Neonatal lupus is a rare disease that can occur in the children of mothers who have SLE or have a disease called Sjogrenís syndrome or actually have no disease at all.
What seems to cause the problem in the baby are autoantibodies in the motherís blood called anti-Ro/SSA and anti-La/SSB. These autoantibodies, independent of whether the mother has SLE or not, are associated with problems that are grouped under the heading of neonatal lupus.
The most serious is permanent heart block, in which the heart beats very slowly. Most of these children require a pacemaker and 20% die. The heart block is almost always detected during pregnancy with the most common time period from 18-24 weeks.
Fortunately this problem called congenital heart block only occurs in 2 of 100 babies born to mothers with these antibodies. The other problem in neonatal lupus is a skin rash which is often brought on by sunlight at 6 weeks after birth. This rash is always on the face and is very red, characteristically being present around the babyís eyes. This rash is generally transient. The name neonatal lupus is misleading, it does not mean the child has lupus.
Dr. Buyon and Dr. Clancy have focused much of their laboratory work on studying why the anti-SSA/Ro and SSB/La antibodies are so highly associated with congenital heart block. They have discovered that the antibodies while necessary are not the whole cause of disease.
Their current work suggests that these antibodies may bind heart cells that are undergoing a specialized form of cell death that occurs during fetal development. When the antibodies bind the heart cells this causes them to be removed by macrophages which in turn may result in the secretion of abnormal proteins that result in scarring of the atrioventricular node. It is hoped that understanding the injury cascade initiated by the transplacental passage of maternal autoantibodies may lead to the discovery of new therapies.
Dr. Buyon is head of the NIH Research Registry for Neonatal Lupus which is the largest database of families in which one child has had neonatal lupus. More information on this can be found at neonatallupus.com.
Dr. Buyon is currently studying whether treatment with intravenous gamma globulin can be effective in preventing congenital heart block if administered early in a pregnancy carried by a mother with anti-SSA/Ro antibodies who has had a previous child with heart block.