Serum p55 and p75 tumour necrosis factor receptors as markers of disease activity in juvenile chronic arthritis

Inflammatory biomarkers predicting long-term remission and active disease in juvenile idiopathic arthritis: a population-based study of the Nordic JIA cohort

OBJECTIVES

To assess the ability of baseline serum biomarkers to predict disease activity and remission status in juvenile idiopathic arthritis (JIA) at 18-year follow-up (FU) in a population-based setting.

METHODS

Clinical data and serum levels of inflammatory biomarkers were assessed in the longitudinal population-based Nordic JIA cohort study at baseline and at 18-year FU. A panel of 16 inflammatory biomarkers was determined by multiplexed bead array assay. We estimated both univariate and multivariate logistic regression models on binary outcomes of disease activity and remission with baseline variables as explanatory variables.

RESULTS

Out of 349 patients eligible for the Nordic JIA cohort study, 236 (68%) had available serum samples at baseline. We measured significantly higher serum levels of interleukin 1β (IL-1β), IL-6, IL-12p70, IL-13, MMP-3, S100A9 and S100A12 at baseline in patients with active disease at 18-year FU than in patients with inactive disease. Computing receiver operating characteristics illustrating the area under the curve (AUC), we compared a conventional prediction model (gender, age, joint counts, erythrocyte sedimentation rate, C reactive protein) with an extended model that also incorporated the 16 baseline biomarkers. Biomarker addition significantly improved the ability of the model to predict activity/inactivity at the 18-year FU, as evidenced by an increase in the AUC from 0.59 to 0.80 (p=0.02). Multiple regression analysis revealed that S100A9 was the strongest predictor of inactive disease 18 years after disease onset.

CONCLUSION

Biomarkers indicating inflammation at baseline have the potential to improve evaluation of disease activity and prediction of long-term outcomes.

Inflammatory Biomarkers Can Differentiate Acute Lymphoblastic Leukemia with Arthropathy from Juvenile Idiopathic Arthritis Better Than Standard Blood Tests

OBJECTIVE

To evaluate the predictive value of biomarkers of inflammation like phagocyte-related S100 proteins and a panel of inflammatory cytokines in order to differentiate the child with acute lymphoblastic leukemia (ALL) from juvenile idiopathic arthritis (JIA).

STUDY DESIGN

In this cross-sectional study, we measured S100A9, S100A12, and 14 cytokines in serum from children with ALL (n = 150, including 27 with arthropathy) and JIA (n = 236). We constructed predictive models computing areas under the curve (AUC) as well as predicted probabilities in order to differentiate ALL from JIA. Logistic regression was used for predictions of ALL risk, considering the markers as the respective exposures. We performed internal validation using repeated 10-fold cross-validation and recalibration, adjusted for age.

RESULTS

In ALL, the levels of S100A9, S100A12, interleukin (IL)-1 beta, IL-4, IL-13, IL-17, matrix metalloproteinase-3, and myeloperoxidase were low compared with JIA (P < .001). IL-13 had an AUC of 100% (95% CI 100%-100%) due to no overlap between the serum levels in the 2 groups. Further, IL-4 and S100A9 had high predictive performance with AUCs of 99% (95% CI 97%-100%) and 98% (95% CI 94%-99%), respectively, exceeding both hemoglobin, platelets, C-reactive protein, and erythrocyte sedimentation rate.

CONCLUSIONS

The biomarkers S100A9, IL-4, and IL-13 might be valuable markers to differentiate ALL from JIA.

Soluble cytokine receptor levels in aqueous humour of patients with specific autoimmune uveitic entities: sCD30 is a biomarker of granulomatous uveitis

Purpose

Soluble cytokine receptors are potential biomarkers for immune activation and have a promising potential as immunotherapeutic agents. We investigated the levels of soluble cytokine receptors in aqueous humour (AH) samples from patients with specific autoimmune uveitic entities.

Methods

Patients with active uveitis associated with Behçet’s disease (BD) (n = 13), sarcoidosis (n = 8), HLA-B27-related inflammation (n = 12), Vogt–Koyanagi–Harada (VKH) disease (n = 12) and control subjects (n = 9) were included. AH samples were analyzed with the use of multiplex assays for the proinflammatory cytokine tumour necrosis factor (TNF)-α and the soluble cytokine receptors sCD30, sCD163, sgp130, sIL-6 receptor-α (sIL-6R), sTNFRI and sTNFRII.

Results

TNF-α and soluble cytokine receptor AH levels were significantly higher in uveitis patients (n = 45) compared with controls (n = 9). When nongranulomatous uveitis (BD and HLA-B27-associated uveitis) was compared with granulomatous uveitis (sarcoidosis and VKH disease), the levels of sCD30 and sTNFRI/TNF-α and sTNFRII/TNF-α ratios were significantly enhanced in granulomatous uveitis. Finally, when comparing the profile in the specific uveitis entities, sCD30 levels were highest in patients with VKH disease. sgp130, sCD163, sIL-6R, sTNFRI and sTNFRII did not differ significantly between the four different clinical uveitic subgroups.

Conclusions

Soluble cytokine receptors are significantly upregulated in autoimmune uveitis. CD30⁺ T cells might contribute to the inflammatory process in granulomatous uveitis, particularly in VKH disease. Granulomatous uveitis is also characterized by significantly higher sTNFRs/TNF-α ratios than nongranulomatous uveitis.

Cytokine Biomarkers of Disease Activity and Therapeutic Response after Initiating Methotrexate Therapy in Patients with Juvenile Idiopathic Arthritis

STUDY OBJECTIVE

To evaluate the relationship between plasma cytokine levels with disease activity and therapeutic response in patients with juvenile idiopathic arthritis (JIA) after initiating methotrexate (MTX) therapy.

DESIGN

Single-center observational prospective cohort study.

SETTING

Outpatient pediatric rheumatology clinic at a tertiary care academic pediatric hospital.

PATIENTS

The study included 61 patients diagnosed with JIA who started therapy with standard-dose MTX 15 mg/m² /week. At 3 months, treating physicians were given the option of maintaining the MTX dose, increasing the MTX dose, or adding etanercept (ETN), based on their clinical judgment.

MEASUREMENTS AND MAIN RESULTS

Patients were evaluated at baseline, 3 months (51 patients), and 6 months (35 patients). Plasma samples from each visit were analyzed for interleukin (IL)-1α, IL-1β, IL-1Ra, IL-6, and tumor necrosis factor-α (TNF-α). Cytokine concentrations were evaluated for relationships with disease activity using the 71-joint count Juvenile Arthritis Disease Activity Score (JADAS). Therapeutic response was assessed by changes in JADAS. Failure to respond to standard-dose MTX was defined as the need for the addition of ETN or a MTX dose increase at or before the 3-month visit. Increased disease severity at baseline was associated with increased IL-6 (p=0.01) and TNF-α (p=0.008) levels. Initiation of MTX was associated with reductions in IL-1α (p=0.009), IL-1β (p=0.01), IL-1Ra (p=0.007), and IL-6 (p=0.03) levels; however, reductions in JADAS were only associated with reductions in IL-6 (p=0.009) and TNF-α levels (p=0.02). Compared with responders, patients failing to respond to standard-dose MTX had increased TNF-α levels at baseline (p=0.02) and at 3 months (p=0.005). Reductions in JADAS by 6 months were observed following either the addition of ETN (p=0.009) or an increase in MTX dose (p=0.007), but the addition of ETN was associated with a median 7-fold increase in TNF-α levels (p=0.003) that corresponded with clinical response.

CONCLUSION

Plasma cytokine levels were responsive to MTX therapy in patients with JIA, but only TNF-α and IL-6 levels were consistently associated with disease activity and therapeutic response. Increased TNF-α levels at baseline were associated with failure to respond to standard-dose MTX and the need for more aggressive drug therapy. Initiation of ETN resulted in increased TNF-α levels that corresponded with therapeutic response, suggesting a potential clinical benefit of monitoring TNF-α levels as a pharmacodynamic marker of etanercept activity.

Characteristic elevation of soluble TNF receptor II : I ratio in macrophage activation syndrome with systemic juvenile idiopathic arthritis

To investigate the clinical significance of soluble tumour necrosis factor receptor (sTNF-R) II/I ratio as an indicator of the diagnosis of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (s-JIA), we measured the serum sTNF-RI and II levels in 117 patients with s-JIA, including 29 patients with MAS, 15 with Epstein-Barr virus-induced haemophagocytic lymphohistiocytosis (EBV-HLH), 15 with Kawasaki disease (KD) and 28 healthy controls (HCs). We determined their correlation with measurements of disease activity and severity. Furthermore, we measured serum interleukin (IL)-18 levels in patients with EBV-HLH and compared these in levels in patients with MAS. The sTNF-RII/I ratio was elevated significantly in MAS and EBV-HLH patients compared with those in the acute phase of s-JIA and KD patients, whereas there were no significant differences between HCs and those in the acute phase of s-JIA. The sTNF-RII/I ratio increased profoundly as MAS developed and correlated positively with disease activity. Serum IL-18 levels were elevated significantly in MAS patients compared with EBV-HLH patients. The monitoring of serum IL-18 and sTNF-RII/I might be useful for the diagnosis of MAS and the differentiation between MAS and EBV-HLH.

Comparison of drug and cell-based delivery: engineered adult mesenchymal stem cells expressing soluble tumor necrosis factor receptor II prevent arthritis in mouse and rat animal models

Rheumatoid arthritis (RA) is a systemic autoimmune disease with unknown etiology where tumor necrosis factor-α (TNFα) plays a critical role. Etanercept, a recombinant fusion protein of human soluble tumor necrosis factor receptor II (hsTNFR) linked to the Fc portion of human IgG1, is used to treat RA based on the rationale that sTNFR binds TNFα and blocks TNFα-mediated inflammation. We compared hsTNFR protein delivery from genetically engineered human mesenchymal stem cells (hMSCs) with etanercept. Blocking TNFα-dependent intercellular adhesion molecule-1 expression on transduced hMSCs and inhibition of nitric oxide production from TNFα-treated bovine chondrocytes by conditioned culture media from transduced hMSCs demonstrated the functionality of the hsTNFR construction. Implanted hsTNFR-transduced mesenchymal stem cells (MSCs) reduced mouse serum circulating TNFα generated from either implanted TNFα-expressing cells or lipopolysaccharide induction more effectively than etanercept (TNFα, 100%; interleukin [IL]-1α, 90%; and IL-6, 60% within 6 hours), suggesting faster clearance of the soluble tumor necrosis factor receptor (sTNFR)-TNFα complex from the animals. In vivo efficacy of sTNFR-transduced MSCs was illustrated in two (immune-deficient and immune-competent) arthritic rodent models. In the antibody-induced arthritis BalbC/SCID mouse model, intramuscular injection of hsTNFR-transduced hMSCs reduced joint inflammation by 90% compared with untransduced hMSCs; in the collagen-induced arthritis Fischer rat model, both sTNFR-transduced rat MSCs and etanercept inhibited joint inflammation by 30%. In vitro chondrogenesis assays showed the ability of TNFα and IL1α, but not interferon γ, to inhibit hMSC differentiation to chondrocytes, illustrating an additional negative role for inflammatory cytokines in joint repair. The data support the utility of hMSCs as therapeutic gene delivery vehicles and their potential to be used in alleviating inflammation within the arthritic joint.

Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) encompasses a complex group of disorders with arthritis as a common feature. This article provides the pediatrician with a review of the epidemiology, classification, clinical manifestations, and complications of JIA. It also provides an update on the current understanding of the cause of JIA and recent developments in management and a recent review of the long-term outcome in JIA.

Tumor necrosis factor inhibitors in the management of juvenile idiopathic arthritis: an evidence-based review

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disorder of unknown origin that is often treated with a variety of disease-modifying agents. Tumor necrosis factor (TNF) inhibitors are a group of genetically engineered biologic agents that target the proinflammatory cytokine TNF. This review focuses on the use of TNF inhibitors in JIA. Etanercept was the first TNF inhibitor approved for use in children with moderate to severe polyarticular-course JIA following encouraging results from a randomized, double-blind, placebo-controlled, multicenter trial in children. Open-label extension studies of the original trial involving 8 years of follow-up demonstrated the long-term safety and efficacy of etanercept in children. Other studies from established registries also corroborate the safety of etanercept in JIA. The second TNF inhibitor to be approved for use in JIA is adalimumab following recent favorable results from another randomized, placebo-controlled, multicenter study in polyarticular-course JIA. While infliximab is not approved by the US FDA for use in JIA, it is frequently used in clinical practice for this indication. However, because the chimeric structure of infliximab incorporates murine components, it has the potential for allergic and infusion reactions. Patient responses to individual TNF inhibitors may vary depending on concomitant medications such as methotrexate, and also on the category of JIA.

Abnormal expression of the genes involved in cytokine networks and mitochondrial function in systemic juvenile idiopathic arthritis identified by DNA microarray analysis

OBJECTIVES

Systemic juvenile idiopathic arthritis (sJIA) is a rheumatic disease in childhood characterised by systemic symptoms and a relatively poor prognosis. Peripheral leukocytes are thought to play a pathological role in sJIA although the exact cause of the disease is still obscure. In this study, we aimed to clarify cellular functional abnormalities in sJIA.

METHODS

We analysed the gene expression profile in peripheral leukocytes from 51 patients with sJIA, 6 patients with polyarticular type JIA (polyJIA) and 8 healthy children utilising DNA microarrays. Gene ontology analysis and network analysis were performed on the genes differentially expressed in sJIA to clarify the cellular functional abnormalities.

RESULT

A total of 3491 genes were differentially expressed in patients with sJIA compared to healthy individuals. They were functionally categorised mainly into a defence response group and a metabolism group according to gene ontology, suggesting the possible abnormalities in these functions. In the defence response group, molecules predominantly constituting interferon (IFN)gamma and tumour necrosis factor (TNF) network cascades were upregulated. In the metabolism group, oxidative phosphorylation-related genes were downregulated, suggesting a mitochondrial disorder. Expression of mitochondrial DNA-encoded genes including cytochrome c oxidase subunit 1(MT-CO1) and MT-CO2 were suppressed in patients with sJIA but not in patients with polyJIA or healthy children. However, nuclear DNA-encoded cytochrome c oxidases were intact.

CONCLUSION

Our findings suggest that sJIA is not only an immunological disease but also a metabolic disease involving mitochondria disorder.

Modeling the impact of COPD on the brain

Previous studies have shown that COPD adversely affects distant organs and body systems, including the brain. This pilot study aims to model the relationships between respiratory insufficiency and domains related to brain function, including low mood, subtly impaired cognition, systemic inflammation, and brain structural and neurochemical abnormalities. Nine healthy controls were compared with 18 age- and education-matched medically stable-COPD patients, half of whom were oxygen-dependent. Measures included depression, anxiety, cognition, health status, spirometry, oximetry at rest and during 6-minute walk, and resting plasma cytokines and soluble receptors, brain MRI, and MR spectroscopy in regions relevant to mood and cognition. ANOVA was used to compare controls with patients and with COPD subgroups (oxygen users [n = 9] and nonusers [n = 9]), and only variables showing group differences at p < or = 0.05 were included in multiple regressions controlling for age, gender, and education to develop the final model. Controls and COPD patients differed significantly in global cognition and memory, mood, and soluble TNFR1 levels but not brain structural or neurochemical measures. Multiple regressions identified pathways linking disease severity with impaired performance on sensitive cognitive processing measures, mediated through oxygen dependence, and with systemic inflammation (TNFR1), related through poor 6-minute walk performance. Oxygen desaturation with activity was related to indicators of brain tissue damage (increased frontal choline, which in turn was associated with subcortical white matter attenuation). This empirically derived model provides a conceptual framework for future studies of clinical interventions to protect the brain in patients with COPD, such as earlier oxygen supplementation for patients with desaturation during everyday activities.

Tumor necrosis factor receptor-associated periodic syndrome mimicking systemic juvenile idiopathic arthritis

BACKGROUND

We report two cases of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) in patients in whom systemic juvenile idiopathic arthritis (JIA) had initially been diagnosed or suspected. One patient, given a diagnosis of systemic JIA, was a 10-year-old boy who had presented with recurrent episodes of spike-fever, skin rash, arthritis, and myalgia. The other patient was his 7-year-old sister, who presented with similar symptoms and was suspected of having systemic JIA.

METHODS

Serum levels of soluble tumor necrosis factor receptor super family 1A (TNFRSF1A), TNF-alpha, Interleukin (IL) -6, and C-reactive protein (CRP) were measured in two siblings and JIA patients. In addition, DNA sequencing of the TNFRSF1A gene in two siblings was also performed.

RESULTS

A detailed family history showed that their mother had an episode of recurrent fever, arthritis, and myalgia with an increased serum CRP after the delivery of a daughter. Both siblings had serum levels of soluble TNFRSF1A that were below the normal reference range, and that did not reach a level corresponding to that of systemic JIA. On TNFRSF1A gene analysis, a single missense mutation resulting in C30Y was found in both siblings.

CONCLUSIONS

Based on the clinical features and the TNFRSF1A mutation, both siblings were given a diagnosis of TRAPS. The serum levels of soluble TNFRSF1A, measured along with the CRP level, may be a useful screening marker for differentiating TRAPS from systemic JIA.

Neutrophils from patients withTNFRSF1A mutations display resistance to tumor necrosis factor–induced apoptosis: Pathogenetic and clinical implications

OBJECTIVE

To explore tumor necrosis factor (TNF)-induced apoptosis in neutrophils from patients with TNF receptor-associated periodic syndrome (TRAPS) and to correlate the results with the different kinds of TNFRSF1A mutations.

METHODS

Two hundred sixty-five patients with clinically suspected inherited autoinflammatory syndrome were screened for mutations of the TNFRSF1A gene. Neutrophils were isolated from heparinized blood by dextran sedimentation and incubated with and without cycloheximide (CHX) and TNFalpha. Cell apoptosis was assessed by human annexin V binding, and caspase 8 activation was assessed by flow cytometry.

RESULTS

Twenty-one patients were found to carry a variant of the TNFRSF1A gene: 13 patients had an R92Q substitution, and 8 patients presented other missense substitutions, 1 splicing mutation, and 1 in-frame interstitial deletion. Neutrophil stimulation with TNF and CHX was associated with induction of apoptosis in 12 normal controls and in 10 subjects with the R92Q mutation. Conversely, neutrophils from 8 TRAPS patients with mutations of cysteine or threonine residues or interstitial deletion did not show any induction of apoptosis after stimulation. The incidence of the R92Q mutation among patients with recurrent autoinflammatory syndromes was similar to that observed in the normal population.

CONCLUSION

Resistance to TNF-mediated apoptosis is a feature in TRAPS patients who have mutations of cysteine residues or interstitial deletion, and may play a pathogenic role. The R92Q mutation does not appear to be significantly associated with TRAPS.

Juvenile idiopathic arthritis

One of the most enigmatic problems in rheumatology has been juvenile idiopathic arthritis (JIA). Firstly, the classification has often depended on clinical features that have variations between patients. Secondly, there are different classification schemes in usage and there are few objective serologic tests that help to resolve the differences between the criteria sets. Thirdly, only recently have significant advances been made in understanding the immunology and immunopathology of JIA and, in particular, new treatment options. In this review, we will define the historical basis of JIA and emphasize not only the clinical features, but also the immunological characteristics, the pathogenesis, and treatment options. We will also discuss, in particular, quality of life, psychosocial functioning, socioeconomic outcomes and the difficult area of mortality. Finally, this review will attempt to bridge genetic observations with clinical presentation. JIA represents a relatively common syndrome of pediatric onset rheumatologic disease and a better understanding of the clinical definition, the relationship to autoimmunity, and novel treatments with biologic agents are critical for improved patient care.

Plasma TNF binding capacity in patients with juvenile idiopathic arthritis

INTRODUCTION

Tumour necrosis factor (TNF)-alpha and TNF-beta, also called lymphotoxin (LT), are bound by soluble truncated TNF receptors (sTNFRI and II) that are released from cell surfaces and act as natural inhibitors of TNF-induced inflammation. We investigated the plasma levels of sTNFRI and II in parallel with LT binding capacity (LTBC) in 44 patients with juvenile chronic arthritis (JIA).

METHODS

LTBC was determined by spiking diluted plasma samples with 1000 pg/ml of human recombinant LT. Detectable LT was measured by an in-house ELISA and LTBC was expressed in arbitrary units (AU) as the percentage value of bound LT to added LT. The levels of sTNFRI and-II were measured by ELISA (R&D).

RESULTS

We found slightly reduced sTNFRI and II levels in JIA patients (n=44) compared with healthy controls sTNFRI: 1118 pg/ml (656-2074) [mean (range)] vs. 1262 pg/ml (819-2280) p=0.015; sTNFRII: 1953 pg/ml (889-4476) vs. 2311 pg/ml (1309-4186) p=0.008. The sTNFRI levels correlated positively with morning stiffness (r=0.30, p=0.044), physician's global assessment (r=0.39; p=0.009) and CRP (r=0.43; p=0.0048). sTNFRII did not correlate with measures of disease activity. In contrast, patient LTBC values were elevated compared to controls: 44 AU (36-52) vs. 31 AU (13-41) [mean (range)], p<0.0001, but did not correlate with disease activity.

CONCLUSION

Despite overall slightly reduced plasma levels of sTNFRI and II, the capacity to bind TNF appeared to be increased in plasma samples from JIA patients.

Increased circulating interleukin-12 (IL-12) p40 in pulmonary sarcoidosis

In sarcoidosis, a T helper 1 (Th1) response is an essential event and the up-regulation of interleukin-12 (IL-12) has been detected in affected disease sites. In order to investigate the clinical usefulness of circulating IL-12, we measured the serum concentrations of IL-12 by ELISA and performed immunohistochemistry using specific MoAbs for IL-12 in the lungs and scalene lymph nodes of patients with sarcoidosis. The serum concentration of IL-12 p40 was detectable in all 45 patients with pulmonary sarcoidosis and 18 normal controls, whereas that of IL-12 p70 was undetectable. The serum concentrations of IL-12 p40 in pulmonary sarcoidosis were significantly higher than those of the normal controls, especially in cases with abnormal intrathoracic findings detected by chest roentogenogram. The serum concentrations of interferon-gamma (IFN-gamma) also increased compared with those of normal controls and there was a significant positive correlation between the serum concentrations of IL-12 p40 and IFN-gamma. Furthermore, serum angiotensin-converting enzyme (ACE) and lysozyme, which are known to be useful markers for disease activity in sarcoidosis, correlated well with the serum concentrations of IL-12 p40. The positive 67Ga scan group (for lung field) had significantly elevated serum IL-12 p40 levels compared with those of the negative group. No bioactivity of IL-12 p70 was detected in three sarcoid cases sera by using the IL-12 responsive cell line. Finally, the immunohistochemical approach revealed that IL-12 p40 was expressed in the epithelioid cells and macrophages of sarcoid lungs and lymph nodes. We concluded that the production of IL-12 p40 was far greater in the sera and we have demonstrated this to be a useful clinical marker for disease activity and the Th1 response in pulmonary sarcoidosis.

Cytokines and juvenile idiopathic arthritis

Cytokines are a large group of polypeptides and small proteins that are effector molecules for cells involved in immune and inflammatory responses. There are agonists and antagonists that interact with each other to maintain a dynamic equilibrium, and ensure eventual recovery of any perturbation, for example, by trauma or infection, of the network toward inflammation. The imbalance between pro- and anti-inflammatory cytokines and the T helper cell subtypes is considered important in the pathogenesis of autoimmune diseases, including juvenile idiopathic arthritis. The measurement of cytokines and chemotactic cytokines in body fluids and synovial tissue has provided insight into the type of immune and inflammatory reaction and the possible presence or absence of regulation. Differences between subtypes of juvenile idiopathic arthritis have been identified with these measurements. But cytokine measurements in serum are not useful for diagnostic purposes, because of the variability during 24 hours, the collection and assay methods, as well as the ease of degradation for most cytokines. The recent interest in the genetic polymorphisms of cytokine genes and their association with juvenile idiopathic arthritis has provided association with a number of cytokine alleles. Confirmation of linkage with disease is only available for tumor necrosis factor and interleukin-6 at present. These genetic variants may be the basis of genetic susceptibility to the persistent imbalance in the inflammatory and immune networks, and determine the phenotype and severity of disease.

Serum and synovial fluid concentration of vascular endothelial growth factor in juvenile idiopathic arthritides

OBJECTIVE

To evaluate the role of vascular endothelial growth factor (VEGF) in the pathogenesis of local joint inflammation in juvenile idiopathic arthritis (JIA).

METHODS

Sera from 50 patients affected with JIA and 10 age-matched healthy controls were tested with a commercial ELISA for VEGF. Corresponding synovial fluid (SF) concentrations of VEGF and p75 soluble tumour necrosis factor receptor (sTNFR) were evaluated in 20 active JIA patients.

RESULTS

Serum concentrations of VEGF were significantly higher in patients with active polyarticular disease than in patients with active and inactive oligoarticular disease and healthy controls. In JIA patients, serum concentrations of VEGF displayed a significant correlation with a number of clinical and laboratory parameters of disease activity. VEGF concentrations in SF were significantly higher than those detected in corresponding sera. Moreover, a clear correlation was found between corresponding SF and serum VEGF concentrations. In SF, VEGF showed a strong positive correlation with p75 sTNFR.

CONCLUSIONS

Concentrations of VEGF in SF in patients with JIA are higher than corresponding serum concentrations, suggesting that this pro-angiogenic factor may have a major role in the outgrowth of hyperplastic pannus and tissue damage at the site of tissue inflammation.

Moderate-intensity regular exercise decreases serum tumor necrosis factor-alpha and HbA1c levels in healthy women

OBJECTIVE

To evaluate the effects of moderate-intensity regular exercise on serum levels of tumor necrosis factor-alpha (TNF-alpha) and glucose and lipid metabolism parameters.

DESIGN

Longitudinal intervention study of a 5 month exercise training program (30-45 min/day, 4-5 days/week).

SUBJECTS

Forty-one healthy Japanese women aged 41-69 y at baseline; 27 participants in the exercise program.

MEASUREMENTS

Body mass index (BMI), waist-to-hip ratio (WHR), percentage body fat, and fasting levels for serum TNF-alpha, serum soluble TNF receptor p55 (TNF-RI) and TNF receptor p75 (TNF-RII), serum lipids, HbA1c, and serum insulin before and after exercise.

RESULTS

In overweight to obese subjects, serum levels of TNF-alpha, TNF-RI and TNF-RII were significantly higher than those in lean subjects. There were significant correlations between log serum TNF-alpha and BMI, percentage body fat, WHR, HbA1c and log insulin. TNF-RI was significantly correlated with BMI, percentage body fat, WHR and HbA1c. TNF-RII was also associated with BMI, percentage body fat and WHR. However, the correlation between TNF-RII and HbA1c did not reach statistical significance. Neither TNF-RI nor TNF-RII was correlated with log insulin. In contrast, TNF-alpha, TNF-RI and TNF-RII were negatively correlated with HDL cholesterol. Regular exercise decreased BMI, percentage body fat, HbA1c, serum TNF-alpha, TNF-RI and TNF-RII and increased HDL cholesterol levels. In addition, exercise-induced change in serum TNF-alpha was independently correlated with changes in HbA1c and serum insulin, after being adjusted for the change in fat-free mass.

CONCLUSION

Changes in serum TNF-alpha that occur with exercise may play an important role in improving glucose metabolism parameters.

Autoantibodies to DEK oncoprotein in human inflammatory disease

OBJECTIVE

To evaluate the specificity of anti-DEK antibodies for juvenile rheumatoid arthritis (JRA).

METHODS

Anti-DEK autoantibodies were measured by enzyme-linked immunosorbent assay (ELISA) using affinity-purified his6-DEK fusion protein. Sera from 639 subjects (417 patients with systemic autoimmune disease, 13 with sarcoidosis, 44 with pulmonary tuberculosis, 125 with uveitis, and 6 with scleritis, and 34 healthy control subjects) were screened. Reactivity was verified by immunoblotting and immunoprecipitation studies using baculovirus-expressed human DEK.

RESULTS

Anti-DEK activity was found at the following frequencies: JRA 39.4% (n = 71), systemic lupus erythematosus (SLE) 25.1% (n = 216), sarcoidosis 46.2% (n = 13), rheumatoid arthritis 15.5% (n = 71), systemic sclerosis 36.0% (n = 22), polymyositis 6.2% (n = 16), and adult Still's disease 0% (n = 21). Autoantibodies also were detected in 9.1% of tuberculosis sera (n = 44), but were undetectable in sera from the 34 healthy controls. Western blot and immunoprecipitation assay results correlated well with the ELISA findings. In general, levels of anti-DEK autoantibodies were higher in SLE than in other patient subsets, including JRA.

CONCLUSION

Anti-DEK autoantibodies are less specific for JRA than previously believed. They are produced in association with a variety of inflammatory conditions, many of which are associated with granuloma formation and/or predominant Thl cytokine production. Anti-DEK antibodies may be a marker for a subset of autoimmunity associated with interferon-gamma production rather than a particular disease subset.

Immunopathogenesis of juvenile rheumatoid arthritis

The immunopathogenic mechanisms of juvenile rheumatoid arthritis (JRA) have been debated. A possible cellular-mediated hypothesis versus a possible B cell hyperreactivity have been entertained. This review will focus on some recent cellular work in JRA and also further evaluation of cytokine levels and their role in inflammation in JRA. Recent studies have evaluated the interrelationship of Th1/Th2 immune responses in the immunopathogenesis of JRA, and their effect on cytokine release. Studies have indicated a pro-inflammatory response in systemic-onset JRA manifested by increased secretion of interleukin-6, whereas an anti-inflammatory response has been noted by increases of IL-4 mRNA and IL-10 mRNA in pauciarticular-onset JRA. The continued finding of elevated levels of tumor necrosis factor-alpha (TNF-alpha) and its receptors in association with inflammatory activity has been seen. The recent use of a TNF fusion protein to block TNF-alpha activity in JRA has further contributed to this finding. Further studies on specific cytokines will be helpful in the future in trying to determine the different roles cytokines play in JRA subtypes and would contribute to the development of better therapeutic regimens.

Soluble cytokine receptors: basic immunology and clinical applications

Cytokine activity is tightly regulated at multiple levels. Soluble cytokine receptors (sCR) contribute to the regulation of cytokine activity by modulating the ability of cytokines to bind their membrane receptors and generating a response. Endogenous sCR are generated by proteolytic cleavage or "shedding" of the membrane receptor and/or by translation from alternatively spliced messages different from those encoding the membrane forms. The resulting soluble receptors retain their ligand-binding ability and with some exceptions act as competitive inhibitors of the binding and biologic activity of their ligand, both in vitro and in vivo. However, sCR can also have certain effects on cytokines, such as structural stabilization, protection from proteolysis, and prolonged in vivo half-life, which are consistent with an added role as carrier proteins, and which may under some conditions result in potentiation of cytokine activity in vivo. The exact contribution of endogenous sCR to the regulation of immune or inflammatory responses has not yet been established unequivocally. Nonetheless, evidence indicates that the levels of certain sCR in serum and biological fluids correlate with immunological activation and/or disease activity in a variety of clinical conditions. Hence, sCR levels may have significant value as markers in disease management and prognosis. Moreover, sCR have also shown promising potential as immunotherapeutic agents for a variety of clinical disorders, including sepsis, inflammation, and autoimmune and malignant diseases.

Enhancement of the surface expression of tumor necrosis factor alpha (TNFalpha) but not the p55 TNFalpha receptor in the THP-1 monocytic cell line by matrix metalloprotease inhibitors

The monocytic cell line THP-1 can be induced to express and release tumor necrosis factor alpha (TNFalpha) and both TNFalpha receptors (p55 and p75) upon exposure to bacterial lipopolysaccharide (LPS). The broad-spectrum matrix metalloprotease (MMP) inhibitors [4-(N-hydroxyamino)-2R-isobutyl-3S-(phenylthiomethyl)succinyl]-L-p henylalanine-N-methylamide (GI-129471) and marimastat [2S-[N4(R*),2R*,3S*]]-N4[2,2-dimethyl-1-[(methylamino)carbonyl]propyl]-N 1,2-dihydroxy-3-(2-methylpropyl)butanediamide (BB-2516) were effective inhibitors of LPS-induced TNFalpha (soluble) release with IC50 values of 0.2 and 4.0 microM, respectively. Upon LPS stimulation, the expression of pro-TNFalpha (membrane associated) on the cell surface (FACS analysis) could not be observed. However, in the presence of GI-129471, a concentration-dependent increase in TNFalpha surface expression was observed. Peak expression (percentage of cells expressing pro-TNFalpha and mean fluorescence units) in the presence of GI-129471 was at 2 hr, and steadily declined to return to near control levels by 8 hr. This time course was similar to TNFalpha release, which also peaked at 2-4 hr after LPS exposure and then declined. Stimulation of THP-1 cells with LPS + phorbol myristate acetate increased the percentage of cells expressing pro-TNFalpha by 10-fold. In the presence of GI-129471, these increases were augmented further and peaked between 2 and 4 hr, but also returned to near control levels of expression by 24 hr. This was in contrast to the release of soluble TNFalpha, which continued to accumulate over a 24-hr time course. TNFalpha receptor I (p55, TNFRI) and II (p75, TNFRII) shedding was also inhibited by GI-129471 (IC50 = 1.5 and 3.1 microM, respectively) and BB-2516 (IC50 = 14 and 15 microM, respectively). Unlike pro-TNFalpha surface expression, surface expression of both TNFalpha receptors steadily increased over 72 hr. In contrast to pro-TNFalpha surface expression, TNFRI surface expression was not augmented by these MMP inhibitors in THP-1 cells after LPS stimulation. Surface expression of TNFRII was augmented by these MMP inhibitors. These results suggest that even in the continued presence of LPS stimulation and an inhibitor of TNFalpha processing, the augmented surface expression of TNFalpha is transient. The potential "deleterious" implications of high levels of surface pro-TNFalpha expression in the presence of these inhibitors may be lessened by its transient nature.

Circulating tumor necrosis factor-alpha concentrations in a native Canadian population with high rates of type 2 diabetes mellitus

Recent research suggests that tumor necrosis factor-alpha (TNF alpha) may play an important role in obesity-associated insulin resistance and diabetes. We studied the relationship between TNF alpha and the anthropometric and physiological variables associated with insulin resistance and diabetes in an isolated Native Canadian population with very high rates of type 2 diabetes mellitus (DM). A stratified random sample (n = 80) of participants was selected from a population-based survey designed to determine the prevalence of type 2 DM and its associated risk factors. Fasting blood samples for glucose, insulin, triglyceride, leptin, and TNF alpha were collected; a 75-g oral glucose tolerance test was administered, and a second blood sample was drawn after 120 min. Insulin resistance was estimated using the homeostasis assessment (HOMA) model. Systolic and diastolic blood pressure (BP), height, weight, and waist and hip circumferences were determined, and percent body fat was estimated using biological impedance analysis. The relationship between circulating concentrations of TNF alpha and the other variables was assessed using Spearman correlation coefficients, analysis of covariance, and multiple linear regression. The mean TNF alpha concentration was 5.6 pg/mL (SD = 2.18) and ranged from 2.0-12.9 pg/mL, with no difference between men and women (P = 0.67). There were moderate, but statistically significant, correlations between TNF alpha and fasting insulin, HOMA insulin resistance (HOMA IR) waist circumference, fasting triglyceride, and systolic BP (r = 0.23-0.34; all P < 0.05); in all cases, coefficients for females were stronger than those for males. Individuals with normal glucose tolerance had lower log TNF alpha concentrations than those with impaired glucose tolerance or type 2 DM (both P = 0.03, adjusted for age and sex), although differences were not significant after adjustment for HOMA IR (both P > 0.25). Regression analysis indicated that log HOMA IR and log systolic BP were significant independent contributors to variations in log TNF alpha concentration (model r2 = 0.32). We conclude that in this homogeneous Native Canadian population, circulating TNF alpha concentrations are positively correlated with insulin resistance across a spectrum of glucose tolerance. The data suggest a possible role for TNF alpha in the pathophysiology of insulin resistance.

Serum interleukin 12 concentration in juvenile chronic arthritis

OBJECTIVES

The aim of this study was to evaluate serum interleukin (IL) 12 concentration in patients with juvenile chronic arthritis (JCA), according to disease subtype, activity, and duration. IL12 has been demonstrated to prime the selective expansion of T helper (Th) cells with a Th1-type pattern of cytokine production.

METHODS

Sixty eight serum samples from 50 JCA patients (12 systemic, 12 polyarticular, 26 pauciarticular), 20 serum samples from age matched healthy controls were tested with two different immunoassays specific for total IL12 (p40 and p70 heterodimer) and for IL12 (p70) heterodimer, respectively. The following disease activity parameters were evaluated: (a) presence of arthritis at least in one joint, (b) physician global estimate of disease activity, (c) disability index according to the Childhood Health Assessment Questionnaire (CHAQ), (d) C reactive protein (CRP).

RESULTS

Total IL12 (p40 and p70 heterodimer) was significantly higher in JCA active patients than in those on clinical remission and in healthy controls (p < 0.001). Conversely, detectable concentrations of IL12 (p70) heterodimer were found in three active JCA patients only. Moreover, total IL12 (p40 and p70 heterodimer) showed a significant negative correlation both with time from disease diagnosis (r = -0.29, p = 0.04) and, for the pauciarticular subgroup, with disease activity duration (r = -0.71, p < 0.001).

CONCLUSIONS

This study shows that the p40 moiety of IL12 is increased in serum samples from active JCA patients, especially in the earliest phases of the disease, whereas biological active IL12 (p70) heterodimer is virtually undetectable.

Cytokines in juvenile chronic arthritis

Cytokines are important mediators of the immune response as well as the inflammatory response. Those concerned primarily with cell growth, differentiation and activation of cells within the immune system are called interleukins, of which there are now 18. Exposure to antigenic and environmental stimuli causes T cells to differentiate and polarise into Th1 or 2-like cells with different cytokine profiles, and requiring different cytokines for differentiation (IL-12 for Th1 and IL-4 for Th2). Homeostasis is usually restored as these cells are mutually inhibitory. Autoimmune diseases have been associated with a persistent imbalance with more Th1-like cells, which are thought to contribute to pathology. With regard to juvenile chronic arthritis (JCA), there is some preliminary evidence of this imbalance in the oligoarticular subgroup. Imbalance of pro-inflammatory cytokines, IL-1 and TNF with their natural inhibitors has also been shown to contribute to persistence of inflammation. In the case of JCA, there has been some evidence that these imbalances could account for some of the disease phenotypes. Furthermore, the tendency to imbalance is genetically determined.

The cytokine network in juvenile chronic arthritis

This article is an overview of the cytokine network in patients with different types of juvenile chronic arthritis. The concept of the production of TH1-cell or TH2-cell differentiation as a result of cytokine production and the concept of the balance between proinflammatory and anti-inflammatory cytokines are explored. The balance of proinflammatory and anti-inflammatory cytokines could be altered as a result differences in the expression levels of a number of key cytokines and could be the critical events leading to chronic inflammation. Identifying molecular targets for intervention therapy to change the balance of the cytokine network is proposed.