoantibodies are thought to be pathogenic for glomerulonephritis, recurrent thrombosis and miscarriages, and neonatal lupus, respectively.
Neonatal lupus is linked to the presence of anti-Ro/SS-A and anti-La/SS-B antibodies in the mother, although other factors probably of fetal origin are important.
The objective of this study was to identify putative Ro52/60-kDa Ro/SSA antigen (Ro60) epitopes associated with neonatal lupus and congenital heart block.
Neonatal lupus erythematosus is an immune-mediated disease associated with the transplacental passage of maternal autoantibodies, primarily anti-Ro (SS-A) and anti-La (SS-B).
Neonatal lupus erythematosus (NLE) is an inflammatory syndrome in the fetus or neonate associated with the presence of anti-Ro(SSA) and anti-La(SSB) antibodies in the mother.
Neonatal lupus erythematosus (NLE) is a rare disease characterized by the transplacental passage from the mother to the fetus of autoantibodies, in particular anti-Ro(SS-A), anti-La(SS-B), or both.
Mothers of children with neonatal lupus erythematosus (NLE) and heart block, as well as patients with Sjögren's syndrome (SS) and systemic lupus erythematosus, have serum autoantibodies that recognize SS-A/Ro autoantigens including the 60-kDa ribonucleoprotein.
Thus, our findings suggest that there may be immunogenetic differences among mothers according to their autoantibody profiles, and that mothers with both anti-Ro/SSA and anti-La/SSB are more likely to have infants with NLE than mothers with anti-Ro/SSA alone.
The HLA class II allele associations with anti-Ro(SS-A) autoantibodies that have been noted in other ethnic groups were also found in Japanese anti-Ro(SS-A)-positive mothers whose infants had NLE, suggesting shared susceptibility factors across racial barriers in maternal predisposition to Ro(SS-A) autoimmune response.
Anti-SS-A/Ro antibodies are commonly found in systemic autoimmune diseases such as Sjögren's syndrome and systemic lupus erythematosus, and some of these antibodies appear to be responsible for certain pathological lesions including congenital heart block in neonatal lupus.
Conversely, maternal HLA-DQB1*0602 carried on HLA-DR2 haplotypes was associated with CHB but not cutaneous NLE; (ii) HLA-DQA1 alleles with glutamine at position 34 of the first domain, which have reportedly been associated with the autoimmune responses to Ro/SSA antigens in other ethnic groups, were increased in the mothers of infants with cutaneous involvement; and (iii) there was no particular class II HLA profile that distinguished the disease manifestations in infants.
The 52-kD SS-A/Ro protein is one of the antigenic targets strongly associated with the autoimmune response in mothers whose children have manifestations of neonatal lupus.
Examination of paternal and maternal C4 genes of additional infants with NLE, in particular those with CCHB, and of normal infants born to anti-Ro(SS-A)-positive mothers--and of the normal infants' parents--is required to determine if abnormal C4B genes are a critical factor rendering susceptibility to the NLE syndrome.
Thus, a mother with positive anti-SSA and SSB antibodies can give birth to one infant with and one infant without or have two infants with neonatal lupus erythematosus.
The present study was designed to test the hypothesis that anti-Ro(SS-A)/La(SS-B) positive Sjogren's/lupus overlap patients and mothers of infants with neonatal lupus erythematosus syndrome are immunogenetically homogenous and closely related.
Since these antibodies may have a pathogenetic role in NLE, screening of infants with isolated CHB and/or cutaneous lesions suggestive of LE, and their mothers, for the presence of Ro(SSA) and La(SSB) antibodies is strongly recommended.