Gene Therapy for SCID-X1 with Low Dose Busulfan and a SIN-lentiviral Vector

使用自体C034+细胞进行基因治疗是治疗原发免疫缺陷的一种有前途的治疗方法， 尤其是对于没有最佳同种异体捐献者的个人。SCIO-X1是由IL2RG突变引起的， 它编码多种细胞因子受体的共同伽马链(YE)。患有SCIO-X1的男孩缺乏T 和NK细胞，其B细胞由于缺乏IL-7、IL-15和IL-21功能而无法产生抗体 分别进行了分析。该项目旨在测试一种新型自灭活慢病毒(LV)的有效性和安全性 载体治疗SCIO-X1。我们假设这项试验将通过改善免疫重建 介绍小剂量白丹调理(目标1)，并通过改变 将先前试验中使用的伽玛逆转录病毒(YRV)载体与本次试验中使用的LV载体(目标2)进行比较。 以前的SCIO-X1基因治疗试验都是在没有化疗条件的情况下注入细胞，这 导致了强劲的T细胞恢复和基因标记，但B细胞的基因标记可以忽略不计， 体液免疫重建。NK细胞的初始发育和标记不能持续。在目标1中 我们将研究低剂量白花丹预适应对1)细胞类型特异性植入和 基因标记， 2)体内T细胞重组、T细胞表型和TRB基因序列的深度测序；3)体内 体液免疫重建、B细胞数量、表型、IL-21依赖功能和免疫球蛋白谱 4)NK细胞的数量、表型和功能。 以前的SCIO-X1基因治疗试验使用的是带有完整病毒的yRV载体 启动子/增强子，导致5/20患者因插入基因而患上T细胞白血病 致癌作用。使用病毒增强剂已被激活的自失活yRV载体进行基因治疗 删除显示了淋巴癌基因附近插入部位减少的令人鼓舞的证据，但最初的 仍然存在风险的插入位置模式。此应用程序中拟议的试验将通过以下方式进一步提高安全性 使用自我灭活的LV载体。在目标2中，我们将研究初始插入位点模式 患者的C034+转导细胞，并将拟议试验的样本与历史试验的样本进行比较 YRV，分析基因治疗后外周血中的插入位点分布，以进行谱系追踪和 将聚类法与以前试验中的样本进行比较。

Gene therapy using autologous C034+ cells is a promising treatment for primary immunodeficiency, particularly for individuals without optimal allogeneic donors. SCIO-X1 is caused by mutations in IL2RG, which encodes the common gamma chain (ye) of multiple cytokine receptors. Boys with SCIO-X1 lack T and NK cells, and their B cells fail to produce antibodies due to the lack of IL-7, IL-15 and IL-21 function respectively. This project seeks to test the efficacy and safety of a new self-inactivating lentiviral (LV) vector to treat SCIO- X1. We hypothesize that this trial will improve immune reconstitution through the introduction of low dose busulfan conditioning (Aim 1) and improve safety through the change from a gammaretroviral (yRV) vector used in previous trials to the LV vector in this trial (Aim 2). Previous trials of gene therapy for SCIO-X1 have infused cells without chemotherapy conditioning, which resulted in robust T cell recovery and gene marking, but negligible gene marking in B cells and failure of humoral immune reconstitution. Initial development and marking in NK cells was not sustained. In Aim 1 we will examine the impact of low dose busulfan conditioning on 1) cell type specific engraftment and gene marking, 2) in vivo T cell reconstitution, T cell phenotype and TRB repertoire by deep sequencing, 3) in vivo humoral immune reconstitution, B cell number, phenotype, IL-21 dependent function and IGH repertoire by deep sequencing, 4) NK cell number, phenotype and function. Previous trials of gene therapy for SCIO-X1 have used a yRV vector with intact viral promoters/enhancers, which resulted in 5/20 patients developing T cell leukemia due to insertional oncogenesis. Gene therapy using a self-inactivating yRV vector in which viral enhancers have been deleted shows encouraging evidence of reduced insertion sites near lymphoid oncogenes, but an initial insertion site pattern that is still risky. The proposed trial in this application will further improve safety by using a self-inactivating LV vector. In Aim 2 we will investigate the initial insertion site pattern in the patients' C034+ transduced cells and compare samples from the proposed trial to historical trials using yRV, analyze insertion site profile in peripheral blood after gene therapy to perform lineage tracing and compare clustering with samples from previous trials.