Leukemia Research 31 (2007) 147–155 Detection of hematopoietic maturation abnormalities by flow cytometry in myelodysplastic syndromes and its utility for the differential diagnosis with non-clonal disorders Irene Lorand-Metze a,∗ , Elisangela Ribeiro a , Carmen S.P. Lima a , Lilia Su´ arez Batista b , Konradin Metze c a Department of Internal Medicine, Hemocentro, State University of Campinas, P.O. Box 6198, BR-13081-970 Campinas, S˜ ao Paulo, Brazil b Centro de Investigaci´ on del C ´ ancer Servicio General de Citometr´ıa, Departamento de Medicina, Universidad de Salamanca, Salamanca, Spain c Department of Pathology, State University of Campinas, Campinas, S˜ ao Paulo, Brazil Received 6 March 2006; received in revised form 24 April 2006; accepted 25 April 2006 Available online 5 June 2006 Abstract The diagnosis of myelodysplastic syndromes (MDS) is based on peripheral cytopenias, bone marrow (BM) morphology and karyotyping. This may be difficult in cases with few dysplastic elements in BM and a normal karyotype. We examined the utility of flow cytometric analysis for the differential diagnosis between MDS and non-clonal disorders (NCD) presenting peripheral cytopenias. Quantitative assessment of CD45, CD16, CD13, CD11b, CD10 and CD64 in granulocytes and monocytes, and CD71 and glycophorin A in erythroblasts besides CD34+ cell count was performed in BM of 31 consecutive newly diagnosed patients with MDS, 11 patients with NCD and 11 healthy controls (BM donors). In MDS, the median number of phenotypic abnormalities found was 3 (1–8). The WPSS score showed a correlation with the total number of changes per case (r = 0.48; p = 0.002). Decreased SSC in promyelocytes correlated with the peripheral neutrophil count (r = −0.46; p = 0.007). In NCD, the normal variation of antigen expression along granulocytic and erythroblast maturation was always maintained. In the discriminant analysis, SSC of CD34+ cells, together with that of promyelocytes and metamyelocytes were able to correctly classify 87% of the cases as clonal or non-clonal. Our quantitative approach permitted to detect at least one abnormality in antigen expression in every case of MDS. However, the most important parameters for differential diagnosis with NCD were the analysis of the granularity in immature cells, especially of the granulocytic series. © 2006 Elsevier Ltd. All rights reserved. Keywords: Myelodysplastic syndromes; Bone marrow; Cell maturation; Antigen expression; Monocytes; Flow cytometry 1. Introduction Myelodysplastic syndromes (MDS) are clonal disorders of the hematopoietic stem cell leading to alterations in prolifera- tion, maturation and apoptosis of erythroid, myelomonocytic and megakaryocytic precursors [1–5]. Usually, the diagno- sis is based on peripheral blood counts, bone marrow (BM) cytology and histology as well as cytogenetics. However, when few cell atypias are seen in BM examination and kary- otype is normal, the differential diagnosis with non-clonal ∗ Corresponding author. Tel.: +55 19 3788 87 40; fax: +55 19 3788 86 00. E-mail address: ilmetze@unicamp.br (I. Lorand-Metze). disorders presenting cytopenias may be difficult [3,5]. Multi- parameter flow cytometry (FCM) has been extensively used to analyze hemopoietic precursors both in normal BM as well as in several diseases and constitutes a fast and highly reproducible technique to analyze cell lineages, abnormal co-expressions and maturation asynchrony [6–8]. Recently, several approaches have been made to examine some fea- tures of BM in MDS [7–19]. Abnormal phenotype of blasts, such as CD7/CD56/CD117, co-expression of CD34/CD10 and CD34/CD11b has been described, especially in RAEB [11,14,15]. Asynchronous expression of several antigens dur- ing the maturation of granulocytic precursors, monocytes and erythroblasts has been reported [5,7–11,13]. Emphasis 0145-2126/$ – see front matter © 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.leukres.2006.04.010