Analysis of the Immunophenotypic Features of Blast Cells, Lymphocytes and Granulocytes by Multiparametric Flow Cytometry in Bone Marrow (BM) Cells of Myelodysplastic Syndromes.

The myelodysplastic syndromes (MDS) are a group of clonal heterogeneous bone marrow disorders characterized by peripheral cytopenias, ineffective hematopoiesis, and unilineage or multilineage dysplasia. Multiparametric flow cytometry is increasingly being used as an adjunct to the establishing of MDS. While many antigens have been described to be aberrantly expressed in MDS the findings are generally heterogeneous and there is no consistent finding that would be present in all cases with MDS.

To investigate the immunophenotypic features of MDS and non-MDS patients and the characteristic of subtypes of MDS.

BM samples were collected from 22 MDS patients including 3 RA (2 male, 1 female, median age 57), 3 RAS (2 male, 1 female, median age 72), 12 RAEB (6 male, 6 female, median age 67.5), 4 MDS-AML (2 male, 2 female, median age 69.5) and 20 non-MDS (11 male, 9 female, median age 32.5, 7 AA, 5 PNH, 3 IDA, 1 ALL, 2 CML, 2 MM). The multiparametric flow cytometric analysis was performed using an extensive panel of monoclonal antibodies and using the conventional and secondary gating strategies to analysis the immunophenotypic features of BM cells.

This study showed that the proportion of blast cells increased significantly than non-MDS group (P=0.002). As the disease progressing, the percentage of blast cells became higher and significantly difference compared to the non-MDS group (P=0.226, P=0.464, P=0.001 and P=0.000, respectively). The expressions of CD34+ and CD7+ on blast cells were significantly difference between MDS and non-MDS groups (P=0.005, and P=0.002, respectively). Compared with the subtypes of MDS and non-MDS group, the expressions of CD34+ and CD7+ on blast cells became high gradually (P=0.534, P=0.487, P=0.009, P=0.004 and P=0.294, P=0.166, P=0.002, P=0.001) and the high percentage of blast cells and high expression levels of CD34+ and CD7+ might indicate poor prognosis. The expression of CD7+ on lymphocytes was similar with CD34+ and CD7+ on blast cells, but the expressions of CD19+ and CD56+ on lymphocytes were no significantly difference (P=0.076, P=0.252, respectively). The expressions of antigens on granulocytes showed that the expressions of CD15+CD11b+, CD10+ and HLA-DR were significantly difference between MDS and non-MDS groups(P=0.000, P=0.009 and P=0.007, respectively), meanwhile, as the disease progressing, the expression rates of CD15+CD11b+, CD10+ and HLA-DR in subtypes of MDS increased gradually and the survival time of these patients who had over-expression of these antigens was shorter than control group(P=0.002). However, the expressions of CD33+, CD13+, CD56+ and CD15+CD11b- were significantly difference between subtypes of MDS and non-MDS group (P=0.059, P=0.588, P=0.063 and P=0.207, respectively).

Our results showed that using multiparametric flow cytometry to analyze the immunophenotypic features of BM cells could provide clinically useful information for the diagnosis, classification and prognosis of MDS patients. Particularly, the percentage of blast cells, the expression of CD34+ and CD7+ on blast cells, the expression of CD7+ on lymphocytes and the expression of CD15+CD11b+, CD10+ and HLA-DR on granulocytes may provide the much more useful information. However, further studies including larger number of patients with a longer follow-up are necessary to confirm these results.

No relevant conflicts of interest to declare.