Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China.
Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China.
Front Immunol. 2023 Jun 20;14:1098602. doi: 10.3389/fimmu.2023.1098602. eCollection 2023.
Krebs von den Lungen 6 (KL-6) is a potential biomarker for determining the severity of interstitial lung disease (ILD) in patients with connective tissue disease (CTD). Whether KL-6 levels can be affected by potential confounders such as underlying CTD patterns, patient-associated demographics, and comorbidities needs further investigation.
From the database created by Xiangya Hospital, 524 patients with CTD, with or without ILD, were recruited for this retrospective analysis. Recorded data included demographic information, comorbidities, inflammatory biomarkers, autoimmune antibodies, and the KL-6 level at admission. Results of CT and pulmonary function tests were collected one week before or after KL-6 measurements. The percent of predicted diffusing capacity of the lung for carbon monoxide (DLCO%) and computed tomography (CT) scans were used to determine the severity of ILD.
Univariate linear regression analysis showed that BMI, lung cancer, TB, lung infections, underlying CTD type, white blood cell (WBC) counts, neutrophil (Neu) counts, and hemoglobin (Hb) were related to KL-6 levels. Multiple linear regression confirmed that Hb and lung infections could affect KL-6 levels independently; the β were 9.64 and 315.93, and the P values were 0.015 and 0.039, respectively. CTD-ILD patients had higher levels of KL-6 (864.9 vs 463.9, < 0.001) than those without ILD. KL-6 levels were closely correlated to the severity of ILD assessed both by CT and DLCO%. Additionally, we found that KL-6 level was an independent predictive factor for the presence of ILD and further constructed a decision tree model to rapidly determine the risk of developing ILD among CTD patients.
KL-6 is a potential biomarker for gauging the incidence and severity of ILD in CTD patients. To use this typical value of KL-6, however, doctors should take Hb and the presence of lung infections into account.
肺表面活性剂相关蛋白 6（KL-6）是一种潜在的生物标志物，可用于判断结缔组织病（CTD）患者间质性肺病（ILD）的严重程度。KL-6 水平是否会受到潜在混杂因素的影响，如潜在的 CTD 模式、患者相关的人口统计学特征和合并症，需要进一步研究。
从湘雅医院创建的数据库中，共招募了 524 名患有 CTD 且伴有或不伴有 ILD 的患者进行回顾性分析。记录的数据包括人口统计学信息、合并症、炎症生物标志物、自身抗体和入院时的 KL-6 水平。在 KL-6 测量前后一周内收集 CT 和肺功能测试的结果。通过预测的一氧化碳弥散量百分比（DLCO%）和计算机断层扫描（CT）扫描来确定 ILD 的严重程度。
单变量线性回归分析表明，BMI、肺癌、TB、肺部感染、基础 CTD 类型、白细胞（WBC）计数、中性粒细胞（Neu）计数和血红蛋白（Hb）与 KL-6 水平有关。多元线性回归证实，Hb 和肺部感染可以独立影响 KL-6 水平；β值分别为 9.64 和 315.93，P 值分别为 0.015 和 0.039。与无 ILD 患者相比，CTD-ILD 患者的 KL-6 水平更高（864.9 与 463.9，<0.001）。KL-6 水平与 CT 和 DLCO%评估的 ILD 严重程度密切相关。此外，我们发现 KL-6 水平是ILD 存在的独立预测因素，并进一步构建了决策树模型，以快速确定 CTD 患者发生ILD 的风险。
KL-6 是评估 CTD 患者 ILD 发生率和严重程度的潜在生物标志物。然而，为了使用 KL-6 的这一典型值，医生应考虑 Hb 和肺部感染的存在。
