Neonatal Lupus Syndrome (NLS) is an autoimmune disease associated to the presence of autoantibodies against ribonucleoproteins SSA/Ro and/or SSB/La in the maternal-fetal circulation and is characterized by isolated congenital heart block (ICHB) and/or cutaneous and hematological manifestations. Despite the rarity, NLS is the main cause of ICHB, which is responsible for the significant mortality (20%-30%) and morbidity of these patients. The neonatal lupus designation comes from the observation of cutaneous lesions similarities between NLS and systemic lupus erythematosus. The isolated term to define the CHB in NLS is employed to exclude cardiac abnormalities secondary to congenital structural malformations or infections. NLS is considered a model of passively acquired autoimmunity in which maternal autoantibodies cross the placenta and, once in fetal circulation, may play a role in the pathogenesis of the syndrome. The almost universal presence of anti-SSA/Ro and/or anti-SSB/La antibodies in the maternal and fetal circulation validates them as serological markers of NLS. Contrasting with the fetal cardiac tissue lesion, which is an irreversible process, cutaneous and hematological involvements are transitory manifestations and disappear after the clearance of maternal autoantibodies from the infant's circulation. It is important to notice that NLS represents a multidisciplinary challenge involving rheumatologists, obstetricians, neonatologists, dermatologists and pediatric cardiologists to identify the pregnancy at risk for NLS development and to introduce appropriate in utero or postnatal therapeutic strategies.
neonatal lupus; congenital heart block; anti-Ro/SSA antibodies
