EMM negative: Rare blood type discovered in Rajkot man

AHMEDABAD: A 65-year-old man from Rajkot was in for a surprise when he could not find blood matching his blood group for a cardiac surgery in 2020. The surprise was compounded as his known blood group was AB positive, the universal acceptor. His long struggle eventually led to the discovery of India's first 'EMM negative' blood case - the 11th such case across the globe.
The paper 'Anti Emm, a rare specificity to the high incidence antigen Emm in an Indian patient defining the new blood group system EMM (ISBT042)' has been published in Asian Journal of Transfusion Science by Ripal Shah, Snehal Senjaliya and Sanmukh Joshi among others. Dr Ripal Shah, director of the Prathama Blood Bank in Ahmedabad, said when matching blood was not found at Rajkot blood banks, the patient arrived in Ahmedabad with the same result. "He needed it for a coronary artery bypass grafting surgery. An antibody in the blood was reacting in saline and antiglobulin phases. Even his children's blood did not match his," she said.
The blood samples were later sent to Surat for advanced analysis and eventually to a facility in the US. The results indicated that the blood lacked the EMM phenotype. "It's present in almost all human red blood cell (RBC). Thus, its absence made it difficult to match with any existing samples. As there was no history of transfusion in the patient, it happened naturally. Among his relatives, only his brother has a similar blood type, but not the same," said Dr Shah, adding that in case of an emergency, his brother could have given him blood. "But the patient succumbed to other health complications."
'The case was instrumental in recognizing Emm as a new blood group system, assigned the symbol ISBT042,' the paper said.