Study design and conditional knockout transplants.

KLS cells were collected from Cre (+) or Cre (–) mice and were transplanted as described above. PMF presence was determined +14 days after transplant. Mice with WBCs of > 8 × 10³/ml and >25% donor-derived cells (CD45.2) were included. In preliminary experiments, 95% of mice meeting these criteria developed PMF (data not shown). Mice received tamoxifen 75 mg/kg or corn oil vehicle (MilliporeSigma) by intraperitoneal injection day +15–19 after transplant. Animals were monitored for survival and secondary endpoints. Only male mice were utilized to ensure no confounding hormonal or immune effects of tamoxifen in females (44–46).