Enthesitis-related arthritis

Presentation of enthesitis-related arthritis and juvenile-onset spondyloarthritis: a cross-sectional study in a pediatric and adult clinic

BACKGROUND

Juvenile idiopathic arthritis (JIA) comprises a whole spectrum of chronic arthritis starting before 16 years of age. The study aims to explore the clinical and demographic descriptors, treatment, and disease progression of enthesitis-related arthritis (ERA) in comparison with juvenile-onset spondyloarthritis (SpA).

METHODS

Cross-sectional analysis of consecutive patients in two dedicated clinics, with a single visit and retrospective case-notes review. Arthritis, enthesitis and sacroiliitis were evaluated by scoring disease activity and damage. Continuous variables were reported by median, interquartile range; categorical variables were reported by the frequency comparison of the two groups.

RESULTS

Thirty-three cases were included, being 23 (69.7%) with ERA. The median age at diagnosis was 12.5 y (SpA) vs. 9 y (ERA) (p < 0.01); the time from symptom onset to diagnosis was 5.5 y (SpA) vs. 1.5 y (ERA) (p < 0.03). In both groups, the predominant presentation was a single joint or < 5 lower limb joints and asymmetric involvement, with a high frequency of enthesitis. There was a higher frequency of mid-tarsal and ankle synovitis in the ERA group and hip involvement in those with SpA. The comparison of the frequency of spine symptoms at presentation, 30% SpA vs. 21.7% ERA (p = 0.7), was not significant, and radiographic progression to spinal involvement occurred in 43.5% of ERA patients. The median time for spinal progression and age at onset was 2.2 and 12 y for ERA, and 4 and 16.5 y for SpA, respectively. Activity and damage scores were not significantly different between the groups. Treatment comparison resulted in 91.3% of ERA and 100% SpA being treated, predominantly with NSAIDs in both groups, followed by DMARDs and biologics, with a higher frequency of biologics in SpA.

CONCLUSION

The main differences were the late diagnoses of SpA, and the hip and spine involvement, with higher frequency of biologic treatment in juvenile-onset SpA compared to ERA.

A clinical perspective on imaging in juvenile idiopathic arthritis

In recent years, imaging has become increasingly important to confirm diagnosis, monitor disease activity, and predict disease course and outcome in children with juvenile idiopathic arthritis (JIA). Over the past few decades, great efforts have been made to improve the quality of diagnostic imaging and to reach a consensus on which methods and scoring systems to use. However, there are still some critical issues, and the diagnosis, course, and management of JIA are closely related to clinical assessment. This review discusses the main indications for conventional radiography (XR), musculoskeletal ultrasound (US), and magnetic resonance imaging (MRI), while trying to maintain a clinical perspective. The diagnostic-therapeutic timing at which one or the other method should be used, depending on the disease/patient phenotype, will be assessed, considering the main advantages and disadvantages of each imaging modality according to the currently available literature. Some brief clinical case scenarios on the most frequently and severely involved joints in JIA are also presented.

Predictors of long-term functional outcomes of juvenile idiopathic arthritis-enthesitis-related arthritis: a single centre experience

OBJECTIVES

Long-term functional outcomes in enthesitis-related arthritis (ERA) is limited from developing countries. We assessed the clinical and genetic factors that predicted the long-term functional outcome in ERA.

METHODS

Patients with ERA having ≥5 years of disease and >16 years of age were included in this cross-sectional study. Data on clinical features within 6 months of disease onset was collected from hospital records. Bath indices, HAQ Disability Index (HAQ-DI) and World Health Organization's Quality of Life (WHO-QOL) were assessed at last visit. Poor functional outcome (PFO) was defined as BASFI > 1.5 or HAQ-DI > 1. Persistent disease activity (PDA) was defined as BASDAI ≥ 4. Endoplasmic reticulum aminopeptidase 1 (ERAP1) and IL-23 receptor single nucleotide polymorphism genotyping was performed with the TaqMan method and HLA-B27 by PCR.

RESULTS

One hundred and eighty-one patients [170 male, median (interquartile range) age of disease onset 12.5 (10-15) years, disease duration 7 (5-11) years] were recruited. There was a delay in diagnosis of 3 (1-5) years. The median Ankylosing Spondylitis Disease Activity Score (ASDAS)-ESR, BASDAI, HAQ-DI and BASFI at inclusion were 2.6 (1.8-3.6), 2.6 (1-5.2), 0.5 (0-0.5) and 1.6 (0.3-3.2), respectively. BASFI and HAQ-DI correlated with ASDAS-ESR, ASDAS-CRP and WHO-QOL-BREF. Those with PFO (n = 98) had a longer delay in diagnosis (4 vs 2 years, P < 0.001), lower prevalence of arthritis at onset [odds ratio (OR) = 0.3; 95% CI: 0.1, 0.8], higher prevalence of ERAP1 (rs27044) allele C (OR = 7.2; 95% CI: 1.5, 33.7) and higher disease activity currently. Delay in diagnosis (OR = 1.2; 95% CI: 1.08, 1.4) was the sole predictor of PFO in multivariate analysis. One-third of patients had PDA. Tarsitis at disease onset was the sole predictor of PDA (OR = 2.3; 95% CI: 1.009, 5.4).

CONCLUSIONS

PFO was seen in one-half of JIA-ERA in the long-term and was associated with active disease with delay in diagnosis as its sole predictor.

Macrophage migration inhibitory factor (MIF) and IgA anti CD74 antibodies in Indian patients with enthesitis-related arthritis category of Juvenile idiopathic arthritis

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine and has been implicated in pathogenesis of ankylosing spondylitis (AS). CD 74 is the receptor for MIF and IgA antiCD74 autoantibodies have been described from different parts of the world in patients with AS. As enthesitis-related arthritis (ERA) is a form of juvenile spondyloarthropathy, we studied the serum and synovial fluid levels of MIF in ERA and looked for the IgA antiCD74 antibodies in patients with ERA in our population. Patients with JIA (ILAR classification) were studied. Serum MIF levels were measured by ELISA in 101 patients of ERA (synovial fluid also where available) and compared to 28 patients of other categories of JIA, 25 patients each of ankylosing spondylitis and rheumatoid arthritis, and 38 healthy controls. In addition, association of MIF with disease activity was assessed. Ig A antiCD74 antibodies were measured in sera of ERA, AS and healthy controls. Median serum MIF levels were higher in ERA [2.50 (1.20-4.85) ng/ml] than in healthy controls [0.28 (0.16-0.48); p < 0.0001] and patients with RA [1.13 (0.44-2.45); p < 0.01] MIF levels in ERA were comparable to other categories of JIA [2.63 (1.70-4.05)] and patients with AS [3.62 (0.52-6.51)]. Synovial fluid MIF levels were higher than serum levels (p < 0.01). Serum MIF level had an association with the JSpADA score (r = 0.29, p < 0.01). Serum MIF levels had no association with presence of inflammatory markers, enthesitis, inflammatory back pain or sacroiliitis. IgA AntiCD74 antibody was positive only in 3/88 (3.41%) of ERA patients and was not detected in any patients of AS or healthy controls. Patients with ERA have high MIF levels that show modest correlation with disease activity. Higher synovial fluid MIF levels suggest that it may play a role in synovitis seen in ERA. IgA antiCD74 antibodies are rarely seen in ERA.

IL-36γ in enthesitis-related juvenile idiopathic arthritis and its association with disease activity

IL-36 has been implicated in the pathogenesis of spondyloarthropathies (SpA) like psoriasis and inflammatory bowel disease. Enthesitis-related arthritis (ERA) category of juvenile idiopathic arthritis is a form of juvenile SpA, however, no data is available on the role of IL-36 in this disease. IL-36α, β, γ and IL-36R mRNA expression in blood and synovial fluid mononuclear cells and IL-36α, γ, IL-36Ra, IL-6, and IL-17 levels were measured in serum and synovial fluid (SF). IL-36γ production by fibroblast-like synoviocytes (FLS) upon stimulation with pro-inflammatory cytokines and its effect on FLS were also studied. mRNA levels of IL-36α, IL-36γ, and IL-36R were increased in PBMCs of ERA patients as compared to healthy controls however only IL-36γ was measurable in the serum of one-third of patients. In SFMCs, all four mRNA were detectable but were lower than RA patients. SF IL-36γ levels correlated with disease activity score (r = 0.51, P < 0.0001), SF IL-6 (r = 0.4, P = 0.0063) and IL-17 levels (r = 0.57, P = 0.0018). Pro-inflammatory cytokines increased the expression of IL-36γ and IL-6 in FLS cultures. SFs from five ERA patients also increased expressions of IL-36γ and IL-6 in FLS which could be blocked by using IL-36Ra. This suggests that pro-inflammatory cytokines aid in the upregulation of IL-36γ which in turn may upregulate the expression of IL-6. This might lead to a positive feedback loop of inflammation in ERA. Association of SF levels of IL-36γ with disease activity further supports this possibility. IL-36Ra based therapy may have a role in ERA.

Joint involvement, disease activity and quality of life in pediatric Crohn's disease - a cross-sectional study

BACKGROUND

Few published data describe how joint involvement, the most prevalent extraintestinal manifestation, affects quality of life (QoL) of children with Crohn's disease (CD). Arthritis and arthralgia rates in pediatric CD patients are reportedly 3-24% and 17-22%, respectively, but studies on pre-emptive and systematic screening of joint involvement with detailed musculoskeletal rheumatological exam are lacking. More detailed data collection on joint involvement improves our understanding of how arthropathy relates to disease activity and QoL measured by the Pediatric CD Activity Index (PCDAI) and IMPACT-III questionnaire. Our study aims were to assess joint involvement in pediatric CD and correlate it with the PCDAI and IMPACT-III.

METHODS

In this cross-sectional, observational study, a pediatric gastroenterologist assessed consecutively-seen pediatric CD patients at a tertiary care center. Patients were screened for prevalence of current and previous arthropathy, including arthritis, enthesitis and arthralgia. A single experienced pediatric rheumatologist evaluated detailed musculoskeletal history, joint status, and modified Juvenile Arthritis Multidimensional Assessment Reports (JAMAR). PCDAI, IMPACT-III, sacroiliac MRI, and HLA-B27 genetic testing were also completed.

RESULTS

A total of 82 (male:female, 1.2:1; age, 13.7 ± 3.2 years) patients were involved in this study. Mean disease duration at time of study was 21.6 ± 21 months; eight of the patients were newly-diagnosed. Of the 82 patients, 29 (35%) had evidence of arthritis; for 24 of those, this was revealed by physical exam during cross-sectional screening, and by prior documentation for the remaining five patients. Joint examination confirmed active arthritis in 8/24 (33%), active enthesitis in 1/24 (4%), and evidence of previous arthritis in 15/24 (62.5%) patients. Hip (41%) and knee (38%) joints were most commonly affected. Cumulative incidence of arthralgia was 48% (39/82), and 46% (18/39) of those patients had only arthralgia without arthritis, usually affecting the knee. Axial involvement was present in 10/82 (12%) patients. Joint involvement correlated with more severe CD disease activity, specifically higher PCDAI and lower IMPACT-III scores, and increased requirement for infliximab treatment. Sacroiliitis and HLA-B27 positivity were insignificant factors in this cohort.

CONCLUSIONS

When a rheumatologist performed the assessment, joint involvement in pediatric CD was more prevalent than previously reported, in this cross-sectional study. Arthritis was associated with more severe CD disease activity and lower QoL.

Similarities and Differences Between Juvenile and Adult Spondyloarthropathies

Spondyloarthritis (SpA) encompasses a broad spectrum of conditions occurring from childhood to middle age. Key features of SpA include axial and peripheral arthritis, enthesitis, extra-articular manifestations, and a strong association with HLA-B27. These features are common across the ages but there are important differences between juvenile and adult onset disease. Juvenile SpA predominantly affects the peripheral joints and the incidence of axial arthritis increases with age. Enthesitis is important in early disease. This review article highlights the similarities and differences between juvenile and adult SpA including classification, pathogenesis, clinical features, imaging, therapeutic strategies, and disease outcomes. In addition, the impact of the biological transition from childhood to adulthood is explored including the importance of musculoskeletal and immunological maturation. We discuss how the changes associated with adolescence may be important in explaining age-related differences in the clinical phenotype between juvenile and adult SpA and their implications for the treatment of juvenile SpA.

Current status of MR imaging of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy in the pediatric population. Although the diagnosis is essentially clinical for many affected joints, MR imaging has become an important tool for the assessment of joints that are difficult to evaluate clinically, such as temporomandibular and sacroiliac joints, and for screening of inflammatory changes in the entire body by whole body MRI (WBMRI) assessment. The utilization of MR imaging is challenging in the pediatric population given the need for discrimination between pathological and physiological changes in the growing skeleton. Several multicentric multidisciplinary organizations have made major efforts over the past decades to standardize, quantify, and validate scoring systems to measure joint changes both cross-sectionally and longitudinally according to rigorous methodological standards. In this paper, we (1) discuss current trends for the diagnosis and management of JIA, (2) review challenges for detecting real pathological changes in growing joints, (3) summarize the current status of standardization of MRI protocols for data acquisition and the quantification of joint pathology in JIA by means of scoring systems, and (4) outline novel MR imaging techniques for the evaluation of anatomy and function of joints in JIA. Optimizing the role of MRI as a robust biomarker and outcome measure remains a priority of future research in this field.

Juvenile idiopathic arthritis and the gut microbiome: Where are we now?

In recent decades, because of advances in technology there has been an explosion of knowledge on how microbiome affects human health. In most chronic immune-inflammatory diseases, alterations in gut microbiome has been shown. The successful use of faecal microbial transplants for the treatment of clostridium difficile associated diarrhoea has also paved the way for novel therapies. Gut microbiome is affected by early life events like the mode of delivery, breast feeding, the use of antibiotics, etc. and that may have an indirect effect on the developing immune system as well as on the predisposition to juvenile idiopathic arthritis (JIA). Multiple studies have found altered gut microbiome in JIA though no single organism or microbial community has been found to be associated with JIA. In JIA, attempts to modify gut microbiome by using probiotics, exclusive enteral nutrition and other modalities have had variable success. The current review discusses the current data available on gut microbiome in different categories of JIA and how this knowledge can translate into new therapies.

Current and emerging biologics for the treatment of juvenile idiopathic arthritis

INTRODUCTION

The management of a child with juvenile idiopathic arthritis (JIA) requires a combination of pharmacological, physical, and psychosocial therapies in order to induce disease remission, by controlling articular and systemic inflammation. This review aims to provide a comprehensive discussion on the biological therapies currently in use in the treatment of JIA referring to existing recommendations and clinical evidence. We also discuss on the emerging biological drugs actually under consideration.

AREAS COVERED

Recent findings on immunological mechanisms involved in the pathogenesis of the disease allowed us to identify several specific targets for biologic therapies. A systematic literature review was conducted between January 1997 and January 2020 on PubMed including national and international guidelines and recommendations, trials and case-control studies.

EXPERT OPINION

There is now a plethora of therapies that are directed against variable targets, and the physician has to choose the most appropriate available medication in order to achieve early and sustained remission with as few side effects as possible. Research is advancing very fast in order to be more and more specific in suppressing inflammatory pathways without harming natural defenses. Finally, pharmacoeconomic considerations will also be very important to deal with, considering the high cost of most of these molecules.

Musculoskeletal ultrasound in children: Current state and future directions

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of chronic inflammatory arthritides that if inadequately treated, may be associated with chronic disability and deformity. Early diagnosis and treatment initiation is essential in the management of patients with JIA. Conventional means of evaluation of disease presence, disease activity and response to therapy including physical exam, labs and x-rays are at times limited and may be insufficient in making an accurate assessment. Musculoskeletal ultrasound (MSUS) is a well-established modality that is patient and family-friendly, non-invasive, does not require sedation and can be performed at the bedside in real-time. MSUS offers information that cannot be attained by standard outcome measures, and may help to advance both diagnosis and treatment of patients with JIA ultimately improving patient outcomes. This review explores the background of MSUS and the current evidence to support its potential role as a diagnostic, disease activity monitoring and interventional tool.

Successful treatment in a child with enthesitis-related arthritis involving the sternoclavicular joint: a case report

Background

Although the sternoclavicular joint (SCJ) may be involved in ankylosing spondylitis, rheumatic arthritis, and Behçet’s disease and participates in the systemic inflammatory process of arthritis, it is often neglected during routine rheumatologic clinical examinations. To the best of our knowledge, this is the first study to report etanercept treatment in juvenile idiopathic arthritis (JIA) with SCJ involvement.

Case presentation

In this study, we describe an unusual case of a child with juvenile idiopathic arthritis with an initial presentation of sternoclavicular mass. The patient (age, 14 years 10 months) presented with an insidious onset atraumatic swelling of the left SCJ and complained of right hip and bilateral ankle tenderness without an apparent cause. Initial ultrasonography indicated a heterogeneous mass in the left SCJ, while computed tomography identified mild swelling of the left SCJ with a thickened synovial lining, mild bone erosion, and some turbid fluid. The patient ultimately underwent left SCJ arthrotomy, during which tapping of the SCJ revealed 2 cc of yellowish fluid, inflammation and necrosis of tissues within the SCJ. A clear yellow joint fluid was aspirated, and testing revealed a negative culture result. The patient was diagnosed with JIA. The joint tenderness improved and erythrocyte sedimentation rate decreased after administering anti-tumor necrosis factor etanercept. An additional ultrasonography demonstrated that the initial imaging findings have been resolved. At the end of a 2-year follow-up period, the patient was completely symptom-free.

Conclusions

JIA with SCJ involvement is an uncommon presentation in adolescents. Etanercept may be a beneficial treatment for SCJ involvement in patients with JIA. The upper limbs showed no signs of limited range of motion during the follow-up period. Further studies are warranted to elucidate the efficacy of etanercept in JIA with sternoclavicular joint involvement.

Update on the management of uveitis in children: an overview for the clinician

INTRODUCTION

Pediatric uveitis comprises a range of ocular inflammatory diseases that may lead to vision impairment, often due to ocular complications from the disease itself or side effects of therapies. The impact on vision, visual functioning, and vision-related quality-of-life over the lifetime horizon can be substantial, underscoring the importance of appropriate ophthalmic evaluation, diagnostic testing and treatment. This review focuses on the anatomic classification, laboratory diagnosis, associated systemic diseases, and management of pediatric uveitis.

AREAS COVERED

A review of the literature was performed to synthesize our current understanding of the anatomic classification of pediatric uveitis, disease epidemiology, associated systemic diseases, and management principles. We also review important corticosteroid-sparing strategies including non-biologic and biologic agents such as the anti-tumor necrosis factor (TNF)-alpha family of medications, given their key role in the treatment of pediatric uveitis, particularly juvenile idiopathic arthritis (JIA). Recent advances in the assessment of vision-related quality-of-life using the Effects of Youngsters' Eyesight on Quality of Life (EYE-Q) instrument are discussed.

EXPERT OPINION

Pediatric uveitis can lead to long-term vision impairment if not appropriately screened and treated. JIA is the most common systemic disease associated with uveitis, is typically asymptomatic, and thus requires rigorous screening to detect uveitis and avoid secondary ocular complications. While topical and systemic corticosteroids are useful for the acute treatment of uveitis, the disease chronicity of many pediatric uveitis syndromes including JIA, often warrants early escalation of therapy to immunosuppressive medications including methotrexate (MTX) and anti-TNF-alpha inhibitors. Future directions include an improved understanding of risk factors for uveitis and better metrics to evaluate the impact of disease on vision-related quality-of-life of pediatric uveitis patients.

Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis is the most common chronic rheumatic disease of unknown aetiology in childhood and predominantly presents with peripheral arthritis. The disease is divided into several subgroups, according to demographic characteristics, clinical features, treatment modalities and disease prognosis. Systemic juvenile idiopathic arthritis, which is one of the most frequent disease subtypes, is characterized by recurrent fever and rash. Oligoarticular juvenile idiopathic arthritis, common among young female patients, is usually accompanied by anti-nuclear antibodie positivity and anterior uveitis. Seropositive polyarticular juvenile idiopathic arthritis, an analogue of adult rheumatoid arthritis, is seen in less than 10% of paediatric patients. Seronegative polyarticular juvenile idiopathic arthritis, an entity more specific for childhood, appears with widespread large- and small-joint involvement. Enthesitis-related arthritis is a separate disease subtype, characterized by enthesitis and asymmetric lower-extremity arthritis. This disease subtype represents the childhood form of adult spondyloarthropathies, with human leukocyte antigen-B27 positivity and uveitis but commonly without axial skeleton involvement. Juvenile psoriatic arthritis is characterized by a psoriatic rash, accompanied by arthritis, nail pitting and dactylitis. Disease complications can vary from growth retardation and osteoporosis secondary to treatment and disease activity, to life-threatening macrophage activation syndrome with multi-organ insufficiency. With the advent of new therapeutics over the past 15 years, there has been a marked improvement in juvenile idiopathic arthritis treatment and long-term outcome, without any sequelae. The treatment of juvenile idiopathic arthritis patients involves teamwork, including an experienced paediatric rheumatologist, an ophthalmologist, an orthopaedist, a paediatric psychiatrist and a physiotherapist. The primary goals of treatment are to eliminate active disease, to normalize joint function, to preserve normal growth and to prevent long-term joint damage. Timely and aggressive treatment is important to provide early disease control. The first-line treatment includes disease-modifying anti-rheumatic drugs (methotrexate, sulphasalazine, leflunomide) in combination with corticosteroids, used in different dosages and routes (oral, intravenous, intra-articular). Intra-articular application of steroids seems to be an effective treatment modality, especially in monoarthritis. Biological agents should be added in the treatment of unresponsive patients. Anti-tumour necrosis factor agents (etanercept, infliximab, adalimumab), anti-interleukin-1 agents (anakinra, canakinumab), anti- interleukin-6 agents (tocilizumab) and T-cell regulatory agents (abatacept) have been shown to be safe and effective in childhood patients. Recent studies reported sustained reduction in joint damage with even complete clinical improvement in paediatric patients, compared to previous data.

Clinical features of children with enthesitis-related juvenile idiopathic arthritis / juvenile spondyloarthritis followed in a French tertiary care pediatric rheumatology centre

BACKGROUND

Childhood-onset spondyloarthropathies usually start with enthesitis and peripheral arthritis. However, axial disease may develop afterward. Patients are most often classified, following revised (Edmonton 2011) ILAR criteria, as enthesitis-related arthritis, psoriatic arthritis, or unclassified juvenile idiopathic arthritis, particularly in cases of psoriasis in the patient or a first-degree relative. In adults, peripheral spondyloarthritis is classified by ASAS criteria.

METHODS

We retrospectively studied patients with childhood-onset spondyloarthropathies followed for more than one year in our referral centre. We did not exclude patients with a personal or familial history of psoriasis.

RESULTS

We included 114 patients followed between January 2008 and December 2015 for a median of 2.5 years (IQR = 2.3). Sixty-nine per-cent of patients fulfilled the revised ILAR classification criteria for enthesitis-related arthritis, and 92% the ASAS criteria for peripheral spondyolarthritis (p <  0.001). Axial disease and sacroiliitis were rare at disease onset. However, they appeared during follow-up in 63% and 47% of cases respectively, after a median disease duration of 2.6 (IC 95% [2.2-4.4]) and 5.3 years (IC 95% [4.1-7.7]), respectively. Multivariable analysis showed that familial history of spondyloarthritis was associated with the presence of sacroiliitis and active disease at the latest follow-up (OR = 3.61 [1.5-8.7], p <  0.01 and 2.98 [1.2-7.3], p = 0.02, respectively).

CONCLUSION

Axial involvement developed in most patients within five years. Revised Edmonton criteria were less sensitive than ASAS criteria to classify patients as having childhood-onset spondyloarthropathies. The main risk factor for both sacroiliitis and persistent active disease was a familial history of spondyloarthritis.

Decreased PD-1 expression on circulating CD4+T cell and PD-L1 expression on myeloid dendritic cell correlate with clinical manifestations in systemic juvenile idiopathic arthritis

OBJECTIVES

Programmed cell death-1 (PD-1) and its ligand (PD-L1) mediate negative signal in autoimmune diseases. While little is known about its role in juvenile idiopathic arthritis (JIA). The study aimed to reveal the circulating cell profile and the relative PD-1/PD-L1 expression of JIA subsets, elucidating their underlying immunomodulatory mechanisms.

METHODS

We detected the circulating cells and the relative PD-1/PD-L1 signaling in 101 JIA patients and 50 controls by flow cytometry and analyzed their association with disease activity and clinical manifestations.

RESULTS

Different from other JIA types, active systemic JIA (sJIA) patients had lower percentage and count of CD4⁺T cells and lower PD-1 expression on them compared with healthy controls (P<0.05), active polyarthritis (P<0.05) and enthesitis-related arthritis (ERA) patients (P<0.05). Also, they had higher percentage and count of myeloid dendritic cell (mDC) and lower PD-L1 expression on mDC compared with healthy controls (P<0.05). Both PD-1 on CD4⁺T cell and PD-L1 on mDC were negatively correlated with JADAS-27 in sJIA patients (P<0.05). In addition, PD-1 expression on CD4⁺T cell was negatively associated with the number of involved joints (P<0.05) and PD-L1 on mDC was lower in patients with fever (P<0.01), which could further divide patients into two groups of different manifestations.

CONCLUSIONS

Our finding displayed decreased CD4⁺T cell, increased mDC and reduced PD-1/PD-L1 signal in sJIA PBMC comparing with other JIA subsets, which might be helpful in JIA differential diagnosis and responsible for distinct clinical manifestations via different mechanisms.

Juvenile Spondyloarthropathies

Juvenile spondyloarthropathies represent a clinical entity separate from the adult disease. Initial clinical signs of juvenile spondyloarthropathies often include lower extremity arthritis and enthesopathy, without axial involvement at the disease onset. Asymmetrical oligoarthritis of lower extremities is typically seen in this type of arthritis. Enthesopathy, which is the hallmark of the disease, is most commonly seen in the Achilles tendon, being manifested by heel pain. Anterior uveitis and HLA-B27 positivity are seen in a proportion of cases. Sacroiliitis is generally asymptomatic in the pediatric population. Ineffective treatment of childhood disease results in disease progression to typical adult form of ankylosing spondylitis. Therefore, early diagnosis and classification remains one of the most relevant questions in pediatric rheumatology. It should be kept in mind that the disease could be misdiagnosed as FMF or Behçet's syndrome in countries with a high incidence of those conditions. This review revises available classification criteria, clinical manifestations and therapeutic options for patients with juvenile spondyloarthropathies.

The performance of classification criteria for juvenile spondyloarthropathies

Juvenile spondyloarthropathies (JSpA) are a group of rheumatologic diseases with a disease onset before 16; characterized with enthesitis, lower extremity oligoarthritis, involvement of the axial skeleton and HLA B27 positivity. The diversity of classification criteria along with the phenotype heterogeneity makes the classification of JSpA challenging. The aim of our study was to evaluate the performance of the pre-determined and recently proposed classification criteria for JSpA. The study group consisted of 113 patients with JSpA and 150 patients with juvenile idiopathic arthritis (JIA). Eligible criteria for JSpA were applied to all of the enrolled patients. The analysis of sensitivity, specificity and the kappa index were used to verify the performance of the JSpA criteria. The Amor criteria showed the highest sensitivity (98.2%) while the ASAS criteria for the axial SpA had highest specificity (100%). The sensitivity and specificity of the remaining criteria were: 93.8 and 63.8% for ESSG, 95.6 and 62.7% for Garmisch-Partenkirchen, 91.2 and 75.3% for ASAS criteria for peripheral SpA, respectively. Criteria proposed by our group showed the high sensitivity, specificity and kappa value: 90.3, 90.7, 0.843%, respectively. We suggest that criteria proposed by us could be used in the classification of JSpA. However, neither the pre-determined nor the new criteria are totally adequate and efficacious for the classification and diagnosis of this disease. The evaluation of the validity and reliability of proposed criteria in multicentric studies are mandatory, to increase its utility in routine clinical practice.

Management of Juvenile Idiopathic Arthritis: A Clinical Guide

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease of childhood. The outcome in patients with JIA has markedly improved with the advent of biologic drugs. Although early aggressive therapy with biologics seems to be very effective, this approach leads to overtreatment in patients who would respond to classic disease-modifying anti-rheumatic drugs. Therefore, methotrexate remains first-line long-term therapy for most children with polyarticular JIA. Tumor necrosis factor-α inhibitors have shown tremendous benefit in children with refractory non-systemic JIA. Similar effects have been observed with interleukin-1 and interleukin-6 blockade in patients with systemic JIA. Correct choice and timely use of available medications to achieve early and sustained remission with as few side effects as possible remain challenges for the treating physician. In this review, a practical, clinically oriented guide to the management of JIA is provided, focusing on pharmacological treatment with non-steroidal anti-inflammatory drugs, intra-articular and systemic corticosteroids, disease-modifying anti-rheumatic drugs, and biologic agents. In addition, issues regarding treatment failure, early aggressive treatment, and drug tapering are discussed, with alternative treatment options being suggested.

Alteration of Fecal Microbiota Profiles in Juvenile Idiopathic Arthritis. Associations with HLA-B27 Allele and Disease Status

Alteration of gut microbiota is involved in several chronic inflammatory and autoimmune diseases, including rheumatoid arthritis, and gut microbial “pro-arthritogenic” profiles have been hypothesized. Intestinal inflammation may be involved in spondyloarthropathies and in a subset of patients affected by Juvenile Idiopathic Arthritis (JIA), the most common chronic rheumatic disease of childhood. We compared the fecal microbiota composition of JIA patients with healthy subjects (HS), evaluating differences in microbial profiles between sub-categories of JIA, such as enthesitis-related arthritis (JIA-ERA), in which inflammation of entheses occurs, and polyarticular JIA, non-enthesitis related arthritis (JIA-nERA). Through taxon-level analysis, we discovered alteration of fecal microbiota components that could be involved in subclinical gut inflammation, and promotion of joint inflammation. We observed abundance in Ruminococcaceae in both JIA categories, reduction in Clostridiaceae and Peptostreptococcaceae in JIA-ERA, and increase in Veillonellaceae in JIA-nERA, respectively, compared with HS. Among the more relevant genera, we found an increase in Clostridium cluster XIVb, involved in colitis and arthritis, in JIA-ERA patients compared with HS, and a trend of decrease in Faecalibacterium, known for anti-inflammatory properties, in JIA-nERA compared with JIA-ERA and HS. Differential abundant taxa identified JIA patients for the HLA-B27 allele, including Bilophila, Clostridium cluster XIVb, Oscillibacter, and Parvimonas. Prediction analysis of metabolic functions showed that JIA-ERA metagenome was differentially enriched in bacterial functions related to cell motility and chemotaxis, suggesting selection of potential virulence traits. We also discovered differential microbial profiles and intra-group variability among active disease and remission, suggesting instability of microbial ecosystem in autoimmune diseases with respect to healthy status. Similarly to other chronic autoimmune and inflammatory diseases, different microbial profiles, as observed among different JIA subgroups compared to HS, and potential functional acquisition related to migration, could promote inflammation and contribute to the disease pathogenesis.