Pathogenic effects of maternal antinuclear antibodies during pregnancy in women with lupus

Lupus is an autoimmune disease that primarily affects young women of childbearing age. Fertility rates in lupus patients depend on various factors, including disease activity, nephritis, and the presence of antiphospholipid antibodies; however, after lupus patients become pregnant, different factors may affect the course of pregnancy, such as the production of autoantibodies, pre-existing renal disease, and eclampsia, among others. The placenta is a temporary hemochorial organ that prevents immunological conflict due to exposure to alloantigens at the maternal-fetal interface; placental regulatory T cells play a major role in maternal-fetal tolerance. Typically, significant amounts of maternal IgG class antibodies cross the placenta and enter the fetal circulation. This transition depends on the distribution of Fc receptors along the syncytiotrophoblast. The production of antinuclear antibodies (ANA) is a hallmark of lupus, and these autoantibodies can form immune complexes that are typically trapped in the placenta during gestation. However, the entry of ANA into the fetal circulation depends on the IgG-ANA concentration and the FcR placental density. Maternal antinuclear antibodies with anti-Ro or anti-La specificity might be pathogenic to the fetus if transfused by the placental pathway and could induce neonatal pathologies, such as neonatal lupus and congenital heart block. Here, we review the experimental and clinical data supporting a pathogenic role for maternal autoantibodies transmitted to the fetus