Achievement of clinical remission in patients with juvenile idiopathic arthritis under a 2-10-year Etanercept exposure

The objective of this retrospective study was to record the achievement of clinical remission (CR) in juvenile idiopathic arthritis patients under a 2-10 years' administration of Etanercept (ETN) and to detect any variables associated with CR. Patients previously resistant to conventional regimens were enrolled. The annual impact of ETN was assessed by: (a) the American College of Rheumatology pediatric criteria (ACRpedi), (b) the pre- and posttreatment disease activity score (juvenile arthritis disease activity score [JADAS71]), and (c) Wallace's criteria for CR. A total of 41 patients (F: 31) were registered. The median age and disease duration at baseline were 10.6 and 4.17 years, respectively, and their disease course was mainly polyarthritis (32/41). In respect to baseline, there was an impressive JADAS71 reduction posttreatment, most prominent after the first year. From year 1 to 5, more than 50 % of the patients achieved and retained CR and 66 % reached an ACRpedi 70, whereas after the 5th year, no patient was withdrawn due to an ACRpedi <30. JADAS71 at baseline was not associated with the subsequent CR achievement. However, JADAS71 1-year posttreatment had a significant association with the CR of the second posttreatment year, (p = 0.028, OR 0.79; 95 % CI 0.63-0.98) and a similar trend was observed for the following years. These findings emphasize the sustained impact of ETN in the achievement of CR. A low JADAS71 score 1-year posttreatment, may be associated with the maintenance of CR over the next treatment year.

CLARITY - ChiLdhood Arthritis Risk factor Identification sTudY

BACKGROUND

The aetiology of juvenile idiopathic arthritis (JIA) is largely unknown. We have established a JIA biobank in Melbourne, Australia called CLARITY - ChiLdhood Arthritis Risk factor Identification sTudY, with the broad aim of identifying genomic and environmental disease risk factors. We present here study protocols, and a comparison of socio-demographic, pregnancy, birth and early life characteristics of cases and controls collected over the first 3 years of the study.

METHODS

Cases are children aged ≤18 years with a diagnosis of JIA by 16 years. Controls are healthy children aged ≤18 years, born in the state of Victoria, undergoing a minor elective surgical procedure. Participant families provide clinical, epidemiological and environmental data via questionnaire, and a blood sample is collected.

RESULTS

Clinical characteristics of cases (n = 262) are similar to those previously reported. Demographically, cases were from families of higher socio-economic status. After taking this into account, the residual pregnancy and perinatal profiles of cases were similar to control children. No case-control differences in breastfeeding commencement or duration were detected, nor was there evidence of increased case exposure to tobacco smoke in utero. At interview, cases were less likely to be exposed to active parental smoking, but disease-related changes to parent behaviour may partly underlie this.

CONCLUSIONS

We show that, after taking into account socio-economic status, CLARITY cases and controls are well matched on basic epidemiological characteristics. CLARITY represents a new study platform with which to generate new knowledge as to the environmental and biological risk factors for JIA.

Genome-scale case-control analysis of CD4+ T-cell DNA methylation in juvenile idiopathic arthritis reveals potential targets involved in disease

BACKGROUND

Juvenile Idiopathic Arthritis (JIA) is a complex autoimmune rheumatic disease of largely unknown cause. Evidence is growing that epigenetic variation, particularly DNA methylation, is associated with autoimmune disease. However, nothing is currently known about the potential role of aberrant DNA methylation in JIA. As a first step to addressing this knowledge gap, we have profiled DNA methylation in purified CD4+ T cells from JIA subjects and controls. Genomic DNA was isolated from peripheral blood CD4+ T cells from 14 oligoarticular and polyarticular JIA cases with active disease, and healthy age- and sex-matched controls. Genome-scale methylation analysis was carried out using the Illumina Infinium HumanMethylation27 BeadChip. Methylation data at >25,000 CpGs was compared in a case-control study design.

RESULTS

Methylation levels were significantly different (FDR adjusted p<0.1) at 145 loci. Removal of four samples exposed to methotrexate had a striking impact on the outcome of the analysis, reducing the number of differentially methylated loci to 11. The methotrexate-naive analysis identified reduced methylation at the gene encoding the pro-inflammatory cytokine IL32, which was subsequently replicated using a second analysis platform and a second set of case-control pairs.

CONCLUSIONS

Our data suggests that differential T cell DNA methylation may be a feature of JIA, and that reduced methylation at IL32 is associated with this disease. Further work in larger prospective and longitudinal sample collections is required to confirm these findings, assess whether the identified differences are causal or consequential of disease, and further investigate the epigenetic modifying properties of therapeutic regimens.

Membrane-bound toll-like receptors are overexpressed in peripheral blood and synovial fluid mononuclear cells of enthesitis-related arthritis category of juvenile idiopathic arthritis (JIA–ERA) patients and lead to secretion of inflammatory mediators

We examined expression and function of TLRs in enthesitis-related arthritis (ERA) patients. RNA levels of TLR1, TLR3, and TLRs 5–8 were measured in 24 ERA peripheral blood mononuclear cells (PBMC), 18 synovial fluid mononuclear cells (SFMC), and IRAK1, IRAK4, TRIF, TRAF3, and TRAF6 in 18 PBMC and 10 SFMC. IL-6 and IL-8 were measured in supernatants from ERA PBMC (n=7), SFMC (n=3), and healthy PBMC (n=5) cultured with ligands for TLR1/2 (Pam 3-cys), TLR3 (polyI:C), TLR5 (flagellin), and TLR2/6 (zymosan). TLRs 1, 3, 5, and 6 were measured in whole blood (n=20 ERA, seven healthy) and SFMC (n=2) by flow cytometry. ERA PBMC compared to healthy PBMC and SFMC compared to ERA PBMC had higher RNA expression of TLR1, TLR3, TLR5, TLR6, IRAK1, IRAK4, TRIF, TRAF3, and TRAF6. TLR7 and TLR8 RNA expression was similar in all study groups. IL-6 and IL-8 levels were higher in stimulated ERA SFMC compared to ERA PBMC and in ERA PBMC compared to control PBMC. TLRs 1, 3, and 6 were also overexpressed at the protein level.

Synovial fluid mononuclear cell gene expression profiling suggests dysregulation of innate immune genes in enthesitis-related arthritis patients

OBJECTIVE

Microarray studies have provided insight into the pathogenesis of systemic JIA and have opened new avenues for therapy. Data on the pathogenesis of the enthesitis-related arthritis (ERA) category of JIA are limited, thus we studied the expression profile of ERA patients' peripheral blood and SF mononuclear cells (PBMCs and SFMCs, respectively). PBMCs from healthy subjects were used as controls.

METHODS

RNA from PBMCs of ERA patients (n=17) and healthy controls (n=8) and seven ERA SFMCs were converted to labelled cRNA and hybridized to Illumina Human WG-6_v3_BeadChip chips. Expression profiles were analysed using GeneSpring software. Selected genes of interest were validated by real-time PCR.

RESULTS

There was no significant difference in PBMC gene expression of ERA and control groups. However, there was a significant difference between expression profiles of SFMCs and PBMCs of patients with ERA, with 131 genes being overexpressed and 216 being underexpressed in SFMCs. Among genes involved with immune function, cluster of differentiation (CD)1b, CD1d, MHC class II alpha and beta chain, and soluble CD163 were overexpressed, whereas genes related to NK cell function, namely, Granzyme H, killer cell lectin-like receptor subfamily F member 1, killer cell immunoglobulin-like receptor, three domains, long cytoplasmic tail (KIR3DL3), natural killer group 7 (NKG7) and other genes like CD244, CD248 and Fas apoptotic inhibitory molecule 3 (FAIM3) were underexpressed.

CONCLUSION

ERA SFMCs had a distinct gene expression profile from PBMCs and had higher expression of genes associated with antigen presentation, scavenger function, chemotaxis and proteases, whereas genes involved in NK cell function, cell adhesion and inhibitors of apoptosis were underexpressed.

Chronic smoke exposure induces rheumatoid factor and anti-heat shock protein 70 autoantibodies in susceptible mice and humans with lung disease

The impact of cigarette smoke (CS), a risk factor for rheumatoid arthritis (RA), on sauto-antibody production was studied in humans and mice with and without chronic lung disease (LD). Rheumatoid factor (RF), anti-cyclic citrullinated peptides (CCPs), and anti-HSP70 autoantibodies were measured in several mouse strains and in cohorts of smokers and nonsmokers with and without autoimmune disease. Chronic smoking-induced RFs in AKR/J mice, which are most susceptible to LD. RFs were identified in human smokers, preferentially in those with LD. Anti-HSP70 auto-antibodies were identified in CS-exposed AKR/J mice but not in ambient air exposed AKR/J controls. Whereas inflammation could induce anti-HSP70 IgM, smoke exposure promoted the switch to anti-HSP70 IgG autoantibodies. Elevated anti-CCP autoantibodies were not detected in CS-exposed mice or smokers. AKR/J splenocytes stimulated in vitro by immune complexes (ICs) of HSP70/anti-HSP70 antibodies produced RFs. The CD91 scavenger pathway was required as anti-CD91 blocked the HSP70-IC-induced RF response. Blocking Toll-like receptors did not influence the HSP70-IC-induced RFs. These studies identify both anti-HSP70 and RFs as serological markers of smoke-related LD in humans and mice. Identification of these autoantibodies could suggest a common environmental insult, namely CS, in a number of different disease settings.

Soluble receptor for advanced glycation endproducts is decreased in patients with juvenile idiopathic arthritis (ERA category) and inversely correlates with disease activity and S100A12 levels

OBJECTIVE

Membrane-bound receptor for advanced glycation endproducts (mRAGE) is overexpressed in response to increasing concentrations of its ligand (e.g., S100A12) and triggers an inflammatory immune response. In contrast, soluble RAGE (sRAGE) acts as a decoy receptor and downmodulates inflammation. Decreased sRAGE levels are associated with autoimmune diseases; however, limited data are available in juvenile idiopathic arthritis (JIA). We studied sRAGE levels in patients with JIA [enthesitis-related arthritis (ERA) category].

METHODS

sRAGE levels were estimated in the serum of patients with ERA JIA (n = 101), systemic-onset JIA and polyarticular JIA (n = 10 each), and healthy controls (n = 45). Synovial fluid (SF) sRAGE was measured in patients with ERA, rheumatoid arthritis, reactive arthritis, and osteoarthritis (n = 10). Levels of S100A12 were also measured. Twenty-four patients with ERA were followed for 4 months. Disease activity was assessed by swollen joint count (SJC), tender joint count (TJC), and erythrocyte sedimentation rate (ESR). All levels are expressed as median (range).

RESULTS

The serum sRAGE (pg/ml) level was significantly lower in patients compared to healthy controls [515 (64-1887) vs 1542 (627-3159); p < 0.0001]. In paired samples, SF had lower levels compared to corresponding plasma level [102 (51-799) vs 481 (134-1006); p < 0.0001]. The level of S100A12 (ng/ml) was higher in SF (1042; 573-1415) than serum (638; 208-779). Serum sRAGE correlated negatively with S100A12 levels (r = -0.474; p < 0.01.), ESR (r = -0.306; p < 0.01), and SJC (r = -0.237; p < 0.05), but not with TJC (r = -0.134; p = NS). The levels of sRAGE remained stable over time in patients with stable disease.

CONCLUSION

Levels of sRAGE are reduced in patients with ERA and correlate negatively with disease activity and S100A12 levels. sRAGE may be a modulator of inflammation in these patients.

Juvenile idiopathic arthritis: new insights into classification, measures of outcome, and pharmacotherapy

Significant advances have taken place in recent years in our understanding of the aetiopathogenesis, management, and clinical outcome of juvenile idiopathic arthritis (JIA). Fundamental to this advancement has been international collaborative efforts of the clinical scientific community and all those involved in the multidisciplinary care of children and young people with JIA. A key factor has been facing the challenge of developing a robust classification system for JIA, a clinically very heterogeneous group of conditions. JIA illustrates the necessity of disease classification to enable scientific progress but also the iterative and evolving process this entails. What is emerging is the imperative to improve our understanding of the biologic and genetic basis of JIA to underpin classification systems. Growing emphasis is centered on improved holistic care and outcome of children and young people with JIA. The expectation of patients, their families, and clinicians is the goal of inactive disease, remission off treatment, and the health and psychosocial well-being of young people emerging into adulthood. Validated tools that reflect these challenges are being developed, including those measuring disease improvement, flare, remission and minimal disease activity, health-related quality of life, and composite scores of activity and damage. Clinical research networks have driven success in developing an evidence-base for the treatment of JIA. Randomized comparative trials have demonstrated the benefit of early use of intra-articular corticosteroid injections, and the importance of methotrexate as the first-line, disease-modifying antirheumatic drug in JIA. The introduction of biologic therapies has opened a major new epoch in the medical management of JIA, with recent trials published on etanercept, infliximab, adalimumab, abatacept, tocilizumab, and anakinra. This review focuses on recent advances in JIA, especially developments in its classification, validation of appropriate measures of holistic outcome, and the specific contribution of established and newer pharmacologic agents available for treating children and young people.

Expression of Toll-like receptors 2 and 4 is increased in peripheral blood and synovial fluid monocytes of patients with enthesitis-related arthritis subtype of juvenile idiopathic arthritis

OBJECTIVE

Bacterial trigger possibly causes disease exacerbation in enthesitis-related arthritis (ERA) patients. Microbes initiate immune responses through Toll-like receptors (TLRs). We studied TLR expression on blood and SF monocytes and the effect of TLR ligands on peripheral blood (PB) mononuclear cells (PBMCs) in ERA patients.

METHODS

PB from 26 ERA patients and 19 healthy subjects and paired SF from 13 patients were collected. Dual-colour flow cytometry was done for TLR and CD14 expression. Results are expressed as median fluorescence intensity (MFI). Real-time PCR was done for TLRs. PBMCs were stimulated with lipopolysaccharide (LPS) or peptidoglycan and levels of IL-6 and MMP-3 measured in the culture supernatants.

RESULTS

PBMCs from ERA patients had higher expression of TLR-2 [MFI 295.5 (48.1-598) vs 179 (68.7-442); P < 0.05] and TLR-4 [MFI 448 (178-2581) vs 402 (229-569); P < 0.05] as compared with controls. TLR-9 expression showed no significant difference between the two groups. In paired samples, SF mononuclear cells (SFMCs) had higher expression of both TLR-2 [MFI 485 (141-1683) vs 353 (118-598); P < 0.05] and TLR-4 [MFI 1016 (42.4-3159) vs 513 (193-2581); P < 0.05] as compared with PBMCs. Difference in TLR-9 expression was not significant. TLR RNA expression data were similar. Patients' PBMCs produced more IL-6 (13.51 vs 6.54 ng/ml) and MMP-3 (61 vs 32.9 ng/ml) as compared with those of the controls, on stimulation by LPS. With peptidoglycan also, IL-6 (30.58 vs 10.84) and MMP-3 (102.54 vs 49.45) were higher than in controls.

CONCLUSION

Increased TLR-2 and TLR-4 expression on PBMCs and SFMCs may recognize microbial/endogenous ligands and up-regulate IL-6 and MMP-3 leading to disease exacerbation.