Yokoyama Akihito, Kondo Keiichi, Nakajima Masamitsu, Matsushima Toshiharu, Takahashi Toru, Nishimura Masaharu, Bando Masashi, Sugiyama Yukihiko, Totani Yoshitaka, Ishizaki Takeshi, Ichiyasu Hidenori, Suga Moritaka, Hamada Hironobu, Kohno Nobuoki
Department of Molecular and Internal Medicine, Hiroshima University, Hiroshima, Japan.
Respirology. 2006 Mar;11(2):164-8. doi: 10.1111/j.1440-1843.2006.00834.x.
Circulating levels of KL-6, a high MW glycoprotein (MUC1 mucin), are elevated in a majority of patients with a number of interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF). However, KL-6 levels vary from patient to patient. The aim of the present study was to determine whether the serum KL-6 level at the time of diagnosis predicts prognosis in IPF.
The relationship between clinical variables and prognosis in 27 patients with IPF were analysed retrospectively. The diagnosis was made by histological examination (n = 16) or on clinical findings including high-resolution CT scanning (n = 11). All patients were followed up for at least 3 years. Variables such as age, FVC%, PaO(2) at rest, initial LDH level, C-reactive protein and KL-6 were used for analysis.
At the cut-off level determined by receiver operating characteristic curves, LDH and KL-6 showed a significant correlation with the patient's prognosis by univariate analysis. However, multivariate analysis revealed that only KL-6 was a predictor of prognosis. The patients were categorized by their serum KL-6 levels (as above or below the cut-off level of 1000 U/mL) and their survival estimated using the Kaplan-Meier method. The difference in median survival between the two groups was significant. The median survival of patients with low KL-6 was more than 36 months, whereas that of patients with high KL-6 was only 18 months.
These results suggest that initial evaluation of serum KL-6 level can predict survival in patients with IPF.
KL-6是一种高分子量糖蛋白（MUC1粘蛋白），在包括特发性肺纤维化（IPF）在内的多种间质性肺疾病的大多数患者中，其循环水平会升高。然而，KL-6水平在患者之间存在差异。本研究的目的是确定诊断时的血清KL-6水平是否可预测IPF患者的预后。
回顾性分析27例IPF患者临床变量与预后之间的关系。诊断通过组织学检查（n = 16）或包括高分辨率CT扫描在内的临床检查结果（n = 11）做出。所有患者均随访至少3年。分析使用年龄、FVC%、静息时PaO₂、初始LDH水平、C反应蛋白和KL-6等变量。
在通过受试者工作特征曲线确定的临界值水平下，单因素分析显示LDH和KL-6与患者预后显著相关。然而，多因素分析显示只有KL-6是预后的预测指标。根据患者血清KL-6水平（高于或低于1000 U/mL的临界值水平）进行分类，并使用Kaplan-Meier方法估计其生存率。两组之间的中位生存期差异显著。KL-6水平低的患者中位生存期超过36个月，而KL-6水平高的患者中位生存期仅为18个月。
这些结果表明，血清KL-6水平的初始评估可预测IPF患者的生存情况。
