Maternal autoantibodies and congenital heart block: no evidence for the existence of a unique heart block-associated anti-Ro/SS-A autoantibody profile.

One of the rare examples of the transfer of autoimmune disease from mother to (unborn) child is the neonatal lupus syndrome. This syndrome comprises the development of fetal heart disease (congenital heart block) or neonatal skin rash and is specifically associated with maternal anti-Ro/SS-A autoantibodies. Previous studies have suggested that especially maternal autoantibody reactivity against the 52 kDa protein of the Ro/SS-A antigen and/or against the La/SS-B antigen is responsible for the development of congenital heart block (CHB). To determine the CHB-associated antibody response in more detail, we analysed the presence of autoantibodies in sera from mothers of children with isolated heart block. All 14 mothers of children with congenital heart block were positive for anti-Ro/SS-A antibodies. Remarkably, their antibody profile, including recognition of different Ro/SS-A proteins and autoantibody levels against these proteins, did not differ from anti-Ro/SS-A positive mothers of healthy children. In contrast, all 8 anti-Ro/SS-A negative mothers had children with acquired heart block. We conclude from our data that maternal anti-Ro/SS-A antibodies are essential for CHB but that fine analysis of this autoantibody response does not predict the occurrence of CHB.