Purification and cell surface marker expression of ALDH^lo and ALDH^hi cells isolated from human BM. (A) Human BM cells were selected for low side scatter and low (R2 = 8.2% ± 1.3%) or high (R3 = 0.8% ± 0.2%) Aldefluor fluorescence (n = 11). (B,C) ALDH^hi cells showed increased forward scatter mean fluorescence intensity compared with ALDH^lo cells. (D,E) Representative FACS of ALDH^lo and ALDH^hi cells for human cell surface markers expressed on primitive progenitors (CD34, CD133), monomylocytic cells (CD14, CD33), ECs (CD31, CD144), B lymphocytes (CD20, CD19), and T lymphocytes (CD4, CD8).