INTRODUCTION Interleukin (IL)-6 is a proinflammatory cytokine involved in systemic juvenile idiopathic arthritis (SJIA). Since these patients are often treated with tocilizumab (TCZ), anti-IL-6 receptor (IL-6R) antibody, we investigated correlations between serum IL-6 and soluble IL-6R-levels and disease activity in SJIA patients treated with or without TCZ. MATERIAL AND METHODS 164 serum samples were taken from 42 SJIA patients treated with or without TCZ (69 and 95 samples, respectively). Patients were assigned to three groups according to disease status: 1) systemic (patients with systemic features and/or arthritis), 2) arthritis (patients with arthritis but no systemic features), and 3) inactive (clinically inactive disease). Disease activity was assessed using the Juvenile Arthritis Disease Activity Score-27 (JADAS-27) at the time of blood collection. RESULTS IL-6 levels were highest in SJIA patients with predominant systemic features, while serum sIL-6R levels were highest in patients with persistent arthritis. Serum IL-6 correlated with JADAS-27 in patients treated with and without TCZ (r = 0.38 and r = 0.65, respectively), whereas serum sIL-6R levels correlated with JADAS-27 in patients treated without (r = 0.30) but not with (r = -0.14) TCZ. The sIL-6R/IL-6 ratio negatively correlated with JADAS-27 in patients treated with and without TCZ (r = -0.49 and r = -0.56, respectively). CONCLUSIONS Serum IL-6 levels correlated more strongly with disease activity parameters than did sIL-6R levels and could be useful for monitoring disease activity in SJIA patients. The sIL-6R/IL-6 ratio might be a promising disease activity marker in both SJIA patients treated with and without TCZ.

中文翻译：

---

在接受或不接受托珠单抗治疗的全身性幼年特发性关节炎患者中，血清白细胞介素 6、血清可溶性白细胞介素 6 受体与疾病活动性之间的相关性。

简介 白细胞介素 (IL)-6 是一种参与全身性幼年特发性关节炎 (SJIA) 的促炎细胞因子。由于这些患者经常接受托珠单抗 (TCZ)、抗 IL-6 受体 (IL-6R) 抗体治疗，我们研究了接受或不接受治疗的 SJIA 患者血清 IL-6 和可溶性 IL-6R 水平与疾病活动之间的相关性TCZ。材料和方法 164 份血清样本取自 42 名接受或不接受 TCZ 治疗的 SJIA 患者（分别为 69 份和 95 份样本）。根据疾病状态将患者分为三组：1) 全身性（具有全身性特征和/或关节炎的患者），2) 关节炎（具有关节炎但没有全身性特征的患者），和 3) 非活动性（临床上无活动性疾病）。在采血时使用青少年关节炎疾病活动评分 27 (JADAS-27) 评估疾病活动。结果 IL-6 水平在具有主要全身特征的 SJIA 患者中最高，而血清 sIL-6R 水平在持续性关节炎患者中最高。在接受和不接受 TCZ 治疗的患者中，血清 IL-6 与 JADAS-27 相关（分别为 r = 0.38 和 r = 0.65），而在未经治疗的患者中，血清 sIL-6R 水平与 JADAS-27 相关（r = 0.30）但不相关与 (r = -0.14) TCZ。在接受和不接受 TCZ 治疗的患者中，sIL-6R/IL-6 比率与 JADAS-27 呈负相关（分别为 r = -0.49 和 r = -0.56）。结论 与 sIL-6R 水平相比，血清 IL-6 水平与疾病活动参数的相关性更强，可用于监测 SJIA 患者的疾病活动。