Clinically significant hemolytic disease of the newborn secondary to passive transfer of anti-D from maternal RhIG.
BACKGROUND
RhIG is used worldwide to reduce the incidence of alloimmunization to D during pregnancy. We report a case of clinically significant neonatal hemolysis mediated by maternally administered RhIG.


METHODS
A 25-year-old, O-, primigravid mother with a negative antenatal antibody screen delivered a 6-lb 4-oz, blood group A, D+ baby girl at 36.5 weeks' gestation. Prenatal care included a dose of intramuscular RhIG at 28 weeks' gestation. At delivery, the newborn was markedly jaundiced with a total bilirubin of 6.3 mg/dL, which reached more than 20 mg/dL after 6 days. The newborn's lactate dehydrogenase (LDH) was 485 U/L (normal, <226 U/L) and further laboratory studies revealed reticulocytosis (17.2%; normal range, 0.36%-1.9%) and a hemoglobin (Hb) of 14.3 g/dL (normal for age range, 13.4-19.8 g/dL) that decreased to 11.5 g/dL (normal for age range, 13.5-22.6 g/dL) by Day-of-life 7. Although the maternal antibody screen was negative, the newborn's direct antiglobulin test (DAT) was positive for immunoglobulin (Ig)G, with an anti-D identified by elution studies. The possibility of hemolytic disease of the newborn (HDN) due to anti-A was considered, but ultimately ruled out by the absence of anti-A1 in the eluate. The newborn's hyperbilirubinemia was adequately managed with phototherapy. Analysis of the mother's plasma 10 days postpartum revealed an anti-D titer of 8. Two months after birth, the child's laboratory studies, DAT, antibody screen, and peripheral smear were unremarkable.


CONCLUSIONS
In the context of neonatal anemia, elevated LDH, and reticulocytosis, a positive IgG DAT with anti-D identified in the eluate suggests RhIG-mediated HDN. This appears to be a rarely reported event.
Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center and Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee.
Daniel N
DN
Cohen
Mary S
MS
Johnson
Wayne H
WH
Liang
Heather L
HL
McDaniel
Pampee P
PP
Young
D000328:Adult; D004899:Erythroblastosis, Fetal / Q000097:blood* / Q000209:etiology* / Q000517:prevention & control / Q000628:therapy*; D005260:Female; D006801:Humans; D006932:Hyperbilirubinemia / Q000097:blood; D007231:Infant, Newborn; D007518:Isoantibodies; D007770:L-Lactate Dehydrogenase / Q000097:blood; D011247:Pregnancy; D011295:Prenatal Care; D018029:Rho(D) Immune Globulin
D007518:Isoantibodies; C061961:RHO(D) antibody; D018029:Rho(D) Immune Globulin; D007770:L-Lactate Dehydrogenase