Adoptive transfer of marrow cells from Mx1-Cre, Nf1 ^flox/flox mice with MPD. (A) WBCs in recipient mice that received a lethal or sublethal dose of radiation over time. Cells from 2 Cre⁺ mice were injected into equal numbers of lethally and sublethally irradiated mice. Data represent the mean ± SEM. Asterisks indicate significant differences between recipients that received lethal versus sublethal radiation (P < .05). (B) PCR analysis of blood leukocytes from lethally irradiated recipients demonstrates reconstitution with mutant (Δ31) cells with absence of a signal from the wild-type host (lanes 1-5). By contrast, some sublethally irradiated recipients that were analyzed 6 months after adoptive transfer showed absence of mutant Δ31 cells (lanes 6-8), some showed repopulation with donor cells (lanes 11-13), and others demonstrated the presence of both wild-type and mutant cells (lanes 9,10). None of these sublethally irradiated recipients had developed evidence of MPD by 8 months after adoptive transfer.