Background: Intimal smooth muscle cells (SMCs) play an important role in the vasculitis caused by Kawasaki disease (KD). Lipoprotein receptor 11 (LR11) is a member of the low-density lipoprotein receptor family, which is expressed markedly in intimal vascular SMCs and secreted in a soluble form (sLR11). sLR11 has been recently identified as a potential vascular lesion biomarker. sLR11 is reportedly elevated in patients with coronary artery lesions long after KD, but there is no description of sLR11 in acute KD. Our aim was to determine the sLR11 dynamics in acute KD and to assess its usefulness as a biomarker.

Methods and Results: 106 acute KD patients and 18 age-matched afebrile controls were enrolled. KD patients were classified into the following subgroups: intravenous immunoglobulin (IVIG) responders (n=85) and non-responders (n=21). Serum sLR11 levels before IVIG therapy were higher in non-responders (median, 19.6 ng/mL; interquartile range [IQR], 13.0–24.9 ng/mL) than in controls (11.9 ng/mL, 10.4–14.9 ng/mL, P<0.01) or responders (14.3 ng/mL, 11.7–16.5 ng/mL, P<0.01). Using a cutoff of >17.5 ng/mL, non-responders to initial IVIG therapy were identified with 66.7% sensitivity and 78.8% specificity.

Conclusions: sLR11 can reflect the state of acute KD and might be a biomarker for patient response to IVIG therapy.

背景：内膜平滑肌细胞（SMCs）在川崎病（KD）引起的血管炎中起重要作用。脂蛋白受体 11 (LR11) 是低密度脂蛋白受体家族的成员，它在内膜血管 SMC 中显着表达并以可溶形式 (sLR11) 分泌。sLR11 最近已被确定为潜在的血管病变生物标志物。据报道 sLR11 在 KD 后长期存在冠状动脉病变的患者中升高，但没有关于急性 KD 中 sLR11 的描述。我们的目的是确定急性 KD 中的 sLR11 动力学并评估其作为生物标志物的有用性。

方法和结果：招募了 106 名急性 KD 患者和 18 名年龄匹配的无发热对照。KD 患者分为以下亚组：静脉内免疫球蛋白 (IVIG) 应答者 (n=85) 和无应答者 (n=21)。IVIG 治疗前的血清 sLR11 水平在无应答者（中位数，19.6 ng/mL；四分位距 [IQR]，13.0–24.9 ng/mL）中高于对照组（11.9 ng/mL，10.4–14.9 ng/mL，P <0.01) 或应答者 (14.3 ng/mL, 11.7–16.5 ng/mL, P<0.01)。使用 >17.5 ng/mL 的截止值，对初始 IVIG 治疗的无反应者被确定为具有 66.7% 的敏感性和 78.8% 的特异性。

结论： sLR11可以反映急性KD的状态，可能是患者对IVIG治疗反应的生物标志物。