No abstract

A 22-year-old woman with symptomatic anaemia, who had never been transfused, was hospitalized in a county hospital and a cross-match was requested. Two populations of erythrocytes were observed on direct ABO typing using monoclonal antibodies; there was a smaller group A population and a larger population that did not react with anti-A (top). The smaller subpopulation reacted with anti-A1 lectin, indicating an A1 subgroup. There was strong agglutination of group B cells on reverse typing. Because of these reactions, the diagnosis of a haematological malignancy, with abnormal DNA methylation was suspected. Subsequently, the patient was admitted to the university hospital and was diagnosed with acute myeloid leukaemia, with maturation. She was treated with standard induction therapy followed by two cycles of consolidation chemotherapy, and achieved complete remission. Three months after the last transfusion, she typed as group A (bottom), indicating that the initial loss of A antigen was due to the leukaemia.