Abstract:

Objective To evaluate peripheral blood circulating CD34⁺ cell count in patients with myelodysplastic syndrome（MDS）-refractory anemia（RA）/refractory anemia with ring siderblasts（RARS）/refractory cytopenia with multilineage dysplasia（RCMD）. Methods A total of 52 MDS-RA/RARS/RCMD patients and 19 hematopoietic stem cell donors （healthy controls） were enrolled,and their peripheral blood circulating CD34⁺ cell percentages and counts were determined by flow cytometry. They were classified into low risk, intermediate-Ⅰ risk,intermediate-Ⅱ risk,high risk subgroups and very low risk,low risk, intermediate risk,high risk, very high risk subgroups according to the International Prognostic Scoring System （IPSS） and World Health Organization （WHO）-Based Prognostic Scoring System （WPSS）,respectively. The correlation of peripheral blood circulating CD34⁺ cell count with the clinical characteristics of MDS-RA/RARS/RCMD patients was analyzed. Results MDS-RA/RARS/RCMD patients had higher percentage and count of peripheral blood circulating CD34⁺ cells compared with healthy controls（P<0.01）. There was no correlation between peripheral blood circulating CD34⁺ cell count in MDS-RA/RARS/RCMD patients and patients' sex,age,cytopenia degree,white blood cell count decreasing and abnormal localization of immature precursor （ALIP）（r<0.625,P>0.05）,and there was correlation between peripheral blood circulating CD34⁺ cell count and abnormal karyotype,IPSS score, WPSS score and myelofibrosis（r>0.995,P<0.01）. There were 16 MDS-RA/RARS/RCMD patients with peripheral blood circulating CD34⁺ cell count >10.00×10⁶/L. Among them, there were 12 patients with complex karyotype abnormalities （10 patients with chromosome 7 abnormalities）. A total of 12 and 13 patients belonged to IPSS intermediate-Ⅱ risk and WPSS high risk subgroups,respectively. There were 9 patients with myelofibrosis. Among 36 MDS-RA/RARS/RCMD patients with peripheral blood circulating CD34⁺ cell count <10.00×10⁶/L,no patient had complex karyotype abnormalities or chromosome 7 abnormalities. Except for 1 patient in WPSS high risk subgroup,other patients were in IPSS low,intermediate-Ⅰ risk subgroups and WPSS very low,low and intermediate risk subgroups. Only 1 patient had myelofibrosis. Conclusions The count of peripheral blood circulating CD34⁺ cells increases in MDS-RA/RARS/RCMD patients,which can be further used for the classification of MDS risk.

Key words: Circulating CD34⁺ cell, Peripheral blood, Myelodysplastic syndrome