title: Biological implications of circulating CD34(+) cells in myelodysplastic syndromes.
abstract: OBJECTIVE
  to evaluate the biological and clinical significance of circulating CD34(+) cells in patients with myelodysplastic syndromes (MDS).
  
  
  METHODS
  the relative count of CD34(+) cells in peripheral blood was evaluated by flow cytometry and the results were recorded on the total number of mononuclear cells (MNCs). CD34(+) status was correlated with the percentage of circulating and bone marrow blasts, cytogenetic studies, CFU-GM colony growth, overall survival and transformation to acute myeloid leukemia (AML).
  
  
  RESULTS
  the number of MNC positive for anti-CD34 monoclonal antibody in the healthy control group ranged from 0.00% to 0.73%. Therefore, the cutoff value for overexpression of CD34 antigen on peripheral blood MNC of MDS patients was ≥ 1% (CD34(+) cases). The mean number of circulating CD34(+) MNCs in 30 MDS patients was significantly higher than in the control group (p=0.009). The proportion of circulating CD34(+) MNCs did not correlate with the blast count in the peripheral blood (r=0.282, p=0.131), neither with the blast count in the bone marrow. In contrast, the proportion of circulating CD34(+) cells in MDS patients was significantly correlated with the proportion of bone marrow CD34(+) cells (r=0.461, p=0.035). The proportion of circulating CD34(+) cells did not correspond to the percentage of blast count in the bone marrow, neither with the presence of cytogenetic abnormalities or abnormal growth of GM-progenitors. The median actuarial survival of 19 patients with elevated proportion of circulating CD34(+) cells was 16 months, as compared to >57 months in 11 patients with CD34(+) cells within normal range (p=0.16). Five patients with elevated proportion of circulating CD34(+) cells progressed to AML, as compared to only one of CD34(-)negative (CD34(-)) cases.
  
  
  CONCLUSIONS
  the presence of circulating CD34(+) cells is a common finding in MDS, but no significant correlations with clinical and/or biological features of the disease have been found.
authors.affiliation: Medical Center "Bezanijska kosa", Department of Hematology, Belgrade, Serbia. maris@tehnicom.net
authors.forename: D
authors.initials: D
authors.lastname: Marisavljevic
authors.forename: N
authors.initials: N
authors.lastname: Kraguljac-Kurtovic
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000097:blood*; D001853:Bone Marrow / Q000276:immunology / Q000378:metabolism; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D003114:Colony-Forming Units Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000097:blood*; D022423:Myeloid Cells / Q000378:metabolism; D011379:Prognosis; D015996:Survival Rate
chemical_list: D018952:Antigens, CD34