The Production of Megakaryocytic Macrocytosis by Systemic Factors in S1/S1dMice1

Bone marrow tissue was cross-transplanted subcutaneously between S1/ Sldmice and their normal +/+ littermates. Megakaryocyte size was evaluated in bone marrow from donors, hosts, and regenerated implants. Macromegakaryocytosis was found in Sl/Sldmarrow in situand in all implants in Sl/Sldhosts. Megakaryocytes were of normal size in +/+ marrow and in all implants in +/+ hosts. The macrocytosis of megakaryocytes in Sl/Sldmice appeared to be due to systemic factors or host elements that were incorporated into the regenerated implants rather than to a stromal abnormality that persisted with graft regeneration after transplantation.