BACKGROUND Polymorphonuclear (PMN) elastase plays an important role in a variety of inflammatory disorders. Our aim was to analyse PMN elastase in idiopathic inflammatory myopathies (IIMs) and its association with disease activity. METHODS PMN elastase levels were measured using enzyme-linked immunosorbent assay in serum samples obtained from 74 patients with myositis (58 with dermatomyositis [DM] and 16 with polymyositis [PM]) and 22 healthy controls. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the discriminant capacity of PMN elastase level and PMN elastase-to-neutrophil ratio (ENR) in patients with active and remission myositis. The association of serum PMN elastase level and ENR with disease variables was evaluated in patients with IIMs. The disease specificity of PMN elastase level and ENR was further examined in 60 patients with other systemic autoimmune diseases. RESULTS PMN elastase level and ENR were significantly higher in patients with active IIMs, DM, and PM than in patients with remission. ROC curve analysis revealed that PMN elastase level and ENR both outperformed creatine kinase (CK), the currently used laboratory marker, and strongly discriminated patients with active disease and those with remission of IIMs, DM, and PM (area under the ROC curve [AUC] 0.9, 0.9, and 0.88 for PMN elastase; AUC 0.96, 0.96, and 1.0 for ENR; AUC 0.72, 0.70, and 0.80 for CK, respectively). PMN elastase level and ENR were positively correlated with myositis disease activity assessment, CK, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, C-reactive protein, and erythrocyte sedimentation rate. PMN elastase level and ENR were higher in the anti-PM-Scl positive myositis group than those in the anti-PM-Scl negative myositis group. Nevertheless, PMN elastase was not a specific disease marker for IIMs when compared with other autoimmune diseases. CONCLUSIONS PMN elastase, particularly ENR, were significantly correlated with disease activity and could serve as useful biochemical markers for evaluating the disease activity of patients with IIMs. Thus, they are potentially helpful in monitoring disease progression and guiding treatment.

中文翻译：

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肌炎患者中PMN弹性蛋白酶和PMN弹性蛋白酶与中性粒细胞的比率与疾病活动的相关性。

背景技术多形核（PMN）弹性蛋白酶在多种炎性疾病中起重要作用。我们的目的是分析特发性炎症性肌病（IIMs）中的PMN弹性蛋白酶及其与疾病活动的关系。方法采用酶联免疫吸附法测定74例肌炎患者（58例皮肌炎[DM]和16例多发性肌炎[PM]）和22例健康对照者的血清样本中的PMN弹性蛋白酶水平。进行受试者工作特征（ROC）曲线分析以评估活动性和缓解性肌炎患者的PMN弹性蛋白酶水平和PMN弹性蛋白酶与嗜中性粒细胞比率（ENR）的判别能力。IIM患者评估了血清PMN弹性蛋白酶水平和ENR与疾病变量的关系。在60例其他全身性自身免疫性疾病患者中，进一步检查了PMN弹性蛋白酶水平和ENR的疾病特异性。结果活动IIM，DM和PM患者的PMN弹性蛋白酶水平和ENR明显高于缓解患者。ROC曲线分析显示，PMN弹性蛋白酶水平和ENR均胜过当前使用的实验室指标肌酸激酶（CK），并强烈区分患有活动性疾病和IIM，DM和PM缓解的患者（ROC曲线下面积[AUC对于PMN弹性蛋白酶，分别为0.9、0.9和0.88；对于ENR，分别为AUC 0.96、0.96和1.0；对于CK，分别为AUC 0.72、0.70和0.80。PMN弹性蛋白酶水平和ENR与肌炎疾病活动性评估，CK，乳酸脱氢酶，天冬氨酸转氨酶，丙氨酸转氨酶，C反应蛋白，和红细胞沉降率。抗PM-Scl阳性肌炎组的PMN弹性蛋白酶水平和ENR高于抗PM-Scl阴性肌炎组的PMN弹性酶水平和ENR较高。但是，与其他自身免疫性疾病相比，PMN弹性蛋白酶不是IIM的特异性疾病标志物。结论PMN弹性蛋白酶，特别是ENR，与疾病活动密切相关，可作为评估IIMs患者疾病活动的有用生化指标。因此，它们潜在地有助于监测疾病的进展并指导治疗。与其他自身免疫性疾病相比，PMN弹性蛋白酶不是IIM的特异性疾病标志物。结论PMN弹性蛋白酶，特别是ENR，与疾病活动密切相关，可作为评估IIMs患者疾病活动的有用生化指标。因此，它们潜在地有助于监测疾病的进展并指导治疗。与其他自身免疫性疾病相比，PMN弹性蛋白酶不是IIM的特异性疾病标志物。结论PMN弹性蛋白酶，特别是ENR，与疾病活动密切相关，可作为评估IIMs患者疾病活动的有用生化指标。因此，它们潜在地有助于监测疾病的进展并指导治疗。