Shift in megakaryocyte ploidy distribution induced by PEG-rHuMGDF treatment of HIV-infected thrombocytopenic chimpanzees. Baseline megakaryocyte ploidy distribution (□) was shifted to a modal ploidy of 32N (P = .5 compared with a modal ploidy of 16N in normal controls). By contrast, 2 weeks after initiating high-dose PEG-rHuMGDF therapy (subcutaneous injections of 25 μg/kg for 3 doses administered twice weekly), there was a 30-fold expansion of megakaryocyte numbers with a modal ploidy of 8N (P = .01).