Pathophysiology of JIA-associated uveitis

A clearer vision: insights into juvenile idiopathic arthritis-associated uveitis

The aim of this narrative review is to synthesize existing evidence-based knowledge on juvenile idiopathic arthritis-associated uveitis (JIA-U). We highlight epidemiology, pathophysiology, causes and genetics, risk factors, clinical features, diagnosis and screening, laboratory biomarkers, treatment options, trials with recent advances, and research challenges pertaining to JIA-U. The prevalence of JIA-U varies with different JIA subtypes, most frequently associated with the oligoarticular subtype. The risk factors involved in the development of JIA-U include younger age, antinuclear antibody (ANA) positivity, and the oligoarticular subtype of JIA, along with some specific major histocompatibility complex genes. Certain laboratory biomarkers, such as ANA, rheumatoid factor, interferon-λ, erythrocyte sedimentation rate, and transthyretin, have been used in JIA-U diagnosis, progress monitoring, and prognostication. Clinical features of JIA-U can range from asymptomatic to ophthalmic symptoms like redness, blurred vision, decreased visual acuity, hypopyon, and posterior uveitis, which can lead to retinal detachment and macular edema. The management protocol involves topical and systemic steroids, cycloplegics, disease-modifying antirheumatic drugs, biologic drugs, and surgical options. Early detection combined with prompt treatment is crucial to preventing irreversible vision loss in JIA-U.

Uveitis Associated with Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is the most common cause of uveitis in children. While symptoms are usually mild, persistent eye inflammation could lead to severe complications and impaired vision. It is essential that JIA patients at risk are diagnosed with uveitis early, receive adequate treatment, and avoid developing complications, such as cataract, glaucoma, and amblyopia. The purpose of this mini-review is to summarize the screening strategies and clinical management for JIA-associated uveitis (JIA-U) as well as the current state of molecular markers linked to this condition. Because glaucoma is one of the most common causes of visual loss in JIA-U, special focus will be put on this serious complication. We conclude by describing the current evidence regarding the long-standing question of whether chronic anterior uveitis without arthritis may be the same disease entity as JIA-U.

Tumor necrosis factor (TNF) inhibitors for juvenile idiopathic arthritis-associated uveitis

BACKGROUND

Uveitis is the most common extra-articular manifestation of juvenile idiopathic arthritis (JIA) and a potentially sight-threatening condition characterized by intraocular inflammation. Current treatment for JIA-associated uveitis (JIA-U) is largely based on physician experience, observational evidence and consensus guidelines, resulting in considerable variations in practice.  OBJECTIVES: To evaluate the effectiveness and safety of tumor necrosis factor (TNF) inhibitors used for treatment of JIA-U.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Sciences Literature Database (LILACS); ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We last searched the electronic databases on 3 February 2022.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing TNF inhibitors with placebo in participants with a diagnosis of JIA and uveitis who were aged 2 to 18 years old.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and graded the certainty of the body of evidence for seven outcomes using the GRADE classification.

MAIN RESULTS

We included three RCTs with 134 participants. One study conducted in the USA randomized participants to etanercept or placebo (N = 12). Two studies, one conducted in the UK (N = 90) and one in France (N = 32), randomized participants to adalimumab or placebo. All studies were at low risk of bias. Initial pooled estimates suggested that TNF-inhibitors may result in little to no difference on treatment success defined as 0 to trace cells on Standardization of Uveitis Nomenclature (SUN)-grading; or two-step decrease in activity based on SUN grading (estimated risk ratio (RR) 0.66; 95% confidence interval (CI) 0.21 to 2.10; 2 studies; 43 participants; low-certainty evidence) or treatment failure defined as a two-step increase in activity based on SUN grading (RR 0.31; 95% CI 0.01 to 7.15; 1 study; 31 participants; low-certainty evidence). Further analysis using the individual trial definitions of treatment response and failure suggested a positive treatment effect of TNF inhibitors; a RR of treatment success of 2.60 (95% CI 1.30 to 5.20; 3 studies; 124 participants; low-certainty evidence), and RR of treatment failure of 0.23 (95% CI 0.11 to 0.50; 3 studies; 133 participants). Almost all the evidence was on adalimumab and the evidence on etanercept was very limited.  For secondary outcomes, one study suggests that adalimumab may have little to no effect on risk of recurrence after induction of remission at three months (RR 2.50, 95% CI 0.31 to 20.45; 90 participants; very low-certainty evidence) and visual acuity, but the evidence is very uncertain; mean difference in longitudinal logMAR score change over six months was -0.01 (95% CI -0.06 to 0.03) and -0.02 (95% CI -0.07 to 0.03) using the best and worst logMAR measurement, respectively (low-certainty evidence). Low-certainty evidence from one study suggested that adalimumab treatment results in reduction of topical steroid doses at six months (hazard ratio 3.58; 95% CI 1.24 to 10.32; 74 participants who took one or more topical steroid per day at baseline). Adverse events, including injection site reactions and infections, were more common in the TNF inhibitor group. Serious adverse events were uncommon.

AUTHORS' CONCLUSIONS

Adalimumab appears to increase the likelihood of treatment success and decrease the likelihood of treatment failure when compared with placebo. The evidence was less conclusive about a positive treatment effect with etanercept. Adverse events from JIA-U trials are in keeping with the known side effect profile of TNF inhibitors. Standard validated JIA-U outcome measures are required to homogenize assessment and to allow for comparison and analysis of multiple datasets.

Paediatric non-infectious uveitis in Cape Town, South Africa: a retrospective review of disease characteristics and outcomes on immunomodulating treatment

BACKGROUND

Non-infectious uveitis is a well-reported cause of blindness in more developed countries, however data from sub-Saharan Africa is lacking. Here we aim to describe the diseases associated with paediatric non-infectious uveitis and the effect of currently available treatment in this setting.

METHODS

A retrospective observational analysis of children with non-infectious uveitis from January 2010 to December 2017, attending the tertiary paediatric rheumatology and ophthalmology referral units in Cape Town was conducted. Statistical analysis utilising STATA13 software was performed with p < 0.05 considered significant.

RESULTS

Twenty-nine children were identified: median age at first visit of 74 months (IQR 49-86 months), female to male ratio of 0.9:1, predominantly of mixed ancestry (72.4%). Juvenile idiopathic arthritis associated uveitis (JIAU) (48.3%), idiopathic uveitis (41.4%), sarcoidosis (6.9%) and Behcet's disease (3.5%) were diagnosed. Chronic anterior uveitis (72.4%) was the most frequent finding. Fifty-five percent had complications at presentation and all children with idiopathic uveitis presented with cataracts. Only 6.5% of the JIA cohort had JIAU. All JIA children had chronic anterior uveitis. There were no differences between JIA children with uveitis and those without uveitis, for sex (p = 0.68) and race (p = 0.58). Significantly, children with uveitis presented at an overall younger age (p = 0.008), had oligo-articular JIA (p = 0.01) and were antinuclear antibody positive (p < 0.001). Children with idiopathic uveitis were predominantly male (66.6%) with chronic anterior uveitis (41.7%). Nineteen children (65.5%) in the cohort had inactive disease on treatment at 12 months from diagnosis, which included 10 on topical corticosteroid therapy. At the last clinical visit 17 (58.6%) on standard initial therapy, 8 (27.6%) on tumour necrosis factor inhibitors and 2 on additional DMARDs were in remission. Five of these children still required topical corticosteroids. Surgery was performed in 41.4%, primarily in the idiopathic group. Visual acuity improved or was maintained on treatment.

CONCLUSION

Current practice seems to detect children with potentially sight-threatening disease but the high rate of complications and the low percentage of children with JIAU raises concerns of delayed healthcare intervention. Tumour necrosis factor inhibitors have improved outcomes in refractory cases in this cohort, however further studies are needed.

Tissue-Resident Memory T Cells in Chronic Inflammation-Local Cells with Systemic Effects?

Chronic inflammatory diseases such as rheumatoid arthritis (RA), Juvenile Idiopathic Arthritis (JIA), psoriasis, and inflammatory bowel disease (IBD) are characterized by systemic as well as local tissue inflammation, often with a relapsing-remitting course. Tissue-resident memory T cells (TRM) enter non-lymphoid tissue (NLT) as part of the anamnestic immune response, especially in barrier tissues, and have been proposed to fuel chronic inflammation. TRM display a distinct gene expression profile, including upregulation of CD69 and downregulation of CD62L, CCR7, and S1PR1. However, not all TRM are consistent with this profile, and it is now more evident that the TRM compartment comprises a heterogeneous population, with differences in their function and activation state. Interestingly, the paradigm of TRM remaining resident in NLT has also been challenged. T cells with TRM characteristics were identified in both lymph and circulation in murine and human studies, displaying similarities with circulating memory T cells. This suggests that re-activated TRM are capable of retrograde migration from NLT via differential gene expression, mediating tissue egress and circulation. Circulating 'ex-TRM' retain a propensity for return to NLT, especially to their tissue of origin. Additionally, memory T cells with TRM characteristics have been identified in blood from patients with chronic inflammatory disease, leading to the hypothesis that TRM egress from inflamed tissue as well. The presence of TRM in both tissue and circulation has important implications for the development of novel therapies targeting chronic inflammation, and circulating 'ex-TRM' may provide a vital diagnostic tool in the form of biomarkers. This review elaborates on the recent developments in the field of TRM in the context of chronic inflammatory diseases.

Ocular diseases: immunological and molecular mechanisms

Many factors, such as environmental, microbial and endogenous stress, antigen localization, can trigger the immunological events that affect the ending of the diverse spectrum of ocular disorders. Significant advances in understanding of immunological and molecular mechanisms have been researched to improve the diagnosis and therapy for patients with ocular inflammatory diseases. Some kinds of ocular diseases are inadequately responsive to current medications; therefore, immunotherapy may be a potential choice as an alternative or adjunctive treatment, even in the prophylactic setting. This article first provides an overview of the immunological and molecular mechanisms concerning several typical and common ocular diseases; second, the functions of immunological roles in some of systemic autoimmunity will be discussed; third, we will provide a summary of the mechanisms that dictate immune cell trafficking to ocular local microenvironment in response to inflammation.

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.

Treatment of Juvenile Idiopathic Arthritis-Associated Uveitis

Pediatric uveitis may be a serious health problem because of the lifetime burden of vision loss due to severe complications if the problem is not adequately treated. Juvenile idiopathic arthritis (JIA)-associated uveitis is characterized by insidious onset and potentially blinding chronic anterior uveitis. Periodic ophthalmologic screening is of utmost importance for early diagnosis of uveitis. Early diagnosis and proper immunomodulatory treatment are essential for good visual prognosis. The goal of treatment is to achieve enduring drug-free remission. The choice of therapeutic regimen needs to be tailored to each individual case. One must keep in mind that patients under immunomodulatory treatment should be monitored closely due to possible side effects. Local and systemic corticosteroids have long been the mainstay of therapy; however, long-term corticosteroid therapy should be avoided due to serious side effects. Steroid-sparing agents in the treatment of JIA-associated uveitis include antimetabolites and biologic agents in refractory cases. Among the various immunomodulatory agents, methotrexate is generally the first choice, as it has a well-established safety and efficacy profile in pediatric cases and does not appear to increase the risk of cancer. Other classic immunomodulators that may also be used in combination with methotrexate include azathioprine, mycophenolate mofetil, and cyclosporin A. Biologic agents, primarily tumor necrosis factor alpha inhibitors including infliximab or adalimumab, should be considered in cases of treatment failure with classic immunomodulatory agents.

Uveitis associated with juvenile idiopathic arthritis

Uveitis is a potentially sight-threatening complication of juvenile idiopathic arthritis (JIA). JIA-associated uveitis is recognized to have an autoimmune aetiology characterized by activation of CD4(+) T cells, but the underlying mechanisms might overlap with those of autoinflammatory conditions involving activation of innate immunity. As no animal model recapitulates all the features of JIA-associated uveitis, questions remain regarding its pathogenesis. The most common form of JIA-associated uveitis is chronic anterior uveitis, which is usually asymptomatic initially. Effective screening is, therefore, essential to detect early disease and commence treatment before the development of visually disabling complications, such as cataracts, glaucoma, band keratopathy and cystoid macular oedema. Complications can result from uncontrolled intraocular inflammation as well as from its treatment, particularly prolonged use of high-dose topical corticosteroids. Accumulating evidence supports the early introduction of systemic immunosuppressive drugs, such as methotrexate, as steroid-sparing agents. Prospective randomized controlled trials of TNF inhibitors and other biologic therapies are underway or planned. Future research should aim to identify biomarkers to predict which children are at high risk of developing JIA-associated uveitis or have a poor prognosis. Such biomarkers could help to ensure that patients receive earlier interventions and more-potent therapy, with the ultimate aim of reducing loss of vision and ocular morbidity.

Inhibition of ocular aldose reductase by a new benzofuroxane derivative ameliorates rat endotoxic uveitis

The study investigated the effects of the aldose reductase (AR) inhibitor benzofuroxane derivative 5(6)-(benzo[d]thiazol-2-ylmethoxy) benzofuroxane (herein referred to as BF-5m) on the biochemical and tissue alterations induced by endotoxic uveitis in rats. BF-5m has been administered directly into the vitreous, in order to assess the expression and levels of (i) inflammatory markers such as the ocular ubiquitin-proteasome system, NF-κB, TNF-α, and MCP-1; (ii) prooxidant and antioxidant markers such as nitrotyrosine, manganese superoxide dismutase (MnSOD), and glutathione peroxidase (GPX); (iii) apoptotic/antiapoptotic factors caspases and Bcl-xl; (iv) markers of endothelial progenitor cells (EPCs) recruitment such as CD34 and CD117. 5 μL of BF-5m (0.01; 0.05; and 0.1 μM) into the right eye decreased in a dose-dependent manner the LPS-induced inflammation of the eye, reporting a clinical score 1. It reduced the ocular levels of ubiquitin, 20S and 26S proteasome subunits, NF-κB subunits, TNF-α, MCP-1, and nitrotyrosine. BF-5m ameliorated LPS-induced decrease in levels of MnSOD and GPX. Antiapoptotic effects were seen from BF-5m by monitoring the expression of Bcl-xl, an antiapoptotic protein. Similarly, BF-5m increased recruitment of the EPCs within the eye, as evidenced by CD34 and CD117 antibodies.