局限型系统性硬皮病和抗 Th/To 抗体在系统性硬化症中的比较：不同自身抗体检测方法的比较。
PM-Scl and Th/To in systemic sclerosis: a comparison of different autoantibody assays.
机构信息
Division of Rheumatology, Johns Hopkins School of Medicine, 5200 Eastern Ave, MFL Bldg, Center Tower, Suite 4100, Baltimore, MD, 21224, USA.
出版信息
Clin Rheumatol. 2021 Jul;40(7):2763-2769. doi: 10.1007/s10067-021-05586-x. Epub 2021 Jan 18.
OBJECTIVE
To compare test characteristics of the Euroimmun line blot assay with other assays for two uncommon autoantibody specificities in systemic sclerosis (SSc).
METHODS
Patients from the Johns Hopkins Scleroderma Center were assayed routinely using the Euroimmun platform. Patients positive for anti-Th/To (N = 73) and anti-PM-Scl (PM75 and/or PM100; N = 290) by Euroimmun were compared with SSc patients negative for these autoantibodies. For Th/To antibodies, the comparison assay was immunoprecipitation (IP), performed using 4 Th/To complex components: POP1, RPP40, RPP30, and RPP25. For anti-PM-Scl, IPs were performed with PM100 and PM75. Different Euroimmun cut-offs for assigning antibody positive status (≥ 15/+, ≥ 36/++, ≥ 71/+++) were examined. Kappa statistics were calculated to determine agreement between assays.
RESULTS
The best performing thresholds for defining anti-PM-Scl positivity were both PM75 and PM100 ≥ 15/+ on Euroimmun, corresponding to a kappa statistic of 0.79, sensitivity 72% and specificity 100%. For anti-Th/To, kappa values were lower for all comparisons (κ < 0.5). Given the high sensitivity of defining anti-Th/To by ≥ 15/+ (91-95%), a potential approach is to use Euroimmun screening (15/+ cut-off), followed by confirmatory IP.
CONCLUSION
Given the increasing utilization of Euroimmun and the importance of comparing data across cohorts, continued use of this platform is warranted, acknowledging discordance with IP for some specificities. For these, using a two-step approach (Euroimmun to maximize sensitivity, confirmatory assay to increase specificity) is suggested.
KEY POINTS
• For less common SSc autoantibody specificities, some discordances exist between IP and Euroimmun LIA. • The best performing thresholds for defining anti-PM-Scl positivity were both PM75 and PM100 ≥ 15/+ on Euroimmun. • For Th/To, a two-step approach (Euroimmun to maximize sensitivity, confirmatory assay to increase specificity) is suggested.
目的
比较 Euroimmun 印迹法与其他方法检测系统性硬皮病（SSc）两种罕见自身抗体特异性的检测特征。
方法
约翰霍普金斯硬皮病中心的患者常规使用 Euroimmun 平台进行检测。通过 Euroimmun 检测到抗-Th/To（N=73）和抗-PM-Scl（PM75 和/或 PM100；N=290）阳性的患者与这些自身抗体阴性的 SSc 患者进行比较。对于 Th/To 抗体，比较检测方法为免疫沉淀（IP），使用 4 种 Th/To 复合物成分：POP1、RPP40、RPP30 和 RPP25 进行。对于抗-PM-Scl，使用 PM100 和 PM75 进行 IPs。检查了用于分配抗体阳性状态（≥15/ +、≥36/++、≥71/+++）的不同 Euroimmun 截止值。计算 Kappa 统计量以确定检测方法之间的一致性。
结果
在 Euroimmun 上，定义抗-PM-Scl 阳性的最佳性能阈值均为 PM75 和 PM100≥15/ +，Kappa 统计量为 0.79，灵敏度为 72%，特异性为 100%。对于抗-Th/To，所有比较的 Kappa 值均较低（κ<0.5）。鉴于通过≥15/ +定义抗-Th/To 的高灵敏度（91-95%），一种潜在的方法是使用 Euroimmun 筛选（15/+ 截止值），然后进行确认性 IP。
结论
鉴于 Euroimmun 的使用不断增加，以及比较队列之间数据的重要性，有必要继续使用该平台，同时承认与某些特异性的 IP 存在差异。对于这些特异性，建议采用两步法（Euroimmun 最大限度提高敏感性，确认性检测提高特异性）。
关键点
• 在不太常见的 SSc 自身抗体特异性中，免疫印迹法和 Euroimmun LIA 之间存在一些差异。• 在 Euroimmun 上，定义抗-PM-Scl 阳性的最佳性能阈值均为 PM75 和 PM100≥15/ +。• 对于 Th/To，建议采用两步法（Euroimmun 最大限度提高敏感性，确认性检测提高特异性）。
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