Ex vivo culture of Fancc^−/−cells compromises repopulating ability.

Peripheral blood donor chimerism was determined by fluorescence cytometry 3, 6, and 9 months following transplantation. Individual data points represent donor chimerism of single mice transplanted with either WT or Fancc^−/− donor cells that were freshly isolated or cultured for 4 days in hIL-6 and mSCF, identical to the culture conditions used to maintain donor cells in the gene transfer competitive repopulation experiments. Repopulating ability ofFancc^−/− cells after ex vivo culture was significantly lower than the repopulating ability of freshly isolatedFancc^−/− cells at all timepoints evaluated (Student t test *P < .0006). Donor chimerism of mice transplanted with ex vivo culturedFancc^−/− cells increased significantly from 6 to 9 months after transplantation (Student t test **P < .001).