Urgent Transfusion in a New Patient with Rare Blood Type

Background/Case Studies: Bombay is a rare blood group characterized by the absence of H substance at the surface of RBCs leading to naturally occurring anti-H antibodies. Anti-H presents the risk of severe hemolytic transfusion reactions in these patients. The case presented is of a 32-year-old female of Middle Eastern origin, who presented with a traumatic vertebral fracture with spinal cord compression and required urgent neurosurgery. Her presenting hemoglobin was 84 g/L. She had no previous group and screen on record, had never been transfused and had a history of a remote miscarriage. Study Design/Methods: Forward blood group with an automated gel-method instrument revealed the following reactions: negative with anti-A, unable to interpret (?) with anti-B, 4+ with anti-D. Reverse grouping revealed the following reactions: 4+ with A1-cells and an unexpected 1+ with B-cells. The antibody screen and 11 cell panel in gel (Micro Typing Systems) 2+; the panel, with enhancement reacted 3+ in Ficin. The auto control was negative. A second panel and pre-warm panel produced the same findings. An antibody reacting at 37C against a high-frequency antigen was suspected. Patient specimen was sent for investigation to the reference lab (RL), which performed blood group by manual tube test, antibody identification with panels by manual tube PEG-IAT method; RL also sent a sample for ABH sequencing (Sanger). Results/Findings: A thawed frozen plasma sample from a previous Bombay patient 12 years prior showed no reactivity against the patient's RBCs; positive control included. A frozen Bombay RBC unit was ordered urgently from the blood supplier and was crossmatch compatible. The patient underwent surgery and was transfused with a single unit of RBC for peri-operative bleeding. She was treated with erythropoietin and IV iron post-operatively and did not require any further transfusions. The investigation at the RL showed mixed field reaction on forward blood typing with anti-B and anti-A,B and negative reaction with anti-A commercial reagents. The RL reverse grouping showed 4+ with all O H+ and A1 red cells, but 2+ with B cells. The autocontrol and group O H- cells did not react, confirming anti-H and suggesting Para-Bombay group. ABH sequencing revealed a normal B allele (ABO*B.01) while genotyping of FUT1 revealed a null allele (FUT1*01N.12) and weak H allele (FUT1*01W.23). FUT2 genotyping (FUT2*01N.02) predicted a nonsecretor (sese) phenotype. Conclusions: This patient with non-secretor status, variant H production, clinically significant anti-H, greatly reduced B antigen expression, should be treated as a Bombay (Oh) for transfusion purposes. She was counselled and provided with an antibody card and a letter. This case illustrates the importance of timely communication with the clinical team about the risks and benefits of transfusion pending antibody identification, as it could have proved fatal in this case. Figure Disclosures Pavenski: Bioverativ:Research Funding;Shire/Takeda:Honoraria;Octapharma:Research Funding;Alexion:Honoraria, Research Funding;Sanofi:Research Funding;Ablynx/Sanofi:Honoraria, Research Funding.

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