Vitamin D Levels and Risk of Juvenile Idiopathic Arthritis: A Mendelian Randomization Study.

OBJECTIVES: Observational studies report mixed findings regarding the association between vitamin D and juvenile idiopathic arthritis (JIA) incidence or activity; however, such studies are susceptible to considerable bias. Because low vitamin D levels are common within the general population and easily corrected, there is potential public health benefit in identifying a causal association between vitamin D insufficiency and JIA incidence. To limit bias due to confounding and reverse causation, we examined the causal effect of the major circulating form of vitamin D, 25-hydroxy vitamin D (25-[OH]D), on JIA incidence using Mendelian randomization (MR). METHODS: In this 2-sample MR analysis, we used summary level data from the largest and most recent genome-wide association study of 25-(OH)D levels (sample size 443,734), alongside summary data from 2 JIA genetic studies (sample sizes 15,872 and 12,501), all from European populations. To test and account for potential bias due to pleiotropy, we employed multiple MR methods and sensitivity analyses. RESULTS: We found no evidence of a causal relationship between genetically predicted 25-(OH)D levels and JIA incidence (odds ratio 1.00 [95% confidence interval (95% CI) 0.76, 1.33] per SD increase in standardized natural-log transformed 25-[OH]D levels). This estimate was consistent across all methods tested. Additionally, there was no evidence that genetically predicted JIA causally influences 25-(OH)D levels (-0.002 SD change in standardized natural-log transformed 25-[OH]D levels per doubling odds in genetically predicted JIA [95% CI -0.006, 0.002]). CONCLUSION: Given the lack of a causal relationship between 25-(OH)D levels and JIA, population level vitamin D supplementation is unlikely to reduce JIA incidence.

Outcomes of non-infectious Paediatric uveitis in the era of biologic therapy.

BACKGROUND: There is a paucity of data on the ocular outcomes in paediatric non-infectious uveitis since the introduction of the biologic agents. The purpose of this study was to outline the clinical characteristics of children with non-infectious uveitis and determine the visual outcomes and ocular complication rates in the modern era. METHODS: Children with non-infectious uveitis from January 2011 to December 2015 were identified. Data was collected at baseline, 1, 3, 5, and 10 years post diagnosis. The incidence rates of visual impairment, structural ocular complications and surgical intervention were calculated. Using logistic regression the association between various baseline characteristics and later visual impairment was investigated. RESULTS: Of the 166 children, 60.2% (n = 100) had a systemic disease association. 72.9% (n = 121) children received methotrexate, 58 children progressed to a biologic. The incidence rates of visual acuity loss to > 0.3 LogMAR (6/12) and to ≥1.0 LogMAR (6/60) were 0.05/Eye Year (EY) and 0.01/EY, respectively. Visual outcomes in the Juvenile Idiopathic Arthritis associated Uveitis (JIA-U) and Idiopathic Uveitis cohorts were not statistically significant. Of the 293 affected eyes, posterior synechiae was the predominant complication on presentation, while cataract had the highest incidence rate (0.05/EY). On direct comparison, children with JIA-U were statistically significantly more likely to develop glaucoma while children with Idiopathic Uveitis were statistically significantly more likely to develop macular oedema. CONCLUSION: One third of children received a biological therapy, reflecting increasing utilisation and importance of biological agents in the management of inflammatory conditions. Rates of visual impairment and ocular complications are an improvement on previously published data.

A phase II trial protocol of Tocilizumab in anti-TNF refractory patients with JIA-associated uveitis (the APTITUDE trial).

BACKGROUND: Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in children. Children with JIA are at risk of intraocular inflammation (uveitis). In the initial stages of mild-moderate inflammation uveitis is asymptomatic. Most children with mild-moderate uveitis are managed on topical steroid drops with or without systemic methotrexate (MTX). When children with moderate-severe uveitis are refractory to MTX, monoclonal anti-tumour necrosis factor agents have been trialled, interim analysis data showed positive results. However, several children with severe recalcitrant disease or non-responsive to anti-tumour necrosis factor agents remain and are at greater risk of significant ocular complications and visual loss. Further evidence of alternative therapies is needed with evidence of a potential role of anti-interleukin-6 agents in the management of severe refractory uveitis. METHODS: The trial will be conducted following a two-stage Simon design. The trial will register at least 22 patients aged 2 to 18 years with active JIA-associated uveitis, who have taken MTX for at least 12 weeks and have failed an anti-TNF agent. It will take place in 7 centres across the UK. All participants will be treated for 6 months, with follow up of 9 months from registration. Participants will receive a stable dose of MTX and those weighing ≥30 kg will be dosed with 162 mg of Tocilizumab every 2 weeks and participants weighing < 30 kg dosed with 162 mg of Tocilizumab every 3 weeks. Primary outcome is treatment response at 12 weeks. Adverse events will be collected up to 30 calendar days following treatment cessation. DISCUSSION: This is a novel adaptive design study of subcutaneous IL-6 inhibition in anti-TNF refractory JIA associated uveitis which will be able to determine if further research should be conducted. This is the first trial to look at ophthalmology outcomes in the efficacy of Tocilizumab in uveitis.This is the first paediatric clinical trial to assess the clinical effectiveness and safety of tocilizumab with MTX in JIA associated uveitis. TRIALS REGISTRATION: The Trial is registered on the ISRCTN registry (ISRCTN95363507) on the 10/06/2015 and EU Clinical Trials Register on the 03/07/2015 (EudraCT Number: 2015-001323-23).

Juvenile idiopathic arthritis-associated uveitis.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease of childhood, with JIA-associated uveitis its most common extra-articular manifestation. JIA-associated uveitis is a potentially sight-threatening condition and thus carries a considerable risk of morbidity. The aetiology of the condition is autoimmune in nature with the predominant involvement of CD4(+) T cells. However, the underlying pathogenic mechanisms remain unclear, particularly regarding interplay between genetic and environmental factors. JIA-associated uveitis comes in several forms, but the most common presentation is of the chronic anterior uveitis type. This condition is usually asymptomatic and thus screening for JIA-associated uveitis in at-risk patients is paramount. Early detection and treatment aims to stop inflammation and prevent the development of complications leading to visual loss, which can occur due to both active disease and burden of disease treatment. Visually disabling complications of JIA-associated uveitis include cataracts, glaucoma, band keratopathy and macular oedema. There is a growing body of evidence for the early introduction of systemic immunosuppressive therapies in order to reduce topical and systemic glucocorticoid use. This includes more traditional treatments, such as methotrexate, as well as newer biological therapies. This review highlights the epidemiology of JIA-associated uveitis, the underlying pathogenesis and how affected patients may present. The current guidelines and criteria for screening, diagnosis and monitoring are discussed along with approaches to management.