Biologics in red cell and platelet alloimmunizations: State of the science and future perspectives.

Hemolytic disease of the fetus and newborn (HDFN) is routinely treated with the intrauterine transfusion (IUT) of compatible donor red cells once fetal anemia is detected. Intravenous immune globulin (IVIG) is often used in patients with a previous history of early onset disease in a previous pregnancy. Although IUT's are still required in the majority of these pregnancies, IVIG appears to prolong the gestational age until these are necessary. IVIG with or without oral steroids is utilized in most countries to prevent thrombocytopenia and intracranial hemorrhage in cases of fetal/neonatal alloimmune thrombocytopenia (FNAIT). Nipocalimab, a humanized monoclonal antibody that blocks the neonatal Fc receptor, is currently undergoing clinical trials in both HDFN and FNAIT as a potential new form of immunotherapy for these alloimmune disorders of pregnancy.