PB Inc⁺CD34⁺CXCR-4^high cells have a primitive progenitor phenotype.

PB CD34⁺ cells were purified after incubation on a plastic support (Inc⁺), stained for CD34-PerCP, CD38-FITC, CD71-PE, c-Kit-PE, or Thy-1-PE and CXCR-4-biotin-APC and analyzed by 4-color cytometry. A first dot plot (FSC versus SSC) was produced to select the lymphomonocytic cell population in a first gate (R1). A second dot plot (CD34-PerCP versus SSC) was displayed on the R1 gate. The CD34⁺ population was then selected by a second R2 gate. Dot plots 3 to 6, displayed on the additive regions R1 plus R2, show CXCR-4-APC versus CD38-FITC, Thy-1-PE, CD71-PE, and c-Kit-PE expression. On plot 3, a blue gate (R3) was drawn around the cell population coexpressing a high level of CXCR-4 and a low level of CD38. Cells corresponding to the R3 gate (CXCR-4^highCD38^low subset) are shown in blue on each dot plot. The results shown are from 1 experiment out of the 8 performed.