title: Combined flow cytometric assessment of CD45, HLA-DR, CD34, and CD117 expression is a useful approach for reliable quantification of blast cells in myelodysplastic syndromes.
abstract: BACKGROUND
  Quantification of bone marrow (BM) blasts by cytomorphology is essential for the diagnosis of myelodysplastic syndromes (MDS). Owing to its subjectivity and the potential impact of dysplastic features on accurate identification of blast cells, more objective approaches are required, multiparameter flow cytometry (MFC) being a particularly promising approach in this regard. However, no consensus exists about the optimal combination of markers and strategy to be used.
  
  
  METHODS
  BM blast counts from 74 MDS patients were evaluated by morphology versus four different MFC phenotypic criteria: "CD34⁺", "CD34⁺ and/or CD117⁺", "CD34⁺, and/or CD117⁺ HLA-DR⁺", and "CD34⁺ and CD117⁺ HLA-DR⁺ plus CD64⁺ CD14(-/lo) " cells. For each criterium, the percentage of blasts was calculated using either all BM nucleated cells or non-erythroid CD45⁺ cells as denominator. RESULTS.: The number of "CD34⁺ and/or CD117⁺ HLA-DR⁺"cells showed the highest correlation and agreement with morphological counts, only a minor proportion of cases being misclassified by MFC vs. morphology for the >5% and >10% classification thresholds. In turn, a CD34⁺ phenotype was insufficient to correctly identify and quantify blasts. Conversely, usage of non-erythroid BM cells as denominator, or inclusion of "CD34⁺ and/or CD117⁺ HLA-DR⁺ plus CD64⁺ CD14(-lo") cells were both associated with overestimated blast counts.
  
  
  CONCLUSIONS
  Quantification of "CD34⁺ and/or CD117⁺ HLA-DR⁺" cells (from all nucleated BM cells) by MFC is an efficient method for the enumeration of blasts in MDS. However, caution should be taken with replacing morphology by MFC blast counts; its combined use may rather provide complementary information increasing the accuracy and reproducibility of BM blast cell counts in these patients.
authors.affiliation: Division of Hematology, Department of Clinical and Experimental Oncology, Escola Paulista de Medicina-Universidade Federal de São Paulo, UNIFESP-EPM, São Paulo, Brazil.
authors.forename: Alex F
authors.initials: AF
authors.lastname: Sandes
authors.forename: Daniella M B
authors.initials: DM
authors.lastname: Kerbauy
authors.forename: Sergio
authors.initials: S
authors.lastname: Matarraz
authors.forename: Maria de Lourdes L F
authors.initials: Mde L
authors.lastname: Chauffaille
authors.forename: Antonio
authors.initials: A
authors.lastname: López
authors.forename: Alberto
authors.initials: A
authors.lastname: Orfao
authors.forename: Mihoko
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000032:analysis* / Q000235:genetics; D015415:Biomarkers / Q000032:analysis; D002452:Cell Count; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression; D042381:Granulocyte Precursor Cells / Q000378:metabolism* / Q000473:pathology; D006684:HLA-DR Antigens / Q000032:analysis* / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping; D017493:Leukocyte Common Antigens / Q000032:analysis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis* / Q000235:genetics; D015203:Reproducibility of Results
chemical_list: D018952:Antigens, CD34; D015415:Biomarkers; D006684:HLA-DR Antigens; D019009:Proto-Oncogene Proteins c-kit; D017493:Leukocyte Common Antigens