Prognosticating of Relapse Risk Based on Multiparameter Flow Cytomeric Assessment of Minimal Residual Disease in Patients with Acute Myeloid Leukemia

Abstract Objective: To investigate the prognosticating of relapse risk based on assessment of minimal residual disease(MRD) in patients with acute myeloid leukemia(AML).

Methods: Multiparameter flow cytometry (MPFC) analysis were used to detect the leukemia-associated aberrant immunophenotype (LAIP)of the pretreated patients with AML and assess the level of MRD after remission induction(Post-Ind MRD) and consolidation therapy(Post-Cons MRD).

Results: The results showed that definite LAIP could be detected in about 94.3%of patients (115/122) with AML (except APL). Only one LAIP was identified in 15 cases (13.0%), but in other 100 cases (87.0%), two or more LAIP were identified. The most frequent LAIP identified was cross-lineage antigen expression (40.9%). The percentages of asynchronous antigen expression, antigen over-expression and antigen lack expression were 20.9%, 27.0% and 34.8% respectively. MRD frequency was monitored in 41 CR patients with AML after remission induction chemotherapy and 2 or more cycles of consolidation chemotherapy. 24 patients were Post-Ind MRD+ and 17 patients were Post-Ind MRD−. The percentages of relapse in Post- Ind MRD+ and Post-Ind MRD− were 75.0%(18/24) and 29.4%(5/17) respectively after consolidation chemotherapy. The relapsed free survival(RFS) of the patients with Post-Ind MRD+ and Post-Ind MRD− was 49.06±6.53 months and 11.92±1.64 months(P<0.0001) respectively. 18 patients were Post-Cons MRD+ and 23 patients were Post-Cons MRD−. The percentages of relapse in Post-Cons MRD+ and Post-Cons MRD− patients were 100%(18/18) and 21.7%(5/23) respectively after consolidation chemotherapy. The RFS of the patients with Post-Cons MRD+ and Post-Cons MRD− was 41.74±5.52 months and 10.06±1.72 months (P<0.0001) respectively.

Conclusions: The level of post-Ind MRD and post-Cons MRD identified in the patients with AML was highly associated with their RFS. MRD measured by MPFC provided prognostic information in AML patients.