Neonatal lupus erythematosus: a transplacentally acquired autoimmune disorder.

Neonatal lupus erythematosus (NLE) is a rare disorder characterized by congenital heart block and/or cutaneous disease and less commonly is associated with hepatic and hematological abnormalities. The majority of affected infants acquire Ro/SS-A (Ro) autoantibodies transplacentally from the maternal circulation and it is generally thought that these antibodies are pathogenic. Mothers at increased risk of having a child affected by NLE should be followed closely during pregnancy to detect the development of fetal heart block, as this is associated with significant morbidity and mortality. Mothers of affected infants are at increased risk of developing a rheumatic disease if they have not already done so.