The DNA methylation landscape of CD4+ T cells in oligoarticular juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is presumed to be driven by an adverse combination of genes and environment. Epigenetic processes, including DNA methylation, act as a conduit through which the environment can regulate gene activity. Altered DNA methylation has been associated with adult autoimmune rheumatic diseases such as rheumatoid arthritis, but studies are lacking for paediatric autoimmune rheumatic diseases including JIA. Here, we performed a genome-scale case-control analysis of CD4+ T cell DNA methylation from 56 oligoarticular JIA (oJIA) cases and 57 age and sex matched controls using Illumina HumanMethylation450 arrays. DNA methylation at each array probe was tested for association with oJIA using RUV (Remove Unwanted Variation) together with a moderated t-test. Further to this 'all-inclusive' analysis, we stratified by age at diagnosis (≤6yrs, >6yrs) and by sex as potential sources of heterogeneity. Following False Discovery Rate (FDR) adjustment, no probes were associated with oJIA in the all-inclusive, >6yrs-diagnosed, or sex-stratified analyses, and only one probe was associated with oJIA in the ≤6yrs-diagnosed analysis. We attempted technical validation and replication of 14 probes (punadj<0.01) at genes of known/potential relevance to disease. At VPS53, we demonstrated a regional shift towards higher methylation in oJIA (all-inclusive) compared to controls. At REEP3, where polymorphism has been previously associated with JIA, we demonstrated higher DNA methylation in male oJIA compared to male controls. This is the most comprehensive JIA case-control analysis of DNA methylation to date. While we have generated some evidence of altered methylation in oJIA, substantial differences are not apparent in CD4+ T cells. This may indicate a lesser relevance of DNA methylation levels in childhood, compared to adult, rheumatic disease.

Australian Paediatric Rheumatology Group standards of care for the management of juvenile idiopathic arthritis.

This standards document outlines accepted standards of management for children, adolescents and young adults with juvenile idiopathic arthritis (JIA) in Australia. This document acknowledges that the chronic inflammatory arthritis conditions (JIA) in childhood are different diseases from inflammatory arthritis in adults and that specific expertise is required in the care of children with arthritis.

Case mix in paediatric rheumatology: implications for training in Australia.

BACKGROUND: Despite a move towards the provision of specialist training in Australia in settings that extend beyond the public hospital system, formal comparisons of case mix between public and private specialty clinics have rarely been performed. It is therefore unclear for many specialties how well training in one setting prepares trainees for practice in the other. AIMS: This study aims to compare the case mix of paediatric rheumatology patients seen in public and private settings and the referral sources of patients in each. METHODS: An audit of all new patients seen in the public and private paediatric rheumatology clinics on campus at Royal Children's Hospital between June 2009 and January 2011. Data related to demographics, primary diagnosis, referral source and location seen were abstracted and compared. RESULTS: Eight hundred and seventy-six new patients were seen during the period of interest. Of these, 429 patients (48.9%) were seen in private clinics. The commonest diagnostic categories for both type of clinics were non-inflammatory musculoskeletal pain/orthopaedic conditions (public 39.4%, private 33.6%) followed by juvenile idiopathic arthritis (public 16.6%, %, private 18.6%), other skin/soft tissue disorders (public 8.7%, private 9.6%) and pain syndromes (public 4.9%, private 11.4%). Patients with haematological and vasculitic disorders were predominantly seen in public clinics. The commonest source of referrals to both clinics was general practitioners (public 40.6%, private 53.1%). CONCLUSION: The case mix in private paediatric rheumatology clinics closely mirrors that of public clinics at our centre. Training in either setting would provide sufficient case-mix exposure to prepare trainees for practice in the other.

Association of Increased Sun Exposure Over the Life-course with a Reduced Risk of Juvenile Idiopathic Arthritis.

Cutaneous sun exposure is an important determinant of circulating vitamin D. Both sun exposure and vitamin D have been inversely associated with risk of autoimmune disease. In juvenile idiopathic arthritis (JIA), low circulating vitamin D appears common, but disease-related behavioral changes may have influenced sun exposure. We therefore aimed to determine whether predisease sun exposure is associated with JIA. Using validated questionnaires, we retrospectively measured sun exposure for 202 Caucasian JIA case-control pairs born in Victoria Australia, matched for birth year and time of recruitment. Measures included maternal sun exposure at 12 weeks of pregnancy and child sun exposure across the life-course prediagnosis. We converted exposure to UVR dose and looked for case-control differences using logistic regression, adjusting for potential confounders. Higher cumulative prediagnosis UVR exposure was associated with reduced risk of JIA, with a clear dose-response relationship (trend P = 0.04). UVR exposure at 12 weeks of pregnancy was similarly inversely associated with JIA (trend P = 0.011). Associations were robust to sensitivity analyses for prediagnosis behavioral changes, disease duration and knowledge of the hypothesis. Our data indicate that lower UVR exposure may increase JIA risk. This may be through decreased circulating vitamin D, but prospective studies are required to confirm this.

Bisphosphonate treatment in chronic recurrent multifocal osteomyelitis.

OBJECTIVE: To test the safety and efficacy of biphosphonates in chronic recurrent multifocal osteomyelitis (CRMO). STUDY DESIGN: Five patients with CRMO, all of whom had ongoing pain and loss of function despite conventional treatment with non-steroidal anti-inflammatory agents, were treated with pamidronate (1 mg/kg/dose with a dosing frequency of 2 to 4 monthly for a total treatment duration of 12 to 42 months). RESULTS: Pain decreased after the first infusion for 4 of 5 patients, with symptomatic improvement maintained with time. Significant improvement was seen in radiological lesions for these 4 patients. CONCLUSION: Bisphosphonates appear to be a useful and safe adjunctive treatment in CRMO when simple therapies such as anti-inflammatory agents fail to control symptoms or cases in which lesion expansion continues.

Sibling Exposure and Risk of Juvenile Idiopathic Arthritis.

OBJECTIVE: Susceptibility to juvenile idiopathic arthritis (JIA) is presumed to be determined by both genes and environment. However, the environmental factors remain largely unknown. The hygiene hypothesis suggests that exposure to siblings, as a marker of exposure to microbes in early life, may protect against the development of later immune disorders. Some prior evidence suggests this may also be true for JIA. The present study was undertaken to test this hypothesis in detail. METHODS: We conducted a comprehensive analysis of the role of sibling exposure in JIA risk within the Childhood Arthritis Risk Factor Identification Study JIA case-hospital control sample (302 cases and 676 controls) from Victoria, Australia. RESULTS: We found that, compared to being an only child, having any siblings was protective against JIA, with an adjusted odds ratio (OR) of 0.46 (95% confidence interval [95% CI] 0.28-0.74) (P = 0.001). The protective association appeared to increase with increasing number of siblings (e.g., for ≥3 siblings, adjusted OR 0.25 [95% CI 0.13-0.48], P < 0.001). A protective association of siblings was also observed when we considered cumulative sibling years by age 6 (e.g., for ≥3 years of exposure versus no exposure, adjusted OR 0.49 [95% CI 0.30-0.79], P = 0.003). We also compared cases to a second control sample (n = 341) collected from the community and weighted to represent the child population of Victoria. Data remained supportive of an association between sibling exposure and protection against JIA, particularly for exposure to younger siblings. CONCLUSION: Increased exposure to siblings is associated with a reduced risk of disease in our sample. This suggests that increased microbial exposure in childhood may confer protection against the development of JIA.

DNA methylation at IL32 in juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is the most common autoimmune rheumatic disease of childhood. We recently showed that DNA methylation at the gene encoding the pro-inflammatory cytokine interleukin-32 (IL32) is reduced in JIA CD4+ T cells. To extend this finding, we measured IL32 methylation in CD4+ T-cells from an additional sample of JIA cases and age- and sex-matched controls, and found a reduction in methylation associated with JIA consistent with the prior data (combined case-control dataset: 25.0% vs 37.7%, p = 0.0045). Further, JIA was associated with reduced IL32 methylation in CD8+ T cells (15.2% vs 25.5%, p = 0.034), suggesting disease-associated changes to a T cell precursor. Additionally, we measured regional SNPs, along with CD4+ T cell expression of total IL32, and the γ and ß isoforms. Several SNPs were associated with methylation. Two SNPs were also associated with JIA, and we found evidence of interaction such that methylation was only associated with JIA in minor allele carriers (e.g. rs10431961 p(interaction) = 0.011). Methylation at one measured CpG was inversely correlated with total IL32 expression (Spearman r = -0.73, p = 0.0009), but this was not a JIA-associated CpG. Overall, our data further confirms that reduced IL32 methylation is associated with JIA, and that SNPs play an interactive role.

Epistasis amongst PTPN2 and genes of the vitamin D pathway contributes to risk of juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is a leading cause of childhood-onset disability. Although epistasis (gene-gene interaction) is frequently cited as an important component of heritability in complex diseases such as JIA, there is little compelling evidence that demonstrates such interaction. PTPN2, a vitamin D responsive gene, is a confirmed susceptibility gene in JIA, and PTPN2 has been suggested to interact with vitamin D pathway genes in type 1 diabetes. We therefore, tested for evidence of epistasis amongst PTPN2 and the vitamin D pathway genes GC, VDR, CYP24A1, CYP2R1, and DHCR7 in two independent JIA case-control samples (discovery and replication). In the discovery sample (318 cases, 556 controls), we identified evidence in support of epistasis across six gene-gene combinations (e.g., GC rs1155563 and PTPN2 rs2542151, ORint=0.45, p=0.00085). Replication was obtained for three of these combinations. That is, for GC and PTPN2, CYP2R1 and VDR, and VDR and PTPN2, similar epistasis was observed using the same SNPs or correlated proxies in an independent JIA case-control sample (1008 cases, 9287 controls). Using SNP data imputed across a 4 MB region spanning each gene, we obtained highly significant evidence for epistasis amongst all 6 gene-gene combinations identified in the discovery sample (p-values ranging from 5.6×10(-9) to 7.5×10(-7)). This is the first report of epistasis in JIA risk. Epistasis amongst PTPN2 and vitamin D pathway genes was both demonstrated and replicated.

Independent confirmation of juvenile idiopathic arthritis genetic risk loci previously identified by immunochip array analysis.

BACKGROUND: Our understanding of the genetic factors underlying juvenile idiopathic arthritis (JIA) is growing, but remains incomplete. Recently, a number of novel genetic loci were reported to be associated with JIA at (or near) genome-wide significance in a large case-control discovery sample using the Immunochip genotyping array. However, independent replication of findings has yet to be performed. We therefore attempted to replicate these newly identified loci in the Australian CLARITY JIA case-control sample. FINDINGS: Genotyping was successfully performed on a total of 404 JIA cases (mean age 6.4 years, 68% female) and 676 healthy child controls (mean age 7.1 years, 42% female) across 19 SNPs previously associated with JIA. We replicated a significant association (p < 0.05, odds ratio (OR) in a direction consistent with the previous report) for seven loci, six replicated for the first time--C5orf56-IRF1 (rs4705862), ERAP2-LNPEP (rs27290), PRR5L (rs4755450), RUNX1 (rs9979383), RUNX3 (rs4648881), and UBE2L3 (rs2266959). CONCLUSIONS: We have carried out the first independent replication of association for six genes implicated in JIA susceptibility. Our data significantly strengthens the evidence that these loci harbor true disease associated variants. Thus, this study makes an important contribution to the growing body of international data that is revealing the genetic risk landscape of JIA.

Clinical features and disease course of patients with juvenile dermatomyositis.

OBJECTIVE: To describe the clinical features and course of a cohort of patients with juvenile dermatomyositis (JDM) at a tertiary referral pediatric centre in Australia and examine changes in diagnostic and therapeutic approach over time. METHODS: Retrospective review of patients diagnosed with JDM at the Royal Children's Hospital, Melbourne, between 1989 and 2010. RESULTS: Fifty-seven patients were identified. The female : male ratio was 2 : 1 and median age at diagnosis was 7.1 years (2.2-15.3). At diagnosis, 95% had weakness, all had typical rash and 68% had nailfold capillary changes. Calcinosis was not present in any patients at diagnosis and occurred in 18% over time. Creatine kinase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase and aldolase levels were abnormal in 65%, 92%, 88%, 58% and 100%, respectively. Magnetic resonance imaging (MRI) was abnormal in 97% of patients, electomyograph (EMG) in 83% and muscle biopsy in all four patients in whom it was performed. MRI was used in 86% (24/28) of patients diagnosed after 2000. Muscle biopsy was used in four and EMG in no patients over the same period. Treatment used throughout the disease course included oral steroids (93%), high-dose pulse intravenous steroids (82%), methotrexate (63%), intravenous immunoglobulin (32%) and cyclosporin (18%). The disease was monophasic in 46.7% (21/45), polyphasic in 17.7% (8/45) and chronic in 35.5% (16/45). CONCLUSIONS: Australian patients with JDM have similar characteristics to previously described cohorts. In practice, MRI has replaced the invasive diagnostic tests included in the Bohan and Peter criteria for the diagnosis of JDM. The early use of disease-modifying anti-rheumatic drugs has become the most common treatment approach.

Out-of-clinic patient communication in paediatric rheumatology: the extent and nature of demand.

BACKGROUND: Traditional funding models for public paediatric rheumatology care are typically based on providing medical services for a defined number of clinics per week. Anecdotally there is significant demand by patients and families for out-of-clinic communication with care providers and services provided under traditional funding models may not meet this need. Our aim was to determine the extent and nature of this 'hidden' demand in a tertiary paediatric rheumatology centre. METHODS: Communication data and diagnoses were extracted from the Rheumatology service database at our centre for the period 1/1/2009 to 31/12/2011. Clinical activity data over the same time were obtained from hospital clinic databases. RESULTS: There were 5672 instances of communication with 749 patients/families over 3 years, (mean 7.3/weekday). This increased over time in parallel with clinical activity. 41% of clinic patients sought communication with the team out of clinic hours. 58% were telephone calls, 36% emails and 6% letters. The communication topics were for advice, results or general updates (28%), medication queries (24%), appointment/admission coordination (20%), disease flare or other disease events (14%), psychosocial, school or transition issues (6%) and miscellaneous queries (8%). Of the most frequent communicators, those with juvenile idiopathic arthritis were the majority (85%). The remainder had other chronic inflammatory conditions. CONCLUSIONS: The communication and support needs of patients with chronic rheumatic diseases and their families extend beyond that which can be provided in the clinic environment. It is essential that funding for paediatric rheumatology services allows for staffing sufficient to meet this need.

Independent replication analysis of genetic loci with previous evidence of association with juvenile idiopathic arthritis.

BACKGROUND: Over the last five years, there have been numerous reports of association of juvenile idiopathic arthritis with single nucleotide polymorphisms (SNPs) at various loci outside the major histocompatibility complex (MHC) region. However, the majority of these association findings have been generated using a limited number of international cohorts, and thus there is benefit in further independent replication. To address this, we examined a total of 56 SNPs in 42 non-MHC gene regions previously reported to be associated with JIA, in the ChiLdhood Arthritis Risk factor Identification sTudY (CLARITY), a new Australian collection of cases and healthy child controls. FINDINGS: Genotyping was performed on a total of 324 JIA cases (mean age 9.7 years, 67.3% female) and 568 controls (mean age 7.8 years, 40.7% female). We demonstrated clear evidence for replication of association of JIA with SNPs in or around c12orf30, c3orf1, PTPN22, STAT4, and TRAF1-C5, confirming the involvement of these loci in disease risk. Further, we generated evidence supportive of replication of association of JIA with loci containing AFF3, CD226, MBL2, PSTPIP1, and RANTES (CCL5). These results were robust to sensitivity analyses for ethnicity. CONCLUSION: We have provided valuable independent data as to the underlying genetic architecture of this understudied pediatric autoimmune disease, further confirming five loci outside the MHC, and supporting a role for a further five loci in determining disease risk.

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.

Improving the management of paediatric rheumatic diseases globally.

This article aims to review the various aspects of paediatric rheumatology that might be looked on as having a more global emphasis, the advances achieved through new technology and communication, the importance of education for both the medical community as well as the patient population, the epidemiologic variation of diseases and how population migration has brought potential changes as well as canvassing some of the considerable new challenges that still need to be addressed.

Chronic recurrent multifocal osteomyelitis: clinical outcomes after more than five years of follow-up.

OBJECTIVE: To determine the clinical outcomes of children with chronic recurrent multifocal osteomyelitis (CRMO). STUDY DESIGN: Inception cohorts of children with CRMO were established at two tertiary pediatric centers. Outcome data were obtained through review of hospital charts, interview and examination of patients, and completion of questionnaires by patients. RESULTS: Of 45 eligible subjects, 23 (51%) were assessed. Median time since diagnosis was 13 years (range, 6-25). At evaluation, 6 (26%) had active disease; 18 (78%) had Health Assessment Questionnaire scores of 0 (no/minimal physical disability), and 5 had scores >0. Some impairment was seen in all domains of measurement of quality-of-life test, especially those concerning nonphysical aspects of health. Six (26%) subjects continued to have pain as a result of CRMO. Associated medical problems included arthritis in 6, sacroiliitis in 3, psoriasis in 5, recurrent pustular rashes in 2, and inflammatory bowel disease in 3. CONCLUSIONS: Long-term clinical outcomes for children with CRMO appear to be generally good, with most subjects having no evidence of disease activity or sequelae. However, a number of subjects had persistent disease and, therefore, remain at risk of physical and psychologic complications. Further research is required to identify patients at risk for persistent disease, and to determine therapies that may prevent morbidity.