Introduction. Myelodysplastic Syndromes (MDS) are hemopoietic clonal disorders characterized by a heterogeneous clinical course, which is currently predicted on the basis of clinical, morphologic and cytogenetic data. Only a few reports have studied the impact of flow cytometry immunophenotypic data on the prognosis of the disease.

Objectives: To evaluate the immunophenotypic characteristics of CD34+ myeloid precursor cells in MDS and their association with the prognosis of the disease.

Material & Methods: Overall, 39 patients with MDS - 8 with refractory anemia (RA), 9 RA with ringed sideroblasts (RARS), 12 refractory cytopenias with multilineage dysplasia (RCMD), 2 RA with excess of blasts (RAEB)-1, 5 RAEB-2, 2 with 5q- Syndrome and one unclassifiable MDS - were studied. Bone marrow cells were stained with an extensive panel of MoAbs.

Results: the most frequent phenotypic abnormalities on CD34+ myeloid cells were: CD7+ (36%), CD25+ (33%) and CD56+ (15%) followed by overexpression of CD13 and/or CD33 (33%). Abnormal expression of CD7, CD25, CD13 and CD33 were evenly distributed within the WHO and IPSS subgroups of the disease, although CD56 expression was more frequently detected in low risk IPSS cases. From the prognostic point of view, patients that showed altered expression of CD25, CD56 and CD33 had a shorter median overall survival (OS): 30 vs 109 months (p = 0.0003), 19 vs 102 months (p=0.009), and 21 vs 102 months (p=0.009), for CD25, CD56 and CD33, respectively. Reactivity for CD7 and overexpression of CD13 did not influence OS. A phenotypic score was built where a score of 1 was given to abnormal CD25, CD56 or CD33 expression. Significantly different median OS rates (p<0.04) were found for cases with a score of 0 (101±11 months), 1 (47 ±6 months) and >1 (15 ± 5 months).

Discussion: Our results show that flow cytometry immunophenotyping of CD34+ myeloid precursors provides clinically useful information for the prognostic stratification of MDS patients. Further studies including larger number of patients with a longer follow-up are necessary to confirm these results.

Topics:
myelodysplastic syndrome, cd33 antigen, antigens, cd25, cd56 antigens, neural cell adhesion molecules, alanine aminopeptidase, flow cytometry, prostatic hypertrophy risk score, refractory anemia with excess blasts, 5q syndrome

Disclosures: No relevant conflicts of interest to declare.

(Support: FAPESP proc. 05/59113-2)

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2008, The American Society of Hematology
2008
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