Yu J F, Jin Y B, He J, An Y, Li Z G
Department of Rheumatology and Immunology, Peking University People's Hospital, Beijing 100044, China; Department of Nephrology and Rheumatology, The Third People's Hospital in Hubei Province, Wuhan 430000, China.
Department of Rheumatology and Immunology, Peking University People's Hospital, Beijing 100044, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2017 Oct 18;49(5):910-914.
Interstitial lung diseases (ILDs) are a diverse group of pulmonary disorders characterized by various patterns of inflammation and fibrosis in the interstitium of the lung. The underlying pathogenesis of ILDs is complex and associated with multiple rheumatologic conditions, such as systemic sclerosis, rheumatoid arthritis, pollymyositis and dermatomyositis, Sjögren's syndrome, and systemic lupus erythematosus. As the disease progresses, excessive pulmonary fibrosis impairs alveolar gas exchange and damages pulmonary function. The common methods to diagnose ILDs, such as clinical manifestations, pulmonary function test, and radiological examinations are not specific for ILDs and not able to diagnose ILDs at the early stage due to their low sensitivity. So, the easy way is important to diagnose ILDs. One important biomarker for ILDs is the high-molecular-weight glycoprotein, Krebs von den Lungen-6(KL-6). KL-6 encoded by the MUC1 gene is a mucin-like glycoprotein with high molecular weight and expressed predominantly on the cell surface of type II alveolar epithelial cells, and is detectable in the serum of patients with ILDs. We here report a case of ILDs associated with dermatomyositis and secondary Sjögren's syndrome. A 60-year-old woman was admitted to our hospital with the chief complaints of debilitation, dry mouth, dyspnea and astasia. ILDs associated with dermatomyositis and secondary Sjögren's syndrome was diagnosed clinically when the following criteria were satisfied: (1) development of dyspnea within 2 months of presentation, (2) pulmonary dispersion dysfunction, (3) bilateral infiltrative shadows on chest high resolution computed tomography (HRCT). She was treated with prednisone 50 mg/d prior to admission, but the result of therapy was not good. In our hospital she was treated with intravenous methylprednisolone and cyclophosphamide and oral hydroxychloroquine sulfate. Subsequently, her serum KL-6 levels gradually decreased after treatment, pulmonary diffuse function improved, and the improvement in the clinical manifestation and HRCT findings were observed. Nevertheless, the combination treatment of glucocorticoid and cyclophosphamide had contributed to the favourable outcomes. In conclusion, detection of serum KL-6 levels in ILDs associated with connective tissue diseases may be beneficial to making a definitive diagnosis, predicting the prognosis and monitoring the disease activity, which would be of great help in clinical practice. However, a well-designed clinical study with more patients and a longer follow-up period are required to arrive at a more conclusive judgment on the role of serum KL-6 in patients with ILDs.
间质性肺疾病（ILDs）是一组多样的肺部疾病，其特征是肺间质存在各种炎症和纤维化模式。ILDs的潜在发病机制复杂，与多种风湿性疾病相关，如系统性硬化症、类风湿关节炎、多发性肌炎和皮肌炎、干燥综合征以及系统性红斑狼疮。随着疾病进展，过度的肺纤维化会损害肺泡气体交换并破坏肺功能。诊断ILDs的常用方法，如临床表现、肺功能测试和影像学检查，对ILDs并不具有特异性，且由于其敏感性低，无法在早期诊断ILDs。因此，简便的诊断方法对于ILDs很重要。ILDs的一个重要生物标志物是高分子量糖蛋白，即克雷布斯冯登龙根-6（KL-6）。由MUC1基因编码的KL-6是一种高分子量的粘蛋白样糖蛋白，主要在II型肺泡上皮细胞的细胞表面表达，并且在ILDs患者的血清中可检测到。我们在此报告一例与皮肌炎和继发性干燥综合征相关的ILDs病例。一名60岁女性因虚弱、口干、呼吸困难和站立不稳为主诉入院。当满足以下标准时，临床上诊断为与皮肌炎和继发性干燥综合征相关的ILDs：（1）就诊后2个月内出现呼吸困难，（2）肺弥散功能障碍，（3）胸部高分辨率计算机断层扫描（HRCT）显示双侧浸润影。入院前她接受了泼尼松50mg/d的治疗，但治疗效果不佳。在我院，她接受了静脉注射甲泼尼龙和环磷酰胺以及口服硫酸羟氯喹治疗。随后，治疗后她的血清KL-6水平逐渐下降，肺弥散功能改善，并且观察到临床表现和HRCT结果有所改善。尽管如此，糖皮质激素和环磷酰胺的联合治疗促成了良好的治疗效果。总之，检测与结缔组织疾病相关的ILDs患者血清KL-6水平可能有助于明确诊断、预测预后和监测疾病活动，这在临床实践中会有很大帮助。然而，需要一项设计良好、纳入更多患者且随访期更长的临床研究，才能对血清KL-6在ILDs患者中的作用得出更确凿的判断。
