Immunohematological Investigation in a Polytransfused Patient With Transformation to Acute Myeloid Leukemia: Limits of Hemagglutination
Year: 2026
Type: article
Study design: Case Report
Abstract: Introduction Transformation of myelodysplastic syndrome into high-risk acute myeloid leukemia may have a rapid course. In transfused patients, the concomitant circulation of autologous and donor red blood cells produces a dual erythrocyte population, making it difficult to determine the autologous serologic phenotype and to interpret immunohematological tests. Case report Male patient, with a history of multiple transfusions, aged between 70 and 79 years, blood group O RhD positive, with myelodysplastic syndrome transformed into acute myeloid leukemia. He was admitted with febrile neutropenia of pulmonary focus and colitis, and the condition progressed over eight days. Leukocyte count increased from 12,010/µL to 212,750/µL, with the proportion of blasts increasing from 50% to 79%. Hemoglobin remained below 7 g/dL, with a nadir of 5.9 g/dL. Extramedullary infiltration occurred, characterized by hemorrhagic pleural effusion with 59% blasts. The direct antiglobulin test and autocontrol were positive, both with 1+ intensity, and crossmatches showed incompatibility ranging from 2+ to 4+. Rh/Kell phenotyping demonstrated a K-negative profile, while CcEe indicated the presence of a dual erythrocyte population, consistent with the transfusion history. Screening for irregular antibodies in low ionic strength solution and human antiglobulin, performed at cold temperature, was negative, and reactivity of 1+ was observed only in the enzymatic medium with papain, without specificity being defined. Despite treatment of the hyperleukocytosis, the patient developed neurological, respiratory, renal, and metabolic complications, followed by multiple organ failure. The patient required transition to palliative care and subsequently died. Discussion The dual erythrocyte population is an expected phenomenon after transfusions, but by itself it does not characterize alloimmunization. In this context, serologic phenotyping was compromised because it did not exclusively represent the autologous red blood cells. The association between incompatible crossmatches, negative screening in human antiglobulin, and positive autocontrol allows for different interpretations, as it may simultaneously assess autologous and donor red blood cells, including autoantibody or reactivity against transfused red blood cells. Complementary methods may broaden the investigation: acid elution helps characterize antibodies bound to red blood cells, while erythrocyte genotyping allows inference of the autologous antigenic profile without interference from transfused red blood cells. In the present case, the serologic findings did not allow definitive differentiation among the hypotheses considered, due to the rapid clinical course with leukemic progression, hyperleukocytosis, and multiple organ failure. Conclusion In polytransfused patients, hemagglutination may be insufficient to determine the autologous phenotype and interpret complex immunohematological reactivities. The integration of transfusion history, serologic tests, and complementary methods allows for a more accurate assessment, considering that acid elution and erythrocyte genotyping better address diverse diagnostic questions.
Institution: Universidade Federal de Goiás
Language: English
Topic: Blood groups and transfusion
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7223119622