Humblet C, Greimers R, Boniver J, Defrense M P
Department of Pathology, University Hospital of Liège, Belgium.
Exp Hematol. 1997 Feb;25(2):109-13.
Fractionated whole body irradiation induces thymic lymphomas in C57 BL/Ka mice after 6-12 months. A graft of normal congenic bone marrow cells immediately after the last irradiation prevents the development of lymphomas by inducing the disappearance of preleukemic cells. When such a graft is performed one month later, it does not inhibit the emergence of tumors. It could be because, one month after irradiation, preleukemic cells become insensitive to the effects of the grafted bone marrow on their leukemogenic potential. To check this hypothesis, we have investigated the capacity of grafted bone marrow cells to prevent the development of lymphomas in mice inoculated with radiation-induced preleukemic cells collected at several time intervals after the completion of the radiation regimen. It was found that the bone marrow graft reduced the incidence of thymic lymphoma at day 2 (10 vs. 43%; p < 0.01) and 10 (39 vs. 86%; p < 0.01) but not at day 15 (64 vs. 80%; NS) or 30 (93 vs. 82%; NS). The inefficacy of the marrow graft was not associated with proliferation of the inoculate in the recipient thymus nor with inhibition by preleukemic cells of thymic repopulation by bone marrow precursors. The data provide evidence that preleukemic cells undergo intrinsic changes which are reflected by the acquisition of resistance to bone marrow grafts.
分次全身照射在6 - 12个月后可诱导C57 BL/Ka小鼠发生胸腺淋巴瘤。在最后一次照射后立即移植正常同基因骨髓细胞，可通过诱导白血病前期细胞消失来预防淋巴瘤的发生。如果在一个月后进行这种移植，则不能抑制肿瘤的出现。这可能是因为，照射后一个月，白血病前期细胞对移植骨髓对其致白血病潜能的影响变得不敏感。为了验证这一假设，我们研究了移植骨髓细胞在预防接种了放疗后不同时间间隔收集的辐射诱导白血病前期细胞的小鼠发生淋巴瘤方面的能力。结果发现，骨髓移植在第2天（10%对43%；p < 0.01）和第10天（39%对86%；p < 0.01）降低了胸腺淋巴瘤的发生率，但在第15天（64%对80%；无显著性差异）和第30天（93%对82%；无显著性差异）则没有。骨髓移植无效与接种物在受体胸腺中的增殖无关，也与白血病前期细胞对骨髓前体细胞胸腺再填充的抑制无关。这些数据提供了证据，表明白血病前期细胞发生了内在变化，这表现为获得了对骨髓移植的抗性。
