Fred Hutchinson Cancer Research Center
University of Washington School of Medicine, Seattle, WA, USA.
Haematologica. 2018 Nov;103(11):1806-1814. doi: 10.3324/haematol.2018.194571. Epub 2018 Jul 5.
A hallmark of Fanconi anemia is accelerated decline in hematopoietic stem and progenitor cells (CD34 +) leading to bone marrow failure. Long-term treatment requires hematopoietic cell transplantation from an unaffected donor but is associated with potentially severe side-effects. Gene therapy to correct the genetic defect in the patient's own CD34 cells has been limited by low CD34 cell numbers and viability. Here we demonstrate an altered ratio of CD34 to CD34 cells in Fanconi patients relative to healthy donors, with exclusive repopulating ability in only CD34 cells, underscoring a need for novel strategies to preserve limited CD34 cells. To address this need, we developed a clinical protocol to deplete lineage(CD3, CD14, CD16 and CD19) cells from blood and marrow products. This process depletes >90% of lineagecells while retaining ≥60% of the initial CD34cell fraction, reduces total nucleated cells by 1-2 logs, and maintains transduction efficiency and cell viability following gene transfer. Importantly, transduced lineage cell products engrafted equivalently to that of purified CD34 cells from the same donor when xenotransplanted at matched CD34 cell doses. This novel selection strategy has been approved by the regulatory agencies in a gene therapy study for Fanconi anemia patients ().
范可尼贫血的一个特征是造血干细胞和祖细胞（CD34+）的加速减少，导致骨髓衰竭。长期治疗需要从未受影响的供体进行造血细胞移植，但与潜在的严重副作用相关。纠正患者自身 CD34 细胞中遗传缺陷的基因治疗受到 CD34 细胞数量和活力低的限制。在这里，我们证明了范可尼患者相对于健康供体的 CD34 与 CD34 细胞的比例发生改变，只有 CD34 细胞具有排他性的再生成能力，这突出表明需要新的策略来保存有限的 CD34 细胞。为了解决这一需求，我们开发了一种从血液和骨髓产品中去除谱系（CD3、CD14、CD16 和 CD19）细胞的临床方案。该过程可去除 >90%的谱系细胞，同时保留初始 CD34 细胞分数的≥60%，减少 1-2 个对数级的总核细胞，并在基因转移后保持转导效率和细胞活力。重要的是，当以匹配的 CD34 细胞剂量异种移植时，转导的谱系细胞产物与来自同一供体的纯化 CD34 细胞的植入相当。这种新的选择策略已在范可尼贫血患者的基因治疗研究中获得监管机构的批准（）。
