Division of Rheumatology, Centre hospitalier de l'Université de Montréal (CHUM), CHUM Research Center, Department of Medicine, Université de Montréal, Montréal, Québec, Canada.
Service de Physiologie-Explorations Fonctionnelles Musculaire, Service de Rhumatologie et Centre de Référence des Maladies Autoimmunes Rares, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Autoimmun Rev. 2021 Jul;20(7):102851. doi: 10.1016/j.autrev.2021.102851. Epub 2021 May 7.
Scleromyositis (SM) is an emerging subset of myositis associated with features of systemic sclerosis (SSc) but it is currently not recognized as a distinct histopathological subset by the European NeuroMuscular Center (ENMC). Our aim was to review studies reporting muscle biopsies from SSc patients with myositis and to identify unique histopathological features of SM.
A scoping review was conducted and included all studies reporting histopathological findings in SSc patients with myositis searching the following databases: PubMed, MEDLINE, EMBASE, CINAHL and EBM-Reviews. Clinical, serological, and histopathological data were extracted using a standardized protocol.
Out of 371 citations, 77 studies that included 559 muscle biopsies were extracted. Fifty-seven percent (n = 227/400) had inflammatory infiltrates, predominantly T cells, which were endomysial (49%), perimysial (42%) and perivascular (41%). Few studies (18%, n = 8/44) evaluated the presence of B-cells. Myofiber atrophy was present in 48% (n = 104/218) of biopsies, and was predominantly perifascicular in 19% (n = 6/31), with necrosis reported in 56% (n = 162/290) of cases. Sarcolemmal MHC-I upregulation was found in 72% (n = 64/89) of biopsies. Non-specified C5b-9 deposition was described in 39% of muscle biopsies (n = 28/72). Neurogenic features were present in 23% (n = 44/191); endomysial fibrosis was reported in 35% (n = 120/340); and rimmed vacuoles were observed in 32% (n = 11/34) of biopsies. Capillaropathy, such as capillary dropout and/or ultrastructural endothelial abnormalities, was reported in 33% (n = 43/129) of cases. Reported ENMC categories were mainly polymyositis (21%), non-specific myositis (19%), immune-mediated necrotizing myopathy (16%), and dermatomyositis (8%). Histopathological features were analyzed according to serological subtypes in 28 studies, including anti-PM-Scl (n = 48), -Ku (n = 23) and -U1RNP (n = 90). Most of these biopsies demonstrated inflammatory infiltrates (range 49-85%) as well as MHC-I expression (range 63-81%). Necrosis was associated with anti-Ku (85%) and anti-U1RNP (73%), while anti-Ku was also associated with neurogenic features and rimmed vacuoles in 57% and 25% of cases, respectively.
Our review suggests that SM is characterized by heterogeneous pathological features using definitions included in current histopathological criteria. Whether a distinct histopathological signature exists in SM remains to be determined. SSc-specific and SSc-associated autoantibodies may help define more homogeneous histopathological subsets.
硬皮病性肌炎（SM）是一种与系统性硬皮病（SSc）相关的新兴肌炎亚群，但目前尚未被欧洲神经肌肉中心（ENMC）确认为一种独特的组织病理学亚群。我们的目的是回顾报道 SSc 患者肌炎活检的研究，并确定 SM 的独特组织病理学特征。
进行了范围性综述，纳入了所有报道 SSc 患者肌炎的组织病理学发现的研究，检索了以下数据库：PubMed、MEDLINE、EMBASE、CINAHL 和 EBM-Reviews。使用标准化协议提取临床、血清学和组织病理学数据。
在 371 条引文中，提取了 77 项包含 559 块肌肉活检的研究。57%（n=227/400）有炎症浸润，主要是 T 细胞，位于肌内膜（49%）、肌周膜（42%）和血管周围（41%）。很少有研究（18%，n=8/44）评估 B 细胞的存在。48%（n=104/218）的活检存在肌纤维萎缩，19%（n=6/31）以近肌纤维萎缩为主，56%（n=162/290）的病例报告有坏死。72%（n=64/89）的活检中发现了肌细胞膜 MHC-I 上调。39%的肌肉活检（n=28/72）描述了非特异性 C5b-9 沉积。23%（n=44/191）存在神经源性特征；35%（n=120/340）报告了肌内膜纤维化；32%（n=11/34）的活检观察到边缘空泡。33%（n=43/129）的病例报告了毛细血管病，如毛细血管丢失和/或超微结构内皮异常。报告的 ENMC 类别主要是多肌炎（21%）、非特异性肌炎（19%）、免疫介导的坏死性肌病（16%）和皮肌炎（8%）。28 项研究根据血清学亚型分析了组织病理学特征，包括抗 PM-Scl（n=48）、-Ku（n=23）和 -U1RNP（n=90）。这些活检中的大多数都显示出炎症浸润（范围 49-85%）和 MHC-I 表达（范围 63-81%）。坏死与抗 Ku（85%）和抗 U1RNP（73%）相关，而抗 Ku 还与神经源性特征和边缘空泡相关，分别在 57%和 25%的病例中出现。
我们的综述表明，SM 的特征是使用当前组织病理学标准中包含的定义存在异质性的病理学特征。SM 是否存在独特的组织病理学特征仍有待确定。SSc 特异性和 SSc 相关自身抗体可能有助于定义更同质的组织病理学亚群。
