MuSK肌无力临床改善的血清学标志物

IF 7.8 1区医学 Q1 CLINICAL NEUROLOGY

Neurology® Neuroimmunology & Neuroinflammation Pub Date : 2024-09-09 DOI:10.1212/nxi.0000000000200313

Gregorio Spagni,Angela Vincent,Bo Sun,Silvia Falso,Leslie W Jacobson,Sean Devenish,Amelia Evoli,Valentina Damato

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引用次数: 0

摘要

背景和目的在这项回顾性纵向研究中，我们使用并比较了不同的抗体检测技术，旨在探索(a) MuSK-免疫球蛋白 G (IgG) 水平、(b) 主要 MuSK-IgG 亚类和(c) 抗体亲和力作为 MuSK-MG 严重程度和预后的候选生物标志物的作用。方法使用转染了 MuSK-eGFP 的 HEK293 细胞，通过放射免疫分析法（RIA）、酶联免疫吸附法、流式细胞术和细胞检测法（CBA）系列稀释法对 MuSK-IgGs 总量进行量化。流式细胞术测定了 MuSK-IgG 亚类。结果从20名MuSK-MG患者（中位发病年龄：48岁，四分位间范围=27.5-72.5；女性，16/20）的不同时间点获得了43份血清样本，其中9人（45%）接受了利妥昔单抗治疗。流式细胞术测量的 MuSK-IgG 水平与 RIA 滴度之间存在很强的相关性（rs = 0.74，95% CI 0.41-0.89，p = 0.0003），CBA 终点滴度与 RIA 滴度之间也存在中度相关性（rs = 0.47，95% CI 0.01-0.77，p = 0.0414）。MuSK-IgG 流式细胞术水平与疾病严重程度之间存在明显相关性（rs = 0.39，95% CI 0.06-0.64，p = 0.0175；混合效应模型估计值：2.296e-06，std：1.024e-06, t = 2.243, p = 0.032）。通过流式细胞术或 CBA 终点滴定法测量，个别患者的临床改善与 MuSK-IgG 水平的下降有关。在所有样本中，MuSK-IgG4 是最常见的同种型（平均值±标度：90.95%±13.89）。在临床结果良好的患者中，MuSK-IgG4 明显减少，MuSK-IgG2 减少较少。在接受利妥昔单抗治疗的亚组患者中也证实了类似的趋势。在一名患者中，MuSK-IgG 的亲和力在症状加重期间增加（KD 值：62 nM vs 0.6 nM），而 MuSK-IgG 和 IgG4 的总水平保持稳定，这表明亲和力成熟可能是临床恶化的驱动因素。通过多模式研究方法，我们发现总 MuSK-IgG 水平、MuSK-IgG4 和 MuSK-IgG2 水平以及 MuSK-IgG 亲和力可能是 MuSK-MG 疾病预后的有希望的生物标志物。

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Serological Markers of Clinical Improvement in MuSK Myasthenia Gravis.

BACKGROUND AND OBJECTIVES In this retrospective longitudinal study, we aimed at exploring the role of (a) MuSK-immunoglobulin G (IgG) levels, (b) predominant MuSK-IgG subclasses, and (c) antibody affinity as candidate biomarkers of severity and outcomes in MuSK-MG, using and comparing different antibody testing techniques. METHODS Total MuSK-IgGs were quantified with radioimmunoassay (RIA), ELISA, flow cytometry, and cell-based assay (CBA) serial dilutions using HEK293 cells transfected with MuSK-eGFP. MuSK-IgG subclasses were measured by flow cytometry. SAffCon assay was used for determining MuSK-IgG affinity. RESULTS Forty-three serum samples were obtained at different time points from 20 patients with MuSK-MG (median age at onset: 48 years, interquartile range = 27.5-72.5; women, 16/20), with 9 of 20 (45%) treated with rituximab. A strong correlation between MuSK-IgG levels measured by flow cytometry and RIA titers was found (rs = 0.74, 95% CI 0.41-0.89, p = 0.0003), as well as a moderate correlation between CBA end-point titers and RIA titers (rs = 0.47, 95% CI 0.01-0.77, p = 0.0414). A significant correlation was found between MuSK-IgG flow cytometry levels and disease severity (rs = 0.39, 95% CI 0.06-0.64, p = 0.0175; mixed-effects model estimate: 2.296e-06, std. error: 1.024e-06, t = 2.243, p = 0.032). In individual patients, clinical improvement was associated with decrease in MuSK-IgG levels, as measured by either flow cytometry or CBA end-point titration. In all samples, MuSK-IgG4 was the most frequent isotype (mean ± SD: 90.95% ± 13.89). A significant reduction of MuSK-IgG4 and, to a lesser extent, of MuSK-IgG2, was seen in patients with favorable clinical outcomes. A similar trend was confirmed in the subgroup of rituximab-treated patients. In a single patient, MuSK-IgG affinity increased during symptom exacerbation (KD values: 62 nM vs 0.6 nM) while total MuSK-IgG and IgG4 levels remained stable, suggesting that affinity maturation may be a driver of clinical worsening. DISCUSSION Our data support the quantification of MuSK antibodies by flow cytometry. Through a multimodal investigational approach, we showed that total MuSK-IgG levels, MuSK-IgG4 and MuSK-IgG2 levels, and MuSK-IgG affinity may represent promising biomarkers of disease outcomes in MuSK-MG.

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来源期刊

Neurology® Neuroimmunology & Neuroinflammation Neuroscience-Neurology

CiteScore

15.60

自引率

2.30%

发文量

219

审稿时长

8 weeks

期刊介绍： Neurology Neuroimmunology & Neuroinflammation is an official journal of the American Academy of Neurology. Neurology: Neuroimmunology & Neuroinflammation will be the premier peer-reviewed journal in neuroimmunology and neuroinflammation. This journal publishes rigorously peer-reviewed open-access reports of original research and in-depth reviews of topics in neuroimmunology & neuroinflammation, affecting the full range of neurologic diseases including (but not limited to) Alzheimer's disease, Parkinson's disease, ALS, tauopathy, and stroke; multiple sclerosis and NMO; inflammatory peripheral nerve and muscle disease, Guillain-Barré and myasthenia gravis; nervous system infection; paraneoplastic syndromes, noninfectious encephalitides and other antibody-mediated disorders; and psychiatric and neurodevelopmental disorders. Clinical trials, instructive case reports, and small case series will also be featured.