Prognostic value of circulating CD34+ cells in myelodysplastic syndromes.

We studied circulating (C)CD34(+) cells by flow cytometry in 96 patients with myelodysplastic syndromes (MDS) at diagnosis, and in a subset of 35 cases during follow-up. CCD34(+) counts were stratified within both International Prognostic Scoring System (IPSS) and World Health Organization (WHO) categories. Counts >10/microl were associated with poorer leukemia-free survival, a prognostic value for evolution independent from that of WHO, and a higher progression probability within intermediate-risk IPSS and WHO classes. When serial measurements were performed, counts >10/microl more frequently correlated to evolution. Separating newly diagnosed patients on the basis of 10/microl cut-off of circulating CD34(+) cells retains prognostic utility, especially in intermediate-risk MDS.