This study was supported by grants from the intramural innovative medical research program of Muenster University medical faculty (grant no. KE121201 to C.K.) and the German Research Foundation (DFG, grant no. WI3176/2-1 to H.W. and grant no. Fo354/3-1 to D.F.). Disclosure of potential conflict of interest: C. Kessel & D. Foell have filed a patent application on ''means and methods for diagnosing and treating inflammatory disorders'' regarding proinflammatory S100A12 homomultimers (WO 2016/178154 A1). The rest of the authors declare that they have no relevant conflicts of interests.

Objective To analyze the reported association of IL1RN polymorphisms with response to interleukin‐1 (IL‐1) blockade in a German cohort of patients with systemic juvenile idiopathic arthritis (JIA), and to assess the impact of other factors on treatment response. Methods Sixty‐one patients with systemic JIA who had received IL‐1 blockade were identified within the German Autoinflammatory Disease registry DNA biobank. Response to IL‐1 blockade was assessed according to 1) the clinical response (initially at least a transient response or good response compared to a poor response), 2) switch (or no switch) to anti–IL‐6 receptor therapy following IL‐1 blockade, 3) achievement of clinically inactive disease within 6 months of IL‐1 blockade, 4) improvement in disease activity measured using the modified Juvenile Arthritis Disease Activity Score, and 5) achievement of a glucocorticoid‐free state. In addition, basic demographic data, key features of the disease course, laboratory data, and IL1RN single‐nucleotide polymorphisms (SNPs) were assessed. Results Six of 7 IL1RN SNPs reported to be associated with response to anakinra therapy were analyzed. These 6 IL1RN SNPs were inherited as haplotypes. An association of IL1RN haplotypes and SNPs with response to IL‐1 blockade could not be confirmed in this cohort of patients with systemic JIA. Patients who received tocilizumab following IL‐1 blockade had a longer duration from disease onset to diagnosis than those who did not receive tocilizumab (median 0.27 years versus 0.08 years). Conclusion The results of this study could not confirm an impact of IL1RN SNPs on response to IL‐1 blockade therapy with either anakinra or canakinumab in a cohort of patients with systemic JIA. However, a longer time frame from disease onset to diagnosis was associated with poorer long‐term treatment response, thereby supporting the “window of opportunity” hypothesis that suggests improved long‐term treatment response with shorter time from disease onset to diagnosis (and treatment).

Objective Juvenile idiopathic arthritis (JIA) is a heterogeneous group of inflammatory joint disorders with a chronic-remitting disease course. Treat-to-target approaches have been proposed but monitoring disease activity and predicting the response to treatment remains challenging. Methods We analyzed biomarkers and their relationship to outcome within the first year after JIA diagnosis in the German Inception Cohort of Newly diagnosed patients with JIA (ICON-JIA). CRP, CXCL9, CXCL10, CXCL11, erythrocyte sedimentation rate, G-CSF, IL-6, IL-17A, IL-18, MCP-1, MIP-1α, MMP-3, S100A8/A9, S100A12, TNFα, and TWEAK were measured at baseline and 3 months later. Results Two-hundred-sixty-six JIA patients with active disease at baseline were included, with oligoarthritis and rheumatoid factor-negative polyarthritis representing the most frequent categories (72.9%). Most biomarkers were elevated in JIA compared to healthy pediatric controls. Patients with systemic JIA had higher CRP, S100A8/A9 and S100A12 levels compared to other JIA categories. Baseline levels of TWEAK, G-CSF and IL-18 were lower in oligoarthritis patients with disease extension within 1 year. Increased baseline levels of CRP, S100A8/A9, S100A12 and ESR were associated with the subsequent addition of biologic disease-modifying antirheumatic drugs (DMARDs). Higher baseline ESR, G-CSF, IL-6, IL-17A and TNF levels indicated an increased risk for ongoing disease activity after 12 months. Conclusion Our data demonstrate that elevated baseline levels of CRP, S100A8/A9 and S100A12 as well as increased ESR are associated with the necessity to escalate therapy during the first 12 month of follow-up. Furthermore, biomarkers related to Th17 activation may inform on future disease course in previously treatment-naïve JIA patients.

Background An association of different autoimmune diseases is suspected. In juvenile idiopathic arthritis (JIA), only few and partially conflicting data on the co-existence of other autoimmune disorders are available. The prevalence of autoantibodies in patients with JIA in Germany is not known. Methods Samples from 499 patients (median age at time of blood collection 11 years, median disease duration 4.4 years) in the prospective, multicenter inception cohort of children newly diagnosed with JIA (ICON-JIA) were analysed for the presence of anti-thyroid antibodies, celiac disease-specific antibodies (anti-tTG IgA, anti-tTG IgG), and connective tissue disease-associated antibodies (CTD-screen). Results A total of 76 (15.2%) patients had either clinically diagnosed autoimmune comorbidity or elevated autoantibodies. Of 21 patients with clinical autoimmune comorbidity, only 8 were also serologically positive at the time of testing, while 55 patients had autoantibodies without clinical diagnosis. Thus, 63 patients (12.6%) had at least one elevated autoantibody. Antibodies against thyroglobulin were found in 3% and against thyreoperoxidase in 4% of the samples. TSH receptor antibodies could not be detected in any of the 499 patients. Tissue transglutaminase antibodies were elevated in 0.4% of the patients. A positive screen for CTD-specific antinuclear antibodies was found in 7%, but only rarely specific antibodies (anti-dsDNA 1.4%, anti-SS-A and -SS-B 0.2% each, anti-CENP-B 0.4%) were confirmed. Conclusions In our study, a specific correlation between JIA and other autoimmune phenomena could not be confirmed. The lack of well-matched control groups makes interpretation challenging. Further data need to corroborate the suspected increased risk of developing other autoimmune phenomena in JIA patients.

Purpose A recent phase II open-label study of the interleukin 1 (IL-1) receptor antagonist (IL-1Ra) anakinra in treating IVIG-resistant Kawasaki disease (KD) patients reported promising results. Here, we aimed to characterize the immunological impact of IL-1 blockade in this unique study population. Methods Patients’ and control sera and supernatants of cells (whole blood, neutrophils, coronary artery endothelial cells) stimulated with recombinant IL-1β were analyzed for single or multiple marker (n = 22) expression by ELISA or multiplexed bead array assay. Data were analyzed using unsupervised hierarchical clustering, multiple correlation, and multi-comparison statistics and were compared to retrospective analyses of KD transcriptomics. Results Inflammation in IVIG-resistant KD (n = 16) is hallmarked by over-expression of innate immune mediators (particularly IL-6 > CXCL10 > S100A12 > IL-1Ra). Those as well as levels of immune or endothelial cell activation markers (sICAM-1, sVCAM-1) declined most significantly in course of anakinra treatment. Prior as well as following IL-1R blockade, over-expression of leucine-rich-α2-glycoprotein 1 (LRG1) associated best with remnant inflammatory activity and the necessity to escalate anakinra dosage and separated inflammatory KD patients from sJIA-MAS (n = 13) and MIS-C (n = 4). Protein as well as retrospective gene expression analyses indicated tight association of LRG1 with IL-1β signaling and neutrophilia, while particularly neutrophil stimulation with recombinant IL-1β resulted in concentration-dependent LRG1 release. Conclusion Our study identifies LRG1 as known trigger of endothelial activation and cardiac re-modeling to associate with IL-1β signaling in KD. Besides a potential patho-mechanistic implication of these findings, our data suggest blood leukocyte and neutrophil counts to best predict response to IL-1Ra treatment in IVIG-resistant KD.