Using biology of disease to understand and guide therapy of JIA

Growth and the Growth Hormone-Insulin Like Growth Factor 1 Axis in Children With Chronic Inflammation: Current Evidence, Gaps in Knowledge, and Future Directions

Growth failure is frequently encountered in children with chronic inflammatory conditions like juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis. Delayed puberty and attenuated pubertal growth spurt are often seen during adolescence. The underlying inflammatory state mediated by proinflammatory cytokines, prolonged use of glucocorticoid, and suboptimal nutrition contribute to growth failure and pubertal abnormalities. These factors can impair growth by their effects on the GH-IGF axis and also directly at the level of the growth plate via alterations in chondrogenesis and local growth factor signaling. Recent studies on the impact of cytokines and glucocorticoid on the growth plate further advanced our understanding of growth failure in chronic disease and provided a biological rationale of growth promotion. Targeting cytokines using biological therapy may lead to improvement of growth in some of these children, but approximately one-third continue to grow slowly. There is increasing evidence that the use of relatively high-dose recombinant human GH may lead to partial catch-up growth in chronic inflammatory conditions, although long-term follow-up data are currently limited. In this review, we comprehensively review the growth abnormalities in children with juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis, systemic abnormalities of the GH-IGF axis, and growth plate perturbations. We also systematically reviewed all the current published studies of recombinant human GH in these conditions and discussed the role of recombinant human IGF-1.

Association of neopterin as a marker of immune system activation and juvenile rheumatoid arthritis activity

OBJECTIVE

To evaluate neopterin plasma concentrations in patients with active juvenile idiopathic arthritis (JIA) and correlate them with disease activity.

METHODS

Sixty patients diagnosed as active JIA, as well as another 60 apparently healthy age- and gender-matched children as controls, were recruited from the Pediatrics Allergy and Immunology Clinic, Ain Shams University. Disease activity was assessed by the Juvenile Arthritis Disease Activity Score 27 (JADAS-27). Laboratory investigations were performed for all patients, including determination of hemoglobin concentration (Hgb), erythrocyte sedimentation rate (ESR), and C-reactive protein. Serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and neopterin were measured.

RESULTS

Significant differences were found between JIA patients and controls with regard to the mean levels of Hgb, ESR, TNF-α, IL-6, and MCP-1 (p<0.05). A statistically significant higher mean level serum neopterin concentration (p<0.05) was found in JIA patients (20.43±8.73 nmol/L) than in controls (6.88±2.87 nmol/L) (p<0.05). Positive significant correlations were detected between serum neopterin and ESR, TNF-α, IL-6, MCP-1, and JADAS-27 (p<0.05). No correlation was found between serum neopterin and CRP (p>0.05). Multiple linear regression analysis showed that JADAS- 27 and ESR were the main variables associated with serum neopterin in JIA patients (p<0.05).

CONCLUSION

The elevation of plasma neopterin concentrations in early JIA patients may indicate stimulation of immune response. Serum neopterin can be used as a sensitive marker for assaying background inflammation and disease activity score in JIA patients.

Distinct effects of methotrexate and etanercept on the B cell compartment in patients with juvenile idiopathic arthritis

Objective

B cells have been shown to play an important role in the pathogenesis of rheumatoid arthritis and juvenile idiopathic arthritis (JIA). Current treatments include the disease-modifying antirheumatic drugs methotrexate (MTX) and tumor necrosis factor α inhibition with etanercept. This study was undertaken to determine how these drugs influence the B cell compartment in patients with JIA.

Methods

B cell subpopulations and follicular helper T (Tfh) cells in the peripheral blood of JIA patients were investigated by multicolor flow cytometry. Serum immunoglobulin and BAFF levels were determined by enzyme-linked immunosorbent assay.

Results

There was a significant decrease in transitional B cells and significantly lower serum immunoglobulin levels in patients receiving MTX than in untreated patients and those receiving etanercept. In contrast, etanercept treatment had no effect on most of the B cell subpopulations, but resulted in significantly lower BAFF levels and increased numbers of Tfh cells. Thus, our findings indicate an unexpected and previously unknown direct effect of low-dose MTX on B cells, whereas etanercept had a more indirect influence.

Conclusion

Our results contribute to a better understanding of the potency of MTX in autoantibody-mediated autoimmune disease and present a possible mechanism of prevention of the development of drug-induced antibodies to biologic agents. The finding that MTX and etanercept affect the B cell compartment differently supports the notion that combination therapy with etanercept and MTX is more effective than monotherapy.

Synovial membrane protein expression differs between juvenile idiopathic arthritis subtypes in early disease

Introduction

Juvenile idiopathic arthritis (JIA) is the most common rheumatological disease of childhood with a prevalence of around 1 in 1,000. Without appropriate treatment it can have devastating consequences including permanent disability from joint destruction and growth deformities. Disease aetiology remains unknown. Investigation of disease pathology at the level of the synovial membrane is required if we want to begin to understand the disease at the molecular and biochemical level. The synovial membrane proteome from early disease-stage, treatment naive JIA patients was compared between polyarticular and oligoarticular subgroups.

Methods

Protein was extracted from 15 newly diagnosed, treatment naive JIA synovial membrane biopsies and separated by two dimensional fluorescent difference in-gel electrophoresis. Proteins displaying a two-fold or greater change in expression levels between the two subgroups were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry with expression further verified by Western blotting and immunohistochemistry.

Results

Analysis of variance analysis (P ≤ 0.05) revealed 25 protein spots with a two-fold or greater difference in expression levels between polyarticular and oligoarticular patients. Hierarchical cluster analysis with Pearson ranked correlation revealed two distinctive clusters of proteins. Some of the proteins that were differentially expressed included: integrin alpha 2b (P = 0.04); fibrinogen D fragment (P = 0.005); collagen type VI (P = 0.03); fibrinogen gamma chain (P = 0.05) and peroxiredoxin 2 (P = 0.02). The identified proteins are involved in a number of different processes including platelet activation and the coagulation system.

Conclusions

The data indicate distinct synovial membrane proteome profiles between JIA subgroups at an early stage in the disease process. The identified proteins also provide insight into differentially perturbed pathways which could influence pathological events at the joint level.

Cost of biologics in the treatment of juvenile idiopathic arthritis: a factor not to be overlooked

Biologics are a promising treatment option for juvenile idiopathic arthritis (JIA) but drug costs are very high compared to conventional treatment. From a socioeconomic view the additional costs of new interventions should be weighed against their incremental health benefits compared to standard care. Therefore we evaluated data on cost-effectiveness of biologics in JIA. We searched Medline, Embase, and The York Centre for Reviews and Dissemination database for relevant literature. Current data show that biologics are reducing direct and indirect healthcare costs if one excludes the costs of the drug itself. The costs of biologics are more than ten times as high as conventional drug treatment. As a result of limited data, no comparison on cost-effectiveness between biologics could be performed. Although data on long-term cost-effectiveness of biologics are lacking, the expectation is that they will be cost-effective in the long-term. The idea behind this is that biologic treatment should be administered to patients that without these drugs would incur high direct and indirect costs due to continuous severe disease resulting in irreversible disabilities. In our opinion the best cost benefit could be gained if these patients receive biologic treatment introduced early in the disease. This is in order to minimize irreversible damage to the joints and minimize need for long-term biologic therapy by early suppression of the disease. To support these hypotheses future research is needed on long-term cost-effectiveness of all biologics used in JIA.

Infections in children and adolescents with juvenile idiopathic arthritis and inflammatory bowel disease treated with tumor necrosis factor-α inhibitors: systematic review of the literature

Tumor necrosis factor alpha (TNF-α) inhibitors are increasingly administered to children and adolescents with juvenile idiopathic arthritis (JIA) and pediatric inflammatory bowel disease (pIBD). Adult studies indicate that TNF-α inhibitors lead to an increased risk of serious infections compared to other disease-modifying antirheumatic drugs. We report herein a systematic literature review detailing the epidemiology and types of infections reported in children with JIA and pIBD treated with TNF-α inhibitors. The most frequently reported infections were mild and characterized as viral in etiology. Severe bacterial and fungal infections also occurred, but were less common and possibly associated with intrinsic risk factors and concurrent immunosuppressive therapy. Few pediatric patients developed Mycobacterium tuberculosis, likely due to effective screening. There were 8 infectious fatalities in children treated with TNF-α inhibitors. Overall, although rare, serious infections occur in immunocompromised children and adolescents with JIA and pIBD receiving TNF-α inhibitors.

Juvenile idiopathic arthritis

Juvenile idiopathic arthrithis (JIA) is the most common rheumatic disease of childhood.JIA is a chronic disease that is associated with periods of disease flares and periods of disease inactivity.Early, aggressive treatment with nonsteroidal anti-inflammatory drugs, intra-articular corticosteroid injections, or methotrexate, has significantly improved the outcome of most children who have JIA. Biologics have been shown to be both safe and effective for the treatment of more aggressive forms of arthritis and for uveitis. Long-term safety data of biologics is still uncertain. In the near future, it is hoped that genetic testing will allow earlier diagnosis of JIA as well as help predict the disease course of children who have JIA. Genetic analysis also may allow physicians to target therapies more effectively. It is hoped that development of more specific therapies will decrease overall immunosuppression and other associated toxicities.

Early juvenile idiopathic arthritis

Early juvenile idiopathic arthritis (JIA) is important to recognize as timely diagnosis and treatment improves prognosis. It is a misconception that complications of JIA arise only from long-standing disease and that children will outgrow it. Early aggressive treatment is the paradigm as early disease activity has long-term consequences. There are predictors of persistent disease and joint erosions that may identify patients at higher risk. Control of disease activity within the first 6 months of onset confers improved clinical course and outcomes. The treatment perspective is thus one of early aggressive treatment for induction of disease control and ultimately remission.

Evidence of the transient nature of the Th17 phenotype of CD4+CD161+ T cells in the synovial fluid of patients with juvenile idiopathic arthritis

OBJECTIVE

To investigate the phenotype and function of CD4+ T cells in synovial fluid (SF) from the affected joints of children with oligoarticular-onset juvenile idiopathic arthritis (JIA), and to establish a possible link with disease activity.

METHODS

CD4+ T cells were obtained from the peripheral blood (PB) and SF of 23 children with oligoarticular-onset JIA, as well as from the PB of 15 healthy children. The cells were analyzed for the expression of CXCR3, CCR6, and CD161 and for the production of interferon-γ and interleukin-17A (IL-17A). Spectratyping and clonotype analyses were performed to assess different T cell subsets.

RESULTS

The numbers of CD4+CD161+ cells showing either the Th1 or the Th17/Th1 phenotype were higher in the SF than in the PB of children with JIA. The few Th17 cells from JIA SF underwent a spontaneous shift to the Th1 phenotype in vitro, whereas Th17 cells from the PB of healthy children shifted only in the presence of JIA SF; this effect was neutralized by antibody blockade of IL-12 activity. Spectratyping and clonotype analyses showed a similar skewing of the T cell receptor V(β) repertoire in both CD161+ Th17 cells and CD161+ Th1 cells derived from the SF of the same JIA patient. The frequencies of CD4+CD161+ cells, particularly the Th17/Th1 cells, in the JIA SF positively correlated with the erythrocyte sedimentation rate and levels of C-reactive protein.

CONCLUSION

These findings suggest that a shifting of CD4+CD161+ T cells from Th17 to the Th17/Th1 or Th1 phenotype can occur in the SF of children with oligoarticular-onset JIA, and indicate that the accumulation of these cells is correlated with parameters of inflammation. Thus, the results support the hypothesis that these cells may play a role in JIA disease activity.

Juvenile idiopathic arthritis

Juvenile idiopathic arthritis is a heterogeneous group of diseases characterised by arthritis of unknown origin with onset before age of 16 years. Pivotal studies in the past 5 years have led to substantial progress in various areas, ranging from disease classification to new treatments. Gene expression profiling studies have identified different immune mechanisms in distinct subtypes of the disease, and can help to redefine disease classification criteria. Moreover, immunological studies have shown that systemic juvenile idiopathic arthritis is an acquired autoinflammatory disease, and have led to successful studies of both interleukin-1 and interleukin-6 blockade. In other forms of the disease, synovial inflammation is the consequence of a disturbed balance between proinflammatory effector cells (such as T-helper-17 cells), and anti-inflammatory regulatory cells (such as FOXP3-positive regulatory T cells). Moreover, specific soluble biomarkers (S100 proteins) can guide individual treatment. Altogether these new developments in genetics, immunology, and imaging are instrumental to better define, classify, and treat patients with juvenile idiopathic arthritis.

Abatacept in the treatment of polyarticular JIA: development, clinical utility, and place in therapy

Juvenile idiopathic arthritis (JIA) is a group of chronic arthritides affecting children. The polyarthritis category, affecting five or more joints in the first six months, tends to be more aggressive, leading to a destructive joint disease with significant morbidity, disability, and costs to society. The current treatment regimen, which primarily combines methotrexate and tumor necrosis factor alpha (TNF-α) blockade, still leaves a significant group of patients with an inadequate response. Therefore, the development of new medications that act via other mechanisms of pathogenesis is necessary. T cell lymphocytes are key components in the immune reaction in JIA. Cytotoxic lymphocyte-associated antigen-4 (CTLA-4) is a potent inhibitor of the costimulation pathway necessary to activate T cells. Abatacept is a recombinant fusion protein comprising the extracellular part of human CTLA-4 connected to a modified Fc part of IgG-1. In a randomized, multinational, blinded withdrawal study in children with polyarticular JIA, abatacept was found to be effective in about 70% of the patients, including 39% of TNF-α blockade failures, with significantly fewer flares occurring during the withdrawal phase than in patients receiving placebo. Abatacept continued to show good efficacy in a three-year open-label extension study, with a beneficial effect on health-related quality of life. The safety profile of abatacept is generally good. In 2008, the US Food and Drug Administration approved abatacept for use in children over six years of age with JIA and a polyarticular course. In 2010, the European Medicines Agency gave approval for abatacept to be used in combination with methotrexate for those who fail at least one disease-modifying medication and TNF-α blockade.

Emerging role of antioxidants in the protection of uveitis complications

Current understanding of the role of oxidative stress in ocular inflammatory diseases indicates that antioxidant therapy may be important to optimize the treatment. Recently investigated antioxidant therapies for ocular inflammatory diseases include various vitamins, plant products and reactive oxygen species scavengers. Oxidative stress plays a causative role in both non-infectious and infectious uveitis complications, and novel strategies to diminish tissue damage and dysfunction with antioxidant therapy may ameliorate visual complications. Preclinical studies with experimental animals and cultured cells demonstrate significant anti-inflammatory effects of a number of promising antioxidant agents. Many of these antioxidants are under clinical trial for various inflammatory diseases other than uveitis such as cardiovascular, rheumatoid arthritis and cancer. Well planned interventional clinical studies in the field of ocular inflammation will be necessary to sufficiently investigate the potential medical benefits of antioxidant therapies for uveitis. This review summarizes the recent investigations of novel antioxidant agents for ocular inflammation, with selected studies focused on uveitis.