[Neonatal lupus and congenital heart block]

Neonatal lupus (NL) is a rare syndrome resulting from the transplacental transfer of maternal anti-Ro/SSA autoantibodies, with or without anti-La/SSB antibodies, and is clinically characterized by cutaneous, hematological, hepatic, and especially cardiac manifestations. The most severe manifestation is congenital heart block (CHB), which occurs in structurally normal fetal hearts, is most often complete and irreversible, and is associated with substantial morbidity and mortality. Although anti-Ro/SSA antibodies are common in women with systemic lupus erythematosus and Sjögren disease, most cases of CHB occur in asymptomatic women, the fetal diagnosis leading to the discovery of the maternal autoantibodies. The pathophysiology of NL is multifactorial, involving autoantibodies, inflammation, and genetic and environmental factors, ultimately leading to fibrosis of the fetal cardiac conduction system. Cutaneous NL is more frequent but transient and generally associated with a favorable prognosis. CHB is usually diagnosed before 24 weeks of gestation and often requires pacemaker implantation during childhood. Screening strategies have evolved, with less emphasis on systematic echocardiographic surveillance. There is growing interest in identifying predictive factors for CHB in order to enable the development of a curative treatment, which to date remains undefined. Indeed, corticosteroid therapy has not demonstrated clear efficacy in this indication and may be associated with substantial adverse effects. In the absence of curative treatment, the management of cardiac NL relies on specialized obstetric and pediatric coordination and long-term cardiology follow-up. Hydroxychloroquine may reduce the risk of recurrence in women who had a first pregnancy complicated with CHB.