Division of Rheumatology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
Front Immunol. 2018 Dec 18;9:2995. doi: 10.3389/fimmu.2018.02995. eCollection 2018.
Systemic juvenile idiopathic arthritis (SJIA) is a chronic childhood arthropathy with features of autoinflammation. Early inflammatory SJIA is associated with expansion and activation of neutrophils with a sepsis-like phenotype, but neutrophil phenotypes present in longstanding and clinically inactive disease (CID) are unknown. The objective of this study was to examine activated neutrophil subsets, S100 alarmin release, and gene expression signatures in children with a spectrum of SJIA disease activity. Highly-purified neutrophils were isolated using a two-step procedure of density-gradient centrifugation followed by magnetic-bead based negative selection prior to flow cytometry or cell culture to quantify S100 protein release. Whole transcriptome gene expression profiles were compared in neutrophils from children with both active SJIA and CID. Patients with SJIA and active systemic features demonstrated a higher proportion of CD16CD62L neutrophil population compared to controls. This neutrophil subset was not seen in patients with CID or patients with active arthritis not exhibiting systemic features. Using imaging flow cytometry, CD16CD62L neutrophils from patients with active SJIA and features of macrophage activation syndrome (MAS) had increased nuclear hypersegmentation compared to CD16CD62L neutrophils. Serum levels of S100A8/A9 and S100A12 were strongly correlated with peripheral blood neutrophil counts. Neutrophils from active SJIA patients did not show enhanced resting S100 protein release; however, regardless of disease activity, neutrophils from SJIA patients did show enhanced S100A8/A9 release upon PMA stimulation compared to control neutrophils. Furthermore, whole transcriptome analysis of highly purified neutrophils from children with active SJIA identified 214 differentially expressed genes (DEG) compared to neutrophils from healthy controls. The most significantly upregulated gene pathway was Immune System Process, including , and . Interestingly, this gene set showed intermediate levels of expression in neutrophils from patients with long-standing CID yet persistent serum IL-18 elevation. Indeed, all patient samples regardless of disease activity demonstrated elevated inflammatory gene expression, including inflammasome components and . We identify features of neutrophil activation in SJIA patients with both active disease and CID, including a proinflammatory gene expression signature, reflecting persistent innate immune activation. Taken together, these studies expand understanding of neutrophil function in chronic autoinflammatory disorders such as SJIA.
全身型幼年特发性关节炎（SJIA）是一种慢性儿童关节病，具有自身炎症的特征。早期炎症性 SJIA 与中性粒细胞的扩张和激活有关，具有类似脓毒症的表型，但长期和临床无活动疾病（CID）中存在的中性粒细胞表型尚不清楚。本研究的目的是研究具有 SJIA 疾病活动谱的儿童中激活的中性粒细胞亚群、S100 警报素释放和基因表达特征。使用两步密度梯度离心法和基于磁性珠的负选择法分离高度纯化的中性粒细胞，然后进行流式细胞术或细胞培养以定量 S100 蛋白释放。比较 SJIA 活动期和 CID 患儿中性粒细胞的全转录组基因表达谱。SJIA 患儿和全身表现活跃的患者与对照组相比，CD16CD62L 中性粒细胞比例较高。CID 患者或表现出全身特征但无活动关节炎的患者中未观察到这种中性粒细胞亚群。使用成像流式细胞术，与 CD16CD62L 中性粒细胞相比，SJIA 活动期且有巨噬细胞活化综合征（MAS）特征的患者的 CD16CD62L 中性粒细胞核分叶过多。S100A8/A9 和 S100A12 的血清水平与外周血中性粒细胞计数呈强相关。SJIA 活动期患者的中性粒细胞未显示出增强的静止 S100 蛋白释放；然而，无论疾病活动如何，SJIA 患者的中性粒细胞在 PMA 刺激下释放 S100A8/A9 的水平均高于对照中性粒细胞。此外，对 SJIA 活动期患儿高度纯化中性粒细胞的全转录组分析与健康对照相比，发现 214 个差异表达基因（DEG）。最显著上调的基因途径是免疫系统过程，包括 、和 。有趣的是，该基因集在长期 CID 但持续升高的血清 IL-18 的患者中性粒细胞中表达水平处于中间状态。事实上，所有患者样本，无论疾病活动如何，均表现出炎症基因表达升高，包括炎症小体成分和 。我们在 SJIA 患者中发现了活跃疾病和 CID 中中性粒细胞激活的特征，包括促炎基因表达谱，反映持续的固有免疫激活。综上所述，这些研究扩展了对慢性自身炎症性疾病（如 SJIA）中性粒细胞功能的理解。
