Para-Bombay phenotype - report of a rare blood group

Abstract

The blood sample of a 54-year-old male patient who presented with signs and symptoms suggestive of anaemia was submitted to the Blood Bank for blood grouping and cross-matching. In forward grouping, no agglutination was observed with A, B and AB antisera, but agglutination was noticed with D antiserum (Group O). In reverse grouping, there was agglutination in tube labelled A and no agglutination in tubes B and O (Group B) resulting in discrepancy between forward and reverse grouping. Further testing confirmed that the individual's blood group was Para-Bombay B (Para-BH), which is a rare entity. The Para-Bombay phenotype is very rare. Only a few cases of Para-Bombay were reported in India till now and none from Andhra Pradesh. This entity is characterized by the absence of H, A and B antigens on the red cells but their presence in saliva and secretions of gastrointestinal and genitourinary tracts. Proper identification of this phenotype is very important; otherwise this particular blood group may be mislabelled as group O.