急性髓系白血病（AML）治疗仍然具有挑战性。CD70被报道为有前途的AML特异性抗原。在临床前阶段，使用具有单链变量片段（scFv）或缩短CD27靶向CD70的CAR T细胞已被报道用于治疗AML。然而，包括自发性耗竭、蛋白酶介导的功能受体丧失和高免疫原性等各种缺点限制了其进一步应用于临床。相反，重链上的单变量区（VHH），也称为纳米抗体，具有可比较的结合能力和特异性，提供了一种可选的解决方案。 我们产生了CD70敲除的基于新型纳米抗体的anti-CD70-CAR T细胞（nb70CAR-T），并使用两种不同的VHH进行抗原检测。接下来，我们使用流式细胞术检测原发性AML爆发物中的CD70表达，并将nb70CAR-T的疗效与靶抗原密度相关联。最后，调控CD70在AML细胞上的表达的表观遗传调控剂被研究以促进nb70CAR-T的功能性。 我们的nb70CAR-T对CD70表达的细胞系和原发性AML爆发物表现出预期的抗肿瘤功能。然而，在原发性AML爆发物中，CD70的表达并不一致高，并且只有当CD70表达水平超过1.6（MFI比率）的阈值时，nb70CAR-T才能有效地对大约40.4%的AML患者做出反应。表观遗传调控剂Decitabine和Chidamide可以上调AML细胞上的CD70表达，增强nb70CAR-T的治疗效果。 AML爆发物中CD70的表达并不完全支持其在AML靶向治疗中的作用，正如报道的那样。使用Chidamide和Decitabine与nb70CAR-T的联合使用可能为AML的治疗提供新的潜力。©2023。作者。

Acute myeloid leukemia (AML) treatment remains challenging. CD70 was reported as a promising AML-specific antigen. Preclinically, CAR T-cell with single-chain-variable fragment (scFv) or truncated CD27 targeting CD70 has been reported to treat AML. However, various disadvantages including spontaneous exhaustion, proteinase-mediated loss of functional receptors, and high immunogenicity, limited its further application to clinical settings. Alternatively, the single-variable domain on heavy chain (VHH), also known as nanobodies, with comparable binding ability and specificity, provides an optional solution.We generated CD70 knocked-out novel nanobody-based anti-CD70-CAR T-cells (nb70CAR-T) with two different VHHs for antigen detection. Next, we detected the CD70 expression on primary AML blasts by flow cytometry and associated the efficacy of nb70CAR-T with the target antigen density. Finally, epigenetic modulators were investigated to regulate the CD70 expression on AML cells to promote the functionality of nb70CAR-T.Our nb70CAR-T exhibited expected tumoricidal functionality against CD70-expressed cell lines and primary AML blasts. However, CD70 expression in primary AML blasts was not consistently high and nb70CAR-T potently respond to an estimated 40.4% of AML patients when the CD70 expression level was over a threshold of 1.6 (MFI ratio). Epigenetic modulators, Decitabine and Chidamide can up-regulate CD70 expression on AML cells, enhancing the treatment efficacy of nb70CAR-T.CD70 expression in AML blasts was not fully supportive of its role in AML targeted therapy as reported. The combinational use of Chidamide and Decitabine with nb70CAR-T could provide a new potential for the treatment of AML.© 2023. The Author(s).