Clinical Study Of Minimal Residual Disease Of Acute Myeloid Leukemia Detecting By Flow Cytometry

Objective To establish the method of detecting minimal residual disease (MRD) ofacute myeloid leukemia (AML) by flow cytometry (FCM), analyse the immuno-phenotypes of the AML patients, screening out the leukemia associatied immuno-phenotypes (LAIP) for monitoring the MRD, and investigat the relationship between MRDand outcome of the patients, then identify the changes LAIP. At last,to discuss the cut-offvalue of a level similarly genetic remission, and the relationship between MRD andinitiating cells with reproducible genetics abnormaity. Methods The samples of bonemorrow from12non-leukemia&limphoma patients and5reborn BM of non-AML patientsafter hematopoietic stem cell transplantation were examined with high frequency LAIPpanels.81AML patients non-APL were diagnosed by MFC and monitoring MRDpost-remission, then collected the outcomes and other clinical items. Results (1) thebackground of asynchronous antigen expression in CD34+cells were less than5×10-4,the background of cross-lineage antigen expression were less than2x10-4; the results ofrepracticed were less than12%,and10-4leukemia cells could be detected in a AMLsample with10times dilution.(2)69cases (85.0%) could be detected specific LAIP of81de novo or relapsed AML patients, CD34were negative in26cases (32.1%), of whichseven (8.6%) were both CD34and CD117negative. In11following up cases of CD34negative patients,10could still detect MRD in CD34+cells post-chemotherapy, and theresults were consistent with clinical outcome or genetic results.176times of MRDexamination of41AML non-M3patients were tested, the survival rate was72.8%in theones that MRD≤0.06%after induction or consolidation chemotherapy, and the otherwas27.5%.22cases were detected before morphology1～6months who had trends ofrelapse,13cases(60%) relapsed in2～3months among them.(4) in24cases of AMLpatients with reproducible cytogenetic abnormalities, MRD values of cross-lineageexpression in CR&genetics positive group was (0.167±0.371)%,and the one in geneticsnegative’s was (0.009±0.010)%.The figure of asynchronous antigen expression were (0.242±0.350)%and (0.043±0.034)%(p<0.01).the optima cut-off values betweennon-CR, CR&genetics positive and genetics negative’s of cross-lineage expression were0.326%,0.08%; the value of asynchronous antigen expression were0.276%,0.023%.40samples(89.5%) of genetics positive patients could be identified with the cut-off values,and only3ones(7.7%) in genetics negative group were not accordant.(5) the ratio ofMRD and the abnormal CD34+cells was57.15(1.24～177.27) of13patients withreproducible chromosomal abnormalities who were CR but carrying low level of geneticspositive in stem or progenitor cells; the ratio of MRD and the abnormal CD34+CD38-cells was353.2(20～1950) in12cases; Conclusions (1) The method of detectingAML-MRD by flow cytometry is reliable and stable, the background is less than10-3,andthe sensitivity is between10-3-10-4.(2) LAIPs can be detected in most AML patients. Andthe MRD detection is also necessary in the ones who can’t detect LAIP at diagnosis.(3)MRD quantitation after induction or consolidation are prognostic with the outcome. AndMRD can early predict relapse trend in most patients.(4) There are significant differencesof MRD value and cut-off between the asynchronous and cross-lineage LAIPs in geneticpositive and negative patients, that the cut-off values are available.(5)It’s overall accordantwith the concept of MRD/LSC is more than2logs of the results about MRDCD34+CD38-cells with chromosomal abnormalities, but the individual variance is visible.