(P-IG-26) Importance of prenatal transfusion work-up: A case of anti-e and anti-Rh17 in a pregnancy complicated by hemolytic disease of the fetus and newborn

Background/Case Studies: Antibodies against Rh17 (anti-CcEe, anti-Hr0) are rare and develop in sensitized Rh D - - individuals. The clinically significant IgG antibody can develop in patients sensitized through transfusion, pregnancy, or solid organ transplantation leading to complications such as hemolytic transfusion reactions and hemolytic disease of the fetus and newborn (HDFN).

Study

Design/Methods: Antibody identification work up was completed at a hospital-based blood bank and immunohematology reference laboratory. Electronic medical records were reviewed and investigation into clinical indications for rare donor matching was completed.

Results/Findings: Hereon we report a multiparous patient who developed anti-e and anti-Rh17 antibodies and subsequently delivered an infant with HDFN. The patient is a G4P4004, blood type O, D-positive, Hispanic female whose indirect antibody test (IAT) became seropositive during her second pregnancy. Further testing revealed both anti-e and anti-Rh17 antibodies. Molecular antigen typing confirmed C-E-c-e- phenotype. During her third pregnancy, the patient’s serum was reactive with e and Rh17 antigens, but non-reactive with Rh null and D- - cells. Rh17 titer increased throughout third trimester of pregnancy from 4 to 32. Neonate phenotype was confirmed C-E+c+e-, DAT was positive, and eluate detected maternal anti-Rh17.

Her first three gestations resulted in uncomplicated births, however her fourth delivery raised concerns for a need for blood product at delivery. Five siblings were tested discovering one sibling who was also D- - but ABO incompatible. D - - blood was found at a Japanese blood center and imported for the case. Her fourth pregnancy resulted in a 39w1d neonate who was jaundiced at birth with an elevated bilirubin of 16.8 mg/dL at hour 7 of life, positive DAT, and elution identified anti-e and anti-Rh17 antibodies. The neonate was admitted and treated with multiple doses of IVIG, phototherapy, and received one maternal directed donation collected postpartum. The neonate responded well to therapy and was discharged with normalized bilirubin levels.

Conclusions: Rh-17 antibodies can cause significant clinical outcomes including HDFN. Furthermore, antibodies against high prevalence antigens have the added complication for finding compatible blood products and may require international collaboration. In individuals with a D - - phenotype it is important to provide education and discuss the possibility of autologous donation for frozen storage. Pregnant patients have additional education needs on donation, possible need for intrauterine transfusions in severe cases of HDFN, and possible directed donation to offspring. Overall, this case highlights the importance of blood transfusion work-up during the prenatal testing period in identifying clinically significant antibodies and different methods of procuring rare blood types.

Importance of research: This case highlights the importance of antibody detection for rare phenotypes with emphasis on pregnant patients. Additional discussion on procurement of rare donor products including autologous and self directed are presented.