Internal Medicine D, Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, Muenster, Germany.
Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease, University Hospital Muenster, Muenster, Germany.
J Inherit Metab Dis. 2020 Mar;43(2):334-347. doi: 10.1002/jimd.12176. Epub 2019 Nov 14.
Fabry disease (FD) is a lysosomal storage disease, treatable by enzyme replacement therapy (ERT) that substitutes deficient α-galactosidase A (AGAL). The formation of neutralising anti-drug antibodies (ADA) inhibiting AGAL activity during infusion is associated with disease progression in affected male patients. In this study we analysed if ADAs also inhibit endothelial enzyme uptake as well as intracellular enzyme activity. Therefore, fluorescence-labelled AGAL in combination with ADA-positive sera from FD patients (n = 8) was used to analyse enzyme uptake in endothelial and FD-specific cells. Furthermore, immune adsorption and a comprehensive ADA epitope mapping were performed. Pre-incubation of AGAL with ADAs significantly inhibited intracellular enzyme activity, which was rescued by immune adsorption (both P < .01). ADAs from some patients also inhibited enzyme uptake. ADA epitope mapping identified an epitope at position 121 to 140 aa potentially responsible for uptake inhibition for these patients. Further analyses revealed the presence of stable AGAL/ADA-immune complexes at pH 4.5 and decreased intracellular enzyme activity in endothelial cells (P < .001). Finally, the pre-incubation of AGAL with ADAs resulted in a reduced depletion of intracellular globotriaosylceramide in patient-derived AGAL-deficient cells, demonstrating a direct negative impact of ADAs on intracellular clearance. Neutralising ADAs may not only inhibit infused AGAL activity, but according to their epitopes can also inhibit endothelial AGAL uptake. Indeed, internalised AGAL/ADA-complexes may not dissociate, underlining the importance of novel therapeutic approaches for ADA reduction and prevention to increase therapy efficiency in affected patients.
法布里病（FD）是一种溶酶体贮积病，可通过酶替代疗法（ERT）治疗，ERT 可替代缺乏的α-半乳糖苷酶 A（AGAL）。在输注过程中形成中和抗药物抗体（ADA）抑制 AGAL 活性与受影响的男性患者的疾病进展有关。在这项研究中，我们分析了 ADA 是否也抑制内皮细胞酶摄取以及细胞内酶活性。因此，使用荧光标记的 AGAL 结合来自 FD 患者的 ADA 阳性血清（n = 8）来分析内皮细胞和 FD 特异性细胞中的酶摄取。此外，还进行了免疫吸附和全面的 ADA 表位作图。AGAL 与 ADA 预孵育显著抑制细胞内酶活性，免疫吸附可挽救该活性（均 P <.01）。一些患者的 ADA 也抑制了酶摄取。ADA 表位作图确定了位置 121 到 140 aa 的一个表位，可能是这些患者的摄取抑制的原因。进一步的分析显示，在 pH 4.5 时存在稳定的 AGAL/ADA-免疫复合物，并且内皮细胞中的细胞内酶活性降低（P <.001）。最后，AGAL 与 ADA 预孵育导致患者来源的 AGAL 缺乏细胞中细胞内神经节苷脂 Gb3 的消耗减少，表明 ADA 对细胞内清除具有直接的负面影响。中和 ADA 不仅可以抑制输注的 AGAL 活性，而且根据其表位，还可以抑制内皮细胞的 AGAL 摄取。实际上，内化的 AGAL/ADA 复合物可能不会解离，这强调了减少 ADA 和预防 ADA 的新治疗方法的重要性，以增加受影响患者的治疗效率。
