Abstract
Abstract 4846
Myelodysplastic syndrome (MDS) is heterogeneous clonal hematopoietic stem cell disorder characterized by cytopenia(s) and dysplasia in one or more cell lineage. Though flow cytometry (FCM) is an important diagnostic tool in hematopoietic cell disorders, a prominent immunophenotyping feature in MDS may not be determined. In this study, we retrospectively evaluated flow cytometric features of bone marrow samples diagnosed as MDS with clinical and hematological findings.
Between Feb 2004 and March 2009, flow cytometric parameters of 73 patients (M/F: 50/23) with MDS were re-analyzed. Median age was 59 years (17-89 ys). Our general principles are to evaluate quality of bone marrow samples, to determine proportion of the cells and features of their light scatter, and to give percentage of the blast. When detected a finding of dysplasia in the first analysis, the second step includes the determination of the maturation of the cells and the presence of the aberrant antigen expression.
The samples were interpreted as MDS in % 76.7, MDS-RAEB-1 or RAEB-2 in %16.4, myeloproliferative disorder in %1.4 and non-diagnostic in %6.8 of the cases by flow cytometric examination. We detected variable degrees of hypogranulation in myeloid lineage in %82.2 of the samples by the light scatter features of the cells: 85% of severe and 15% of moderate or mild hypogranulation. The ratio of myeloid and lymphoid was changing from 0.3 to 17.5 (median 2). The decreasing of this ratio (<1) was observed in 19.4% of the samples. We detected altered expression of mature granulocyte. These included decreasing or lack of expression in CD15 45/73 (61.4%), CD13 38/70 (54.3%), CD16 53/67 (79.1%), CD11b 51/71 (71.8%), CD24 44/69 (65.2%), CD10 23/72 (31.9%) and MPO 14/72 (19.4%). Besides, bright expression of CD33 in 53.5% of the samples was observed. CD36 and CD56 in myeloid lineage were co-expressed in about 50 % of the samples. In 80.8 % of the samples dysplasia in erythroid compartment could be evaluated: Expression of CD71 according to glycophorin A (ratio <1) was decreased in 23.7 %. When we made similar analysis in the samples without RAEB-1 and -2 as pathological examination of bone marrow, 13.4 % of the samples could not be evaluated in favor of dysplasia. Of the samples with dysplasia hypogranulation, aberrant antigen expression of myeloid lineage and eryhtroid dysplasia were observed in 92.1%, 34.1% and 31.5%, respectively. In conclusion, FCM events may help to the differantial diagnosis of MDS especially when combining with clinical events. Improving of the analysis by focusing on the blast characteristics may be a standard approach to evaluate for low risk MDS.
No relevant conflicts of interest to declare.
Author notes
Asterisk with author names denotes non-ASH members.
