Snyder R O, Miao C H, Patijn G A, Spratt S K, Danos O, Nagy D, Gown A M, Winther B, Meuse L, Cohen L K, Thompson A R, Kay M A
Somatix Therapy Corporation, Alameda, California 94501, USA.
Nat Genet. 1997 Jul;16(3):270-6. doi: 10.1038/ng0797-270.
Haemophilia B, or factor IX deficiency, is a X-linked recessive disorder that occurs in about one in 25,000 males, and severely affected people are at risk for spontaneous bleeding into numerous organs. Bleeding can be life-threatening or lead to chronic disabilities with haemophilic arthropathy. The severity of the bleeding tendency varies among patients and is related to the concentration of functional plasma factor IX. Patients with 5-30% of the normal factor IX have mild haemophilia that may not be recognized until adulthood or after heavy trauma or surgery. Therapy for acute bleeding consists of the transfusion of clotting-factor concentrates prepared from human blood and recombinant clotting factors that are currently in clinical trials. Both recombinant retroviral and adenoviral vectors have successfully transferred factor IX cDNA into the livers of dogs with haemophilia B. Recombinant retroviral-mediated gene transfer results in persistent yet subtherapeutic concentrations of factor IX and requires the stimulation of hepatocyte replication before vector administration. Recombinant adenoviral vectors can temporarily cure the coagulation defect in the canine haemophilia B model; however, an immune response directed against viral gene products made by the vector results in toxicity and limited gene expression. The use of recombinant adeno-associated virus (rAAV) vectors is promising because the vector contains no viral genes and can transduce non-dividing cells. The efficacy of in vivo transduction of non-dividing cells has been demonstrated in a wide variety of tissues. In this report, we describe the successful transduction of the liver in vivo using r-AAV vectors delivered as a single administration to mice and demonstrate that persistent, curative concentrations of functional human factor IX can be achieved using wild-type-free and adenovirus-free rAAV vectors. This demonstrates the potential of treating haemophilia B by gene therapy at the natural site of factor IX production.
乙型血友病，即因子IX缺乏症，是一种X连锁隐性疾病，约每25000名男性中就有1人患病，严重患者有多个器官自发出血的风险。出血可能危及生命，或导致血友病性关节病等慢性残疾。出血倾向的严重程度在患者中各不相同，且与功能性血浆因子IX的浓度有关。因子IX含量为正常水平5%-30%的患者患有轻度血友病，可能直到成年或遭受严重创伤或手术后才被发现。急性出血的治疗方法包括输注从人血制备的凝血因子浓缩物以及目前正在临床试验中的重组凝血因子。重组逆转录病毒和腺病毒载体都已成功地将因子IX cDNA导入患有乙型血友病的犬肝脏。重组逆转录病毒介导的基因转移导致因子IX持续处于亚治疗浓度，并且在载体给药前需要刺激肝细胞复制。重组腺病毒载体可以暂时治愈犬乙型血友病模型中的凝血缺陷；然而，针对载体产生的病毒基因产物的免疫反应会导致毒性和有限的基因表达。使用重组腺相关病毒（rAAV）载体很有前景，因为该载体不包含病毒基因，并且可以转导非分裂细胞。非分裂细胞的体内转导功效已在多种组织中得到证实。在本报告中，我们描述了通过单次给药将r-AAV载体成功地在体内转导至小鼠肝脏，并证明使用无野生型和无腺病毒的rAAV载体可以实现功能性人因子IX的持续治愈浓度。这证明了通过基因治疗在因子IX产生的天然部位治疗乙型血友病的潜力。
