Lentiviral vector (LV)-mediated ex vivo gene therapy for haematopoietic stem and progenitor cells (HSPCs) has delivered on the promise of a ‘one-and-done’ treatment for several genetic diseases¹. However, ex vivo manipulation and patient conditioning before transplantation are major hurdles that could be overcome by an in vivo approach. Here we demonstrate that in vivo gene delivery to HSPCs after systemic LV administration is enabled by the substantial trafficking of these cells from the liver to the bone marrow in newborn mice. We improved gene-transfer efficiency using a phagocytosis-shielded LV, successfully reaching bona fide HSPCs capable of long-term multilineage output and engraftment after serial transplantation, as confirmed by clonal tracking. HSPC mobilization further increased gene transfer, extending the window of intervention, although permissiveness to LV transduction declined with age. We successfully tested this in vivo strategy in mouse models of adenosine deaminase deficiency, autosomal recessive osteopetrosis and Fanconi anaemia. Interestingly, in vivo gene transfer provided a selective advantage to corrected HSPCs in Fanconi anaemia, leading to near-complete haematopoietic reconstitution and prevention of bone marrow failure. Given that circulating HSPCs in humans are also most abundant shortly after birth, in vivo HSPC gene transfer holds strong translational potential across multiple diseases.

慢病毒载体 （LV） 介导的用于造血干细胞和祖细胞 （HSPC） 的离体基因疗法已经兑现了对多种遗传疾病的“一劳永逸”治疗的承诺 ¹。然而，移植前的离体作和患者调节是体内方法可以克服的主要障碍。在这里，我们证明，在全身 LV 给药后，这些细胞从肝脏大量运输到新生小鼠的骨髓，使体内基因递送到 HSPC 成为可能。我们使用吞噬作用屏蔽的 LV 提高了基因转移效率，成功达到能够在连续移植后长期多系输出和植入的真正 HSPC，克隆追踪证实了这一点。HSPC 动员进一步增加了基因转移，延长了干预窗口，尽管对 LV 转导的容忍度随着年龄的增长而下降。我们在腺苷脱氨酶缺乏症、常染色体隐性遗传性骨硬化症和 Fanconi 贫血的小鼠模型中成功测试了这种体内策略。有趣的是，体内基因转移为 Fanconi 贫血中校正的 HSPC 提供了选择性优势，导致几乎完全的造血重建和预防骨髓衰竭。鉴于人类循环的 HSPC 在出生后不久也最丰富，体内 HSPC 基因转移在多种疾病中具有很强的转化潜力。