The Role of Serum Calprotectin in Defining Disease Outcomes in Non-Systemic Juvenile Idiopathic Arthritis: A Pilot Study.

Serum calprotectin (MRP8/14) is currently being studied as a promising biomarker of disease activity and outcome in patients with juvenile idiopathic arthritis (JIA) but the data in the literature are conflicting. The aim of our study was to investigate the potential role of serum calprotectin as biomarker of disease activity and flare/remission in a group of nsJIA patients during a follow-up period of 18 months. In this prospective longitudinal study, two groups of patients with ns-JIA (55 active patients and 56 patients in remission according to Wallace's criteria) and a control group (50 children) were recruited at baseline from January 2020 to September 2021. JIA patients were followed for up to 18 months at four timepoints: 3 months (T1), 6 months (T2), 12 months (T3) and 18 months (T4). At each timepoint, the following were recorded: JADAS27, blood counts, ESR, CRP, albumin, ferritin and serum calprotectin. To illustrate the performance of calprotectin, Kaplan-Meier curves were constructed from baseline to relapse/remission, dichotomizing patients at baseline in positive/negative on the basis progressive calprotectin cut-offs. Associations between baseline factors and relapse were determined using Cox regression models. Multivariate models were constructed to analyze the effect of covariates. Comparing baseline clinical and laboratory data of the three groups (active vs. inactive JIA vs. controls), only serum calprotectin reached statistical significance (active patients vs. inactive (p = 0.0016) and vs. controls (p = 0.0012)). In the inactive group, during the 18 months of follow up, 31 patients (55.3%) had a relapse. Comparing the baseline data of relapsers vs. non-relapsers, serum calprotectin showed higher levels (p = 0.001) in relapsers. In survival analysis, a log rank test showed significant differences of up to 12 ng/mL (p = 0.045). Multivariate Cox regression confirmed that only baseline calprotectin levels were independently associated with disease recurrence. In the active group, in the 12 months of follow-up, 19 patients (38%) entered remission of the disease. In addition, in this group, the only statistical difference at the baseline was the value of MPR8/14 (p = 0.0001). Log rank test showed significant differences up to 10 ng/mL (p = 0.003). In the multivariate Cox regression, serum calprotectin levels at baseline were independently associated with remission. In conclusion, our study would suggest a dual role for calprotectin in predicting future relapse and treatment response in patients with nsJIA, thus influencing therapeutic decisions and management of these patients during follow up.

Causal analysis of serum polyunsaturated fatty acids with juvenile idiopathic arthritis and ocular comorbidity.

BACKGROUND & OBJECTIVE: To investigate the causal effects of plasma Polyunsaturated fatty acids (PUFAs) on the risk of juvenile idiopathic arthritis (JIA) and ocular comorbidity through Mendelian randomization (MR) analysis. METHODS: Genetic variants (formerly single nucleotide polymorphisms, SNPs) that are strongly associated with PUFAs levels (P < 5×10-8) were selected as instrumental variables. Summary-level MR was performed with outcome estimates for JIA (n = 31,142) and JIA associated iridocyclitis (n = 94,197). The inverse variance-weighted (IVW) method was employed as the main approach to combine the estimation for each SNP. Two set of models with summary statistics were conducted and multiple sensitivity analyses were applied for testing of pleiotropic bias. RESULTS: In model 1, genetically predicted n-6 PUFAs linoleic acid (LA) and arachidonic acid (AA) were associated with lower and higher risk of JIA associated iridocyclitis using IVW (ORLA = 0.940, 95% CI: 0.895-0.988, P = 0.015; ORAA = 1.053, 95% CI: 1.007-1.101, P = 0.024). No such association was observed between each plasma PUFAs and JIA susceptibility (P > 0.05). In further MR analysis, results from model 2 also showed a consistent trend. Besides, multiple sensitivity analyses revealed that there was no obvious evidence for unknown pleiotropy (P > 0.05). CONCLUSIONS: Our MR study provides genetic evidence on the possible causality that plasma LA level might protect against JIA associated iridocyclitis, whereas AA was responsible for opposite effect.

Prevalence of autoantibodies in patients with juvenile idiopathic arthritis: results from the German inception cohort ICON-JIA.

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.

Proteomics based markers of clinical pain severity in juvenile idiopathic arthritis.

INTRODUCTION: Juvenile idiopathic arthritis (JIA) is a cluster of autoimmune rheumatic diseases occurring in children 16 years of age or less. While it is well-known that pain may be experienced during inflammatory and non-inflammatory states, much remains ambiguous regarding the molecular mechanisms that may drive JIA pain. Thus, in this pilot study, we explored the variability of the serum proteomes in relation to pain severity in a cohort of JIA patients. METHODS: Serum samples from 15 JIA patients (male and female, 12.7 ± 2.8 years of age) were assessed using liquid chromatography/mass spectrometry (LC/MS). Correlation analyses were performed to determine the relationships among protein levels and self-reported clinical pain severity. Additionally, how the expression of pain-associated proteins related to markers of inflammation (Erythrocyte Sedimentation Rate (ESR)) or morphological properties of the central nervous system (subcortical volume and cortical thickness) implicated in JIA were also evaluated. RESULTS: 306 proteins were identified in the JIA cohort of which 14 were significantly (p < 0.05) associated with clinical pain severity. Functional properties of the identified pain-associated proteins included but were not limited to humoral immunity (IGLV3.9), inflammatory response (PRG4) and angiogenesis (ANG). Associations among pain-associated proteins and ESR (IGHV3.9, PRG4, CST3, VWF, ALB), as well as caudate nucleus volume (BTD, AGT, IGHV3.74) and insular cortex thickness (BTD, LGALS3BP) were also observed. CONCLUSIONS: The current proteomic findings suggest both inflammatory- and non-inflammatory mediated mechanisms as potential factors associated with JIA pain. Validation of these preliminary observations using larger patient cohorts and a longitudinal study design may further point to novel serologic markers of pain in JIA.

Immunoprofiling of active and inactive systemic juvenile idiopathic arthritis reveals distinct biomarkers: a single-center study.

BACKGROUND: This study aimed to perform an immunoprofiling of systemic juvenile idiopathic arthritis (sJIA) in order to define biomarkers of clinical use as well as reveal new immune mechanisms. METHODS: Immunoprofiling of plasma samples from a clinically well-described cohort consisting of 21 sJIA patients as well as 60 age and sex matched healthy controls, was performed by a highly sensitive proteomic immunoassay. Based on the biomarkers being significantly up- or down-regulated in cross-sectional and paired analysis, related canonical pathways and cellular functions were explored by Ingenuity Pathway Analysis (IPA). RESULTS: The well-studied sJIA biomarkers, IL6, IL18 and S100A12, were confirmed to be increased during active sJIA as compared to healthy controls. IL18 was the only factor found to be increased during inactive sJIA as compared to healthy controls. Novel factors, including CASP8, CCL23, CD6, CXCL1, CXCL11, CXCL5, EIF4EBP1, KITLG, MMP1, OSM, SIRT2, SULT1A1 and TNFSF11, were found to be differentially expressed in active and/or inactive sJIA and healthy controls. No significant pathway activation could be predicted based on the limited factor input to the IPA. High Mobility Group Box 1 (HMGB1), a damage associated molecular pattern being involved in a series of inflammatory diseases, was determined to be higher in active sJIA than inactive sJIA. CONCLUSIONS: We could identify a novel set of biomarkers distinguishing active sJIA from inactive sJIA or healthy controls. Our findings enable a better understanding of the immune mechanisms active in sJIA and aid the development of future diagnostic and therapeutic strategies.

Mycoplasma pneumoniae Seroprevalence and Total IgE Levels in Patients with Juvenile Idiopathic Arthritis.

BACKGROUND: Mycoplasma pneumoniae (M. pneumoniae) is implicated in several immune-mediated extrapulmonary manifestations, including reactive arthritis. Recently, increased total serum IgE were reported in children developing M. pneumoniae-related extrapulmonary diseases (MpEPDs). Here, we aimed at analyzing these aspects in children affected with rheumatic disorders and, in detail, Juvenile Idiopathic Arthritis (JIA). METHODS: M. pneumoniae serology (IgG and IgM) and total serum IgE were concomitantly analyzed in 139 pediatric patients diagnosed with: JIA (Group 1, n = 85), or any rheumatic disease other than JIA (Group 2, n = 27), or non-inflammatory endocrinological disorders (Group 3, n = 27). RESULTS: Overall, 19.4% M. pneumoniae seroprevalence was observed in this hospitalized pediatric population, without signicant differences among the three groups. No significant differences in total serum IgE levels were noted among these groups; however, a second analysis excluding children with very high (and clearly abnormal) IgE levels suggested that JIA patients and, in detail, those with oligopolyarticular forms may have higher serum IgE concentrations. This relative difference among groups in serum IgE level seems to be more pronounced in M. pneumoniae seropositive children. CONCLUSIONS: M. pneumoniae infection should be actively sought in children developing immune-mediated diseases, including patients affected with JIA and, especially, in oligopolyarticular forms. There is some evidence that total serum IgE levels may tend to be increased in patients with oligopolyarticular JIA subtype and especially in those resulting as M. pneumoniae seropositive. However, further and focused research is needed to confirm these preliminary results and to clarify the relation between M. pneumoniae infection, atopic status, and immune-mediated arthritis.

Definition and Validation of the American College of Rheumatology 2021 Juvenile Arthritis Disease Activity Score Cutoffs for Disease Activity States in Juvenile Idiopathic Arthritis.

OBJECTIVE: To develop and validate new Juvenile Arthritis Disease Activity Score 10 (JADAS10) and clinical JADAS10 (cJADAS10) cutoffs to separate the states of inactive disease (ID), minimal disease activity (MiDA), moderate disease activity (MoDA), and high disease activity (HDA) in children with oligoarthritis and with rheumatoid factor-negative polyarthritis, based on subjective disease assessment by the treating pediatric rheumatologist. METHODS: The cutoffs definition cohort was composed of 1,936 patients included in the multinational Epidemiology, Treatment and Outcome of Childhood Arthritis (EPOCA) study. Using the subjective physician rating as an external criterion, 4 methods were applied to identify the cutoffs: mapping, Youden index, 90% specificity, and maximum agreement. The validation cohort included 4,014 EPOCA patients, patients from 2 randomized trials, and 88 patients from the PharmaChild registry. Cutoff validation was conducted by assessing discriminative and predictive ability. RESULTS: The JADAS10 cutoffs were 1.4, 4, and 13, respectively, for oligoarthritis and 2.7, 6, and 17, respectively, for polyarthritis. The cJADAS10 cutoffs were 1.1, 4, and 12, respectively, for oligoarthritis and 2.5, 5, and 16, respectively, for polyarthritis. The cutoffs discriminated strongly among different levels of pain and morning stiffness, between patients who were and those who were not prescribed a new medication, and between different levels of improvement in clinical trials. Achievement of ID and MiDA according to the new JADAS cutoffs at least twice in the first year of disease predicted better outcome at 2 years. CONCLUSION: The 2021 JADAS and cJADAS cutoffs revealed good metrologic properties in both definition and validation samples, and are therefore suitable for use in clinical trials and routine practice.

Higher concentrations of vitamin D in Canadian children with juvenile idiopathic arthritis compared to healthy controls are associated with more frequent use of vitamin D supplements and season of birth.

A number of studies have demonstrated that patients with autoimmune disease have lower levels of vitamin D prompting speculation that vitamin D might suppress inflammation and immune responses in children with juvenile idiopathic arthritis (JIA).  The objective of this study was to compare vitamin D levels in children with JIA at disease onset with healthy children. We hypothesized that children and adolescents with JIA have lower vitamin D levels than healthy children and adolescents. Data from a Canadian cohort of children with new-onset JIA (n= 164, data collection 2007-2012) were compared to Canadian Health Measures Survey (CHMS) data (n=4027, data collection 2007-2011). We compared 25-hydroxy vitamin D (25(OH)D) concentrations with measures of inflammation, vitamin D supplement use, milk intake, and season of birth. Mean 25(OH)D level was significantly higher in patients with JIA (79 ± 3.1 nmol/L) than in healthy controls (68 ± 1.8 nmol/L P <.05). Patients with JIA more often used vitamin D containing supplements (50% vs. 7%; P <.05). The prevalence of 25(OH)D deficiency (<30 nmol/L) was 6% for both groups. Children with JIA with 25(OH)D deficiency or insufficiency (<50 nmol/L) had higher C-reactive protein levels. Children with JIA were more often born in the fall and winter compared to healthy children. In contrast to earlier studies, we found vitamin D levels in Canadian children with JIA were higher compared to healthy children and associated with more frequent use of vitamin D supplements. Among children with JIA, low vitamin D levels were associated with indicators of greater inflammation.

Association between high mobility group box 1 protein and juvenile idiopathic arthritis: a prospective longitudinal study.

OBJECTIVE: To analyze the levels of high mobility group box 1 (HMGB1) protein on different courses of juvenile idiopathic arthritis (JIA). METHODS: In our prospective longitudinal study, children with JIA were included with their blood samples collected at the first visit, 1-month, 3-month, and 6-month follow-up, respectively. Samples were also collected from healthy controls and children with reactive arthritis at the first visit. Levels of HMGB1 were determined using enzyme-linked immunosorbent assays. Clinical disease characteristics and routine laboratory findings were analyzed as well. RESULTS: A total of 64 children were enrolled, of whom 31 (48.4%) were female. The median age at the first visit for participants with JIA was 9.25 years (range, 1.42-15.42) and the median duration of disease was 2.38 months (range, 1.53-49.31). Serum HMGB1 levels at the first visit were significantly elevated in children with systemic JIA compared with other groups, and so were in enthesitis-related arthritis versus healthy controls. Significant correlations were established at the first visit between HMGB1 levels and duration of disease, C-reactive protein, percentage of neutrophils, and ferritin. Data from all samples revealed that serum HMGB1 levels in JIA were significantly associated with erythrocyte sedimentation rates, C-reactive protein, percentage of neutrophils, and disease activity scores. CONCLUSIONS: Serum HMGB1 may be associated with clinical disease activity of JIA and specifically increased at the first visit in children with systemic JIA, suggesting its function as a sensitive inflammatory marker. Further large-scale studies are warranted to explore its spectrum in JIA.

The vaccine coverage and vaccine immunity status and risk factors of non-protective levels of antibodies against vaccines in children with juvenile idiopathic arthritis: cross-sectional Russian tertiary Centre study.

BACKGROUND: Immunosuppressive drugs, incomplete vaccine coverage, immune system dysregulation might be factors of a low level of anti-vaccine antibodies in JIA patients. The study aimed to evaluate vaccine coverage, post-vaccine immunity, and risk factors of non-protective levels of antibodies against measles, mumps, rubella, hepatitis B, and diphtheria in JIA patients. METHODS: A cross-sectional study included 170 children diagnosed with JIA aged 2 to 17 years who received routine vaccinations against measles, rubella, mumps (MMR), diphtheria, and hepatitis B national vaccine schedule. In all patients, the levels of post-vaccination antibodies (IgG) for measles, rubella, mumps, hepatitis B, and diphtheria were measured with ELISA. RESULTS: Protective level of antibodies were 50% against hepatitis B, 52% - diphtheria, 58% - measles, 80% - mumps, 98% rubella. MMR's best coverage had patients with enthesitis-related arthritis-85%, compared to oligoarthritis-70%, polyarthritis-69%, systemic arthritis-63%. Diphtheria coverage was 50, 51, 46, 63%, respectively. Incomplete MMR vaccination had 39% patients, treated with biologics, 22% with methotrexate and 14% with NSAID (p = 0.025), and 61, 46, 36% for diphtheria (p = 0.021). Incomplete vaccination was a risk factor of non-protective level of antibodies against measles (HR = 2.03 [95%CI: 1.02; 4.0], p = 0.042), mumps (HR = 6.25 [95%CI: 2.13; 17.9], p = 0.0008) and diphtheria (HR = 2.39 [95%CI: 1.18; 4.85], p = 0.016) vaccines, as well as JIA category, biologics, corticosteroids and long-term methotrexate treatment for distinct vaccines. One-third part of JIA patients continued vaccination against MMR and diphtheria without serious adverse events and JIA flare. There were no differences between patients who continued MMR vaccination or denied in the means of JIA category and treatment options. Patients, continued diphtheria vaccination rare received methotrexate (p = 0.02), biologics (p = 0.004), but had higher levels of anti-diphtheria antibodies (p = 0.024) compare who omitted vaccination. Methotrexate (OR = 9.5 [95%CI: 1.004; 90.3]) and biologics (OR = 4.4 [95%CI: 1.6; 12.1]) were predictors of omitted diphtheria revaccination. CONCLUSION: Children with JIA may have lower anti-vaccine antibody levels and required routine checks, especially in children with incomplete vaccination, biologics, systemic arthritis, and long-term methotrexate treatment. Revaccination of JIA patients was safe and effective.

Unbalanced expression of membrane-bound and soluble programmed cell death 1 and programmed cell death ligand 1 in systemic juvenile idiopathic arthritis.

The study aimed to investigate the soluble programmed death-1 (sPD-1) and its ligand (sPD-L1) levels in systemic juvenile idiopathic arthritis (sJIA) patients and elucidate its underlying immunomodulatory mechanisms. Plasma levels of sPD-1, sPD-L1 and related cytokines and proteins were detected using an enzyme-linked immunosorbent assay (ELISA) and Luminex. The effects of PD-1/PD-L1 signal on mDC (myeloid dendritic cell) and IL-6 secretion were measured using flow cytometry. The results revealed decreased levels of sPD-1 in sJIA patients negatively correlated with JADAS-27, PGA, PtGA and CRP. sJIA patients had lower CD86 and MHC-II expression on mDC. When blocking PD-1/PD-L1 signal, IL-6 secretion of DC were increased. Our finding displayed downregulated sPD-1 was related with clinical indicators and could be a new biomarker for sJIA diagnosis. The reduced membrane and soluble forms of PD-1/PD-L1 might take part in sJIA pathogenesis by enhancing mDC proliferation and IL-6 secretion.

A cross-sectional cohort study of the activity and turnover of neutrophil granulocytes in juvenile idiopathic arthritis.

BACKGROUND: The inflammatory process in juvenile idiopathic arthritis (JIA) involves both the innate and the adaptive immune system. The turnover and activity of neutrophil granulocytes may be reflected by proteins secreted from primary or secondary granules and from the cytoplasm of sequestered cells. Our primary aim was to compare the levels of the secondary neutrophil granule protein human neutrophil lipocalin (HNL), in JIA patients and controls, and to explore a possible priming of neutrophils through parallel analyses in plasma and serum. A secondary aim was to relate the levels of HNL to two other well-studied leukocyte proteins, S100A8/A9 and myeloperoxidase (MPO), as well as to clinical aspects of JIA. METHODS: The concentrations of the three biomarkers in serum, two of them also in plasma, were measured using enzyme-linked immunosorbent assay in 37 children with JIA without medical treatment, in high disease activity based on juvenile arthritis disease activity score 27 (JADAS27), 32 children on medical treatment, mainly in lower disease activity, and 16 healthy children. We assessed for differences between two groups using the Mann-Whitney U test, and used the Kruskal-Wallis test for multiple group comparisons. Spearman rank correlation, linear and multiple regression analyses were used for evaluation of associations between biomarker concentrations and clinical scores. RESULTS: The concentrations of HNL and MPO in serum were significantly increased in children with JIA (p < 0.001, p = 0.002) compared with healthy children, but we found no difference in the plasma levels of HNL and MPO between children with JIA and controls. The serum concentrations of MPO and HNL were unaffected by medical treatment, but S100A8/A9 was reduced by medical treatment and correlated with JADAS27 in both univariate (r = 0.58, p < 0.001) and multivariate (r = 0.59, p < 0.001) analyses. CONCLUSIONS: Neutrophil granulocytes in children with JIA are primed to release primary and secondary granule proteins, without relation to medical treatment, whereas signs of increased turnover and sequestration of neutrophil granulocytes are reduced by treatment. Levels of neutrophil-originating proteins in serum most likely reflect underlying disease activities of JIA.

Serum protein signatures differentiate paediatric autoimmune/inflammatory disorders.

Because of their rarity, limited awareness among non-specialists, and significant overlaps in their clinical presentation, childhood autoimmune/inflammatory conditions represent a diagnostic and therapeutic challenge. Juvenile idiopathic arthritis (JIA), with its 7 sub-forms, is the most common paediatric "rheumatic" disease. Juvenile-onset systemic lupus erythematosus (jSLE) is a severe autoimmune/inflammatory disease that can affect any organ system and shares clinical features with JIA. To overcome issues around diagnostic approaches in the context of clinical overlap, we aimed at the definition of disease sub-form specific cytokine and chemokine profiles. Serum samples from patients with JIA (n = 77) and jSLE (n = 48), as well as healthy controls (n = 30), were collected. Samples were analysed using the Meso Scale Discovery (MSD) U-PLEX Biomarker Group 1 (hu) panel. Distinct serum protein signatures associate with JIA vs jSLE disease groups. Proteins with high discriminatory ability include IL-23, MIP-1ß, MCP-1, M-CSF and MDC. Furthermore, serum IL-18, MIF, MIP-5 and YKL-40 discriminate between systemic JIA and other JIA subtypes. Thus, simultaneous quantification of serum proteins in a panel format may provide an avenue for the diagnosis and monitoring of childhood autoimmune/inflammatory conditions.

Lipopolysaccharide stimulation test on cultured PBMCs assists the discrimination of cryopyrin-associated periodic syndrome from systemic juvenile idiopathic arthritis.

Systemic juvenile idiopathic arthritis (sJIA) and cryopyrin-associated periodic syndrome (CAPS) share many common manifestations. We aim to identify an applicable method to assist disease discrimination. Inflammatory cytokines were measured in the plasma of patients with CAPS, sJIA with persistent disease course and healthy controls. Supernatants collected from non-stimulated peripheral blood mononuclear cells (PBMCs) and those undergone inflammasome stimulation tests utilizing lipopolysaccharide (LPS) with and without adenosine triphosphate (ATP) were investigated. Inflammatory cytokines in patient plasma fail to differentiate sJIA from CAPS. PBMCs from sJIA secrets higher amount of IL-1ß and IL-18 while CAPS PBMCs produces more caspase-1 without stimulation. IL-1ß, IL-18, and caspase-1 were significantly elevated among CAPS PBMCs (all p < 0.05) upon LPS stimulation, but not when additional ATPs were provided. Levels of cytokines and PBMC responses to the stimulation assays were similar among all sJIA patients regardless of their history of macrophage activation syndrome. Unstimulated PBMC activities and the LPS inflammasome stimulation assay without exogenic ATPs can assist the differentiation of CAPS from sJIA with persistent disease course.

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.

Factors associated with reduced infliximab exposure in the treatment of pediatric autoimmune disorders: a cross-sectional prospective convenience sampling study.

BACKGROUND: Inadequate systemic exposure to infliximab (IFX) is associated with treatment failure. This work evaluated factors associated with reduced IFX exposure in children with autoimmune disorders requiring IFX therapy. METHODS: In this single-center cross-sectional prospective study IFX trough concentrations and anti-drug antibodies (ADAs) were measured in serum from children diagnosed with inflammatory bowel disease (IBD) (n = 73), juvenile idiopathic arthritis (JIA) (n = 16), or uveitis (n = 8) receiving maintenance IFX infusions at an outpatient infusion clinic in a tertiary academic pediatric hospital. IFX concentrations in combination with population pharmacokinetic modeling were used to estimate IFX clearance. Patient demographic and clinical data were collected by chart review and evaluated for their relationship with IFX clearance. RESULTS: IFX trough concentrations ranged from 0 to > 40 µg/mL and were 3-fold lower in children with IBD compared to children with JIA (p = 0.0002) or uveitis (p = 0.001). Children with IBD were found to receive lower IFX doses with longer dosing intervals, resulting in dose intensities (mg/kg/day) that were 2-fold lower compared to children with JIA (p = 0.0002) or uveitis (p = 0.02). Use of population pharmacokinetic analysis to normalize for variation in dosing practices demonstrated that increased IFX clearance was associated with ADA positivity (p = 0.004), male gender (p = 0.02), elevated erythrocyte sedimentation rate (ESR) (p = 0.02), elevated c-reactive protein (CRP) (p = 0.001), reduced serum albumin concentrations (p = 0.0005), and increased disease activity in JIA (p = 0.009) and IBD (p ≤ 0.08). No significant relationship between diagnosis and underlying differences in IFX clearance was observed. Multivariable analysis by covariate population pharmacokinetic modeling confirmed increased IFX clearance to be associated with anti-IFX antibody positivity, increased ESR, and reduced serum albumin concentrations. CONCLUSIONS: Enhanced IFX clearance is associated with immunogenicity and inflammatory burden across autoimmune disorders. Higher systemic IFX exposures observed in children with rheumatologic disorders are driven primarily by provider drug dose and interval selection, rather than differences in IFX pharmacokinetics across diagnoses. Despite maintenance IFX dosing at or above the standard recommended range for IBD (i.e., 5 mg/kg every 8 weeks), the dosing intensity used in the treatment of IBD is notably lower than dosing intensities used to treat JIA and uveitis, and may place some children with IBD at risk for suboptimal maintenance IFX exposures necessary for treatment response.

Effect of LPS on Cytokine Secretion from Peripheral Blood Monocytes in Juvenile Idiopathic Arthritis-Associated Uveitis Patients with Positive Antinuclear Antibody.

OBJECTIVES: Antinuclear antibody (ANA) positivity is a key finding in JIA-associated uveitis (JIAU), but there are quite a few patients with negative ANA. There is no relevant report on the difference of their clinical manifestations. Previous animal model studies have found that the occurrence of uveitis is related to macrophage activation. In this article, our goal is to investigate changes in the morphology and cytokines of peripheral blood mononuclear cells (PBMCs) in uveitis patients testing positive or negative for ANAs after lipopolysaccharide (LPS) stimulation. METHODS: A total of 30 patients were included in this study (10 in each group). They were divided into three groups (the ANA-positive [ANA+] group, ANA-negative [ANA-] group, and control group). There were ten patients (6 females and 4 males) in each group. Peripheral venous blood was collected into a heparinized tube, and PBMCs were isolated as soon as possible by the Ficoll-Hypaque density gradient separation method. Isolated cells were mixed with RPMI-1640 medium, and the cell concentration was adjusted to ensure that each patient had the same number of cells entering the study. After putting the extracted PBMC into the culture plate, LPS was added carefully to the plate. The cell culture supernatants were collected at 0 h, 3 h, 6 h, 12 h, and 24 h after LPS stimulation to detect the concentrations of IL-6, IL-1, TNF-α, and IL-10. Immunofluorescence was used to discover the deformation of macrophages after LPS stimulation. RESULTS: The newly isolated cells were approximately round. 6 h after LPS stimulation, the ratio of noncircular cells/circular cells was the highest in the ANA+ group. Unlike IL-10 that has been rising during the observation period, IL-6, IL-1, and TNF-α peaked at 6 h after LPS stimulation. CONCLUSION: With LPS motivation, cytokines in the ANA+ group increased the most violently.

Biomarkers of lipid metabolism in patients with juvenile idiopathic arthritis: relationship with disease subtype and inflammatory activity.

BACKGROUND: To describe the biomarkers of lipid metabolism in children and adolescents with polyarticular and systemic JIA and to relate them to diseases subtypes, diseases activity markers, and nutritional status. METHODS: A cross-sectional study including 62 JIA patients was performed. The following variables were evaluated: disease activity and medications used, body mass index, height for age (z-score), skin folds (bicipital, tricipital, subscapular and suprailiac), food intake based on three 24-h food recalls, lipid profile (total cholesterol (CT), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides (TG) and non-HDL (N-HDLc), glycemia and insulin, erythrocyte sedimentation rate (ESR), ultrasensitive C-reactive protein (us-CRP) and apolipoproteins A-I and B (Apo A-I and Apo B). RESULTS: Dyslipidemia was observed in 83.3% of the patients. Based on classical lipid profile, low HDL-c levels was the most frequently alteration observed. Inadequate levels of LDL-c, Apo B and NHDL-c were significantly more frequent in the systemic JIA subtype when compared to the polyarticular subtype (p = 0.017, 0.001 and 0.042 respectively). Patients on biological therapy had a better adequacy of Apo A-I concentrations. The ESR showed a negative correlation with Apo A-I level (r = - 0.25, p = 0.047). CONCLUSION: We concluded that dyslipidemia is common in patients with JIA, especially in systemic subtype. The systemic subtype and an elevated ESR were associated with lower concentrations of Apo A-I, suggesting the participation of the inflammatory process.

Repression of CTSG, ELANE and PRTN3-mediated histone H3 proteolytic cleavage promotes monocyte-to-macrophage differentiation.

Chromatin undergoes extensive reprogramming during immune cell differentiation. Here we report the repression of controlled histone H3 amino terminus proteolytic cleavage (H3ΔN) during monocyte-to-macrophage development. This abundant histone mark in human peripheral blood monocytes is catalyzed by neutrophil serine proteases (NSPs) cathepsin G, neutrophil elastase and proteinase 3. NSPs are repressed as monocytes mature into macrophages. Integrative epigenomic analysis reveals widespread H3ΔN distribution across the genome in a monocytic cell line and primary monocytes, which becomes largely undetectable in fully differentiated macrophages. H3ΔN is enriched at permissive chromatin and actively transcribed genes. Simultaneous NSP depletion in monocytic cells results in H3ΔN loss and further increase in chromatin accessibility, which likely primes the chromatin for gene expression reprogramming. Importantly, H3ΔN is reduced in monocytes from patients with systemic juvenile idiopathic arthritis, an autoinflammatory disease with prominent macrophage involvement. Overall, we uncover an epigenetic mechanism that primes the chromatin to facilitate macrophage development.