A rare case of Bombay blood group presenting as an acute hemolytic transfusion reaction

Blood group antigens are crucial in medical contexts, especially blood transfusions. The ABO system, discovered by Karl Landsteiner in 1900, is the most significant. In 1952, a rare blood group, the Bombay phenotype, was identified in Bombay, India. A 24-year-old male with severe anemia (hemoglobin 2.7 g/dl) was initially mistyped as O-positive and received a transfusion, leading to an acute hemolytic reaction. He presented with severe symptoms and was referred to a higher center. Despite initial blood group testing indicating O Rh D positive, subsequent testing revealed incompatibility with O Rh D positive blood. Further tests diagnosed him with the Bombay blood group (Oh Rh D+). His mother’s blood, matching his phenotype, was used for transfusion. Additional Bombay phenotype blood was sourced from Tamil Nadu with NGO assistance. The patient also received hemodialysis and iron therapy due to kidney dysfunction and iron deficiency. He was managed with diuretics and hematinic and eventually discharged. Bombay phenotype results from a mutation in the FUT1 gene on chromosome 19, preventing the synthesis of the H antigen necessary for A and B antigen expression. Consequently, individuals with this phenotype lack A, B, and H antigens and have anti-A, anti-B, and anti-H antibodies in their plasma, making them incompatible with all other blood types and prone to acute hemolytic reactions if transfused incorrectly. Misidentification as O blood group is common due to similar reactions with antiserum. Para-Bombay is a related phenotype with either weak expression of ABH antigens on red blood cells or in body secretions, unlike the Bombay phenotype, which lacks ABH antigens in both. Accurate identification and compatibility are crucial for safe transfusions, highlighting the need for rigorous blood grouping procedures and a central registry to facilitate blood donations from individuals with the Bombay phenotype. Establishing a national registry and considering cryopreservation are recommended to ensure the availability of compatible blood for those with this rare phenotype.