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.