Sequential analysis of CD34⁺ cell apoptosis and proliferation during MDS progression.

Bone marrow CD34⁺ cell apoptosis and proliferation, using annexin V and Ki-67 labeling, respectively, was evaluated sequentially in 2 patients undergoing MDS evolution. BM blast percentage in patient 1 increased from 3% to 9% non-erythroid cells, whereas, in the second case, transformation from RAEB to RAEB-t was accompanied by karyotypic evolution.