Silva M R, Parreira A, Ascensão J L
Portuguese Institute of Oncology, Lisbon, Portugal.
Exp Hematol. 1995 Dec;23(14):1676-81.
Peripheral blood stem cells (PBSC) are increasingly being used as an alternative to autologous bone marrow (BM) for hematologic rescue after high-dose chemoradiotherapy in the treatment of hematologic and nonhematologic malignancies. Mobilization procedures such as chemotherapy and/or hematopoietic growth factor administration are employed to allow for the graft enrichment in hematopoietic stem cells and progenitors and to accelerate trilineage recovery after transplant. The influence of these mobilization procedures on the lymphoid populations in the graft and on immunologic recovery after transplant remains to be determined. We studied six consecutive patients undergoing PBSC high-volume collections after cyclophosphamide (Cyc) and granulocyte colony-stimulating factor (G-CSF) administration and observed that NK cell numbers (phenotypically defined as CD3-CD56+ by flow cytometry) and activity (evaluated by a 51Cr release assay) fully recovered after 4-5 weeks; high numbers of functionally active NK cells (42.1-212.1 x 10(6)/kg b.w.) were present in the grafts, and their percentage and cytotoxic activity rose from the beginning to the end of the harvesting procedure in most cases. CD3-CD56+ and CD34+ cell numbers peaked at the same time point during harvesting, which differed from one patient to another. T (CD3+) cells were always present during harvest, and CD4 and CD8 numbers showed interdonor variability. When we cultured leukapheresed PBSC in the presence of interleukin-2 (IL-2) (10-1000 U/mL) for 6-8 days, we were able to expand the NK population three- to 5.4-fold; 100 U/mL appears to be the best concentration to generate high numbers of cytotoxic NK cells. Pilot studies also suggest that this short exposure to IL-2 does not affect the CD34+ cells. We conclude that PBSC grafts mobilized by combined Cyc and G-CSF and harvested through high-volume leukapheresis contain high numbers of cytotoxic NK cells that can be expanded in vitro by exposure to IL-2. In the setting of PBSC transplant, ex vivo immunomodulation aimed at increasing the NK cell numbers and activity is feasible and may prove to be useful in inducing a graft-vs.-tumor effect, thereby decreasing the relapse rate after transplant.
外周血干细胞（PBSC）越来越多地被用作自体骨髓（BM）的替代物，用于血液系统和非血液系统恶性肿瘤大剂量放化疗后的血液学挽救。采用化疗和/或给予造血生长因子等动员程序，以使造血干细胞和祖细胞在移植物中富集，并加速移植后三系造血的恢复。这些动员程序对移植物中淋巴细胞群体以及移植后免疫恢复的影响尚待确定。我们研究了6例连续接受环磷酰胺（Cyc）和粒细胞集落刺激因子（G-CSF）治疗后进行大容量PBSC采集的患者，观察到自然杀伤（NK）细胞数量（通过流式细胞术表型定义为CD3-CD56+）和活性（通过51Cr释放试验评估）在4-5周后完全恢复；移植物中存在大量功能活跃的NK细胞（42.1-212.1×10(6)/kg体重），在大多数情况下，其百分比和细胞毒性活性从采集开始到结束均有所上升。CD3-CD56+和CD34+细胞数量在采集过程中的同一时间点达到峰值，但不同患者之间存在差异。采集过程中始终存在T（CD3+）细胞，CD4和CD8细胞数量在不同供体之间存在差异。当我们在白细胞介素-2（IL-2）（10-1000 U/mL）存在的情况下将采集的PBSC培养6-8天时，我们能够将NK细胞群体扩增3至5.4倍；100 U/mL似乎是产生大量细胞毒性NK细胞的最佳浓度。初步研究还表明，这种短时间暴露于IL-2不会影响CD34+细胞。我们得出结论，通过联合Cyc和G-CSF动员并通过大容量白细胞分离术采集的PBSC移植物含有大量细胞毒性NK细胞，这些细胞可通过暴露于IL-2在体外扩增。在PBSC移植的情况下，旨在增加NK细胞数量和活性的体外免疫调节是可行的，并且可能证明在诱导移植物抗肿瘤效应从而降低移植后复发率方面是有用的。
