The applicability of multiparameter flow cytometry for the detection of minimal residual disease using different-from-normal panels to predict relapse in patients with acute myeloid leukemia after allogeneic transplantation.

BACKGROUND: The MRD status detected using multiparameter flow cytometry (MFC) before allogeneic hematopoietic stem cell transplantation (allo-HSCT) has crucial prognostic value for patients with acute myeloid leukemia (AML) in morphologic complete remission (CR). We designed a novel panel of antibodies to identify aberrant differentiation/maturation profiles of residual leukemia cells in patients who were not diagnosed at our institution, relapsed with an antigenic shift, or lack leukemia-associated immunophenotypes.

METHODS: We compared the MRD status detected using MFC and real-time quantitative polymerase chain reaction (RT-qPCR) in the same 158 bone marrow samples collected from 44 AML patients carrying leukemia-specific fusion genes. The clinical performance of the MFC-based MRD status was analyzed in 168 AML patients who exhibited morphologic CR (135) or active disease (33) before HSCT.

RESULTS: Strong concordance was found between MFC-based and RT-qPCR-based MRD status (κ = 0.868). Among the patients displaying CR, the positive MRD status detected using MFC was correlated with a worse prognosis [HRs (P values) for relapse, event-free survival, and overall survival: 4.83 (<0.001), 2.23 (0.003), and 1.79 (0.049), respectively]; the prognosis was similar to patients with an active disease before HSCT. Patients with a positive MRD before HSCT might experience a benefit from developing chronic graft-vs-host disease.

CONCLUSIONS: The assessment of MRD using our self-built different-from-normal AML-MRD detection panel exhibited reliable sensitivity, specificity, and accuracy. In addition, patients with a positive MRD status before transplantation may have higher risk of relapse and worse survival.