Membranous nephropathy (MN) stands as the most common origin of nephrotic syndrome in adults. Nevertheless, it is quite unusual for individuals to simultaneously manifest both chronic inflammatory demyelinating polyneuropathy (CIDP) and MN along with the presence of positive anti-contactin-1 (CNTN1) antibodies. Only a limited number of case reports in scientific literature have described such occurrences to date. Typically, CIDP patients exhibit symptoms characterized by proximal and distal weakness and sensory abnormalities. We present a rare case of CIDP and MN with positive anti-CNTN1 antibodies in our setting and describe our experience in management of the condition. Moreover, noticing the rarity of this condition, we performed an analysis of the existing literature to comprehensively analyze the diagnostic, management, and clinical outcomes for this condition. Our patient, a 45-year-old male, had a pre-existing diagnosis of CIDP at the age of 43, in March 2015. Approximately 18 months later, in September 2016, this patient presented with nephrotic syndrome, leading to a subsequent diagnosis of stage 2 MN. The diagnosis was confirmed through renal biopsy results, which revealed thickening of the glomerular basement membrane and immunoglobulin G4 (IgG4) deposits. However, the patient tested negative for anti-phospholipase 2 antibody. Further diagnostic evaluation was performed, and anti-CNTN1 antibodies were detected. The patient was successfully treated with cyclosporine therapy 150 mg twice a day and prednisone, and no complications were noted; however, partial relapse on remission of cyclosporine was observed. Based on our case analysis and comprehensive review of existing literature, it is evident that there are similarities between CIDP with MN and positive anti-CNTN1 antibodies, but they are not identical conditions. Therefore, we propose the assessment of anti-CNTN1 antibodies as part of the evaluation for patients who exhibit both CIDP and MN symptoms. Anti-CNTN 1 antibody may be a novel diagnostic test in this condition and may allow determination of therapeutic response soon; however, this needs to be backed up with evidence from research studies in the future.

Keywords: anti-contactin-1 antibodies; case; chronic inflammatory demyelinating polyneuropathy (cidp); membranous nephropathy; nephropathy.

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膜性肾病（MN）是成人发生肾病综合征最常见的原因之一。然而，同时出现慢性炎症脱髓鞘多发性神经病（CIDP）和膜性肾病，并且抗接触蛋白-1（CNTN1）抗体呈阳性的病例非常罕见。迄今为止，在科学文献中仅有少数案例报告描述了这种情况的发生。通常情况下，CIDP患者表现出近端和远端肌力下降以及感觉异常的症状。我们在此介绍一例罕见的CIDP与膜性肾病且抗-CNTN1抗体阳性的情况，并详细描述我们在管理该条件过程中的经验。鉴于这种状况极为罕见，我们也对现有的文献进行了分析，以全面探讨诊断、管理和临床结果等方面的内容。本案例中的患者是一名45岁男性，在2015年3月时被诊断为CIDP（年龄43岁时）。大约在随后的18个月后，在2016年9月，该患者出现了肾病综合征的症状，继而被确诊为膜性肾病第2阶段。通过肾活检结果确认了该诊断，结果显示肾小球基底膜增厚和免疫球蛋白G4（IgG4）沉积物的存在。然而，患者的抗磷脂酶2抗体检测结果呈阴性。进一步进行诊断评估后，发现患者存在抗CNTN1抗体。经过环孢素治疗（每天两次，每次150毫克）以及泼尼松的治疗，该患者成功康复，并未出现并发症；但是在环孢素停药期间观察到了部分复发的情况。根据我们的病例分析及对现有文献进行综合回顾，可以看出CIDP与膜性肾病伴抗-CNTN1抗体阳性之间存在相似之处，但它们并不是相同的疾病状态。因此我们建议在评估同时表现出CIDP和膜性肾病症状的患者时，应考虑检测抗CNTN1抗体。抗CNTN1抗体可能在此条件下成为一种新型诊断工具，并且可以用来快速确定治疗反应；然而，这一点需要未来的研究提供支持。

关键词： 抗接触蛋白-1抗体；案例；慢性炎症脱髓鞘多发性神经病（CIDP）；膜性肾病；肾小球疾病。

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