Bombay blood group

Bombay Blood Group Overview

The Bombay blood phenotype is a rare blood group first discovered in Bombay (Mumbai), India, by Dr. Y.M. Bhende in 1952.
Characterized by the absence of the H antigen, also referred to as the Oh blood group.

Dr. Bhende published a significant paper in 1952 detailing the characteristics and implications of the Bombay blood group.
The discovery arose from a case in December 1951 when a patient admitted to K.E.M. hospital was found to be O-Positive but agglutinated all O group cells during cross-matching.
The Bombay and Para-Bombay phenotypes result from a mutation in the FUT1 gene, leading to complete (H deficient) or partial H deficient phenotypes, respectively.

Individuals with the Bombay blood group possess:
- Absence of all normal A, B, and H antigens on their red blood cells.
- Presence of corresponding antibodies (anti-A, anti-B, and anti-H) in their serum.
The H antigen is synthesizable via the H gene (FUT1 and FUT2), which plays a crucial role in red blood cell antigenicity.
Individuals inherit two rare recessive h genes, which are different from the ABO gene locus.
The phenotype results in the unique antibody profile, with anti-H being a significant component that can cause severe transfusion reactions.

Despite lacking A and B antigens, due to the absence of H antigens, individuals are initially classified as O blood group.
Cross-matching reveals incompatibilities that require special attention during transfusions.
Individuals with the Bombay phenotype can only receive blood from other Bombay blood group individuals.
They can donate blood to all ABO blood groups, making it critical for blood banks to identify and reserve Bombay blood for urgent cases.

Bombay phenotype individuals should be cautious, especially during surgeries, to ensure compatible blood is available.
Standard blood donor programs may overlook or misidentify the Bombay blood group due to its rarity.
Proper testing requires anti-H lectin to confirm deficiency and reverse grouping with O cells for anti-H presence.

Absence of H, A, and B antigens leading to no agglutination with anti-A, anti-B, or anti-H lectin.
Presence of potent anti-A, anti-B, and anti-H antibodies in serum, which can cause red cell lysis upon transfusion.
Non-secretion of A, B, or H substances in saliva (non-secretor).
Absence of H enzyme and H antigen on red cells.
Compatibility is limited to transfusions from other Bombay group individuals.

The Bombay blood group remains a significant medical curiosity discovered about 60 years ago, requiring meticulous blood grouping to identify in clinical settings.
Due to its close mimicry with O blood group phenotypes, the need for vigilant testing and awareness is paramount to prevent misdiagnosis and inappropriate transfusions.

Bhende Y M, et al. A new blood group character related to the ABO system. National Medical Journal of India, 2008.
Nirmala Jonnavithula, et al. Perioperative red cell transfusion management in a rare H deficient (para Bombay) blood group variant. Indian Journal of Anaesthesia, 2013.
Various other studies on blood group serology and the implications of the Bombay phenotype.