Apoptosis, Immunity & Cancer Group, University of Zaragoza and Aragón Health Research Institute (IIS Aragón), Zaragoza, Spain.
Immunogenetics-HLA Laboratory, Puerta de Hierro Hospital, Majadahonda, Madrid, Spain.
Sci Rep. 2020 Nov 10;10(1):19398. doi: 10.1038/s41598-020-76051-z.
Adoptive transfer of allogeneic natural killer (NK) cells is becoming a credible immunotherapy for hematological malignancies. In the present work, using an optimized expansion/activation protocol of human NK cells, we generate expanded NK cells (eNK) with increased expression of CD56 and NKp44, while maintaining that of CD16. These eNK cells exerted significant cytotoxicity against cells from 34 B-CLL patients, with only 1 sample exhibiting resistance. This sporadic resistance did not correlate with match between KIR ligands expressed by the eNK cells and the leukemic cells, while cells with match resulted sensitive to eNK cells. This suggests that KIR mismatch is not relevant when expanded NK cells are used as effectors. In addition, we found two examples of de novo resistance to eNK cell cytotoxicity during the clinical course of the disease. Resistance correlated with KIR-ligand match in one of the patients, but not in the other, and was associated with a significant increase in PD-L1 expression in the cells from both patients. Treatment of one of these patients with idelalisib correlated with the loss of PD-L1 expression and with re-sensitization to eNK cytotoxicity. We confirmed the idelalisib-induced decrease in PD-L1 expression in the B-CLL cell line Mec1 and in cultured cells from B-CLL patients. As a main conclusion, our results reinforce the feasibility of using expanded and activated allogeneic NK cells in the treatment of B-CLL.
同种异体自然杀伤 (NK) 细胞过继转移正在成为治疗血液恶性肿瘤的一种可靠免疫疗法。在本工作中，我们使用优化的人 NK 细胞扩增/激活方案，生成表达 CD56 和 NKp44 增加而 CD16 保持不变的扩增 NK 细胞（eNK）。这些 eNK 细胞对来自 34 名 B-CLL 患者的细胞表现出显著的细胞毒性，只有 1 个样本表现出耐药性。这种偶发性耐药性与 eNK 细胞表达的 KIR 配体与白血病细胞之间的匹配无关，而匹配的细胞对 eNK 细胞敏感。这表明在使用扩增 NK 细胞作为效应物时，KIR 不匹配并不相关。此外，我们在疾病的临床过程中发现了两种对 eNK 细胞细胞毒性的新耐药性的例子。在其中一名患者中，耐药性与 KIR 配体匹配相关，但在另一名患者中则不相关，并且与两名患者的细胞中 PD-L1 表达的显著增加相关。其中一名患者用伊德拉利昔治疗与 PD-L1 表达的丧失以及对 eNK 细胞毒性的重新敏感相关。我们在 B-CLL 细胞系 Mec1 和来自 B-CLL 患者的培养细胞中证实了伊德拉利昔诱导的 PD-L1 表达降低。作为主要结论，我们的结果加强了使用扩增和激活的同种异体 NK 细胞治疗 B-CLL 的可行性。
