Krebs von den Lungen-6 (KL-6) has been described as a promising biomarker in the diagnosis and determining the severity of interstitial lung disease in adults with connective tissue disease. This study was performed to determine whether the serum KL-6 level is useful as a biomarker for detecting the interstitial lung disease (ILD) in pediatric cases of connective tissue disease (CTD). In total, 88 patients [36 patients with systemic juvenile idiopathic arthritis (sJIA), 27 patients with juvenile systemic lupus erythematosus (JSLE), 14 patients with juvenile dermatomyositis (JDM), and 11 patients with juvenile systemic sclerosis (JSSc)] and 68 healthy controls were included in this study. Age, sex, and duration of CTD and ILD (if any) were recorded. Blood samples from all the patients and controls were examined by ELISA. Eleven of the 88 patients with CTD (12.5%) had ILD and all of them were symptomatic. Subgroup analysis indicated that eight patients had JSSc, two had JSLE, and one had systemic JIA. The median serum KL-6 level was 1450.5 U/mL (interquartile range (IQR) 742.9–2603.2) in the CTD with ILD group, 415.9 U/mL (IQR 233.4–748.4) in the CTD without ILD group, and 465.9 U/mL (IQR 273.6–1036) in the control group. KL-6 levels were significantly higher in the CTD with ILD group than the CTD without ILD group and the control group (p = 0.003). At a cut-off of 712.5 U/ml identified by ROC curve, serum KL-6 yielded a sensitivity of 81% and specificity of 72% for CTD with ILD group. There was no significant difference in serum KL-6 level among the disease subgroups (sJIA, JSLE, JSSc, JDM), in either the CTD with ILD group or the CTD without ILD group (p > 0.05). In conclusion, KL-6 is a useful biomarker of CTD with ILD in pediatric patients.

Krebs von den Lungen-6（KL-6）被描述为诊断和确定患有结缔组织病的成人间质性肺病严重程度的有前途的生物标志物。进行这项研究以确定血清KL-6水平是否可用作检测儿科结缔组织病（CTD）病例间质性肺病（ILD）的生物标志物。总共88例[36例系统性幼年特发性关节炎（sJIA），27例系统性红斑狼疮（JSLE），14例青少年皮肌炎（JDM）和11例青少年系统性硬化症（JSSc）]和68健康对照纳入本研究。记录年龄，性别和CTD和ILD的持续时间（如果有）。通过ELISA检查所有患者和对照的血样。88例CTD患者中有11例（12.5％）患有ILD，且所有患者均具有症状。亚组分析显示8例患者患有JSSc，2例患有JSLE，1例患有全身性JIA。伴有ILD的CTD患者的血清KL-6的中位值为1450.5 U / mL（四分位间距（IQR）742.9–2603.2），不伴有ILD的CTD患者的平均血清KL-6水平为415.9 U / mL（IQR 233.4–748.4）和465.9 U / mL对照组（IQR 273.6–1036）。有ILD组的CTD的KL-6水平明显高于没有ILD组的CTD和对照组（对照组为465.9 U / mL（IQR 273.6-1036）。有ILD组的CTD的KL-6水平明显高于没有ILD组的CTD和对照组（对照组为465.9 U / mL（IQR 273.6-1036）。有ILD组的CTD的KL-6水平明显高于没有ILD组的CTD和对照组（p  = 0.003）。通过ROC曲线确定的临界值为712.5 U / ml，对于ILD组的CTD，血清KL-6的敏感性为81％，特异性为72％。有ILD组的CTD或无ILD组的CTD在疾病亚组（sJIA，JSLE，JSSc，JDM）之间的血清KL-6水平无显着差异（p  > 0.05）。总之，KL-6是小儿患者CTD和ILD的有用生物标志物。