Montefiore Medical Center Network Hospitals, United States
Background/Case Studies: The Bombay (Oh) phenotype is a rare blood group that lacks A, B, and H antigens, resulting in the development of potent anti-H antibodies. Individuals with this phenotype cannot receive ABO-compatible blood due to the universal presence of H antigen on most red blood cells. This report presents a case of a pregnant patient identified with the Bombay phenotype, emphasizing the critical importance of accurate blood typing, antibody detection, and multidisciplinary clinical management.
Study
Design/Methods: This case study involved serologic blood typing using standard ABO and Rh(D) typing reagents, reverse grouping with A1, B, and O screening cells, confirmatory testing using anti-H Lectin ( Ulex europaeus), and Titration Study. The patient's antibody screen and identification panel were reviewed. In addition, the patient’s sample was submitted for additional DNA analysis of the FUT1 gene to confirm the patient’s Oh (Bombay) phenotype Family studies and donor searches were initiated to find compatible blood.
Results/Findings: < !Anti-H detected at saline RT, LISS IAT, PEG IAT and Papain IAT. No other expected antibodies were detected by the PEG IAT. To facilitate the exclusion of other alloantibodies to the common antigens, the Patient’s plasma was adsorbed onto an untreated phenotypically similar RBC. After four adsorptions at 37’C, no underlying alloantibodies were detected by the PEG IAT.
< ! Titration Study: Testing method is by saline IAT with 60 minutes of incubation at 37’C and using anti-IgG against RBCs with single dose expression of the target antigen. Against group O(H+) RBCs, the titter is 64 (Score 64).
< !The Patient’s sample also submitted for DNA analysis of the FUT1 gene to confirm patient’s Oh (Bombay) phenotype
Conclusions: This case highlights the importance of correctly identifying rare blood phenotypes like Bombay, particularly in pregnant patients. Anti-H will likely cause an immediate, severe hemolytic transfusion reaction. Misclassification may result in serious transfusion complication. Prompt identification, antibody titration, DNA analysis and coordination with MFM and hematology specialists are vital. The case underscores the need for access to rare donor registries and emphasizes the role of preemptive autologous donation or intrauterine transfusion planning in high-risk pregnancies.
