PDF(Pubmed)
Abstract：
UNASSIGNED: Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of autoimmune diseases affecting primarily proximal muscles. Major subtypes include dermatomyositis, polymyositis, inclusion body myositis, immune-mediated necrotizing myopathy and antisynthetase syndrome. Overexpression of sarcoplasmic myxovirus-resistance protein A (MxA) has been observed in muscle biopsy specimens of dermatomyositis but is rarely seen in other subtypes of IIM and other myopathies.
UNASSIGNED: We evaluate the expression of sarcoplasmic MxA and its diagnostic value in IIM and other myopathies.
UNASSIGNED: One hundred and thirty-eight muscle biopsy specimens with the diagnosis of IIM and other myopathies from 2011 to 2020 were reviewed and stained for MxA by immunohistochemistry. The difference of the expression of MxA between IIM and other myopathies was analyzed by Fisher\'s exact test, and the sensitivity and specificity of MxA immunohistochemistry in the diagnosis of IIM were assessed.
UNASSIGNED: MxA protein was positive in 16/138 (11.6%) specimens. All 12 dermatomyositis specimens positive for MxA protein were positive in perifascicular area pattern. Only dermatomyositis specimens had a significantly higher percentage of positive sarcoplasmic MxA expression than specimens of other subtypes of IIM (p<0.001). Sarcoplasmic MxA expression for dermatomyositis diagnosis had a sensitivity of 46.15% (95% CI 26.59-66.63%) and a specificity of 94.44% (95% CI 81.34-99.32%) with the positive and negative likelihood ratio of 8.31 (95% CI 2.03-34.01) and 0.57 (95% CI 0.40-0.82), respectively.
UNASSIGNED: The MxA immunohistochemistry is highly specific for dermatomyositis and should be added to a routine inflammatory panel of muscle biopsy. MxA expression should be cautiously interpreted to avoid pitfalls.
UNASSIGNED: We evaluate the expression of sarcoplasmic MxA and its diagnostic value in IIM and other myopathies.
UNASSIGNED: One hundred and thirty-eight muscle biopsy specimens with the diagnosis of IIM and other myopathies from 2011 to 2020 were reviewed and stained for MxA by immunohistochemistry. The difference of the expression of MxA between IIM and other myopathies was analyzed by Fisher\'s exact test, and the sensitivity and specificity of MxA immunohistochemistry in the diagnosis of IIM were assessed.
UNASSIGNED: MxA protein was positive in 16/138 (11.6%) specimens. All 12 dermatomyositis specimens positive for MxA protein were positive in perifascicular area pattern. Only dermatomyositis specimens had a significantly higher percentage of positive sarcoplasmic MxA expression than specimens of other subtypes of IIM (p<0.001). Sarcoplasmic MxA expression for dermatomyositis diagnosis had a sensitivity of 46.15% (95% CI 26.59-66.63%) and a specificity of 94.44% (95% CI 81.34-99.32%) with the positive and negative likelihood ratio of 8.31 (95% CI 2.03-34.01) and 0.57 (95% CI 0.40-0.82), respectively.
UNASSIGNED: The MxA immunohistochemistry is highly specific for dermatomyositis and should be added to a routine inflammatory panel of muscle biopsy. MxA expression should be cautiously interpreted to avoid pitfalls.
摘要：
■特发性炎性肌病（IIM）是一组异质性的自身免疫性疾病，主要影响近端肌肉。主要亚型包括皮肌炎，多发性肌炎,包涵体肌炎，免疫介导的坏死性肌病和抗合成酶综合征。在皮肌炎的肌肉活检标本中观察到肌浆粘液病毒抗性蛋白A（MxA）的过表达，但在IIM的其他亚型和其他肌病中很少见。
■我们评估了肌浆MxA的表达及其在IIM和其他肌病中的诊断价值。
■回顾了2011年至2020年诊断为IIM和其他肌病的138个肌肉活检标本，并通过免疫组织化学对MxA进行了染色。通过Fisher精确检验分析IIM与其他肌病之间MxA表达的差异，评估MxA免疫组织化学在诊断IIM中的敏感性和特异性。
■MxA蛋白在16/138（11.6％）标本中呈阳性。所有12例MxA蛋白阳性的皮肌炎标本在束周区域模式中均为阳性。只有皮肌炎标本的肌浆MxA阳性表达百分比明显高于其他IIM亚型标本（p<0.001）。肌浆MxA表达对皮肌炎诊断的敏感性为46.15%（95%CI26.59-66.63%），特异性为94.44%（95%CI81.34-99.32%），阳性和阴性似然比为8.31（95%CI2.03-34.01）和0.57（95%CI0.40-0.82），分别。
■MxA免疫组织化学对皮肌炎具有高度特异性，应添加到肌肉活检的常规炎症组中。应谨慎解释MxA表达式以避免陷阱。
■我们评估了肌浆MxA的表达及其在IIM和其他肌病中的诊断价值。
■回顾了2011年至2020年诊断为IIM和其他肌病的138个肌肉活检标本，并通过免疫组织化学对MxA进行了染色。通过Fisher精确检验分析IIM与其他肌病之间MxA表达的差异，评估MxA免疫组织化学在诊断IIM中的敏感性和特异性。
■MxA蛋白在16/138（11.6％）标本中呈阳性。所有12例MxA蛋白阳性的皮肌炎标本在束周区域模式中均为阳性。只有皮肌炎标本的肌浆MxA阳性表达百分比明显高于其他IIM亚型标本（p<0.001）。肌浆MxA表达对皮肌炎诊断的敏感性为46.15%（95%CI26.59-66.63%），特异性为94.44%（95%CI81.34-99.32%），阳性和阴性似然比为8.31（95%CI2.03-34.01）和0.57（95%CI0.40-0.82），分别。
■MxA免疫组织化学对皮肌炎具有高度特异性，应添加到肌肉活检的常规炎症组中。应谨慎解释MxA表达式以避免陷阱。
