Pathologic Changes in Irradiated Monkeys Treated With Bone Marrow2

Abstract

Autopsy was performed on 27 irradiated monkeys. The 7 irradiated nontreated animals died of the bone marrow syndrome. Intestinal radiation death occurred in one treated with autologous bone marrow; bone marrow regeneration was delayed in the other animal that died with anemia and hemorrhagic pulmonary edema. In 3 animals treated with homologous bone marrow, there was no apparent regeneration—death was due to hemorrhage—but it occurred in the 14 others treated with homologous bone marrow cells. The pathologic changes closely resembled those found in mouse, rabbit, and human radiation chimeras suffering from secondary disease, which in the primate radiation chimera seems more severe than usually occurs in irradiated mice treated with foreign bone marrow. Since many lesions found in monkeys are more pronounced than those in rodents, this study has been illuminating in the pathogenesis of secondary disease. Cell loss, possibly a direct effect of an immunological reaction of the foreign bone marrow graft against the tissues of the host, was the primary lesion, amounting to severe necrosis and atrophy in many organs. In lesions of the intestinal tract, degenerative changes prevailed over regenerative while the reverse was true for early skin lesions. Although infectious disease occurred less frequently than in mouse chimeras (possibly because of treatment with antibiotics), impairment of the immunological defense system may have promoted invasion by commensal parasites or activation of latent infections. Mortality in animals treated with foreign bone marrow probably was caused by widespread denudation of ileum and colon and sometimes by massive liver necrosis or infectious disease.