PATHOGENESIS OF THE INTESTINAL LESIONS IN RADIATION CHIMERAS

Irradiated mice treated with homologous lymph node suspensions were serially killed for histological examination. Beginning at the 4th day following irradiation and transplantation, repopulation of the lymphatic tissues by lymphoid cells occurred. Concurrently excessive disintegration of crypt cells in the intestines was observed. The intestinal damage is considered to be the result of a cytotoxic action of the antibody-producing foreign lymphoid cells against the intestinal crypt cells. The intestinal lesons resemble those found in irradiated primates treated with bone marrow, but differ from those found in irradiated mice treated with bone marrow only. The implications of these findings with regard to the mortality pattern and the pathogenesis of secondary disease in radiation chimeras are discussed. (auth)