In the current study we report a novel autoantibody against Purkinje cells in a patient with primary autoimmune cerebellar ataxia (PACA) associated with Sjogren's syndrome (SS). Tissue-based indirect immunofluorescence assay (TBA) of the patient's serum and cerebrospinal fluid (CSF) revealed IgG antibody to Purkinje cells and the granular layer of the rat cerebellum. Rab6A was identified as autoantigen by mass spectrometry (MS) and Western blotting, and the interactions between Rab6A or its homologous Rab6B and autoantibody in patient serum were verified by recombinant cell-based assay (CBA) and neutralization experiments. This autoantibody may represent a novel biomarker in the diagnosis of PACA.

在当前的研究中，我们报告了一位患有与干燥综合征（SS）相关的原发性自身免疫性小脑共济失调（PACA）患者的针对浦肯野细胞的新型自身抗体。对患者血清和脑脊液 (CSF) 进行的基于组织的间接免疫荧光测定 (TBA) 显示针对浦肯野细胞和大鼠小脑颗粒层的 IgG 抗体。通过质谱（MS）和蛋白质印迹法将Rab6A鉴定为自身抗原，并通过重组细胞分析（CBA）和中和实验验证了Rab6A或其同源Rab6B与患者血清中自身抗体之间的相互作用。这种自身抗体可能代表了 PACA 诊断中的一种新型生物标志物。