To develop an inflammation-related immunohistochemistry marker-based algorithm that confers higher diagnostic ability for idiopathic inflammatory myopathies (IIMs) than IIM-related histopathologic features. Muscle biopsy tissues from 129 IIM patients who met the 2017 EULAR/ACR criteria and 73 control tissues from patients with non-inflammatory myopathies or healthy muscle specimens were evaluated for histological features and immunostaining results of CD3, CD4, CD8, CD20, CD68, CD163, MX1, MHC class I, MHC class II, and HLA-DR. Diagnostic algorithms for IIM were developed based on the results of the classification and regression tree (CART) analysis, which used immunostaining results as predictor variables for classifying patients with IIMs. In the analysis set (IIM, n = 129; control, n = 73), IIM-related histopathologic features had a diagnostic accuracy of 87.6% (sensitivity 80.6%; specificity 100.0%) for IIMs. Notably, muscular expression of CD163 (99.2% vs. 20.8%, p < 0.001) and MHC class I (87.6% vs. 23.1%, p < 0.001) was significantly higher in the IIM group than in controls. Based on the CART analysis results, we developed an algorithm combining CD163 and MHC class I expression that conferred a diagnostic accuracy of 95.5% (sensitivity 96.1%; specificity 94.5%). In addition, our algorithm was able to correctly diagnose IIM in 94.1% (16/17) of patients who did not meet the 2017 EUALR/ACR criteria but were diagnosed as having IIMs by an expert physician. Combination of CD163 and MHC class I muscular expression may be useful in diagnosing IIMs.

中文翻译：

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CD163 和主要组织相容性复合物 I 类的表达作为特发性炎症性肌病的诊断标志物


开发一种基于炎症相关免疫组织化学标记的算法，与 IIM 相关的组织病理学特征相比，该算法对特发性炎症性肌病 (IIM) 具有更高的诊断能力。对符合 2017 年 EULAR/ACR 标准的 129 例 IIM 患者的肌肉活检组织和来自非炎症性肌病患者或健康肌肉标本的 73 例对照组织进行组织学特征和 CD3、CD4、CD8、CD20、CD68、CD163 免疫染色结果的评估、MX1、MHC I 类、MHC II 类和 HLA-DR。 IIM 的诊断算法是根据分类和回归树 (CART) 分析的结果开发的，该算法使用免疫染色结果作为对 IIM 患者进行分类的预测变量。在分析集中（IIM，n = 129；对照，n = 73），IIM 相关组织病理学特征对 IIM 的诊断准确性为 87.6%（敏感性 80.6%；特异性 100.0%）。值得注意的是，IIM 组的 CD163（99.2% vs. 20.8%，p < 0.001）和 MHC I 类（87.6% vs. 23.1%，p < 0.001）的肌肉表达显着高于对照组。基于CART分析结果，我们开发了一种结合CD163和MHC I类表达的算法，诊断准确性为95.5%（敏感性96.1%；特异性94.5%）。此外，我们的算法能够正确诊断 94.1% (16/17) 不符合 2017 年 EUALR/ACR 标准但被专家医师诊断为 IIM 的患者。 CD163 和 MHC I 类肌肉表达的组合可能有助于诊断 IIM。