Suggested correlation between radiation-induced immunosuppression and radiogenic leukemia in mice.

Abstract

The reduced incidence of reticulum cell sarcoma in RF mice with glomerulosclerosis (GLO) and the demonstration that GLO partly results from an immune response to wild-type virusassociated antigens have provided a means for the determination of the importance of radiation-induced immunosuppression in leukemogenesis. This finding of reduced leukemia risk in mice with GLO has now been extended to include the 2 radiation-induced types, thymic and myeloid. The incidence of radiation-induced leukemia increased with radiation dose in both GLO- positive and GLO-negative mice, but the presence of GLO was associated within each dose group with a twofold reduction in risk for each leukemia. Doses >100 rads suppressed the immune system and the development of GLO and thereby shifted a fraction of the animals from the low-risk (GLO-positive) group to the high-risk (GLOnegative) group. Since GLO is, at least in part in these RF mice, the product of an immune reaction against a virus-associated antigen, suppressing the ability to cope with leukemogenic virusassociated antigens (suppressing the immune system) contributed to the overall leukemogenic effectivness of radiation, at least for doses >100 rads. Since suppression of GLO development did more » not contribute in the lower dose range (<100 rads) clearly the doseresponse curve for radiation-induced leukemia in the RF mouse cannot be linear. (auth) « less