Allogeneic Transplants of Canine Peripheral Blood Stem Cells Mobilized by Recombinant Canine Hematopoietic Growth Factors

We have studied graft-versus-host disease (GVHD) after transplantation of allogeneic peripheral blood stem cells (PBSC) mobilized by either recombinant canine granulocyte colony-stimulating factor (rcG-CSF) alone or combined with stem cell factor (rcSCF). These studies were prompted by the observation of extremely rapid and sustained engraftment of growth factor-mobilized PBSC in the autologous setting using genetically marked cells and changes in function of T lymphocytes from donors that had undergone mobilization. Specifically, lymphocytes from growth factortreated donors were hyporesponsive in mixed leukocyte culture and in response t o Con A, raising hopes that GVHD in dogs given growth factor mobilized allogenic PBSC might be altered in a beneficial way. Eighteen dogs were given a median of 17.1 x 10’ PBSC/kg from littermate donors after 920 cGy of total body irradiation without postgrafting immunosuppression. Donors were either genotypically DLA-identical (n = 9) or DLA-haploidentical (n = 9). The median