Functional and prognostic relevance of the −173 polymorphism of the macrophage migration inhibitory factor gene in systemic‐onset juvenile idiopathic arthritis

Objective

To address the functional and prognostic relevance of the −173 single‐nucleotide G‐to‐C polymorphism of the macrophage migration inhibitory factor (MIF) gene in patients with systemic‐onset juvenile idiopathic arthritis (systemic‐onset JIA) by evaluating its association with serum and synovial fluid levels of MIF, with glucocorticoid requirement, and with the outcome of the disease.

Methods

A total of 136 patients with systemic‐onset JIA were studied, including 98 patients from the British Paediatric Rheumatology Study Group's National Repository for JIA and 38 patients who were followed up at the IRCCS Policlinico San Matteo (Pavia, Italy) and the IRCCS G. Gaslini (Genoa, Italy). The MIF‐173 polymorphism was genotyped using SnaPshot ddNTP primer extension and capillary electrophoresis. MIF levels were measured by enzyme‐linked immunosorbent assay. The evaluation of the association of the MIF‐173 polymorphism with outcome was performed only in Italian patients who were followed up for >5 years, by analyzing retrospectively 1) the number of joints with active arthritis and the number of joints with limited range of motion; 2) the score, at the last visit, on the Italian version of the Childhood Health Assessment Questionnaire (C‐HAQ); and 3) data concerning the treatment regimens during the disease course.

Results

Systemic‐onset JIA patients carrying a MIF‐173*C allele had serum and synovial fluid levels of MIF significantly higher than those in patients with the GG genotype. The duration of glucocorticoid treatment on a daily regimen was significantly longer in patients carrying a MIF‐173*C allele than in MIF‐173 GG homozygous patients. Moreover, the duration of clinical response to intraarticular injection of triamcinolone hexacetonide was significantly shorter in patients carrying a MIF‐173*C allele. At the last visit, the numbers of joints with active arthritis, the C‐HAQ scores, and the numbers of joints with limited range of motion were significantly higher in patients carrying the MIF‐173*C allele.

Conclusion

Our study shows the functional relevance of the MIF‐173 polymorphism and suggests that the MIF‐173*C allele is a predictor of poor outcome in systemic‐onset JIA.

     

Genetic loci contributing to hemophagocytic lymphohistiocytosis do not confer susceptibility to systemic‐onset juvenile idiopathic arthritis

Objective

To investigate whether single‐nucleotide polymorphisms (SNPs) within the genes PRF1, GZMB, UNC13D, and Rab27a, which are involved in natural killer cell dysfunction and known to contribute to the risk of hemophagocytic lymphohistiocytosis (HLH), confer an increased risk of susceptibility to systemic‐onset juvenile idiopathic arthritis (JIA).

Methods

Four SNPs across the PRF1 gene locus, 5 for GZMB, 7 for UNC13D, and 11 for Rab27a were investigated using MassArray genotyping in 133 UK Caucasian patients with systemic‐onset JIA and 384 ethnically matched unrelated control subjects. Additional control genotypes were accessed from the data generated by the Wellcome Trust Case Control Consortium.

Results

No significant association was found between any SNP within the 4 selected loci and systemic‐onset JIA, by either single‐point or haplotype analysis.

Conclusion

The results of this study demonstrate that genes involved in HLH do not confer a significant risk of association with systemic‐onset JIA.

     

Defective phosphorylation of interleukin‐18 receptor β causes impaired natural killer cell function in systemic‐onset juvenile idiopathic arthritis

Objective

Systemic‐onset juvenile idiopathic arthritis (JIA) is an autoimmune disease characterized by arthritis and systemic features. Its pathogenesis is still largely unknown. It is characterized immunologically by natural killer (NK) cell dysfunction and cytokine signatures that predominantly feature interleukin‐1 (IL‐1), IL‐6, and IL‐18. Since IL‐18 can drive NK cell function, we examined how the high plasma levels of this cytokine are related to the documented NK cell failure in these patients.

Methods

The phenotype and function of NK cells from 10 healthy control subjects, 15 patients with polyarticular JIA, and 15 patients with systemic‐onset JIA were characterized by staining and functional assays in vitro. IL‐18 ligand binding was visualized by fluorescence microscopy. Phosphorylation of several MAP kinases and the IL‐18 receptor β (IL‐18Rβ) were visualized by Western blotting.

Results

IL‐18 from the plasma of systemic‐onset JIA patients stimulated the activation of NK cells from healthy controls and bound its cognate receptor. However, NK cells from systemic‐onset JIA patients failed to up‐regulate cell‐mediated killing molecules, such as perforin and interferon‐γ, after IL‐18 stimulation. Furthermore, treatment with IL‐18 did not induce the phosphorylation of receptor‐activated MAP kinases in NK cells. Alternate activation of NK cells by IL‐12 induced NK cell cytotoxicity. We observed no additive effect of IL‐18 in combination with IL‐12 in systemic‐onset JIA patients. Immunoprecipitation of IL‐18Rβ showed that NK cells from systemic‐onset JIA could not phosphorylate this receptor after IL‐18 stimulation.

Conclusion

The mechanism of the impaired NK cell function in systemic‐onset JIA involves a defect in IL‐18Rβ phosphorylation. This observation has major implications for the understanding and, ultimately, the treatment of systemic‐onset JIA.

     

Positive association of SLC26A2 gene polymorphisms with susceptibility to systemic‐onset juvenile idiopathic arthritis

Objective

To investigate SLC26A2, the gene that causes diastrophic dysplasia, in juvenile idiopathic arthritis (JIA).

Methods

Nine polymorphisms across the SLC26A2 gene locus were investigated using MassArray genotyping in 826 UK Caucasian JIA cases and 617 ethnically matched healthy controls.

Results

Significant associations between multiple single‐nucleotide polymorphisms (SNPs) across SLC26A2 and systemic‐onset JIA were found. In each case, homozygosity for the minor allele conferred the increased risk of disease susceptibility: rs1541915 (odds ratio [OR] 2.3, 95% confidence interval [95% CI] 1.4–3.7, P = 0.0003), rs245056 (OR 2.8, 95% CI 1.7–4.6, P = 0.00002), rs245055 (OR 2.5, 95% CI 1.2–5.0, P = 0.004), rs245051 (OR 2.3, 95% CI 1.4–3.7, P = 0.0005), rs245076 (OR 2.7, 95% CI 1.3–5.4, P = 0.0015), and rs8073 (OR 2.3, 95% CI 0.9–5.6, P = 0.04).

Conclusion

These findings show the value of using monogenic disease loci as candidates for investigation in JIA. We identified a subgroup‐specific association between SNPs within the SLC26A2 gene and systemic‐onset JIA. Our findings also highlight systemic‐onset JIA as being a distinctly different disease from that in the other JIA subgroups.

     

The myeloid‐related proteins 8 and 14 complex,a novel ligand of toll‐like receptor 4, and interleukin‐1β form a positive feedback mechanism in systemic‐onset juvenile idiopathic arthritis

Objective

Fever of unknown origin is a diagnostic challenge in children, especially for differentiation of systemic‐onset juvenile idiopathic arthritis (systemic‐onset JIA) and infectious diseases. We undertook this study to analyze the relevance of myeloid‐related proteins (MRPs) 8 and 14, endogenous activators of Toll‐like receptor 4, in diagnosis and pathogenesis of systemic‐onset JIA.

Methods

Serum concentrations of MRP‐8/MRP‐14 were analyzed in 60 patients with systemic‐onset JIA, 85 patients with systemic infections, 40 patients with acute lymphoblastic leukemia, 5 patients with acute myeloblastic leukemia, 18 patients with neonatal‐onset multisystem inflammatory disease (NOMID), and 50 healthy controls. In addition, we investigated the link between interleukin‐1β (IL‐1β) and MRP‐8/MRP‐14 in systemic‐onset JIA.

Results

Serum MRP‐8/MRP‐14 concentrations were significantly (P < 0.001) elevated in patients with active systemic‐onset JIA (mean ± 95% confidence interval 14,920 ± 4,030 ng/ml) compared with those in healthy controls (340 ± 70 ng/ml), patients with systemic infections (2,640 ± 720 ng/ml), patients with acute lymphoblastic leukemia (650 ± 280 ng/ml), patients with acute myeloblastic leukemia (840 ± 940 ng/ml), and patients with NOMID (2,830 ± 580 ng/ml). In contrast to C‐reactive protein levels, MRP‐8/MRP‐14 concentrations distinguished systemic‐onset JIA from infections, with a specificity of 95%. MRP‐14 in serum of patients with systemic‐onset JIA was a strong inducer of IL‐1β expression in phagocytes.

Conclusion

The analysis of MRP‐8/MRP‐14 in serum is an excellent tool for the diagnosis of systemic‐onset JIA, allowing early differentiation between patients with systemic‐onset JIA and those with other inflammatory diseases. MRP‐8/MRP‐14 and IL‐1β represent a novel positive feedback mechanism activating phagocytes via 2 major signaling pathways of innate immunity during the pathogenesis of systemic‐onset JIA.

     

Wnt‐1–inducible signaling pathway protein 3 and susceptibility to juvenile idiopathic arthritis

Objective

To determine whether Wnt‐1–inducible signaling pathway protein 3 (WISP3) polymorphisms are associated with susceptibility to juvenile idiopathic arthritis (JIA).

Methods

The exons and the intron/exon boundaries of the WISP3 gene were mutation‐screened by denaturing high‐performance liquid chromatography in 86 patients with polyarticular‐course JIA (≥5 joints affected) and 15 controls. Seven single‐nucleotide polymorphisms (SNPs) were genotyped, using allelic discrimination, in a case–control study. Initially, 159 patients with polyarticular‐course JIA and 263 controls were studied, followed by study of a replication cohort of 181 patients with polyarticular‐course JIA and 355 controls. Available parents of patients with polyarticular‐course JIA were also genotyped. Finally, other JIA subgroups were studied (initial cohort, n = 218; replication cohort, n = 213). Single‐point and haplotype analysis was carried out.

Results

Positive association with SNP WISP3*G84A was observed and replicated in 2 cohorts of patients with polyarticular‐course JIA. Specifically, homozygosity of the mutant allele (WISP3*84AA) conferred a 2‐fold increased risk of disease susceptibility (for the initial cohort, odds ratio [OR] 2.1, 95% confidence interval [95% CI] 1.1–4.2, P = 0.03; for the replication cohort, OR 2.0, 95% CI 1.0–4.3, P = 0.05). Strong linkage disequilibrium was observed between SNPs; however, no haplotypic effect of an order of magnitude greater than the single‐point WISP3*G84A association was observed. Using the transmission disequilibrium test, a trend toward overtransmission of the WISP3*84A allele was observed in patients with polyarticular‐course JIA. No association of any WISP3 polymorphism was observed in the other JIA subgroups.

Conclusion

Association and replication of a polymorphism within the first intron of the WISP3 gene have been shown in patients with polyarticular‐course JIA. The functional significance of the WISP3*G84A SNP is being determined.

     

The diagnostic significance of soluble CD163 and soluble interleukin‐2 receptor α‐chain in macrophage activation syndrome and untreated new‐onset systemic juvenile idiopathic arthritis

Objective

Macrophage activation syndrome is characterized by an overwhelming inflammatory reaction driven by excessive expansion of T cells and hemophagocytic macrophages. Levels of soluble interleukin‐2 receptor α (sIL‐2Rα) and soluble CD163 (sCD163) may reflect the degree of activation and expansion of T cells and macrophages, respectively. This study was undertaken to assess the value of serum sIL‐2Rα and sCD163 in diagnosing acute macrophage activation syndrome complicating systemic juvenile idiopathic arthritis (JIA).

Methods

Enzyme‐linked immunosorbent assay was used to assess sIL‐2Rα and sCD163 levels in sera from 7 patients with acute macrophage activation syndrome complicating systemic JIA and 16 patients with untreated new‐onset systemic JIA. The results were correlated with clinical features of established macrophage activation syndrome, including ferritin levels.

Results

The median level of sIL‐2Rα in the patients with macrophage activation syndrome was 19,646 pg/ml (interquartile range [IQR] 18,128), compared with 3,787 pg/ml (IQR 3,762) in patients with systemic JIA (P = 0.003). Similarly, the median level of sCD163 in patients with macrophage activation syndrome was 23,000 ng/ml (IQR 14,191), compared with 5,480 ng/ml (IQR 2,635) in patients with systemic JIA (P = 0.017). In 5 of 16 patients with systemic JIA, serum levels of sIL‐2Rα or sCD163 were comparable with those in patients with acute macrophage activation syndrome. These patients had high inflammatory activity associated with a trend toward lower hemoglobin levels (P = 0.11), lower platelet counts, and significantly higher ferritin levels (P = 0.02). Two of these 5 patients developed overt macrophage activation syndrome several months later.

Conclusion

Levels of sIL‐2Rα and sCD163 are promising diagnostic markers for macrophage activation syndrome. They may also help identify patients with subclinical macrophage activation syndrome.

     

The limited role of interferon‐γ in systemic juvenile idiopathic arthritis cannot be explained by cellular hyporesponsiveness

Objective

Systemic juvenile idiopathic arthritis (JIA) is an autoinflammatory syndrome in which the myelomonocytic lineage appears to play a pivotal role. Inflammatory macrophages are driven by interferon‐γ (IFNγ), but studies have failed to demonstrate an IFN‐ induced gene signature in active systemic JIA. This study sought to characterize the status of an IFN‐induced signature within affected tissue and to gauge the integrity of IFN signaling pathways within peripheral monocytes from patients with systemic JIA.

Methods

Synovial tissue from 12 patients with active systemic JIA and 9 with active extended oligoarticular JIA was assessed by real‐time polymerase chain reaction to quantify IFN‐induced chemokine gene expression. Peripheral monocytes from 3 patients with inactive systemic JIA receiving anti–interleukin‐1β (anti–IL‐1β) therapy, 5 patients with active systemic JIA, and 8 healthy controls were incubated with or without IFNγ to gauge changes in gene expression and to measure phosphorylated STAT‐1 (pSTAT‐1) levels.

Results

IFN‐induced chemokine gene expression in synovium was constrained in active systemic JIA compared to the known IFN‐mediated extended oligoarticular subtype. In unstimulated peripheral monocytes, IFN‐induced gene expression was similar between the groups, except that lower levels of STAT1, MIG, and PIAS were observed in patients with active disease, while higher levels of PIAS1 were observed in patients with inactive disease. Basal pSTAT‐1 levels in monocytes tended to be higher in systemic JIA patients compared to healthy controls, with the highest levels seen in those with inactive disease. Upon stimulation of monocytes, the fold increase in gene expression was roughly equal between groups, except for a greater increase in STAT1 in patients with inactive systemic JIA compared to controls, and a greater increase in IRF1 in those with active compared to inactive disease. Upon stimulation, the fold increase in pSTAT‐1 was highest in monocytes from patients with inactive systemic JIA.

Conclusion

Monocytes in patients with active systemic JIA retain the ability to respond to IFNγ, suggesting that the lack of an IFN‐induced gene signature in patients with active disease reflects a limited in vivo exposure to IFNγ. In patients with inactive systemic JIA who received treatment with anti–IL‐1β, hyperresponsiveness to IFNγ was observed.

     

Biologic similarities based on age at onset in oligoarticular and polyarticular subtypes of juvenile idiopathic arthritis

Objective

To explore biologic correlates to age at onset in patients with juvenile idiopathic arthritis (JIA) using peripheral blood mononuclear cell (PBMC) gene expression analysis.

Methods

PBMCs were isolated from 56 healthy controls and 104 patients with recent‐onset JIA (39 with persistent oligoarticular JIA, 45 with rheumatoid factor–negative polyarticular JIA, and 20 with systemic JIA). RNA was amplified and labeled using NuGEN Ovation, and gene expression was assessed with Affymetrix HG‐U133 Plus 2.0 GeneChips.

Results

A total of 832 probe sets revealed gene expression differences (false discovery rate 5%) in PBMCs from children with oligoarticular JIA whose disease began before age 6 years (early‐onset disease) compared with those whose disease began at or after age 6 years (late‐onset disease). In patients with early‐onset disease, there was greater expression of genes related to B cells and less expression of genes related to cells of the myeloid lineage. Support vector machine analyses identified samples from patients with early‐ or late‐onset oligoarticular JIA (with 97% accuracy) or from patients with early‐ or late‐onset polyarticular JIA (with 89% accuracy), but not from patients with systemic JIA or healthy controls. Principal components analysis showed that age at onset was the major classifier of samples from patients with oligoarticular JIA and patients with polyarticular JIA.

Conclusion

PBMC gene expression analysis reveals biologic differences between patients with early‐and late‐onset JIA, independent of classification based on the number of joints involved. These data suggest that age at onset may be an important parameter to consider in JIA classification. Furthermore, pathologic mechanisms may vary with age at onset, and understanding these processes may lead to improved treatment of JIA.

     

Subtype‐specific peripheral blood gene expression profiles in recent‐onset juvenile idiopathic arthritis

Objective

To identify differences in peripheral blood gene expression between patients with different subclasses of juvenile idiopathic arthritis (JIA) and healthy controls in a multicenter study of patients with recent‐onset JIA prior to treatment with disease‐modifying antirheumatic drugs (DMARDs) or biologic agents.

Methods

Peripheral blood mononuclear cells (PBMCs) from 59 healthy children and 136 patients with JIA (28 with enthesitis‐related arthritis [ERA], 42 with persistent oligoarthritis, 45 with rheumatoid factor [RF]–negative polyarthritis, and 21 with systemic disease) were isolated from whole blood. Poly(A) RNA was labeled using a commercial RNA amplification and labeling system (NuGEN Ovation), and gene expression profiles were obtained using commercial expression microarrays (Affymetrix HG‐U133 Plus 2.0).

Results

A total of 9,501 differentially expressed probe sets were identified among the JIA subtypes and controls (by analysis of variance; false discovery rate 5%). Specifically, 193, 1,036, 873, and 7,595 probe sets were different in PBMCs from the controls compared with those from the ERA, persistent oligoarthritis, RF‐negative polyarthritis, and systemic JIA patients, respectively. In patients with persistent oligoarthritis, RF‐negative polyarthritis, and systemic JIA subtypes, up‐regulation of genes associated with interleukin‐10 (IL‐10) signaling was prominent. A hemoglobin cluster was identified that was underexpressed in ERA patients but overexpressed in systemic JIA patients. The influence of JAK/STAT, ERK/MAPK, IL‐2, and B cell receptor signaling pathways was evident in patients with persistent oligoarthritis. In systemic JIA, up‐regulation of innate immune pathways, including IL‐6, Toll‐like receptor/IL‐1 receptor, and peroxisome proliferator–activated receptor signaling, were noted, along with down‐regulation of gene networks related to natural killer cells and T cells. Complement and coagulation pathways were up‐regulated in systemic JIA, with a subset of these genes being differentially expressed in other subtypes as well.

Conclusion

Expression analysis identified differentially expressed genes in PBMCs obtained early in the disease from patients with different subtypes of JIA and in healthy controls, providing evidence of immunobiologic differences between these forms of childhood arthritis.

     

Cytokine gene polymorphisms and susceptibility to juvenile idiopathic arthritis

Objective

To investigate the involvement of candidate cytokine genes in the pathogenesis of juvenile idiopathic arthritis (JIA).

Methods

Single nucleotide polymorphisms and intragenic microsatellite markers within 8 candidate cytokine genes (interleukin‐1α [IL‐1α], IL‐2, IL‐4, IL‐6, IL‐10, interferon‐α1 [IFNA1], interferon‐γ [IFNG], and interferon regulatory factor 1 [IRF‐1]) were investigated in 417 Caucasian patients with clinically characterized JIA and a panel of 276 unrelated, healthy Caucasian controls, all from the United Kingdom.

Results

A novel 3′–untranslated region (3′UTR) polymorphism in IRF‐1 was found to be associated with susceptibility to JIA (corrected P = 0.002). No significant association with IL‐1α, IL‐2, IL‐4, IL‐6, IL‐10, IFNA1, or IFNG was observed.

Conclusion

An association between JIA and a previously unreported 3′UTR polymorphism of IRF‐1 was observed. This association was not found to be specific to any particular JIA subgroup. This suggests that IRF‐1 may contribute to a common pathogenesis shared by all JIA patients, regardless of clinical phenotype. This is most likely to be a genetic contribution to the chronic inflammatory process that underlies JIA pathology.

     

Long‐term outcome in patients with juvenile idiopathic arthritis

Objective

To describe the long‐term outcome of juvenile idiopathic arthritis (JIA).

Methods

All patients with JIA referred to a pediatric rheumatology center between 1978 and 1988 were identified and invited to undergo an assessment. Patients with JIA from a population‐based cohort from East Berlin were included. The outcome assessment considered changes in body function and structure (e.g., mortality, joint abnormalities, disease activity), activities at the individual level (Health Assessment Questionnaire), and participation in society (e.g., mobility, educational and vocational background).

Results

Of 260 eligible patients, 215 (83%) were evaluated. Subtypes of JIA at disease onset included oligoarthritis (40%), polyarthritis (14%), systemic arthritis (14%), psoriatic arthritis (1%), enthesitis‐related arthritis (15%), and other arthritis (16%). Followup was conducted after a median of 16.5 years. No deaths occurred in this cohort. At followup, approximately half of the patients had active disease and/or changes in body structures to a variable extent. Approximately one‐third of patients rated themselves as being functionally limited. Patients demonstrated good social integration: few mobility problems were reported, and the educational achievements of patients were higher and their rate of unemployment was lower compared with the age‐matched population. No significant differences in outcome were found between the population‐based and the referral‐based cohorts.

Conclusion

Even though approximately half of the JIA patients had more or less distinctive changes in body function and/or structure after a disease duration of >15 years, fewer than 10% were severely disabled or handicapped. Because JIA often persists into adulthood, long‐term followup and care are necessary.

     

Anakinra as first‐line disease‐modifying therapy in systemic juvenile idiopathic arthritis: Report of forty‐six patients from an international multicenter series

Objective

To examine the safety and efficacy of the interleukin‐1 (IL‐1) receptor antagonist anakinra as first‐line therapy for systemic juvenile idiopathic arthritis (JIA).

Methods

Patients with systemic JIA receiving anakinra as part of initial disease‐modifying antirheumatic drug (DMARD) therapy were identified from 11 centers in 4 countries. Medical records were abstracted using a standardized instrument, and resulting data were analyzed to characterize concomitant therapies, clinical course, adverse events, and predictors of outcome.

Results

Among 46 patients meeting inclusion criteria, anakinra monotherapy was used in 10 patients (22%), while 67% received corticosteroids and 33% received additional DMARDs. Outcomes were evaluated at a median followup interval of 14.5 months. Fever and rash resolved within 1 month in >95% of patients, while C‐reactive protein and ferritin normalized within this interval in >80% of patients. Active arthritis persisted at 1 month in 39% of patients, at 3 months in 27%, and at >6 months of followup in 11%. Approximately 60% of patients, including 8 of 10 receiving anakinra monotherapy, attained a complete response without escalation of therapy. Disease characteristics and treatment were similar in partial and complete responders, except that partial responders were markedly younger at onset (median age 5.2 years versus 10.2 years; P = 0.004). Associated adverse events included documented bacterial infection in 2 patients and hepatitis in 1 patient. Tachyphylaxis was not observed.

Conclusion

Anakinra as first‐line therapy for systemic JIA was associated with rapid resolution of systemic symptoms and prevention of refractory arthritis in almost 90% of patients during the interval examined. These results justify further study of IL‐1 inhibition as first‐line, rather than rescue, therapy in systemic JIA.

     

Safety and efficacy of an oral histone deacetylase inhibitor in systemic‐onset juvenile idiopathic arthritis

Objective

The current treatment options for systemic‐onset juvenile idiopathic arthritis (JIA) are methotrexate, steroids, and biologic agents. This study was undertaken to evaluate the safety of the orally active histone deacetylase inhibitor givinostat (ITF2357) and its ability to affect the disease.

Methods

Givinostat was administered orally, for up to 12 weeks at a dosage of 1.5 mg/kg/day, to 17 patients with systemic‐onset JIA who had had active disease for ≥1 month. Disease activity was clinically assessed using the American College of Rheumatology Pediatric 30 (ACR Pedi 30), ACR Pedi 50, or ACR Pedi 70 criteria for improvement and a systemic feature score. The primary goal was safety and the primary efficacy end point was the number of patients completing 12 weeks of treatment who were responders.

Results

Givinostat was safe and well tolerated, with adverse events (AEs) being mild or moderate, of short duration, and self‐limited. The 17 patients from the intent‐to‐treat population reported a total of 44 AEs, and the 9 patients in the per‐protocol population reported a total of 25. Six AEs in 3 patients (nausea, vomiting, and fatigue) were related to the study drug, but each resolved spontaneously and no patient was withdrawn from the study due to drug‐related AEs. In the per‐protocol population at week 4, the improvement as measured by the ACR Pedi 30, ACR Pedi 50, and ACR Pedi 70, respectively, was 77.8%, 55.6%, and 22.2%, and this increased further to 77.8%, 77.8%, and 66.7% at week 12. The most consistent finding was the reduction in the number of joints with active disease or with limited range of motion.

Conclusion

After 12 weeks, givinostat exhibited significant therapeutic benefit in patients with systemic‐onset JIA, particularly with regard to the arthritic component of the disease, and showed an excellent safety profile.

     

Ongoing disease activity and changing categories in a long‐term nordic cohort study of juvenile idiopathic arthritis

Objective

To describe the disease characteristics, long‐term course, and outcome of patients with juvenile idiopathic arthritis (JIA) in a population‐based setting.

Methods

Consecutive cases of JIA from defined geographic areas of Denmark, Finland, Sweden, and Norway in whom disease onset occurred in 1997–2000 were included in a prospective, multicenter cohort study. The study was designed to be as close to a population‐based study as possible, with centers participating only if they were able to include in their catchment area all children in whom JIA was diagnosed.

Results

Of 500 children included, 440 (88.0%) had repeated visits, with the last visit occurring at least 7 years after disease onset (median 98 months, range 84–147 months). Changes in the International League of Associations for Rheumatology category were observed in 10.8% of the children, and, in addition, extended oligoarthritis developed in 34.7% of the group with oligoarticular JIA. During the observation period, 58.0% of the children were treated with disease‐modifying antirheumatic drugs, including biologic medications. Ongoing disease activity was mostly mild, but some JIA‐related damage developed in 22.9% of the children. At the last followup visit, remission off medication was observed in 42.4% of the children, 8.9% were in remission on medication, and 48.7% were not in remission. The highest rates of remission were observed in patients with persistent oligoarticular JIA and in those with systemic JIA.

Conclusion

In this long‐term prospective study of JIA in a population‐based Nordic setting, ongoing disease was evident in a majority of the children. The present results underline the need to identify early predictors of outcome, to further improve therapy, and to continue long‐term followup of patients with JIA.

     

Clinical outcomes after withdrawal of anti–tumor necrosis factor α therapy in patients with juvenile idiopathic arthritis: A twelve‐year experience

Objective

To estimate the length of time to disease flare and the likelihood of achieving clinical remission after discontinuation of treatment with tumor necrosis factor α (TNFα) blockers in patients with juvenile idiopathic arthritis (JIA).

Methods

We conducted a retrospective chart review in a cohort of patients with JIA treated with TNFα inhibitors between January 1, 1998 and November 1, 2009. Demographic information, laboratory data, and medication exposure were extracted using a standardized tool. Outcomes of interest were based on preliminary criteria for remission in JIA.

Results

One hundred seventy‐one patients with 255 discrete episodes of anti‐TNFα treatment were reviewed. The median duration of patient observation was 59.7 months (range 5.8–211.2 months). Among patients in whom disease was inactive after discontinuation of anti‐TNFα therapy, 50% had persistently inactive disease at 6 months, and 33% had clinical remission at 12 months. The median duration of anti‐TNFα therapy after inactive disease was obtained was 6.1 months (range 0–67.9 months). No significant association was observed between the time to disease flare after cessation of treatment with TNFα antagonists and the length of time from the diagnosis of JIA to the initiation of anti‐TNFα therapy, the duration of therapy following the onset of inactive disease, or the total duration of treatment with TNFα antagonists prior to discontinuation. The category of JIA, sex, and age at diagnosis were not associated with the risk of relapse.

Conclusion

One‐third of patients with JIA can successfully undergo withdrawal of treatment with TNFα antagonists and be spared the cost and potential morbidity of treatment for at least 12 months. Further studies are needed to identify factors to accurately identify these patients.

     

Therapeutic efficacy of humanized recombinant anti–interleukin‐6 receptor antibody in children with systemic‐onset juvenile idiopathic arthritis

Objective

To investigate the safety and efficacy of a recombinant human anti–interleukin‐6 (anti–IL‐6) receptor monoclonal antibody (MRA) that indirectly inhibits the effects of IL‐6 in children with systemic‐onset juvenile idiopathic arthritis (JIA) refractory to high‐dose, long‐term corticosteroids.

Methods

An individual escalating‐dose trial was conducted in 11 children with active systemic‐onset JIA who met the inclusion criteria. All were first administered an intravenous dose of 2 mg/kg MRA. Each child without active inflammation was given a second identical dose 2 weeks later and a third identical dose 2 weeks after the second dose. Children with disease flares according to laboratory marker values received a 4‐mg/kg dose. Those without disease flares at this dose received a second 4‐mg/kg dose 2 weeks later and a third 4‐mg/kg dose 2 weeks after the second dose, while those with active inflammation received an additional 3 doses of 8 mg/kg MRA. Efficacy was evaluated every 2 weeks according to responses on the JIA core set of improvement criteria and the results of laboratory tests.

Results

MRA abruptly reduced disease activity in 10 of the 11 children, as assessed by the occurrence of febrile episodes, active arthritis, scores on the Childhood Health Assessment Questionnaire, and levels of acute‐phase reactants. However, levels of inflammatory reactants fluctuated until the proper MRA dose for each child was reached. Two weeks after the third fixed dose of MRA, 90.9% of all patients had a 30% improvement response, 90.9% had a 50% improvement response, and 63.6% had a 70% improvement response.

Conclusion

MRA treatment of children with active systemic disease results in clinical improvement and in normalized levels of acute‐phase reactants. MRA was safe and well tolerated and provided greater clinical benefit than conventional corticosteroids, considering the ill effects of IL‐6 and adverse events.

     

Identification of a novel susceptibility locus for juvenile idiopathic arthritis by genome‐wide association analysis

Objective

Juvenile idiopathic arthritis (JIA) is a chronic rheumatic disease of childhood. Two well‐established genetic factors known to contribute to JIA susceptibility, HLA and PTPN22, account for less than half of the genetic susceptibility to disease; therefore, additional genetic factors have yet to be identified. The purpose of this study was to perform a systematic search of the genome to identify novel susceptibility loci for JIA.

Methods

A genome‐wide association study using Affymetrix GeneChip 100K arrays was performed in a discovery cohort (279 cases and 184 controls). Single‐nucleotide polymorphisms (SNPs) showing the most significant differences between cases and controls were then genotyped in a validation sample of cases (n = 321) and controls, combined with control data from the 1958 UK birth cohort (n = 2,024). In one region in which association was confirmed, fine‐mapping was performed (654 cases and 1,847 controls).

Results

Of the 112 SNPs that were significantly associated with JIA in the discovery cohort, 6 SNPs were associated with JIA in the independent validation cohort. The most strongly associated SNP mapped to the HLA region, while the second strongest association was with a SNP within the VTCN1 gene. Fine‐mapping of that gene was performed, and 10 SNPs were found to be associated with JIA.

Conclusion

This study is the first to successfully apply a SNP‐based genome‐wide association approach to the investigation of JIA. The replicated association with markers in the VTCN1 gene defined an additional susceptibility locus for JIA and implicates a novel pathway in the pathogenesis of this chronic disease of childhood.