Proteomic mapping identifies serum marker signatures associated with MIS-C specific hyperinflammation and cardiovascular manifestation.

Multisystem inflammatory syndrome in children (MIS-C) shares several clinical and immunological features with Kawasaki Disease (KD) and pediatric hyperinflammation, but the immuno-phenotypic overlap among these clinical mimics is still incompletely understood. Here we analyzed serum samples from treatment-naïve patients with MIS-C (n = 31) and KD (n = 11), pediatric hyperinflammation (n = 13) and healthy controls (HC, n = 10) by proximity extension assay (PEA) to profile 184 blood biomarkers. Collectively, immunophenotypic overlap between MIS-C and hyperinflammation exceeds overlap with KD. Overexpression of IL-17A in MIS-C and KD could best separate these conditions from hyperinflammatory conditions, while those were hallmarked by overabundance of adenosin deaminase and IL-18. Depletion in serum TNF-related subfamily member 9 (TNFRSF9) and apoptosis inducing ligand (TRAIL) linked with cardiovascular manifestations and myocarditis in MIS-C. Altogether, our analysis highlights important differences in molecular marker signatures also across different MIS-C and KD cohorts and suggests several previously unidentified molecular associations in context of cardiovascular inflammation.

Treatment of systemic juvenile idiopathic arthritis.

Systemic juvenile idiopathic arthritis (sJIA) is an inflammatory disease with hallmarks of severe systemic inflammation, which can be accompanied by arthritis. Contemporary scientific insights set this paediatric disorder on a continuum with its counterpart, adult-onset Still disease (AOSD). Patients with sJIA are prone to complications, including life-threatening hyperinflammation (macrophage activation syndrome (sJIA-MAS)) and sJIA-associated lung disease (sJIA-LD). Meanwhile, the treatment arsenal in sJIA has expanded markedly. State-of-the-art therapeutic approaches include biologic agents that target the IL-1 and IL-6 pathways. Beyond these, a range of novel agents are on the horizon, some of them already being used on a compassionate use basis, including JAK inhibitors and biologic agents that target IL-18, IFNγ, or IL-1ß and IL-18 simultaneously. However, sJIA, sJIA-MAS and sJIA-LD still pose challenging conundrums to rheumatologists treating paediatric and adult patients worldwide. Although national and international consensus treatment plans exist for the treatment of 'classic' sJIA, the treatment approaches for early sJIA without arthritis, and for refractory or complicated sJIA, are not well defined. Therefore, in this Review we outline current approaches for the treatment of sJIA and provide an outlook on knowledge gaps.

A novel serum calprotectin (MRP8/14) particle-enhanced immuno-turbidimetric assay (sCAL turbo) helps to differentiate systemic juvenile idiopathic arthritis from other diseases in routine clinical laboratory settings.

BACKGROUND: Differential diagnosis in children with signs of unprovoked inflammation can be challenging. In particular, differentiating systemic juvenile idiopathic arthritis (SJIA) from other diagnoses is difficult. We have recently validated the complex of myeloid-related proteins 8/14 (MRP8/14, also known as S100A8/A9 complex or serum calprotectin) as a helpful biomarker supporting the diagnosis of SJIA. The results were subsequently confirmed with a commercial ELISA. However, further optimization of the analytical technology is important to ensure its feasibility for large-scale use in routine laboratory settings. METHODS: To evaluate the accuracy in identifying children with SJIA, the performance of a particle-enhanced immuno-turbidimetric assay for serum calprotectin (sCAL turbo) on an automated laboratory instrument was analyzed. Samples from 615 children were available with the diagnoses SJIA (n = 99), non-systemic JIA (n = 169), infections (n = 51), other inflammatory diseases (n = 126), and acute lymphoblastic leukemia (ALL, n = 147). In addition, samples from 23 healthy controls were included. RESULTS: The sCAL turbo assay correlated well with the MRP8/14 ELISA used in previous validation studies (r = 0.99, p < 0.001). It could reliably differentiate SJIA from all other diagnoses with significant accuracy (cutoff at 10,500 ng/ml, sensitivity 84%, specificity 94%, ROC area under curve 0.960, p < 0.001). CONCLUSIONS: Serum calprotectin analyses are a helpful tool supporting the diagnosis of SJIA in children with prolonged fever or inflammatory disease. Here, we show that an immuno-turbidimetric assay for detection of serum calprotectin on an automated laboratory instrument can be implemented in clinical laboratory settings to facilitate its use as a diagnostic routine test in clinical practice.

Type 1 Interferon-Stimulated Gene Expression and Disease Activity in Pediatric Rheumatic Diseases: No Composite Scores Needed?

OBJECTIVE: Rheumatic diseases are characterized by different patterns of immune overactivation. This study investigated the correlation of whole blood type 1 interferon (IFN) stimulated gene (ISG), IL18, and CXCL9 expression with clinical disease activity in pediatric rheumatic diseases and assessed the required number of ISGs to be included in a composite type 1 IFN score. METHODS: Whole blood-derived RNA and clinical data were collected from 171 mostly pediatric patients with connective tissue diseases (CTDs), systemic autoinflammatory diseases (SAIDs), monogenic interferonopathies (IFNPs) and other inflammatory diseases, and from 38 controls. The expression of six previously established ISGs, IL18, and CXCL9 was assessed by real-time polymerase chain reaction (471 samples). Individual and composite gene expression was assessed, and correlation and threshold analyses were performed. RESULTS: Correlation between ISG expression and clinical disease activity was strongest in CTD, especially in juvenile dermatomyositis (JDM) and IFNP, and modest in patients with SAID. Threshold ISG expression levels for the detection of at least mild clinical disease activity were substantially higher in patients with systemic lupus erythematosus compared with JDM. The correlation of expression levels of limited sets of ISGs and even individual ISGs with clinical disease activity were not inferior to a composite score of six ISGs. CONCLUSION: In a real-world cohort, individual ISG expression levels robustly reflected clinical disease activity in CTD and IFNP, especially in JDM, which would simplify such analyses in clinical routine and be more cost-effective. Threshold levels varied across diseases, potentially reflecting different mechanisms of type 1 IFN overactivation.

Identification of Adult Patients With Classical Dyskeratosis Congenita or Cryptic Telomere Biology Disorder by Telomere Length Screening Using Age-modified Criteria.

Telomere biology disorders (TBD) result from premature telomere shortening due to pathogenic germline variants in telomere maintenance-associated genes. In adults, TBD are characterized by mono/oligosymptomatic clinical manifestations (cryptic TBD) contributing to severe underdiagnosis. We present a prospective multi-institutional cohort study where telomere length (TL) screening was performed in either newly diagnosed patients with aplastic anemia (AA) or if TBD was clinically suspected by the treating physician. TL of 262 samples was measured via flow-fluorescence in situ hybridization (FISH). TL was considered suspicious once below the 10th percentile of normal individuals (standard screening) or if below 6.5 kb in patients >40 years (extended screening). In cases with shortened TL, next generation sequencing (NGS) for TBD-associated genes was performed. The patients referred fell into 6 different screening categories: (1) AA/paroxysmal nocturnal hemoglobinuria, (2) unexplained cytopenia, (3) dyskeratosis congenita, (4) myelodysplastic syndrome/acute myeloid leukemia, (5) interstitial lung disease, and (6) others. Overall, TL was found to be shortened in 120 patients (n = 86 standard and n = 34 extended screening). In 17 of the 76 (22.4%) standard patients with sufficient material for NGS, a pathogenic/likely pathogenic TBD-associated gene variant was identified. Variants of uncertain significance were detected in 17 of 76 (22.4%) standard and 6 of 29 (20.7%) extended screened patients. Expectedly, mutations were mainly found in TERT and TERC. In conclusion, TL measured by flow-FISH represents a powerful functional in vivo screening for an underlying TBD and should be performed in every newly diagnosed patient with AA as well as other patients with clinical suspicion for an underlying TBD in both children and adults.

Aberrant Naive CD4-Positive T Cell Differentiation in Systemic Juvenile Idiopathic Arthritis Committed to B Cell Help.

OBJECTIVE: Systemic juvenile idiopathic arthritis (JIA) features characteristics of autoinflammation and autoimmunity, culminating in chronic arthritis. In this study, we hypothesized that aberrant or incomplete polarization of T helper cells contributes to disease pathology. METHODS: Cells or serum samples were obtained from healthy controls (n = 72) and systemic JIA patients (n = 171). Isolated naive T helper cells were cultured under Th1, Th17, and T follicular helper (Tfh) or T peripheral helper (Tph)-polarizing conditions and were partly cocultured with allogenic memory B cells. Cell samples were then analyzed for surface marker, transcription factor, and cytokine expression, as well as plasmablast generation. Serum samples were subjected to multiplexed bead and self-antigen arrays and enzyme-linked immunosorbent assays, and all data were compared to retrospective RNA profiling analyses. RESULTS: Differentiation of systemic JIA-naive T helper cells toward Th1 cells resulted in low expression levels of interferon-γ (IFNγ) and eomesodermin, which was associated in part with disease duration. In contrast, developing Th1 cells in patients with systemic JIA were found to produce elevated levels of interleukin-21 (IL-21), which negatively correlated with cellular expression of IFNγ and eomesodermin. In both in vitro and ex vivo analyses, IL-21 together with programmed cell death 1 (PD-1), inducible T cell costimulator (ICOS), and CXCR5 expression induced naive T helper cells from systemic JIA patients to polarize toward a Tfh/Tph cell phenotype. Retrospective analysis of whole-blood RNA-sequencing data demonstrated that Bcl-6, a master transcription factor in Tfh/Tph cell differentiation, was overexpressed specifically in patients with systemic JIA. Naive T helper cells from systemic JIA patients which were stimulated in vitro promoted B cellular plasmablast generation, and self-antigen array data indicated that IgG reactivity profiles of patients with systemic JIA differed from those of healthy controls. CONCLUSION: In the pathogenesis of systemic JIA, skewing of naive T helper cell differentiation toward a Tfh/Tph cell phenotype may represent an echo of autoimmunity, which may indicate the mechanisms driving progression toward chronic destructive arthritis.

Update of evidence- and consensus-based guidelines for the treatment of juvenile idiopathic arthritis (JIA) by the German Society of Pediatric and Juvenile Rheumatic Diseases (GKJR): New perspectives on interdisciplinary care.

BACKGROUND: New therapeutic strategies for juvenile idiopathic arthritis (JIA) have evolved within the past ten years, and as a result, an update of the 2011 recommendations of the German management guidelines was initiated. METHODS: A systemic literature review was performed, overarching principles were proposed and pre-selected via an online survey followed by two multidisciplinary consensus conferences. Pharmacological and non-pharmacological treatments were discussed, statements were proposed and ultimately agreed upon by nominal group technique (NGT). RESULTS: 12 overarching therapeutic principles, as well as 9 recommendations on pharmacological and 5 on non-pharmacological treatments for JIA were agreed upon. CONCLUSION: This report summarizes the recent update of the interdisciplinary, consensus-based German guidelines on the management of JIA. The multi- and interdisciplinary participation of all caregivers was central for this patient-focused update. With these guidelines, physicians can choose an evidence-based approach, which allows better tailored treatment in this vulnerable cohort of children and adolescents.

Working Towards a Treat-to-Target Protocol in Juvenile Proliferative Lupus Nephritis - A Survey of Pediatric Rheumatologists and Nephrologists in Germany and Austria.

Background: To describe treatment practices for juvenile proliferative lupus nephritis (LN) class III and IV of pediatric rheumatologists and nephrologists in Germany and Austria in preparation for a treat-to-target treatment protocol in LN. Methods: Survey study by members of the Society for Pediatric and Adolescent Rheumatology (GKJR) and the German Society for Pediatric Nephrology (GPN) on diagnostics and (concomitant) therapy of LN. Results: Fifty-eight physicians completed the survey. Overall, there was a considerable heterogeneity regarding the suggested diagnostics and management of juvenile proliferative LN. Increased urinary protein excretion, either assessed by 24 h urine collection or spot urine (protein-creatinine ratio), and reduced estimated glomerular filtration rate were specified as important parameters for indication of kidney biopsy to diagnose proliferative LN and monitoring of therapy. Corticosteroids were generally proposed for induction and maintenance therapy, most often in conjunction with either mycophenolate mofetil (MMF) or cyclophosphamide (CP) as steroid-sparing immunosuppressants. MMF was clearly preferred over CP for induction therapy of LN class III, whereas CP and MMF were equally proposed for LN class IV. MMF was most often recommended for maintenance therapy in conjunction with oral corticosteroids and continued for at least 3 years and 1 year, respectively, after remission. Hydroxychloroquine was widely accepted as a concomitant measure followed by renin-angiotensin system inhibitors in cases of arterial hypertension and/or proteinuria. Conclusion: The majority of pediatric rheumatologists and nephrologists in Germany and Austria propose the use of corticosteroids, most often in combination with either MMF or CP, for treatment of proliferative LN in children. The considerable heterogeneity of responses supports the need for a treat-to-target protocol for juvenile proliferative LN between pediatric rheumatologists and nephrologists.

Soluble interleukin-2 receptor serum levels facilitate prediction of relapses in subgroups of patients with juvenile idiopathic arthritis.

OBJECTIVES: JIA is characterised by a chronic disease course. Once patients achieve a state of inactive disease, there are no established biomarkers to predict the further course of inflammation for these patients. Therefore, the purpose of this study was to quantify serum biomarkers during quiescent disease to evaluate their use in identifying JIA patients at risk for future disease flare. METHODS: Patients with non-systemic JIA reaching inactive disease status were divided into two groups: 92 patients with future active disease after a median period of 6 months (range 3-9) and 80 patients with persistent inactive disease for the following period (median 11 months, range 7-16) according to the juvenile arthritis DAS (JADAS). Clinical parameters and serum levels of various biomarkers were measured in the state of inactive disease using immunoassays in both groups and were analysed for their potential to predict the further course of disease. RESULTS: Soluble interleukin-2 receptor (sIL-2R) serum levels were significantly higher in patients with future active disease (P = 0.021), which especially applied to patients with RF-negative polyarticular and extended oligoarticular JIA (P < 0.001). Higher sIL-2R serum levels during inactive disease were associated with a greater number of active joints at future active disease. CONCLUSION: Patients without clinical signs of disease activity already presented with increased sIL-2R serum levels several months before disease relapses, whereas conventional inflammation parameters were not elevated. Determination of sIL-2R serum levels during inactive disease may facilitate identifying patients with subclinical disease activity at risk for future active disease.

Myositis-specific autoantibodies and their associated phenotypes in juvenile dermatomyositis: data from a German cohort.

OBJECTIVES: To describe a German cohort of patients with juvenile dermatomyositis (JDM) and to evaluate clinical manifestations, disease course and prognosis in JDM patients with a certain myositis-specific autoantibody. METHODS: Cross-sectional data on patients with JDM documented in the National Paediatric Rheumatologic Database in Germany between 2014 and 2016 were analysed. In a subgroup of the cohort, MSAs were determined with a commercial multiplex array, and a retrospective chart review was conducted to specify the clinical phenotype and patient outcome. RESULTS: The total cohort consisted of 196 patients with JDM (mean age 12.2±4.0 years, mean disease duration 5.1±3.8 years, 70% female). Apart from typical skin changes and muscle weakness, 41% of patients also had arthritis and/or contractures, 27% had calcinosis and approximately 10% had interstitial lung disease. Immunoblot testing was performed on the sera of 91 (46%) patients, detecting MSAs in 44% of patients. Patient groups with specific MSAs differed in clinical characteristics such as calcinosis, dysphagia, and lung and joint involvement. The extent of muscle weakness evaluated by the Childhood Myositis Assessment Scale was significantly associated with an increased level of creatine kinase. Patients with anti-MDA5 were particularly affected by polyarthritis of the small joints. After 5 years, 51 patients of the MSA cohort (56.0%) achieved an inactive disease state, 12/51 (23.5%) were off therapy. CONCLUSIONS: Patients with JDM in Germany show a broad spectrum of clinical manifestations that can be grouped into homogeneous groups using MSA, which also helps to predict the course and prognosis of the disease.

MRP8/14 serum levels as diagnostic markers for systemic juvenile idiopathic arthritis in children with prolonged fever.

OBJECTIVES: Differential diagnosis in children with prolonged fever is challenging. In particular, differentiating systemic-onset JIA (SJIA) from infectious diseases is difficult. Biomarkers are needed that support the diagnostic work-up. The aim of this study was to validate the usefulness of Myeloid-related protein 8/14 (MRP8/14) measurements in the diagnostic work-up of febrile children and to transfer it to clinical practice. METHODS: Data for 1110 paediatric patients were included and divided into two cohorts: (cohort A) for validation of MRP8/14 test performance with three different testing systems: the experimental ELISA, commercial ELISA and an innovative (point-of-care test) lateral flow immunoassay (LFIA); (cohort B) to validate the diagnostic accuracy with the two latter assays. RESULTS: In cohort A (n = 940), MRP8/14 was elevated in SJIA (12 110 ± 2650 ng/ml mean ± 95% CI) compared with other diagnoses (including infections and autoinflammatory diseases; 2980 ± 510 ng/ml) irrespective of fever and anti-inflammatory treatment (P < 0.001). In untreated patients with fever (n = 195) MRP8/14 levels in SJIA (19 740 ± 5080 ng/ml) were even higher compared with other diagnoses (4590 ± 1160 ng/ml) (P < 0.001, sensitivity 73%, specificity 90%). In group B1, the performance of the tests was confirmed in untreated patients with fever (n = 170): commercial ELISA (sensitivity 79%, specificity 89%) and LFIA (sensitivity 84%, specificity 81%). Compared with ferritin, IL-18, ESR, soluble IL-2 receptor and procalcitonin, MRP8/14 showed the best accuracy. CONCLUSION: MRP8/14 serum analyses have been validated as a helpful tool supporting the diagnosis of SJIA in febrile children. The results could be confirmed with commercial ELISA and LFIA enabling a rapid diagnostic point-of-care screening test.

Trajectories of disease courses in the inception cohort of newly diagnosed patients with JIA (ICON-JIA): the potential of serum biomarkers at baseline.

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.

Discrimination of COVID-19 From Inflammation-Induced Cytokine Storm Syndromes Using Disease-Related Blood Biomarkers.

OBJECTIVE: Infection with the novel coronavirus SARS-CoV-2 triggers severe illness with high mortality in a subgroup of patients. Such a critical course of COVID-19 is thought to be associated with the development of cytokine storm, a condition seen in macrophage activation syndrome (MAS) and secondary hemophagocytic lymphohistiocytosis (HLH). However, specific data demonstrating a clear association of cytokine storm with severe COVID-19 are still lacking. The aim of this study was to directly address whether immune activation in COVID-19 does indeed mimic the conditions found in these classic cytokine storm syndromes. METHODS: Levels of 22 biomarkers were quantified in serum samples from patients with COVID-19 (n = 30 patients, n = 83 longitudinal samples in total), patients with secondary HLH/MAS (n = 50), and healthy controls (n = 9). Measurements were performed using bead array assays and single-marker enzyme-linked immunosorbent assay. Serum biomarker levels were assessed for correlations with disease outcome. RESULTS: In patients with secondary HLH/MAS, we observed pronounced activation of the interleukin-18 (IL-18)-interferon-γ axis, increased serum levels of IL-1 receptor antagonist, intercellular adhesion molecule 1, and IL-8, and strongly reduced levels of soluble Fas ligand in the course of SARS-CoV-2 infection. These observations appeared to discriminate immune dysregulation in critical COVID-19 from the well-recognized characteristics of other cytokine storm syndromes. CONCLUSION: Serum biomarker profiles clearly separate COVID-19 from MAS or secondary HLH in terms of distinguishing the severe systemic hyperinflammation that occurs following SARS-CoV-2 infection. These findings could be useful in determining the efficacy of drugs targeting key molecules and pathways specifically associated with systemic cytokine storm conditions in the treatment of COVID-19.

Experiences with IL-1 blockade in systemic juvenile idiopathic arthritis - data from the German AID-registry.

BACKGROUND: Systemic juvenile idiopathic arthritis (sJIA) is a complex disease with dysregulation of the innate immune system driven by cytokines. A major role is ascribed to interleukin-1ß (IL-1ß), supporting the autoinflammatory character of the disease and offering an effective blocking mechanism for treatment. Here we present clinical practice data from the German AID-registry for patients treated with IL-1 inhibition (IL-1i). METHODS: In 2009 a clinical and research consortium (AID-Net) was established, including an online AID-registry. Patients with documented sJIA diagnosis were identified. Data for this retrospective IL-1i study were recorded by 17 centers. Response to treatment was evaluated according to Wallace criteria and additionally by an own classifying clinical response system. RESULTS: In 6 years, 202 patients with confirmed sJIA were recorded in the AID-registry. Out of these, 111 children received therapy with Anakinra (ANA) (n = 84, 39 f) and/or Canakinumab (CANA) (n = 27, 15 f) at a median age of 8.7 y (range 0.6-19.1). During the first 12 months 75/111 (ANA 55, CANA 20) patients were evaluated according to Wallace criteria (achievement of inactive disease 28/55 and 17/20, remission over 6 months under medication 13/55 and 7/20 cases). Over the whole period of time, clinical response was preserved in the majority of patients (ANA 54/80, CANA 20/27). Arthritis mostly persisted in polyarticular (PA) courses. During treatment with IL-1i concomitant medication could be tapered in about 15%. IL-1i was discontinued in 59/111 patients. 45 (15) adverse events (AE)s in ANA (CANA) treated patients (19.7 (26.6) AE/100 ANA (CANA) exposure years, 95%CI: 14.4-26.4 (14.9-43.9)) were reported. CONCLUSION: In a large cohort of sJIA patients from Germany, we can confirm an overall favorable clinical response to both available IL-1 blocking agents. IL-1i was well tolerated with acceptable safety and effectiveness in a real-life clinical setting.

Therapeutic approaches to pediatric COVID-19: an online survey of pediatric rheumatologists.

Data on therapy of COVID-19 in immunocompetent and immunosuppressed children are scarce. We aimed to explore management strategies of pediatric rheumatologists. All subscribers to international Pediatric Rheumatology Bulletin Board were invited to take part in an online survey on therapeutic approaches to COVID-19 in healthy children and children with autoimmune/inflammatory diseases (AID). Off-label therapies would be considered by 90.3% of the 93 participating respondents. In stable patients with COVID-19 on oxygen supply (stage I), use of remdesivir (48.3%), azithromycin (26.6%), oral corticosteroids (25.4%) and/or hydroxychloroquine (21.9%) would be recommended. In case of early signs of "cytokine storm" (stage II) or in critically ill patients (stage III) (a) anakinra (79.5% stage II; 83.6% stage III) or tocilizumab (58.0% and 87.0%, respectively); (b) corticosteroids (oral 67.2% stage II, intravenously 81.7% stage III); (c) intravenous immunoglobulins (both stages 56.5%); or (d) remdesivir (both stages 46.7%) were considered. In AID, > 94.2% of the respondents would not support a preventive adaptation of the immunomodulating therapy. In case of mild COVID-19, more than 50% of the respondents would continue pre-existing treatment with immunoglobulins (100%), hydroxychloroquine (94.2%), anakinra (79.2%) or canakinumab (72.5%), or tocilizumab (69.8%). Long-term corticosteroids would be reduced by 26.9% (< = 2 mg/kg/d) and 50.0% (> 2 mg/kg/day), respectively, with only 5.8% of respondents voting to discontinue the therapy. Conversely, more than 75% of respondents would refrain from administering cyclophosphamide and anti-CD20-antibodies. As evidence on management of pediatric COVID-19 is incomplete, continuous and critical expert opinion and knowledge exchange is helpful.

A dysregulated interleukin-18-interferon-γ-CXCL9 axis impacts treatment response to canakinumab in systemic juvenile idiopathic arthritis.

OBJECTIVES: The monoclonal IL-1ß antibody canakinumab is approved for the treatment of systemic juvenile idiopathic arthritis (SJIA). Its efficacy has been proven in several trials, but not all patients show a complete and sustained response to therapy. We aimed to analyse the association of baseline serum biomarkers with treatment outcome in patients with SJIA treated with canakinumab. METHODS: Serum samples from 54 patients with active SJIA without recent macrophage activation syndrome (MAS) treated with canakinumab in an open-label response characterization study were subjected to a multiplexed bead array assay. Interesting targets from these analyses were validated by ELISA. Clinical treatment outcomes included modified paediatric ACR (pACR) 30 and 90 responses, clinically inactive disease (CID) within 15 days of treatment and sustained complete response, defined as pACR100 or CID within 15 days of treatment plus no future flare or MAS. RESULTS: In canakinumab-naïve patients most biomarkers were elevated when compared with healthy controls at baseline and some rapidly decreased by day 15 [IL-1 receptor antagonist (IL-1RA), IL-6, IL-18 and S100A12]. Responders had higher IL-18 and IFN-γ levels and lower chemokine (C-X-C motif) ligand 9 (CXCL9) levels at baseline, emphasized by the IL-18: CXCL9 and IFN-γ: CXCL9 ratios. These ratios had significant accuracy in predicting treatment responses. CONCLUSION: Differential regulation of the IL-18-IFN-γ-CXCL9 axis is observed in patients with SJIA. Higher IL-18: CXCL9 and IFN-γ: CXCL9 ratios at baseline are associated with a better clinical response to canakinumab treatment in SJIA. Future studies are needed to validate these findings and determine their generalizability to patients with recent MAS.

Definition and validation of serum biomarkers for optimal differentiation of hyperferritinaemic cytokine storm conditions in children: a retrospective cohort study.

BACKGROUND: Cytokine storm syndromes are life-threatening complications that can occur in children with rheumatic conditions (macrophage activation syndrome [MAS]), inherited cytotoxicity defects (ie, primary haemophagocytic lymphohistiocytosis [HLH]), or as a result of infection or malignancies (ie, secondary HLH). To adequately steer treatment, an early and clear discrimination of these entities is essential. We aimed to define and validate serum biomarker profiles that can differentiate between primary HLH, secondary HLH (predominantly infection-associated), and MAS associated with systemic juvenile idiopathic arthritis (systemic JIA-MAS). METHODS: In this multicentre, retrospective, cohort study, serum samples from patients (0-18 years) with a clinical diagnosis of primary HLH, secondary HLH, or systemic JIA-MAS were analysed by immunoassays for 55 cytokines and chemokines. Serum samples were collected from patients treated at seven clinical centres in Europe and North America. 15 serum biomarkers were validated using an independent commercial assay, and the diagnostic accuracy of the best performing biomarkers was tested in an independent validation cohort. FINDINGS: Serum samples were collected between Dec 7, 2010, and Jan 26, 2018. In the discovery cohort of 43 patients (24 girls and 19 boys) multi-marker analyses revealed distinct serum biomarker profiles associated with primary or secondary HLH versus systemic JIA-MAS. Ten biomarkers were identified that were differentially elevated in either HLH or systemic JIA-MAS and distinguished between these clinical entities, six of which were tested in an independent validation cohort of 79 patients (34 girls and 45 boys). Serum concentrations of S100A12 and interleukin-18, as well as ratios of both S100A12 and IL-18 with chemokine (C-X-C motif) ligand (CXCL)9 and CXCL10 were identified as the most promising candidates for differential diagnostics. INTERPRETATION: At initial presentation, when it is unclear whether a patient with excessive hyperferritinaemic inflammation has primary HLH, infection-associated secondary HLH, or MAS, high serum concentrations of S100A12 indicate an initial differential diagnosis of systemic JIA-MAS, thus helping to guide subsequent treatment decisions. We therefore suggest the inclusion of serum S100A12 and IL-18 in the diagnostic investigations for hyperferritinaemic syndromes; however, the definition and introduction of universially applicable cutoff values are still required. FUNDING: German Research Foundation, the Center for Interdisciplinary Clinical Research at University Hospital Muenster, the EU's Horizon 2020 research and innovation programme, and the Deutsche Kinderkrebsstiftung.

Impact of IL1RN Variants on Response to Interleukin-1 Blocking Therapy in Systemic Juvenile Idiopathic Arthritis.

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).