Allogeneic Bone Marrow Transplantation in Irradiated Baboons and Monkeys

Allogeneic hemopoietic cells given to the irradiated baboon or Macaca monkey transform by way of typical hyperbasophilic forms to lymphoid cells which cause a fatal acute secondary disease. This is characterized by an especially rapid course in the baboon, Papio hymadryas. Morphological studies revealed the similarity of these cells to cellular elements which occur in reactions of transplantation immunity. The lymphoid cells undergo rapid degeneration, apparently with allergic death of immunologically competent cells in the presence of excess antigen. Preliminary thymectomy considerably mitigated the course of acute secondary disease in monkeys and facilitated regeneration of donor-type hemopoiesis. It is, therefore, possible that hemopoietic stem cells may take part, along with more mature immunologically competent cells, in the production of an acute reaction or graft-versus-host type. Poor bone marrow repopulation in primates with xenogeneic transplants was seen. Multiple chromosome aberrations were fo...