Neonatal lupus syndrome: The heart as a target of the immune system

Neonatal lupus erythematosus (NLE) is an auto-immune disease related to sys temic lupus erythematosus (SLE). Unlike SLE it is not a spontaneous syndrom e but rather an acquired one. In NLE the most common disease manifestations are a transient cutaneous lesion and cardiac conduction disturbances. The cutaneous lesions and other non-cardiac manifestations of NLE are transient and disappear about six months after birth, at the time when maternal anti bodies disappear from the neonatal circulation. This fact suggests that mat ernal antibodies may cross the placenta leading to an inflamatory reaction in the fetal tissues. NLE is the principal cause of atria-ventricular block , when it is not associated with congenital birth defects. All the clinical studies to date correlate the heart block in NLE with the presence of cert ain types of circulating maternal antibodies, against the Ro/SSA nuclear pr oteins, in the serum of the newborn. In this paper we discuss animal models that have been developed by our and others groups to study the participati on of the anti-Ro/SSA antibodies in the pathogenesis of the cardiac conduct ion blockades that occur in NLE.