Diagnostic Value Of Five-parameter Flow Cytometric Scoring System In Myelodysplastic Syndrome

BackgroundMyelodysplastic syndrome(MDS)is a group of clonal disease derived from hematopoietic stem cell,characterized by myeloid pathological hematopoiesis,cytopenia in peripheral blood cells,and high risk differentiation of acute myeloid leukemia(AML).Diagnosis mainly depends on bone marrow cell morphology and genetic abnormal changes.But there are some patients lack specific abnormalities and is difficult to diagnose and treat in clinical practice.Flow cytometry(FCM)can clearly distinguish the abnormal expression of cells,and plays an increasingly important role in the qualitative and quantitative diagnosis of bone marrow malignant tumors.Many reports had published the potential value of flow cytometry in the diagnosis of MDS.Ogata proposed a four-parameter flow cytometric scoring system in 2009.The results of this study suggest that the method for the diagnosis of MDS is quick,simple,low cost,and have good specificity,but the sensitivity is not ideal(the sensitivity ranges from 30%to 70%,and the specificity ranges from 80%to over 90%).Therefore,more clinical studies are needed to confirm and improve on this basis.The preliminary research results of our group suggest that the system is valuable for the diagnosis of MDS,but with the increase of the sample cases,the Ogata score has a large misdiagnosis rate.Therefore,based on the immunophenotypic characteristics in granulocyte of MDS,we added a new parameter:the granulocyte to lymphocytes CD10 mean fluorescence intensity ratio.We studied the detection and analysis methods of new parameters,and verified the diagnostic value of new flow cytometric scoring system.ObjectiveBased on the traditional four-parameter flow cytometric scoring system,to establish a new five-parameter flow cytometric scoring system for assisting the diagnosis of MDS and validate its clinical applicability.MethodsThe flow parameters were analyzed retrospectively in 320 patients with peripheral blood cell reduction,and divided into two parts according to time:study group,140cases(for the establishment of five-parameter flow cytometric scoring system)and verification group,180 cases(for the validation of the clinical application value of the scoring system).The patients in the study group were diagnosed clearly,including 34patients were diagnosed as MDS,106 patients were diagnosed as non-MDS,the diagnosis of MDS were performed in accordance with the diagnosis and treatment expert consensus standard(2014).The validation group included patients diagnosed as MDS(n=29),non-MDS(n=86)and cytopenia reasons to be investigated(n=65)at the initial diagnosis,after clinical follow-up at least 6 months,31 patients were diagnosed as MDS,149 patients were diagnosed as non-MDS.The parameter were detected by flow cytometry,added a CD10-FITC/CD45-PC7antibodycombinationbasedonthetraditional CD34-FITC/CD19-PE/CD33-APC/CD45-PC7 antibody combination,and the expression of following parameters were compared between the groups.Parameter 1:percentage of cells in the myeloblast-related cluster in all nucleated cells;parameter 2:percentage of cells in B-progenitor-related clusters in all CD34+cells;parameter 3:the lymphocyte to myeloblast CD45 mean fluorescence intensity ratio;Parameter 4:the granulocyte to lymphocyte side scatter(SSC)ratio;parameter 5:the granulocyte to lymphocyte CD10 mean fluorescence intensity ratio,set cut-off value,establish a five-parameter flow cytometric scoring system for the diagnosis of MDS diagnosis,and evaluate the diagnostic value.Results1.Compared with non-MDS patients,MDS patients had significantly increased myeloblast-related cluster size(P=0.008);decreased B-progenitor-related cluster size(P<0.001);the mean fluorescence intensity of CD45 in myeloblast-related cluster was not different significantly(P=0.241),but the expression pattern was abnormal;the granulocyte to lymphocyte side scatter ratio was reduced significantly(P<0.001);the granulocyte to lymphocyte CD10 mean fluorescence intensity ratio was reduced significantly(P<0.001).2.The reference range of each parameter of the flow cytometric scoring system is determined(parameter 1 is≥1.35,parameter 2 is≤0.75,parameter 3 is≤1.0 or≥7.0,parameter 4 is≤5.94,and parameter 5 is≤3.15),one point was given for each parameter inside the reference range,when score 2 or more is defined as positive,the sensitivity and specificity in the study group is 85.3%and 87.7%respectively.3.Compared with the traditional four-parameter flow cytometric scoring system,the improved five-parameter flow cytometric scoring system has significantly improved diagnostic accuracy,the difference was statistically significant(χ~2=13.581,P<0.001).4.The flow score of MDS patients was positively correlated with the risk stratification of revised international prognostic scoring system(r=0.752,P<0.001).ConclusionsThe improved five-parameter flow cytometric scoring system can assist the diagnosis of MDS,and the diagnostic sensitivity and specificity is significantly improved compared with the traditional four-parameter flow cytometric scoring system.The analysis method is simple and easy,which provides a new idea for clinical diagnosis of MDS.