Expansion of total and CD34⁺ cell number in single harvest cultures. Sorted CD34⁺CD38⁺Lin⁻ or CD34⁺CD38⁻Lin⁻ cells were cultured for 17 days in medium supplemented with cytokines as indicated. Columns represent average expansion (fold increase of start cell number) from independent experiments with 6 different donors, error bars indicate standard deviation (SD). Dotted columns, all cells; filled columns, CD34⁺ cells.