To investigate the dynamic changes of Krebs von den Lungen‐6 (KL‐6) among patients with coronavirus disease 2019 (COVID‐19) and the role of KL‐6 as a noninvasive biomarker for predicting long‐term lung injury, the clinical information and laboratory tests of 166 COVID‐19 patients were collected, and a correlation analysis between KL‐6 and other parameters was conducted. There were 17 (10.2%, 17/166) severe/critical and 149 (89.8%, 149/166) mild COVID‐19 patients in our cohort. Serum KL‐6 was significantly higher in severe/critical COVID‐19 patients than in mild patients (median 898.0 vs. 451.2 U/ml, p < .001). KL‐6 was next confirmed to be a sensitive and specific biomarker for distinguishing mild and severe/critical patients and correlate to computed tomography lung lesions areas. Serum KL‐6 concentration during the follow‐up period (>100 days postonset) was well correlated to those concentrations within 10 days postonset (Pearson r = .867, p < .001), indicating the prognostic value of KL‐6 levels in predicting lung injury after discharge. Finally, elevated KL‐6 was found to be significantly correlated to coagulation disorders, and T cells subsets dysfunctions. In summary, serum KL‐6 is a biomarker for assessing COVID‐19 severity and predicting the prognosis of lung injury of discharged patients.

中文翻译：

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KL-6在COVID-19患者疾病严重程度和肺损伤中的预后作用：纵向回顾性分析

为了研究2019年冠状病毒病（COVID-19）患者中Krebs von den Lungen-6（KL-6）的动态变化以及KL-6作为预测长期肺损伤的非侵入性生物标志物的作用，临床信息并收集了166名COVID-19患者的实验室检查结果，并进行了KL-6与其他参数之间的相关性分析。我们的队列中有17名（10.2％，17/166）重度/危重患者和149名（89.8％，149/166）轻度COVID-19患者。重度/重症COVID-19患者的血清KL-6明显高于轻度患者（中位数898.0 vs.451.2 U / ml，p <.001）。接下来证实了KL-6是区分轻度和重度/重症患者的敏感和特异性生物标志物，并且与计算机断层扫描肺部病变区域相关。随访期间（发病后> 100天）的血清KL-6浓度与发病后10天内的那些浓度有很好的相关性（Pearson r  = .867，p  <.001），表明KL-6水平在预后中的价值。预测出院后肺损伤。最后，发现KL-6升高与凝血功能障碍和T细胞亚群功能异常显着相关。总之，血清KL-6是评估COVID-19严重程度并预测出院患者肺损伤预后的生物标志物。