Review of fetal and neonatal immune cytopenias.

The fetoplacental interface plays a unique role in pathologies of the fetus and neonate, and is increasingly being recognized for effects on fetal and neonatal development that resonate into adulthood. In this review, we will use several exemplary disorders involving each of the 3 types of blood cells to explore the effect of perinatal insults on subsequent development of the affected cell line. We will present new data regarding outcomes of infants treated prenatally for fetal and neonatal alloimmune thrombocytopenia (FNAIT) and contrast these with outcomes of infants affected by hemolytic disease of the fetus and newborn. We also will explore the differences between FNAIT and passively transferred antibodies, as seen in maternal idiopathic thrombocytopenic purpura. Neonatal hemochromatosis is an example of a disease that previously was largely fatal, but whose newly discovered etiology as an immune-mediated perinatal disorder has resulted in development of highly effective treatment. Finally, we will examine the interplay between lymphopoiesis and the placenta in an effort to further explore the phenomenon of neutropenia in preeclampsia, whose etiology remains unknown.