Inverse relationship between pre-BMT radiation dose and thymic recovery on day 28.
The absolute number of thymocytes on day 28 in the normal C57/B6 controls (▪) and in the 3 groups of transplanted mice that received either 1000, 1200, or 1400 cGy. For the transplanted mice, the numbers of host (CD45.2+, ■) and donor-derived (CD45.1+, ▨) thymocytes are shown. All values are expressed as the mean cell number × 10−6 ± SD. Statistical differences were analyzed by 2-tailed t test with unequal distributions. For total cell numbers,P < .000 001 (normal vs BMT), P < .001 (1000 vs 1200 or 1400 cGy), P < .0001 (1200 vs 1400 cGy). For donor-derived cell numbers, P < .01 (1000 vs 1200 or 1400 cGy) and P < .0001 (1200 vs 1400 cGy). For recipient-derived cell numbers, P < .01 (1000 vs 1200 or 1400 cGy, P > .05 (1200 vs 1400 cGy).
