To Define The Aberrant Immunophenotypes Of AML For Detection Of Minimal Residual Disease By Flow Cytometry

Objective: To define the aberrant immunophenotypes of AML for detection of minimal residual disease by flow cytometry.Methods:Using the six different monoclonal antibody (MoAb) combinations (CD15/CD33/CD34, CD15/CD117/CD34, CD7/CD33/CD34, CD7/CD13/CD19,CD2/CD14/CD33, HLA-DR/CD33/CD34) for detection 31 AML bone marrows at diagnosis and 10 normal bone marrows to acquire the immunophenotypes of AML and the frequencies of it displaying in AML patients and in normal bone marrows. To acquire the date about immunophenotypes in AML and it in normal bone marrow,the multiparametric live-gates was used by flow cytometry. The discrepancy of immunophenotypes between AML bone marrows and normal bone marrows was caculated by the log difference frequency of AML immunophenotype in leukemic bone marrow /median frequency of AML immunophenorype in normal bone marrow (Log[A/N]). The immunophenotypes which Log[A/N] 2 were defined as aberrant immunophenotypes. Observing the frequency of every aberrant immunophenotype in AML and its representation for total leukemic cells mass in AML patients. In two patients aberrant immunophenotypes was identified at diagnosis and it was investigated after chemotherapy .Results: It was significant that Log[A/N] in definition of aberrant immunophenotypes and its impact. Log[A/N] 5=2 is the threshold of difining aberrant immunophenotypes. The frequencies of aberrant immunophenotypes was 42.20% 9.36% and no aberrant immunophenotypes was 49.50% 11.40%(Mann-Whitney U =35, p=0.126). The representative rate of aberrant immunophenotypes was 52.10% 11.50% and no aberrant immunophenotypes was 63.80% 8.50%( Mann-Whitney U=19, p=0.007). Twenty-two immunophenotypes was identified in 31 AML patients,among them there were 13 aberrant immunophenotypes.There were 25 patients who were identified at least one aberrant immunophenotype and 20 patients who were identified at least 4 or more aberrantimmunophenotypes.Two AML patients was displayed the courses of the reduction in leukemic cell mass.Conclusion: Twenty-two immunophenotypes was identified ,and there was 13 aberrant immunophenotypes in it. Log dif.[A/N] was signigicant to define aberrant immunophenotypes.Log dif.[A/N] was impacted by the frequencies of AML immunophenotypes in normal bone marrow. It was reasonable that Log[A/N] ^2 is the threshold of difining aberrant immunophenotypes. The log difference frequency of AML immunophenotype in leukemic bone marrow /median frequency of AML immunophenotype in normal bone marrow was also corresponds to the therapy-induced reduction in leukemic cell mass that can be quantified. Twenty-five patients who were identified at least one aberrant immunophenotype in 31 AML patients ,so it was suggested that the approach of this research can be applied to more patients with AML than another methods such as RT-PCR.The sensitivity of this method was 2.5 log difference which the reduction in leukemic cell mass.