BM engraftment of cells from different disease phases at 7 to 8 weeks. Cells from 10 patients in CP (CP 1 to 10), four in AP (AP 1 to 4), and four in BP (BP 1 to 4) were injected into groups of two to six preirradiated mice. Seven to 8 weeks after injection, mice were killed and the numbers of human CD45⁺ cells were assessed in BM cell suspensions.