(P-TS-28) Case Study of Weakening ABO Antigen Reaction in Patient with Acute Myeloid Leukaemia

Background/Case Studies: ABO blood typing discrepancy is one of the main challenges faced in blood banking which can directly affect patient care. Weakening of ABO antigens is an uncommon occurrence that has been documented in various clinical conditions, particularly those involving genetic mutations. This phenomenon warrants investigation due to its potential clinical significance. We present an 85 years old Female patient who was diagnosed with Acute Myeloid Leukaemia (AML) in May 2023. In April 2024, approximately 11 months’ post-diagnosis, notable changes were observed in the patient’s ABO forward grouping Anti-A reaction grading.

Patient initially presented as group A POS in May 2023. Later in April 2024, patient forward grouping had a discrepancy in Anti-A testing showing a mixed field reaction. Patient had no previous non-identical blood transfusion and no record of an allogenic stem cell transplant. Sample was sent out to a reference lab and results identified patient as group A POS and the mixed filed reaction was likely due to patient clinical condition. Possibility of weakened antigen expression was suspected due to patient’s diagnosis of Acute Myeloid Leukaemia (AML).

Patient Flow cytometry findings are in keeping with AML, on a background of myelodysplasia. Molecular Genetics identified double mutation in the CEBPA gene a p.Q347dup and a p.A106fs variant were observed.

Study

Design/Methods: Data was studied to co-relate the possible trend of AML progression via Blast % against Anti-A antisera reaction grading (ABO grading data obtained using OrthoBioVue® System on the Ortho VisionMax®).

Blast % was compared to ABO forward grouping reaction grading over the course of patient disease progression from May 2023 till Nov 2024 as shown in Graph 1.

Results/Findings: Observed a trend of increased blast % co-relating to a decrease in Anti-A reactivity from 4+ in May 2023 to reported negative in Oct 2024. Initial Mixed field reaction seen in Anti-A was seen with a gradual increase in the number of blast % from early April 2024 to end of June 2024. After which there was a surge in Blast % with a significant drop in Anti-A reactivity from Mixed field to a 2+ grading.

Conclusions: Data suggests a possible co-relation between AML progression through an increase in Blast % and loss of ABO antigen expression/inactivation over course of disease. This proves useful in future interpretation and direction in resolving ABO discrepancies based on patients with double CEBPA mutation with an increase in Blast %. However, more patients with similar ABO weakening reaction need to be studied to further conclude.