[Prognosticating relapse risk based on multiparameter flow cytometric assessment of minimal residual disease in patients with acute myeloid leukemia].

The objective of this study was to investigate the prognosticating value of multiparameter flow cytometry in detection of minimal residual disease (MRD) and relapse risk of patients with acute myeloid leukemia (AML). Multiparameter flow cytometry (MPFC) analysis was used to detect the leukemia-associated aberrant immunophenotype (LAIP) of the pretreated patients with AML and to assess the levels of MRD after remission induction (Post-Ind MRD) and consolidation therapy (Post-Cons MRD). The results showed that the definite LAIP could be detected in 94.3% of the patients (115/122) with AML (except APL). Among 115 cases only one LAIP was identified in 15 cases (13.0%), but two or more LAIP were identified in other 100 cases (87.0%). 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 AML patients with CR 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 cases of Post-Ind MRD(+) and Post-Ind MRD(-) were 75.0% (18/24) and 29.4% (5/17) respectively after consolidation chemotherapy. The relapse free survival (RFS) times of the patients with Post-Ind MRD(+) and Post-Ind MRD(-) were 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 cases of Post-Cons MRD(+) and Post-Cons MRD(-) patients were 100% (18/18) and 21.7% (5/23) respectively after consolidation chemotherapy. The RFS times of the patients with Post-Cons MRD(+) and Post-Cons MRD(-) were 41.74 +/- 5.52 months and 10.06 +/- 1.72 months (p < 0.0001) respectively. It is concluded that the levels of post-Ind MRD and post-Cons MRD identified in the patients with AML was highly associated with their RFS. The detection of MRD by MPFC provides prognostic information in AML patients.