Severe Hemolytic Disease of the Newborn due to Anti-Di.

Di is a low-frequency member of the Diego blood group system, which is comprised of 23 antigens. The Diego blood group antigens are found on the erythroid membrane glycoprotein band 3, the red cell anion exchanger (AE1). The behavior of anti-Di in pregnancy can only be surmised by rare, published case reports. This is a case report of severe hemolytic disease of the newborn due to a high-titer maternal anti-Di immune response. The neonate's mother was monitored throughout pregnancy with Di antibody titers. In the third trimester, her antibody titer abruptly rose to 32. Her fetus was emergently delivered and was found to be jaundiced at birth with a hemoglobin/hematocrit of 5 g/dL/15.9% and a neonatal bilirubin of 14.6 mg/dL. With simple transfusion, intensive phototherapy, and two doses of intravenous immunoglobulin, the neonate's condition normalized quickly. He was discharged from the hospital after 8 days in excellent condition. Anti-Di is uncommonly encountered in both transfusion services and obstetric practices. Although very rare, anti-Di can be associated with cases of severe hemolytic disease in newborns.