Baylor College of Medicine/Texas Children's Hospital Houston, Texas, United States
Background/Case Studies: The Cartwright (Yt) antigen system carries one antigen [Yt(a)] that is very high prevalence – seen in greater than 99.8% of most populations. As such, anti-Yt(a) is extremely rare. There have been a few published cases of in vivo hemolysis with anti-Yt(a), however the clinical significance of this antibody is uncertain and the hemolytic potential must be interpreted on a case-by-case basis. We describe a case of severe hemolytic disease of the fetus and newborn (HDFN) due to passively acquired anti-Yt(a), anti-D, anti-C, anti-E, and anti-Jk(a) in a fetus who required four intra-uterine transfusions.
Study
Design/Methods: Single case report. Consent was obtained from the patient prior to review of electronic medical record.
Results/Findings: A 31 y.o. group A, RhD-negative, G3P1 Turkish female at 29 weeks and 5 days who presented as a transfer to our institution for severe fetal anemia. Following the delivery of her first baby at our institution in 2017, she received one dose of Rh immunoglobulin (RhIg) for an uncomplicated pregnancy and delivery. In 2019, she lost her second baby following significant bleeding due to placental abruption and received RhIg. She was transferred to our institution for urgent intra-uterine transfusion (IUT) as middle cerebral artery peak systolic velocities were >2 multiples of the median with fetal hydrops (fetal hemoglobin 2.2 g/dL and hematocrit 6%). She was found to have anti-D, anti-C, anti-E, and anti-Yt(a) alloantibodies. The patient was given two emergency, Yt(a)-antigen positive, RhD negative, C-negative, and E-negative red cell units for IUT, which increased the baby’s hemoglobin and hematocrit to 12.1 g/dL and 35.5%, respectively. Subsequently, the patient developed new anti-Jk(a) alloantibodies; likely an anamnestic response as one of the two units had an unknown Jk(a) antigen profile. The American Rare Donor Program was contacted to obtain D, C, E, Jk(a), and Yt(a)-antigen negative units. Before the units came to our hospital, she received another Yt(a)-antigen positive RBC unit for IUT without complications. By the fourth IUT, she received a fully compatible unit. She subsequently delivered a male infant at 37 weeks who developed HDFN with peak total bilirubin 12.4 mg/dL at 57 hours of life. Antibody panel on the newborn showed passively acquired anti-D, anti-C, anti-E, anti-Jk(a), and anti-Yt(a) antibodies causing severe HDFN. After intensive phototherapy for two days, the baby’s bilirubin had normalized with no further signs of anemia.
Conclusions: This patient developed multiple red cell antibodies, including anti-Yt(a). Anti-Yt(a) has been implicated in hemolytic transfusion reactions and can be devastating in the pregnant population causing HDFN. This case report highlights the complexity of managing patients with rare antibodies and how to work closely with national agencies to procure rare units.
