Recipients of Pf4/FF1 marrow displayed a MPS phenotype. Marrow cells from 28-week-old Pf4/FF1 mice or controls (CD45.2) were transplanted into lethally irradiated congenic CD45.1 recipients (n = 5 in each group). Shown here are CD45.2 donor chimerism (a), white blood cell (WBC) (b), red blood cell (RBC) (c), and platelet (d) counts following transplantation. Eight weeks post transplant, recipients of Pf4/FF1 marrow displayed a MPS phenotype, with significantly elevated platelet count and mild elevation of Hb compared with mice transplanted with control marrow cells. *P < 0.05.