Comparable hematopoietic colony formation by annexin⁺ and annexin⁻ CD34 cells from patients with trisomy 8. BMMNCs obtained from patients with significant trisomy 8 populations were stained with annexin-FITC and CD34-PE mAb and sorted into annexin⁺ and annexin⁻ aliquots of CD34 cells. These CD34 cells were plated in methycellulose for short-term culture as described in “Materials and methods.” Annexin⁺ CD34 cells were primarily trisomy 8 and gave rise to more hematopoietic colonies than did annexin⁻ cells in 3 of 4 patients. In all 5 samples obtained from healthy volunteers, the annexin⁺ CD34 cells failed to give rise to any colonies. FISH results on annexin⁺ and annexin⁻ fractions are listed in Table 1. Error bars represent SEM.