Phenotypic analysis of unsorted BM CD34⁺ cells at day 0 and following HUBEC culture versus GM36SF alone. Human BM CD34⁺ cells were cultured with either HUBEC monolayers supplemented with GM36SF or GM36SF alone for 7 days (N = 3). (A) Representative phenotype of BM CD34⁺ cells at day 0, day 4, and day 7 of HUBEC culture, demonstrating a high percentage of CD34⁺CD38^– cells persistent after culture. (B) Representative phenotype of BM CD34⁺ cells at day 0, day 4, and day 7 of culture with GM36SF alone, demonstrating nearly complete loss of CD34⁺CD38^– cells. All cell populations were stained with anti-CD34–FITC and anti-CD38–PE antibodies and analyzed by flow cytometry. Isotype control staining for each time point is shown at top. Numbers indicate the percent of cells in each quadrant.