The transition process for paediatric rheumatology clinic patients at a single tertiary paediatric rheumatology centre in Australia.

AIM: This study aimed to examine the transition process of paediatric rheumatology patients from the Monash Children's Hospital (MCH) in Melbourne in order to identify areas that could be improved. METHODS: Retrospective review of clinical data from the rheumatology database of paediatric rheumatology patients eligible for transition between January 2015 and September 2020. RESULTS: One hundred and sixty-five patients were included; 57 patients were transitioned. Of patients transitioned to an adult service, 38 (88%) were on medication and 14 (33%) had active disease. All patients transitioned to the general practitioner (GP) had inactive disease off medication. Juvenile idiopathic arthritis (JIA) (non-systemic) was the most common diagnosis in patients transitioned. The mean age at which transition was first discussed was 18.0 years; the first referral was made at a mean of 18.3 years. The mean age at the first adult appointment was 18.5 years. Thirty-nine (91%) patients had a referral completed and 8 (19%) had a transfer letter. Thirteen (93%) patients transferred to the GP had a transfer letter. Transfer documents to an adult public rheumatology service rated 4.3 for quality, compared to 5.5 to the GP. Transfer of care was confirmed in 40 (93%) patients transitioned to an adult service; however, correspondence was available for only 3 (7%). CONCLUSION: Although the transition process at MCH was adequate, it could be improved through earlier discussion of the process and improved referrals and documentation. A readiness-to-transfer checklist and a young adult clinic have the potential to improve the process of transition to adult rheumatology care.

Patterns and rates of confirmed transfer of care of patients with juvenile idiopathic arthritis at a tertiary paediatric rheumatology centre.

BACKGROUND: Disease activity in juvenile idiopathic arthritis (JIA) commonly persists into adulthood. Transfer of JIA patients to adult healthcare services can be challenging, with prior studies showing poor rates of success. AIMS: This audit sought to examine characteristics of patients undergoing transfer of care within the rheumatology unit at the Royal Children's Hospital in Melbourne, with the aim of identifying areas for improvement. Specifically, we sought to determine the rate at which confirmation of established care with an adult service (confirmed transfer of care) was documented in the patient chart. METHODS: Patients with a diagnosis of JIA who turned 18 years of age between 2012 and 2019 were identified. A chart review was undertaken to collect relevant data. RESULTS: One hundred and seventy-seven patients were identified. In all, 64% (114/177) were referred for adult care. The commonest JIA subtypes referred were seronegative polyarticular (35/114; 30.7%) and oligoarticular JIA (22/114; 19.3%). Documentation of confirmed transfer of care occurred in 62.3% (71/114), with correspondence received from adult services in 49.1% (56/114). There was no difference in rate of return correspondence from public versus private providers (45% vs 53.8%; P = 0.38). The use of 'backstop appointments' was more likely in those with confirmed transfer of care (66% vs 30%; P = 0.0002). CONCLUSIONS: Lack of confirmed transfer of care for JIA patients is common and carries a risk of suboptimal outcomes. Strategies to improve communication with adult services, the routine use of 'backstop' appointments and vigilance regarding potential loss to follow up at the time of transfer would minimise this risk.

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.

Sarcoidosis: a state of the art review from the Thoracic Society of Australia and New Zealand.

Sarcoidosis is a systemic disease of unknown aetiology, characterised by non-caseating granulomatous inflammation. It most commonly manifests in the lungs and intrathoracic lymph nodes but can affect any organ. This summary of an educational resource provided by the Thoracic Society of Australia and New Zealand outlines the current understanding of sarcoidosis and highlights the need for further research. Our knowledge of the aetiology and immunopathogenesis of sarcoidosis remains incomplete. The enigma of sarcoidosis lies in its immunological paradox of type 1 T helper cell-dominated local inflammation co-existing with T regulatory-induced peripheral anergy. Although specific aetiological agents have not been identified, mounting evidence suggests that environmental and microbial antigens may trigger sarcoidosis. Genome-wide association studies have identified candidate genes conferring susceptibility and gene expression analyses have provided insights into cytokine dysregulation leading to inflammation. Sarcoidosis remains a diagnosis of exclusion based on histological evidence of non-caseating granulomas with compatible clinical and radiological findings. In recent years, endobronchial ultrasound-guided transbronchial needle aspiration of mediastinal lymph nodes has facilitated the diagnosis, and whole body positron emission tomography scanning has improved localisation of disease. No single biomarker is adequately sensitive and specific for detecting and monitoring disease activity. Most patients do not require treatment; when indicated, corticosteroids remain the initial standard of care, despite their adverse side effect profile. Other drugs with fewer side effects may be a better long term choice (eg, methotrexate, hydroxychloroquine, azathioprine, mycophenolate), while tumour necrosis factor-α inhibitors are a treatment option for patients with refractory disease.

Rheumatology and the adolescent patient.

BACKGROUND: Adolescence can be a time when rheumatological conditions present to the general practitioner for diagnosis and management. Diagnosis of rheumatic disease during adolescence and earlier childhood often brings additional challenges such as those relating to body image, schooling and recreational activities, friendships and relationships, compliance with medications and independence with healthcare needs. OBJECTIVE: This article highlights rheumatological conditions that have relevance during adolescence and describes the approach to the history, examination and investigation of young people with rheumatic disease. Some common management issues that may arise when assessing adolescent patients in the primary care setting, including indications for referral to a rheumatologist, are outlined. DISCUSSION: The transition from one of dependence to self-management is a complex but important process as many adolescents with rheumatic disease will have persistent disease activity or ongoing sequelae continuing into their adulthood.

Cryopyrin-associated periodic syndrome in Australian children and adults: Epidemiological, clinical and treatment characteristics.

AIM: Cryopyrin-associated periodic syndromes (CAPS) encapsulate three auto-inflammatory conditions, ranging in severity from mild (familial cold auto-inflammatory syndrome: FCAS), moderate (Muckle-Wells syndrome: MWS) and severe (neonatal onset multi-inflammatory disorder: NOMID). We aimed to describe the epidemiology, clinical features and outcomes of Australian children and adults with CAPS. METHODS: Patients were identified and clinical data collected through a questionnaire sent during 2012-2013 to clinicians reporting to the Australian Paediatric Surveillance Unit and subscribing to the Australasian Societies for Allergy/Immunology, Rheumatology and Dermatology. RESULTS: Eighteen cases of CAPS were identified (8 NOMID; 8 MWS, 2 FCAS); 12 in children <18 years of age. The estimated population prevalence of CAPS was 1 per million persons. Diagnostic delay was frequent, particularly in those with milder phenotypes (median diagnostic delay in MWS/FCAS 20.6 years compared with NOMID 2.1 years; P = 0.04). Common presenting features included urticaria (100%), periodic fever (78%), arthralgia (72%) and sensorineural hearing loss (61%). Almost all (90%) MWS patients had a family member similarly affected compared with none in the NOMID group (P = 0.004). A significant proportion of patients on anti-interleukin (IL)-1 therapy (n = 13) no longer had systemic inflammation. Only 50% with sensorineural hearing loss had hearing restored on anti-IL-1 therapy. CONCLUSIONS: Although CAPS are rare, patients often endured prolonged periods of systemic inflammation. This is despite almost all MWS patients having family members with similar symptoms and children with NOMID presenting with chronic infantile urticaria associated with multi-system inflammation. Hearing loss in NOMID/MWS was frequent, and reversible in only 50% of cases.

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.

Three- and five-year outcomes of an inception cohort of Australian children with juvenile idiopathic arthritis.

BACKGROUND: To describe the 3- and 5-year outcomes of an inception cohort of Australian children with JIA for whom 1-year outcomes have previously been published. METHODS: Data regarding clinical outcomes of the original cohort of 134 patients at 3 and 5 years were sought. Relevant clinical features and medication exposures entered prospectively into an electronic record were collected and analyzed using descriptive statistics. RESULTS: Data were available for 110 and 98 patients at 3 and 5 years, respectively. The proportion of patients with active joints progressively decreased from 34% at 12 months to 21% at 3 years and 16% at 5 years. Cumulative exposure to methotrexate increased between 3 and 5 years (75%-80%), however, point prevalence use decreased (45%-41%). Cumulative exposure and point prevalence use of bDMARDS both increased between 3 and 5 years; 30%-42% and 29%-33%, respectively. Thirty-five percent of patients had inactive joint disease off medications at 5 years, which occurred most frequently in patients with sJIA and oligoarthritis. CONCLUSION: Five-year outcomes of Australian children with JIA are good, with only a small minority having ongoing active joint disease at 5 years. bDMARDS play an increasing role in management over time; however, methotrexate use remains significant. A majority of children remain on medications at 5 years.

Aggrecanase cleavage in juvenile idiopathic arthritis patients is minimally detected in the aggrecan interglobular domain but robust at the aggrecan C-terminus.

OBJECTIVE: To investigate aggrecan degradation in juvenile idiopathic arthritis (JIA). METHODS: The pattern and abundance of aggrecan fragments in synovial fluid (SF) aspirates from JIA patients were analyzed and compared with aggrecan fragments in SF from patients with other arthritides, children with knee injury, and a knee-healthy reference group. Concentrations of sulfated glycosaminoglycan (sGAG) in SF were measured by Alcian blue precipitation assay. Aggrecan fragments were purified by dissociative CsCl density-gradient centrifugation, deglycosylated, and analyzed by Western blot using antibodies specific for either aggrecanase-derived ARGS, SELE, and KEEE neoepitopes or the aggrecan G3 domain. RESULTS: The concentration of sGAG in SF from patients with JIA was significantly lower compared with that in SF from patients with osteoarthritis (OA) (P < 0.001), patients with juvenile knee injury (P = 0.006), and knee-healthy controls (P = 0.022). Western blot analysis revealed KEEE, SELE, and G3 fragments generated by aggrecanase cleavage in the chondroitin sulfate-rich region of aggrecan in patients with JIA. The pattern of aggrecan fragments in JIA patients was not identical to that in pooled OA SF, although there were notable similarities. Surprisingly, aggrecanase-derived ARGS fragments were barely detectable in JIA SF, in marked contrast to levels in OA SF. CONCLUSION: Aggrecanases appear to cleave minimally in the interglobular domain of aggrecan in JIA patients despite robust levels of cleavage in the chondroitin sulfate-rich region. These results suggest that in JIA, unlike other arthritides, aggrecanase cleavage in the aggrecan interglobular domain might not be a major pathogenic event.

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.

A retrospective study of chest pain in benign asbestos pleural disease.

PURPOSE: The aims of this review were to ascertain the incidence of asbestos-related chest pain at presentation in two groups of patients referred with asbestos diseases and the demographics, comorbidities, and chest computed tomography findings associated with chest pain. METHODS: Medical charts of patients presenting 1995-2008, audited for quality assurance, were chosen at random by data managers. Patients with mesothelioma, lung cancer, and angina were excluded. Rigorous attempts had been taken by the authors to exclude other causes of chest pain. RESULTS: There were 167 patients who were medicolegal referrals (Group 1) and 115 clinical referrals (Group 2). Although the patients in Group 1 had more severe disease generally than Group 2, the proportion with pain was not significantly different (45.5% and 55.7%, mean duration 4.8 years, range 1-22 years). Group 1 had more severe disease as a rule. However, the proportion with pain in Groups 1 and 2, respectively, was as follows: diffuse pleural thickening (50.8% and 67.6%, P=0.072), pleural plaques (47.0% and 59.7%, P=0.076), folded atelectasis (70.6% and 83.3%, P=1.000), and asbestosis (43.6% and 53.3%, P=0.346). Of all those with folded atelectasis, 73.9% had pain. CONCLUSION: Chest pain appears to be much more common in patients with benign asbestos diseases than is currently recognized, particularly in those with folded atelectasis and is not restricted to litigants. Improved recognition of this entity is needed along with practical management guidelines for the general practitioner. Further studies are envisaged by the authors.

Differences in treatment and management of indigenous and non-indigenous patients presenting with chest pain: results of the Heart Protection Partnership (HPP) study.

BACKGROUND: Indigenous patients with acute coronary syndromes represent a high-risk group. There are however few contemporary datasets addressing differences in the presentation and management of Indigenous and non-Indigenous patients with chest pain. METHODS: The Heart Protection Project, is a multicentre retrospective audit of consecutive medical records from patients presenting with chest pain. Patients were identified as Indigenous or non-Indigenous, and time to presentation and cardiac investigations as well as rates of cardiac investigations and procedures were compared between the two groups. RESULTS: Of the 2380 patients included, 199 (8.4%) identified as Indigenous, and 2174 (91.6%) as non-Indigenous. Indigenous patients were younger, had higher rates hyperlipidaemia, diabetes, smoking, known coronary artery disease and a lower rate of prior PCI; and were significantly less likely to have private health insurance, be admitted to an interventional facility or to have a cardiologist as primary physician. Following adjustment for difference in baseline characteristics, Indigenous patients had comparable rates of cardiac investigations and delay times to presentation and investigations. CONCLUSIONS: Although the Indigenous population was identified as a high-risk group, in this analysis of selected Australian hospitals there were no significant differences in treatment or management of Indigenous patients in comparison to non-Indigenous.

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.

Juvenile idiopathic arthritis managed in the new millennium: one year outcomes of an inception cohort of Australian children.

BACKGROUND: The advent of new treatments for Juvenile Idiopathic Arthritis (JIA) has prompted interest in systematically studying the outcomes of patients treated in the 'modern era'. Such data provide both benchmarks for assessing local outcomes and important information for use in counselling families of newly diagnosed patients. While data are available for cohorts in Europe and North America, no such data exist for Australian patients. The aim was to examine the demographics, treatment and outcomes at 12 months of an inception cohort of newly diagnosed patients with JIA at a single tertiary referral paediatric rheumatology centre in Australia. METHODS: Retrospective review of prospectively collected data from patients newly diagnosed with JIA between 2010 and 2014 at the Royal Children's Hospital in Melbourne. RESULTS: One hundred thirty four patients were included (62% female). Oligoarthritis was the single largest category of JIA (36%) and rheumatoid factor positive polyarthritis the least common (2%). Undifferentiated JIA accounted for 13% of patients and was the third largest category. Across the cohort 94% received NSAIDs, 53% oral steroids, 62% methotrexate and 15% a biologic DMARD. Intra-articular steroids were used in 62%, most commonly in the oligoarticular subtype (94%). 95% of patients achieved a joint count of zero at a median of 4.1 months, however flares occurred in 42%. At 12 months 65% had no active joint disease, though more than half remained on medication. CONCLUSION: Australian children with JIA managed in the modern era have similar characteristics and achieve short term outcomes comparable to cohorts in Europe and North America, with high rates of joint remission in the first 12 months of follow-up but with a significant relapse rate and requirement for ongoing medication.

Growth During Tocilizumab Therapy for Polyarticular-course Juvenile Idiopathic Arthritis: 2-year Data from a Phase III Clinical Trial.

OBJECTIVE: Evaluate growth in patients with polyarticular-course juvenile idiopathic arthritis (pcJIA) treated with tocilizumab (TCZ) for up to 2 years in a phase III trial. METHODS: Patients with pcJIA lasting at least 6 months and inadequate response to methotrexate received open-label TCZ intravenously every 4 weeks (randomly assigned to 8 or 10 mg/kg if they weighed < 30 kg; received 8 mg/kg if they weighed ≥ 30 kg) for 16 weeks. Patients with JIA American College of Rheumatology 30 response at Week 16 were randomly assigned to TCZ or placebo for 24 weeks, with an open-label extension through Week 104. Mean ± SD height velocity (cm/yr) and World Health Organization (WHO) height SD score (SDS) were measured in patients receiving ≥ 1 dose of TCZ who did not receive growth hormone and in patients whose baseline Tanner stage was ≤ 3. RESULTS: The study included 187 of 188 patients (99.5%) with mean WHO height SDS -0.5 ± 1.2, which was unrelated to age or disease duration (Spearman rank correlations r = 0.08 and r = -0.12, respectively). There were 123 patients at Tanner stage ≤ 3 at baseline, among whom 103 completed the study with 2 years of height SDS data. Mean height SDS increased from baseline to year 2 (+0.40, p < 0.0001). In 74 of 103 patients (72%), height SDS was greater than at baseline, and mean height velocity was 6.7 ± 2.0 cm/year. CONCLUSION: Among patients with pcJIA at Tanner stage ≤ 3 at baseline, 72% (74/103) had increased height SDS at the end of the study.

Physical agents used in the management of chronic pain by physical therapists.

Evidence supporting the use of specific physical agents in the management of chronic pain conditions is not definitive; it is largely incomplete and sometimes contradictory. However, the use of agents in chronic pain management programs is common. Within the broad use of physical agents, they are rarely the sole modality of treatment. A 1995 American Physical Therapy Association position statement asserts that "Without documentation which justifies the necessity of the exclusive use of physical agents/modalities, the use of physical agents/modalities, in the absence of other skilled therapeutic or educational intervention, should not be considered physical therapy". Physical agents may serve as useful adjunctive modalities of pain relief or to enhance the effectiveness of other elements in therapy geared toward resolution of movement impairments and restoration of physical function. Given that a conclusive aggregate of findings is unlikely to exist for all permutations of patient conditions, combined with interacting therapeutic modalities, an evidence-based approach to pain management is not always possible or beneficial to the patient. In the face of inconclusive evidence, a theory-based approach may help determine if the therapeutic effect ofa given physical agent has the possibility of being a useful clinical tool in the context of treating a particular patient's mechanism of pain generation. Until controlled efficacy findings are definitive, careful individual patient response monitoring of thoughtful theoretical application of adjunctive physical agents may be a prudent approach to the management of chronic pain.

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.