低剂量氟达拉滨、环磷酰胺联合供者NK细胞作为非清髓性预处理用于小鼠单倍相合造血干细胞移植

本研究探讨低剂量氟达拉滨、环磷酰胺联合供者异体反应性NK细胞(flu cy allo-NK)作为新的非清髓性单倍相合造血干细胞移植(haploidentical HSCT)预处理方案的可行性。利用免疫磁珠富集F1供鼠(H-2d/b)脾脏NK细胞,检测其中Ly49C 、Ly49A 细胞的比例;LDH法检测其异体反应性。建立小鼠单倍相合造血干细胞移植模型,并比较清髓性方案(9 Gy TBI)、各种非清髓性方案(6.5 Gy TBI,flu cy,及flu cy allo-NK)的体内清髓效果、移植后供者嵌合率、GVHD的发生率及严重程度。结果表明:与其他非清髓性预处理方案相比,flu cy allo-NK组不能增加清髓程度,但可显著提高单倍相合移植后的供者嵌合率,移植后21天的嵌合率在骨髓为(28.70±5.90)%,脾脏为(46.40±5.00)%,并持续2个月。与flu cy组相比,flu cy allo-NK组出现的GVHD反应轻微,仅有50%(5/10)受鼠出现体重减轻,flu cy allo-NK组小鼠的肝脏、小肠、肾脏及皮肤的病理切片均未见明显的组织损伤。结论:供者allo-NK具有促进单倍相合供者造血干细胞植入,减轻GVHD强度的作用;低剂量flu cy allo-NK方案为高龄和一般情况差的肿瘤患者开展单倍相合造血干细胞移植提供了新的途径。

Application of Low Dose of Fludarabine and Cyclophosphamide Combined with Donor NK Cells as a Nonmyeloablative Conditioning Regimen for the Haploidentical Hematopoietic Stem Cell Transplantation in Mice

This study was aimed to investigate the feasibility of low dose of fludarabine, cyclophosphamide combined with donor derived alloreactive NK cells as a new nonmyeloablative conditioning regimen in the haploidentical hematopoietic stem cell transplantation (haploidentical HSCT). F1 derived-NK cells were enriched with MACS magnetic separation system, in which the proportions of the Ly49C+ and Ly49A+ cells were detected by flow cytometry and the alloreactivity was measured by LDH method. The haploidentical HSCT models were constructed, and the myeloablativity in vivo, donor engraftment and the intensity of GVHD were compared between different myeloablative and nonmyeloablative conditioning regimens, including 9 Gy TBI, 6.5 Gy TBI, flu + cy, and flu + cy + allo-NK. The results showed that the flu + cy + allo-NK conditioning was nonmyeloablative, but the rate of donor chimerism after haploidentical HSCT was significantly higher as compared with other nonmyeloablative methods, which were (28.70 +/- 5.90)% in bone marrow and (46.40 +/- 5.00)% in spleen at day 21 post-transplantation. When compared with the flu + cy conditioning, the intensity of GVHD was slight in the flu + cy + allo-NK group, in which only a half of C57BL/6 recipients experienced weight loss, and no distinct pathological damages observed in the liver, intestine, kidney and skin samples. It is concluded donor derived-alloreactive NK cells can facilitate engraftment of the haploidentical hematopoietic stem cells and mitigate GVHD. The flu + cy + allo-NK conditioning provides a new method for those elder patients with high-risk solid tumor undergoing haploidentical-HSCT.