Congenital Heart Block in Neonatal Lupus
Congenital heart block (CHB) is thankfully a rare occurrence.
It affects only one to five percent of babies born to women with systemic lupus erythematosus (SLE) or Sjögren's syndrome who have autoantibodies to the cellular proteins Ro and La. In some cases, asymptomatic women who carry anti-Ro/La antibodies can have babies with neonatal lupus.
However, the risk of this life-threatening condition is five times greater among women who have already had one baby with CHB. As both a researcher and as a clinician specializing in treating SLE and managing pregnancy in women with SLE, I have focused my efforts for the past 15 years on understanding the causes of CHB and finding a basis for in utero therapy.
We can detect CHB at or before birth even in a structurally normal heart. The block can be complete (3rd degree) or incomplete (2nd or 1st degree). In complete block, the mortality rate is about 20 percent; among the babies who survive, 60 percent or more need a permanent pacemaker. Right now, there is no treatment.
We expect to report soon on the findings of a nationwide study funded by the National Institutes of Health (NIH) that assessed treatment possibilities for CHB. In one arm of the PRIDE Trial (PR Interval and Dexamethasone Evaluation in CHB), we evaluated whether oral dexamethasone given to the mother could improve the outcome for a fetus with newly diagnosed CHB. In the second arm, pregnant women with anti-Ro/La antibodies had a weekly sonogram of the fetal heart (echocardiogram) during weeks 16-32 of their pregnancy, with the goal of identifying abnormalities in fetal heart function that might precede development of permanent heart block.
Finding an echocardiographic marker of injury prior to severe damage may provide the best chance for correcting CHB before it becomes untreatable.
We have just begun a new study called PITCH (Prophylactic IVIG Treatment in Congenital Heart block) in which mothers who have had a previous child with CHB will be given intravenous immunoglobulin every three weeks from weeks 12-24 of their pregnancy in hopes of preventing the heart block.
Funding for the basic science portion of the PITCH trial came from the Alliance for Lupus Research. Information on mortality, the need for pacemakers, and CHB recurrence is critical for family counseling, management, and for research.
The national Research Registry for Neonatal Lupus was initiated at NYUHJD in September 1994 with funding from the NIH to establish a database of mothers whose children have CHB or other manifestations of neonatal lupus (skin rash, liver, or blood abnormalities). As of February 2007, 265 mothers of 313 affected children have been enrolled in the registry. We welcome further referrals and encourage interested investigators to submit protocols for researching Registry data.
Our team at NYUHJD will devote the next decade to our research in the hope that we can one day prevent CHB. We also hope that by understanding this one example of autoimmune injury, it will provide insights into other conditions with similar disease mechanisms.
For information about the Registry, please contact: Peg Katholi at (212) 263-0746, or Peg.Katholi@nyumc.org
For information about the PITCH Trial, please contact: Dr. Buyon's office at (212) 263-0746.