Change of ABO blood group in a patient with Acute Myelocytic Leukemia (AML): a case report

Background: ABO and Rhesus blood groups are clinically important, especially in blood transfusion. Blood groups are determined by the antigens found on the erythrocyte membrane. In patients with hematologic malignancies, especially from the myeloid lineage, changes in blood group can occur in the ABO system mainly due to weakness or loss of some ABO antigens. Case Description: A nine-year-old girl was admitted to the hospital with a chief complaint of high fever three days before admission. The patient had been diagnosed with acute non-lymphoblastic leukemia three months ago. From medical history, the patient had undergone chemotherapy and received 22 bags of PRC transfusion with blood group O (+) from February 27th until May 28th 2018. On July 21st 2018, the transfusion procedure was repeated, and the blood group showed B (+). The procedure was repeated using a new sample but the result remained the same. The crossmatch was performed with five blood groups O (+) and two blood groups B (+) showed mayor: negative, minor:+weak, AC:+weak, mayor: negative, minor:+weak, AC:+weak, respectively. Conclusion: Changes in blood group antigens in hematologic malignancies that experience ABO antigen alternation and return to the original blood group reflect the remission from the disease. The expression of H antigen in blood groups A and B may revert to normal with an improvement from the underlying disease.