CMV infection and NK-cell therapy for multiple myeloma

摘要：多发性骨髓瘤（MM）是第二大最常见的血癌，影响约83，367 美国人2014年，预计将有24,050例MM新发病例，11,090人将死于此 疾病大剂量化疗联合自体造血干细胞移植 （HSCT）是MM的标准治疗;然而，需要创新策略来改善治疗 大多数患者在移植后未能达到完全缓解，55.1%的患者在5年内死亡 年巨细胞病毒（CMV）感染是接受HSCT患者的潜在致命并发症，但 最近的证据表明，如果治疗得当，它可以产生有益的临床结果。CMV 急性髓细胞白血病（AML）患者的再激活与复发风险显著降低相关 用同种异体HSCT治疗，虽然机制尚不清楚，但CMV介导的 可能涉及NK细胞亚群的组成。NK细胞在减缓肿瘤进展方面也起着关键作用。 MM和NK细胞的过继转移已被用作减少人类MM生长的手段。 CMV对AML患者临床结局有益的一种可能机制是， 在MM患者中也可能是有益的，是NKG 2Cpos/NKG 2Aneg NK细胞的频率增加， 巨细胞病毒NKG 2C是非经典HLA I类的活化受体，NKG 2A是抑制受体 分子HLA-E。因此，只有NKG 2Cpos/NKG 2Aneg NK细胞能够有效地杀死HLA-Epos靶细胞。 有趣的是，AML和MM细胞都高度表达HLA-E，这可以保护它们免受患者NK细胞的侵害。 大部分是NKG 2Apos由于患者NK细胞靶向其自身MM细胞的能力有限， 已经开发了依赖于供体NK细胞的免疫程序。输注同种异体 NK细胞已显示出作为诱导MM患者缓解的手段的前景;然而，疗效受到以下因素的限制： 获得足够数量的同种异体反应性NK细胞和NKG 2A相对于 扩增的NK细胞中的NKG 2C。因此，需要新的方案来增强NK细胞的抗MM活性。 我们的研究小组已经证明潜伏的CMV感染增强了NK细胞对表达HLA-E的肿瘤细胞的活性， 细胞系（包括MM细胞系U266）通过NKG 2C依赖性机制。在这项研究中，我们建议 扩展这些发现并检查CMV感染的作用和NKG 2Cpos/NKG 2Aneg NK细胞的频率 对接受自体HSCT的MM患者的早期移植后反应。我们还打算表明， 具有高抗MM活性的NKG 2Cpos/NKG 2Aneg NK细胞可以优先从新鲜PBMC扩增， 使用HLA-E转染的饲养细胞冷冻保存的脐带血样品。如果成功，我们的创新 这种方法可以改善用于治疗MM的基于NK细胞的免疫疗法。

Abstract: Multiple myeloma (MM) is the second most prevalent blood cancer affecting approximately 83,367 Americans. In 2014, it is estimated that there will be 24,050 new cases of MM and 11,090 people will die of this disease. High dose chemotherapy in combination with autologous hematopoietic stem cell transplantation (HSCT) is the standard treatment for MM; however, innovative strategies are required to improve treatment outcome as most patients fail to achieve complete remission post-transplant and 55.1% of patients die within 5 years. Cytomegalovirus (CMV) infection is a potentially fatal complication in patients receiving HSCT, but recent evidence suggests that, when properly treated, it can exert beneficial clinical outcomes. CMV reactivation is associated with a markedly reduced risk of relapse in acute myeloid leukemia (AML) patients treated with allogeneic HSCT and while the mechanism is unknown, CMV-mediated alterations in the composition of NK-cell subsets are likely involved. NK-cells also play a critical role in slowing the progression of MM and adoptive transfer of NK-cells has been used as a means of curtailing the growth of MM in humans. One possible mechanism underpinning the beneficial effect of CMV on clinical outcome in AML patients, which might be beneficial in MM patients as well, is the increased frequency of NKG2Cpos/NKG2Aneg NK-cells with CMV. NKG2C is an activating receptor and NKG2A an inhibitory receptor for the non-classical HLA class I molecule HLA-E. Thus, only NKG2Cpos/NKG2Aneg NK-cells are able to effectively kill HLA-Epos target cells. Interestingly, both AML and MM cells highly express HLA-E, which protects them from them patient NK-cells that are mostly NKG2Apos. As a result of the limited ability of patient NK-cells to target their own MM cells, immunotherapeutic procedures that rely on donor NK-cells have been developed. The infusion of allogeneic NK-cells has shown promise as a means of inducing remission in MM patients; however, efficacy is limited by the difficulty of acquiring adequate numbers of alloreactive NK-cells and high expression of NKG2A relative to NKG2C in expanded NK-cells. Thus, new protocols are needed to enhance the anti-MM activity of NK-cells. Our group has shown that latent CMV infection enhances NK-cell activity against HLA-E expressing tumor cell lines (including the MM cell line U266) through an NKG2C-dependent mechanism. In this study, we propose to extend these findings and examine the role of CMV infection and frequency of NKG2Cpos/NKG2Aneg NK-cells on early post-transplant responses in MM patients receiving autologous HSCT. We also intend to show that NKG2Cpos/NKG2Aneg NK-cells with high anti-MM activity can be preferentially expanded from fresh PBMCs and cryopreserved cord blood samples using HLA-E-transfected feeder cells. If successful, our innovative approach could improve NK-cell-based immunotherapy for the treatment of MM.