Kruzik Anita, Fetahagic Damir, Hartlieb Bettina, Dorn Sebastian, Koppensteiner Herwig, Horling Frank M, Scheiflinger Friedrich, Reipert Birgit M, de la Rosa Maurus
Baxalta Innovations GmbH, a member of the Takeda group of companies, Vienna, Austria.
Mol Ther Methods Clin Dev. 2019 Jun 7;14:126-133. doi: 10.1016/j.omtm.2019.05.014. eCollection 2019 Sep 13.
Preexisting immunity against adeno-associated virus (AAV) is a major challenge facing AAV gene therapy, resulting in the exclusion of patients from clinical trials. Accordingly, proper assessment of anti-AAV immunity is necessary for understanding clinical data and for product development. Previous studies on anti-AAV prevalence lack method standardization, rendering the assessment of prevalence difficult. Addressing this need, we used clinical assays that were validated according to guidelines for a comprehensive characterization of anti-AAV1, -AAV2, -AAV5, and -AAV8 immunity in large international cohorts of healthy donors and patients with hemophilia B. Here, we report a higher than expected average prevalence for anti-AAV8 (∼40%) and anti-AAV5 (∼30%) neutralizing antibodies (NAbs), which is supported by strongly correlating anti-AAV IgG antibody titers. A similar anti-AAV8 NAb prevalence was observed in hemophilia B patients. In addition, a high co-prevalence of NAbs against other serotypes makes switching to gene therapy using another serotype difficult. As anti-AAV T cell responses are believed to influence transduction, we characterized anti-AAV T cell responses using interleukin-2 (IL-2) and interferon-γ (IFN-γ) ELISpot assays, revealing a similar prevalence of IFN-γ responses (∼20%) against different serotypes that did not correlate with NAbs. These data, along with the long-term stability of NAbs, emphasize the need to develop strategies to circumvent anti-AAV immunity.
预先存在的针对腺相关病毒（AAV）的免疫力是AAV基因治疗面临的一项重大挑战，导致患者被排除在临床试验之外。因此，正确评估抗AAV免疫力对于理解临床数据和产品开发至关重要。以往关于抗AAV流行率的研究缺乏方法标准化，使得流行率评估变得困难。为满足这一需求，我们使用了根据指南验证的临床检测方法，对来自大型国际健康供体队列和B型血友病患者队列中的抗AAV1、-AAV2、-AAV5和-AAV8免疫力进行全面表征。在此，我们报告抗AAV8（约40%）和抗AAV5（约30%）中和抗体（NAb）的平均流行率高于预期，这得到了抗AAV IgG抗体滴度高度相关的支持。在B型血友病患者中观察到了类似的抗AAV8 NAb流行率。此外，针对其他血清型的NAb高共流行率使得改用另一种血清型的基因治疗变得困难。由于抗AAV T细胞反应被认为会影响转导，我们使用白细胞介素-2（IL-2）和干扰素-γ（IFN-γ）ELISpot检测对抗AAV T细胞反应进行了表征，发现针对不同血清型的IFN-γ反应流行率相似（约20%），且与NAb不相关。这些数据，连同NAb的长期稳定性，强调了制定规避抗AAV免疫策略的必要性。
