Effectiveness and safety of a second and third biological agent after failing etanercept in juvenile idiopathic arthritis: results from the Dutch National ABC Register

Patterns and determinants of response to novel therapies in juvenile and adult-onset polyarthritis

Biologic and targeted synthetic DMARDs (b/tsDMARDs) have revolutionized the management of multiple rheumatic inflammatory conditions. Among these, polyarticular JIA (pJIA) and RA display similarities in terms of disease pathophysiology and response pattern to b/tsDMARDs. Indeed, the therapeutic efficacy of novel targeted drugs is variable among individual patients, in both RA and pJIA. The mechanisms and determinants of this heterogeneous response are diverse and complex, such that the development of true 'precision'-medicine strategies has proven highly challenging. In this review, we will discuss pathophysiological, patient-specific, drug-specific and environmental factors contributing to individual therapeutic response in pJIA in comparison with what is known in RA. Although some biomarkers have been identified that stratify with respect to the likelihood of either therapeutic response or non-response, few have proved useful in clinical practice so far, likely due to the complexity of treatment-response mechanisms. Consequently, we propose a pragmatic, patient-centred and clinically based approach, i.e. personalized instead of biomarker-based precision medicine in JIA.

Biologic switching patterns among children with non-systemic juvenile idiopathic arthritis

BACKGROUND

In juvenile idiopathic arthritis (JIA) clinical remission is unattainable in some patients despite modern biologic disease-modifying antirheumatic drugs (bDMARD) therapy and switching bDMARD is required. The best choice of second-line bDMARD remains unclear. This retrospective observational study aims to describe the pattern, timing, frequency, and reasons for bDMARD switching among children diagnosed with non-systemic JIA.

METHODS

Patients were identified by combining unique personal identification numbers, the International Code of Diagnosis (ICD10) for JIA and biologic therapy. Clinical characteristics were collected retrospectively from the electronic medical records. Included were 200 children diagnosed with non-systemic JIA initiating their first biologic drug between January 1st, 2012, and March 1st, 2021. We compared characteristics of non-switchers vs switchers and early switchers (≤ 6 months) vs late switchers (> 6 months).

RESULTS

The median age at diagnosis was 7.7 years. We found that 37% switched to a different bDMARD after a median age of 6.3 years after diagnosis. In total, and 17.5% of patients switched at least twice, while 6% switched three or more times. The most common reason for switching was inefficacy (57%) followed by injection/infusion reactions (15%) and uveitis (13%). 77% were late switchers, and switched primarily due to inefficacy. All patients started a tumor necrosis factor inhibitor (TNFi) as initial bDMARD (Etanercept (ETN): 49.5%, other TNFis: 50.5%). The patients who started ETN as first-line bDMARD were more likely to be switchers compared to those who started another TNFi.

CONCLUSION

During a median 6.3-year follow-up biologic switching was observed in more than one third, primarily due to inefficacy.

Biological Agent Switching in Patients With Juvenile Idiopathic Arthritis: A Tertiary Center Experience

OBJECTIVE

The purpose of this study is to investigate the causes and outcomes of switching biological agents in juvenile idiopathic arthritis (JIA) patients using biological agents and compare the characteristics of patients whose biological agents are switched and those whose are not.

METHODS

This medical records review study was conducted with 128 patients who were diagnosed with JIA at our clinic between January 2009 and January 2022 and were receiving biologic agents. Factors affecting the biologic agent switching were investigated.

RESULTS

The JIA subtype with the most frequent switching in biological agents was systemic JIA (n = 13, 40.6%). Systemic JIA was followed by rheumatoid factor-negative polyarticular JIA and persistent oligoarticular JIA with 5 patients (15.6%), extended oligoarticular JIA and enthesitis-related JIA with 3 patients (9.3%), rheumatoid factor-positive polyarticular JIA with 2 patients (6.2%), and undifferentiated JIA with 1 patient (3.1%). Among the patients, 32 (25%) patients had their biological agent switched once, and 5 (3.9%) had theirs switched twice. The most frequently used biological agent was etanercept (n = 76, 59.3%), whereas the most frequently observed cases of biological agent switching were from an anti-TNF agent to another anti-TNF agent (40.6%). The reason for switching was unresponsiveness to the agent in 22 patients (68.8%), adverse effects in 6 patients (18.7%), drug intolerance in 1 patient (3.1%), and other reasons in 3 patients (9.3%).

CONCLUSIONS

The most frequently used biological agent was etanercept; the most frequent cases of biological agents switching were from an anti-TNF agent to another anti-TNF agent.

Refractory inflammatory arthritis definition and model generated through patient and multi-disciplinary professional modified Delphi process

OBJECTIVE

Various definitions have been proposed for Refractory Disease in people with Rheumatoid Arthritis; however, none were generated for Polyarticular Juvenile Idiopathic Arthritis or involving adult and paediatric multidisciplinary healthcare professionals and patients. The study aim is to redefine Refractory Disease, using Delphi methodology.

METHODS

Three rounds of surveys (one nominal group and two online (2019-2020)) to achieve consensus using a predetermined cut-off were conducted voting on: a) name, b) treatment and inflammation, c) symptoms and impact domains, and d) rating of individual components within domains. Theoretical application of the definition was conducted through a scoping exercise.

RESULTS

Votes were collected across three rounds from Patients, Researchers and nine multi-disciplinary healthcare professional groups (n = 106). Refractory Inflammatory Arthritis was the most popular name. Regarding treatment and inflammation, these were voted to be kept broad rather than specifying numbers/cut-offs. From 10 domains identified to capture symptoms and disease impact, six domains reached consensus for inclusion: 1) Disease Activity, 2) Joint Involvement, 3) Pain, 4) Fatigue, 5) Functioning and Quality of Life, and 6) Disease-Modifying Anti-Rheumatic Drug Experiences. Within these domains, 18 components, from an initial pool (n = 73), were identified as related and important to capture multi-faceted presentation of Refractory Inflammatory Arthritis, specifically in Rheumatoid Arthritis and Polyarticular Juvenile Idiopathic Arthritis. Feasibility of the revised definition was established (2022-2023) with good utility as was applied to 82% of datasets (n = 61) incorporating 20 outcome measures, with two further measures added to increase its utility and coverage of Pain and Fatigue.

CONCLUSION

Refractory Inflammatory Arthritis has been found to be broader than not achieving low disease activity, with wider biopsychosocial components and factors incorporating Persistent Inflammation or Symptoms identified as important. This definition needs further refinement to assess utility as a classification tool to identify patients with unmet needs.

Efficacy and safety of canakinumab as a second line biologic after tocilizumab treatment failure in children with systemic juvenile idiopathic arthritis: A single-centre cohort study using routinely collected health data

Background

A significant number of systemic juvenile idiopathic arthritis (sJIA) patients discontinue biologic disease-modifying antirheumatic drugs (bDMARDs) due to lack of efficacy or safety concerns. Studies of biologic therapy switch regimens in sJIA are required.

Methods

Patients with sJIA who switched from tocilizumab (due to lack of efficacy or safety) to canakinumab (4 mg/kg every 4 weeks) and were hospitalized at the rheumatology department from August 2012 to July 2020 were included. Primary efficacy outcomes were 30% or greater improvement based on the paediatric criteria of the American College of Rheumatology (ACR30), achievement of inactive disease (JADAS-71 = 0) and clinical remission (ACR sJIA clinical inactive disease criteria). Follow-up from time first canakinumab dose administered was 12 months or the closest time point (not less than 6 and not more than 18 months). Data were extracted from electronic outpatient medical records.

Results

During the study period, 46 patients with sJIA switched from tocilizumab to canakinumab. Median age at baseline was 8.2 [interquartile range (IQR) 4.0-12.9] years, with the median sJIA duration being 1.8 (IQR 0.8-5.8) years; 37 (80%) patients received at least one conventional DMARD (cDMARD; oral corticosteroids, methotrexate and/or cyclosporine A). Study outcomes were followed up in 45 patients (one patient did not attend the follow-up for an unknown reason); median follow-up was 359 (IQR 282-404) days. During the follow-up, 1 patient discontinued canakinumab due to tuberculosis detection and the dose was reduced or the injection interval increased in 4 (9%) patients. In total, 27 (60%) patients continued to receive at least one cDMARD. Improvement according to the ACR30 criteria was achieved in 43 patients [96%; 95% confidence interval (CI) 85-99], inactive disease in 42 (93%; 95%CI 82-98), and remission in 37 (82%; 95% CI 69-91); after adjustment for actual time-at-risk, the rates were 83, 85 and 73 events per 100 person-years, respectively. During follow-up, 23 AEs (most frequently infections) were reported in 19/45 (42%) patients; 5/45 (11%) patients developed macrophage activation syndrome, with a favorable outcome in all cases.

Conclusions

One-year canakinumab therapy was found to be potentially effective as second-line biologic therapy after discontinuation of tocilizumab in patients with sJIA.

2021 American College of Rheumatology Guideline for the Treatment of Juvenile Idiopathic Arthritis: Therapeutic Approaches for Oligoarthritis, Temporomandibular Joint Arthritis, and Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

To provide updated guidelines for pharmacologic management of juvenile idiopathic arthritis (JIA), focusing on treatment of oligoarthritis, temporomandibular joint (TMJ) arthritis, and systemic JIA with and without macrophage activation syndrome. Recommendations regarding tapering and discontinuing treatment in inactive systemic JIA are also provided.

METHODS

We developed clinically relevant Patient/Population, Intervention, Comparison, and Outcomes questions. After conducting a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation approach was used to rate the quality of evidence (high, moderate, low, or very low). A Voting Panel including clinicians and patients/caregivers achieved consensus on the direction (for or against) and strength (strong or conditional) of recommendations.

RESULTS

Similar to those published in 2019, these JIA recommendations are based on clinical phenotypes of JIA, rather than a specific classification schema. This guideline provides recommendations for initial and subsequent treatment of JIA with oligoarthritis, TMJ arthritis, and systemic JIA as well as for tapering and discontinuing treatment in subjects with inactive systemic JIA. Other aspects of disease management, including factors that influence treatment choice and medication tapering, are discussed. Evidence for all recommendations was graded as low or very low in quality. For that reason, more than half of the recommendations are conditional.

CONCLUSION

This clinical practice guideline complements the 2019 American College of Rheumatology JIA and uveitis guidelines, which addressed polyarthritis, sacroiliitis, enthesitis, and uveitis. It serves as a tool to support clinicians, patients, and caregivers in decision-making. The recommendations take into consideration the severity of both articular and nonarticular manifestations as well as patient quality of life. Although evidence is generally low quality and many recommendations are conditional, the inclusion of caregivers and patients in the decision-making process strengthens the relevance and applicability of the guideline. It is important to remember that these are recommendations. Clinical decisions, as always, should be made by the treating clinician and patient/caregiver.

2021 American College of Rheumatology Guideline for the Treatment of Juvenile Idiopathic Arthritis: Therapeutic Approaches for Oligoarthritis, Temporomandibular Joint Arthritis, and Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

To provide updated guidelines for pharmacologic management of juvenile idiopathic arthritis (JIA), focusing on treatment of oligoarthritis, temporomandibular joint (TMJ) arthritis, and systemic JIA with and without macrophage activation syndrome. Recommendations regarding tapering and discontinuing treatment in inactive systemic JIA are also provided.

METHODS

We developed clinically relevant Patient/Population, Intervention, Comparison, and Outcomes questions. After conducting a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation approach was used to rate the quality of evidence (high, moderate, low, or very low). A Voting Panel including clinicians and patients/caregivers achieved consensus on the direction (for or against) and strength (strong or conditional) of recommendations.

RESULTS

Similar to those published in 2019, these JIA recommendations are based on clinical phenotypes of JIA, rather than a specific classification schema. This guideline provides recommendations for initial and subsequent treatment of JIA with oligoarthritis, TMJ arthritis, and systemic JIA as well as for tapering and discontinuing treatment in subjects with inactive systemic JIA. Other aspects of disease management, including factors that influence treatment choice and medication tapering, are discussed. Evidence for all recommendations was graded as low or very low in quality. For that reason, more than half of the recommendations are conditional.

CONCLUSION

This clinical practice guideline complements the 2019 American College of Rheumatology JIA and uveitis guidelines, which addressed polyarthritis, sacroiliitis, enthesitis, and uveitis. It serves as a tool to support clinicians, patients, and caregivers in decision-making. The recommendations take into consideration the severity of both articular and nonarticular manifestations as well as patient quality of life. Although evidence is generally low quality and many recommendations are conditional, the inclusion of caregivers and patients in the decision-making process strengthens the relevance and applicability of the guideline. It is important to remember that these are recommendations. Clinical decisions, as always, should be made by the treating clinician and patient/caregiver.

Re-treatment with etanercept is as effective as the initial firstline treatment in patients with juvenile idiopathic arthritis

Objectives

To determine (i) correlates for etanercept (ETA) discontinuation after achieving an inactive disease and for the subsequent risk of flare and (ii) to analyze the effectiveness of ETA in the re-treatment after a disease flare.

Methods

Data from two ongoing prospective registries, BiKeR and JuMBO, were used for the analysis. Both registries provide individual trajectories of clinical data and outcomes from childhood to adulthood in juvenile idiopathic arthritis (JIA) patients treated with biologic disease-modifying anti-rheumatic drugs (bDMARDs) and conventional synthetic DMARDs (csDMARDs).

Results

A total of 1724 patients were treated first with ETA treatment course (338 with second, 54 with third ETA course). Similar rates of discontinuation due to ineffectiveness and adverse events could be observed for the first (19.4%/6.2%), second (18.6%/5.9%), and third (14.8%/5.6%) ETA course. A total of 332 patients (+/−methotrexate, 19.3%) discontinued ETA after achieving remission with the first ETA course. Younger age (hazard ratio (HR) 1.08, p < 0.001), persistent oligoarthritis (HR 1.89, p = 0.004), and shorter duration between JIA onset and ETA start (HR 1.10, p < 0.001), as well as good response to therapy within the first 6 months of treatment (HR 1.11, p < 0.001) significantly correlated to discontinuation with inactive disease. Reoccurrence of active disease was reported for 77% of patients with mean time to flare of 12.1 months. We could not identify any factor correlating to flare risk. The majority of patients were re-treated with ETA (n = 117 of 161; 72.7%) after the flare. One in five patients (n = 23, 19.7%) discontinued ETA again after achieving an inactive disease and about 70% of the patients achieved an inactive disease 12 months after restarting ETA.

Conclusion

The study confirms the effectiveness of ETA even for re-treatment of patients with JIA. Our data highlight the association of an early bDMARD treatment with a higher rate of inactive disease indicating a window of opportunity.

Approach to switching biologics in juvenile idiopathic arthritis: a real-life experience

The primary aim of the treatment of juvenile idiopathic arthritis (JIA) is complete remission and minimizing the development of complications. Though biologic agents (BAs) provide better disease control, data related to BA switching patterns in JIA patients are scarce. This study aimed to determine the BA switching patterns in JIA patients. The study included children with JIA that received ≥ 1 BAs. Disease activity was evaluated based on the juvenile arthritis disease activity score 71 (JADAS71). Demographic data, clinical and laboratory findings, BA switching patterns, and the rationales for BA switching were recorded. The study included 177 (82 female and 95 male) JIA patients that received ≥ 1 BAs. Mean age at diagnosis of JIA was 9.1 ± 4.9 years. BAs were prescribed a median of 14 months (range: 3-66 months) after diagnosis. Among the 177 patients, 31 (17.5%) required BA switching a median 10.5 months (range: 3-38 months) after initiation of the first BA. Among all the BAs that were switched to after administration of the first BA, tocilizumab was the most commonly switched (n = 15). The most common reason for BA switching was inadequate response (n = 29). BAs were switched 2 times in 5 patients and 3 times in 1 patient. When patients that switched BAs 1 time were compared to those that switched 2 and 3 times there were not any differences in terms of JIA types, whereas those that switched 2 and 3 times had a higher active joint count and JADAS71 score after 6 months of initiation of the first BA. As some of the JIA patients could not achieve remission despite using the prescribed BA, BA switching was required. Herein, we provide data on both BA switching patterns and requirements, which may improve the management of JIA patients.

Comparative risk of infections among real-world users of biologics for juvenile idiopathic arthritis: data from the German BIKER registry

To examine whether treatment with interleukin (IL)-1-, IL-6-, tumour necrosis factor α (TNFα)-inhibitors or Abatacept is associated with an increased risk of common infections, infections requiring hospitalization (SAE) or opportunistic infections among real-world juvenile idiopathic arthritis (JIA) patients. Furthermore, the influence of other patient-related covariates on the occurrence of infections was investigated. Patients diagnosed with JIA and treated with biologics were selected from the German BIKER registry. Incidence rates (IR) of infections per 100 person years were calculated and compared between the different cohorts. Using multivariate logistic regression, odds ratios with 95% confidence intervals (CI) were determined for the influence of patient-related covariates (age, diagnosis, laboratory data, concomitant medication, JIA activity, comorbidities, and premedication) on the occurrence of infections. 3258 patients entered the analysis. A total of 3654 treatment episodes were distributed among TNFα- (Etanercept, Adalimumab, Golimumab, Infliximab, n = 3044), IL-1- (Anakinra, Canakinumab, n = 105), IL-6- (Tocilizumab, n = 400) and T-cell activation inhibitors (Abatacept, n = 105). 813 (22.2%) patients had at least one infection, 103 (2.8%) patients suffered from an SAE infection. Both common and SAE infections were significantly more frequent in IL-1 (IR 17.3, 95% CI 12.5/24 and IR 4.3, 95% CI 2.3/8.3) and IL-6 cohort (IR 16.7, 95% CI 13.9/20 and IR 2.8, 95% CI 1.8/4.4) compared to TNFα-inhibitor cohort (IR 8.7, 95% CI 8.1/9.4 and IR 1, 95% CI 0.8/1.3). When comparing the influencing factors for various infectious diseases, the use of corticosteroids, younger age, cardiac comorbidities and higher JIA-activity are the most striking risk factors. Relative to TNFα inhibitors and Abatacept, IL-1 and IL-6 inhibitors were associated with an increased risk of common and SAE infections. The influencing covariates identified may be helpful for the choice of a suitable biologic to treat JIA.

Current Therapeutic Options for the Treatment of Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease and an exclusion diagnosis that includes all forms of arthritis that persists for more than 6 weeks under the age of 16. Although there is not yet a cure for JIA, and recent advances in the therapeutic field have created a more hopeful present and future for the patients. In the past, therapies for JIA have depended on non-steroidal medication, conventional synthetic disease-modifying antirheumatic drugs and corticosteroids. However, over the last decades, the advent of biologic therapies in JIA contributed to the preservation of functional activity, control of pain, avoidance of joint damage, and extra-articular manifestations. Furthermore, over the last years, international institutions, such as the American College of Rheumatology, have released recommendations and guidelines for rheumatologists for optimal JIA management. All the above have revolutionized the treatment of JIA with promising outcomes. To this end, the relevant literature is reviewed and discussed appropriately.

Biologic Switching Among Nonsystemic Juvenile Idiopathic Arthritis Patients: A Cohort Study in the Childhood Arthritis and Rheumatology Research Alliance Registry

OBJECTIVE

Biologic medications have significantly improved disease control and outcomes of patients with juvenile idiopathic arthritis (JIA). Current treatment recommendations suggest escalating therapy, including changing biologics if needed, when inactive or low disease activity is not attained. The patterns and reasons for switching biologics in clinical practice in North America are not well described.

METHODS

We used the Childhood Arthritis and Rheumatology Research Alliance Registry and included individuals with JIA if they newly started a biologic after January 1, 2008, and had at least 12 months of subsequent observable time. Subjects with systemic JIA were excluded. We compared characteristics of switchers and nonswitchers using chi-square for categorical variables and Wilcoxon rank-sum test for continuous variables, and used linear regression for time analysis.

RESULTS

Of the eligible children, 1361 with JIA in the registry started a biologic (94% tumor necrosis factor inhibitors [TNFi]). Median followup time was 30 months and 349 (26%) switched biologics. Among biologic switchers, ineffectiveness/disease flare was the most common reason for switch (202, 58%). The most common documented switch was from etanercept to another TNFi (221, 63%). The median time to switch to a second biologic decreased substantially from 55.2 months in 2008 to 7.2 months in 2016.

CONCLUSION

In a multicenter cohort of patients with JIA starting a biologic, one-quarter switched to a second biologic, and the time to switching decreased in recent years. Additional studies should evaluate the outcomes and optimal timing of switching and preferred sequence of biologic use.

Biologics in juvenile idiopathic arthritis-main advantages and major challenges: A narrative review

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood. The disease is divided in different subtypes based on main clinical features and disease course. Emergence of biological agents targeting specific pro-inflammatory cytokines responsible for the disease pathogenesis represents the revolution in the JIA treatment. Discovery and widespread usage of biological agents have led to significant improvement in JIA patients’ treatment, with evidently increased functionality and decreased disease sequel. Increased risk of infections remains the main discussion topic for years. Despite the slightly increased frequency of upper respiratory tract infections reported in some studies, the general safety of drugs is acceptable with rare reports of severe adverse effects (SAEs). Tuberculosis (TBC) represents the important threat in regions with increased TBC prevalence. Therefore, routine screening for TBC should not be neglected when prescribing and during the follow-up of biological treatment. Malignancy represents a hypothetical complication that sometimes causes hesitations for physicians and patients in its prescription and usage. On the other hand, current reports from the literature do not support the increased risk for malignancy among JIA patients treated with biological agents. A multidisciplinary approach including a pediatric rheumatologist and an infectious disease specialist is mandatory in the follow- up of JIA patients. Although the efficacy and safety of biological agents have been proven in different studies, there is still a need for long-term, multicentric evaluation providing relevant data.

Towards therapeutic drug monitoring of TNF inhibitors for children with juvenile idiopathic arthritis: a scoping review

OBJECTIVES

Before a clinician decides whether treatment with TNF inhibition in children with JIA has failed, one should ensure adequate systemic exposure has been achieved. Therapeutic drug monitoring might allow for improved treatment outcome with lower treatment-associated costs. However, this requires understanding of the pharmacokinetic (PK) characteristics, and the pharmacokinetic/pharmacodynamic (PK/PD) relationship for children with JIA. We performed a scoping review to summarize the available literature and identify areas for future research.

METHODS

A systematic search was conducted of the Medline, EMBASE, Web of Science and Cochrane databases as well as the clinicaltrials.gov registry. In total, 3959 records were screened and 130 publications were selected for full text assessment.

RESULTS

Twenty publications were included and divided into three categories: PK (n = 9), PK/PD (n = 3) and anti-drug antibodies (n = 13). Industry involvement was significant in 14 publications. Although data are limited, systemic exposure to TNF inhibitors is generally lower in younger children but meta-analysis is not possible. The PK/PD relationship has had limited study but there is partial evidence for infliximab. Anti-drug antibodies are common, and are related to impaired clinical outcome with adalimumab and infliximab therapy.

CONCLUSION

The current knowledge about the PK and PK/PD of TNF inhibitors in the treatment of children with JIA is limited, which prevents the introduction of TDM. Re-analysis of available data from previous trials, incorporation of pharmacologic assessments into existing biorepository studies as well as new prospective PK and PK/PD trials are required to obtain this knowledge.

Immunogenicity of biologic agents in juvenile idiopathic arthritis: a systematic review and meta-analysis

OBJECTIVE

The clinical impact of anti-drug antibodies (ADAbs) in paediatric patients with JIA remains unknown. This systematic review and meta-analysis aimed to summarize the prevalence of ADAbs in JIA studies; investigate the effect of ADAbs on treatment efficacy and adverse events; and explore the effect of immunosuppressive therapy on antibody formation.

METHODS

PubMed, Embase and the Cochrane Library were systematically searched to identify relevant clinical trials and observational studies that reported prevalence of ADAbs. Studies were systematically reviewed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses and appropriate proportional and pairwise meta-analyses were performed.

RESULTS

A total of 5183 references were screened; 28 articles, involving 26 studies and 2354 JIA patients, met eligibility criteria. Prevalence of ADAbs ranged from 0% to 82% across nine biologic agents. Overall pooled prevalence of ADAbs was 16.9% (95% CI, 9.5, 25.9). Qualitative analysis of included studies indicated that antibodies to infliximab, adalimumab, anakinra and tocilizumab were associated with treatment failure and/or hypersensitivity reactions. Concomitant MTX uniformly reduced the risk of antibody formation during adalimumab treatment (risk ratio 0.33; 95% CI 0.21, 0.52).

CONCLUSION

The association of ADAbs with treatment failure and hypersensitivity reactions indicates their clinical relevance in paediatric patients with JIA. Based on our findings, we recommend a preliminary course of action regarding immunogenicity of biologic agents in patients with JIA. Further strategies to predict, prevent, detect and manage immunogenicity could optimize treatment outcomes and personalize treatment with biologic therapies.

Frequency of biologic switching and the outcomes of switching in children and young people with juvenile idiopathic arthritis: a national cohort study

BACKGROUND

Information is scarce about biological disease-modifying antirheumatic drug (DMARD) switching patterns in children and young people (aged ≤16 years) with juvenile idiopathic arthritis in an era of many biologic therapies. The best choice of biologic to use if the first biological DMARD is not beneficial also remains unclear. We aimed to quantify and characterise biologic switching patterns in children and young people with juvenile idiopathic arthritis, and to compare the effectiveness of using a second tumour necrosis factor inhibitor (TNFi) versus non-TNF is following failure of a first TNFi biologic in routine clinical practice.

METHODS

Our study population comprised patients with juvenile idiopathic arthritis who were enrolled in two parallel UK cohort studies (the British Society for Paediatric and Adolescent Rheumatology Etanercept Cohort Study [BSPAR-ETN] and the Biologics for Children with Rheumatic Diseases [BCRD] study) between Jan 1, 2004, and April 11, 2019. Data on disease characteristics and DMARD therapy were collected at the time of initiation of a first biologic, at 6 months, at 1 year, and annually thereafter. Biologic switching patterns were described in all patients who started their first biologic from Jan 1, 2010, onwards. Among patients who started treatment with their first biologic from Jan 1, 2004, onwards, had polyarticular course juvenile idiopathic arthritis (extended oligoarthritis or polyarthritis [positive or negative for rheumatoid factor]), and who had started a second biologic, we assessed changes in outcome variables at 6 months compared with baseline and compared the proportion of patients who achieved an American College of Rheumatology Pediatric (ACR Pedi) 90 response and minimal disease activity at 6 months on the basis of the class of the second biologic (a second TNFi vs non-TNFi biologic). Changes in outcome variables at 6 months were compared using linear regression or logistic regression, adjusted for propensity quintiles to account for confounding by indication. We used multiple imputation to account for missing data.

FINDINGS

Between Jan 1, 2004, and April 11, 2019, 2361 patients were enrolled on initiation of biologic therapy. From Jan 1, 2010, onwards, 1152 patients started their first biologic, most of whom started treatment with TNFis (1050 [91%]). The median follow-up was 2·2 years (IQR 1·1-3·8). During this time, 270 (23%) of 1152 patients started a second biologic, 61 (5%) started a third biologic, and 11 (1%) started a fourth biologic. Among 240 patients with polyarticular-course juvenile idiopathic arthritis, 194 (81%) started a second TNFi and 46 (19%) started a non-TNFi after an initial TNFi had failed. Choice of second treatment (second TNFi vs non-TNFi biologic) did not affect the proportion of patients who achieved an ACR Pedi 90 response (adjusted odds ratio [OR] 2·5, 95% CI 0·8-7·9; p=0·11) or minimal disease activity (adjusted OR 1·6, 95% CI 0·6-3·8; p=0·33).

INTERPRETATION

For many children and young people with juvenile idiopathic arthritis, treatment with a first or second biologic is not beneficial. We found no evidence that switching to a second non-TNFi biologic was more beneficial than a second TNFi.

FUNDING

Versus Arthritis and The British Society for Rheumatology.

Efficacy and safety of tocilizumab in a real-life observational cohort of patients with polyarticular juvenile idiopathic arthritis

Objectives

To evaluate the patterns of usage, efficacy and safety of tocilizumab in polyarticular JIA.

Methods

An observational study of 56 consecutive polyarticular JIA patients was conducted using patient charts and electronic JIA databases. Efficacy was assessed by tocilizumab survival, rates of low disease activity (LDA) and of inactive disease by 10-joint Juvenile Arthritis Disease Activity Score (JADAS-10), and of clinically inactive disease according to Wallace’s preliminary criteria. Efficacy and rate of adverse events (AEs) were evaluated during a 24-month period after tocilizumab commencement.

Results

Tocilizumab was started on average as third-line biological agent (median, range first- to fourth-line) at a median disease duration of 5.2 years (interquartile range 3.0–7.7). Survival rates were 82% at 12 months and 64% at 24 months. The reasons for discontinuation were inadequate treatment effect in 50%, AE plus inadequate treatment effect in 37.5% and AE alone in 12.5%. LDA (JADAS-10 ⩽3.9) was reached in 58% at 12 months and in 84% at 24 months, inactive disease (JADAS-10 ⩽0.7) in 19% and 44%, and clinically inactive disease in 28% and 46%, respectively. The rate of AEs was 200.9/100 patient years and of serious AEs 12.9/100 patient years.

Conclusion

Survival of tocilizumab was high and a large proportion of the treatment-resistant patients reached LDA at 12 months of treatment. The LDA rate continued to increase throughout 24 months. The rates of AEs and serious AEs were higher than in register studies but lower than in the originator study of tocilizumab.

Long-Term Retention Rate of Anakinra in Adult Onset Still's Disease and Predictive Factors for Treatment Response

Background: Anakinra (ANA) is an effective treatment choice in patients with adult onset Still’s disease (AOSD). Variables affecting treatment survival include loss of efficacy or adverse events, but also the decision to discontinue treatment after long-term clinical remission.

Objectives: Aims of this study were: (i) to assess the drug retention rate (DRR) of ANA during a long-term follow-up looking for any difference related to the line of biologic treatment, the concomitant use of conventional disease modifying anti-rheumatic drugs (cDMARDs) and the different type of AOSD (systemic versus chronic articular); (ii) to identify predictive factors of lack of efficacy, loss of efficacy, and ANA withdrawal owing to long-term remission.

Methods: AOSD patients classified according with Yamaguchi criteria and treated with ANA were retrospectively enrolled in 18 Italian tertiary Centers. Demographic, laboratory, clinical and therapeutic data related to the start of ANA (baseline), the 3-month assessment and the last follow-up visit while on ANA treatment were retrospectively collected and statistically analyzed.

Results: One hundred and forty-one AOSD patients (48 males, 93 females) treated with ANA for a mean period of 35.96 ± 36.05 months were enrolled. The overall DRR of ANA was 44.6 and 30.5% at the 60- and 120-month assessments, respectively, with no significant differences between: (i) biologic naïve patients and those previously treated with other biologics (log-rank p = 0.97); (ii) monotherapy and concomitant use of cDMARDs (log-rank p = 0.45); (iii) systemic and chronic articular types of AOSD (log-rank p = 0.67). No variables collected at baseline could predict primary inefficacy, while the number of swollen joints at baseline was significantly associated with secondary inefficacy (p = 0.01, OR = 1.194, C.I. 1.043–1.367). The typical AOSD skin rash was negatively related with ANA withdrawal owing to long-term remission (p = 0.03, OR = 0.224, C.I. 0.058–0.863).

Conclusion: Long-term DRR of ANA has been found excellent and is not affected by different lines of biologic treatment, concomitant use of cDMARDs, or type of AOSD. The risk of losing ANA efficacy increases along with the number of swollen joints at the start of therapy, while the typical skin rash is a negative predictor of ANA withdrawal related to sustained remission.

Drug Retention Rate and Predictive Factors of Drug Survival for Interleukin-1 Inhibitors in Systemic Juvenile Idiopathic Arthritis

Background and Objectives: Few studies have reported the drug retention rate (DRR) of biologic drugs in juvenile idiopathic arthritis (JIA), and none of them has specifically investigated the DRR of interleukin (IL)-1 inhibitors on systemic JIA (sJIA). This study aims to describe IL-1 inhibitors DRR and evaluate predictive factors of drug survival based on data from a real-world setting concerning sJIA. Methods: Medical records from sJIA patients treated with anakinra (ANA) and canakinumab (CAN) were retrospectively analyzed from 15 Italian tertiary referral centers. Results: Seventy seven patients were enrolled for a total of 86 treatment courses. The cumulative retention rate of the IL-1 inhibitors at 12-, 24-, 48-, and 60-months of follow-up was 79.9, 59.5, 53.5, and 53.5%, respectively, without any statistically significant differences between ANA and CAN (p = 0.056), and between patients treated in monotherapy compared to the subgroup co-administered with conventional immunosuppressors (p = 0.058). On the contrary, significant differences were found between biologic-naive patients and those previously treated with biologic drugs (p = 0.038) and when distinguishing according to adverse events (AEs) occurrence (p = 0.04). In regression analysis, patients pre-treated with other biologics (HR = 3.357 [CI: 1.341-8.406], p = 0.01) and those experiencing AEs (HR = 2.970 [CI: 1.186-7.435], p = 0.020) were associated with a higher hazard ratio of IL-1 inhibitors withdrawal. The mean treatment delay was significantly higher among patients discontinuing IL-1 inhibitors (p = 0.0002). Conclusions: Our findings suggest an excellent overall DRR for both ANA and CAN that might be further augmented by paying attention to AEs and employing these agents as first-line biologics in an early disease phase.

Surveillance of adverse drug events associated with etanercept prescribed for juvenile idiopathic arthritis in a single center up to 9-years: A retrospective observational study

The introduction of biologic agents opened a new era of treatment of juvenile idiopathic arthritis (JIA) over the past decade. From clinical experience, it appears that biological agents are well tolerated overall, and serious adverse events are rare. However, such clinical studies have not been conducted in Korea. Therefore, we examined the safety profile of JIA patients with biologics in a single center in Korea. All JIA outpatients treated from April 2004 to June 2013 were enrolled and retrospectively reviewed. Pharmacy-based surveillance of adverse drug events (ADEs) was identified by recording the patient's symptoms in the medical record and suspected ADEs were additionally explored by screening laboratory test values and observing changes in medication orders. Finally, 83 patients were enrolled and experienced 109 ADEs in 52 patients. Most ADEs (99.1%) were mild to moderate in severity assessment. The total follow-up time was 328 patient-treatment years and the overall rate of ADEs was 0.33 per patient-years for etanercept. Infection including upper respiratory tract was the most common ADE and concomitant corticosteroids contributed to the risk of infections. If the dose of prednisolone increases 0.34 mg/kg/day, the probability of developing infections increases 3.29 times. Also, all 11 patients who stopped etanercept with injection site reactions were receiving a single use prefilled syringe. In our study, etanercept appears well tolerated and safe. Children affected by JIA should be carefully monitoring so as to limit the risk of ADEs during etanercept as much as possible. To gain further knowledge about risk profiles, national collaboration for the accumulation of long-term data should be encouraged in Korea.

Infection-Related Death among Persons with Refractory Juvenile Idiopathic Arthritis

Bacterial sepsis led to multiorgan failure in persons receiving immunosuppressive and antiinflammatory drugs.

Severe infections are emerging as major risk factors for death among children with juvenile idiopathic arthritis (JIA). In particular, children with refractory JIA treated with long-term, multiple, and often combined immunosuppressive and antiinflammatory agents, including the new biological disease-modifying antirheumatic drugs (DMARDs), are at increased risk for severe infections and death. We investigated 4 persons with JIA who died during 1994–2013, three of overwhelming central venous catheter–related bacterial sepsis caused by coagulase-negative Staphylococus or α-hemolytic Streptococcus infection and 1 of disseminated adenovirus and Epstein-Barr virus infection). All 4 had active JIA refractory to long-term therapy with multiple and combined conventional and biological DMARDs. Two died while receiving high-dose systemic corticosteroids, methotrexate, and after recent exposure to anti–tumor necrosis factor-α biological DMARDs, and 2 during hematopoietic stem cell transplantation procedure. Reporting all cases of severe infections and especially deaths in these children is of paramount importance for accurate surveillance.

CD3+CD56+ natural killer T cell activity in children with different forms of juvenile idiopathic arthritis and the influence of etanercept treatment on polyarticular subgroup

Juvenile idiopathic arthritis (JIA) has three major onset types with widely varying clinical features. We assessed the natural killer T (NKT) cell function in patients with different JIA subtypes, and found systemic patients exhibited lower NKT cell counts, perforin and granzyme B expression, while the pauciarticular and polyarticular patients displayed higher perforin and granzyme B expression as compared with the controls. The synovial fluid had more NKT cells with higher levels of perforin, granzyme B, and tumour necrosis factor (TNF)-α than peripheral cells. The polyarticular patients that responded to etanercept had lower NKT cell counts, intracellular perforin, granzyme B and the mean fluorescence intensity of TNF-α than the patients that did not respond. Treatment with etanercept reduced the granzyme B and perforin, interferon (IFN)-γ and TNF-α expression in NKT cells in the responsive group. Therefore, a higher NKT cell function may indicate a decreased response to etanercept in polyarticular patients.

Factors associated with choice of biologic among children with Juvenile Idiopathic Arthritis: results from two UK paediatric biologic registers

OBJECTIVE

The objectives of this study were to describe patients starting first-line biologics for JIA, to describe characteristics over time among patients starting etanercept, and to describe patterns of second biologic prescribing.

METHODS

The British Society for Paediatric and Adolescent Rheumatology Etanercept Cohort Study, and the Biologics for Children with Rheumatic Diseases study are ongoing prospective observational cohorts, collecting data on patients starting biologic therapy for JIA. Patients registered from 1 January 2010 starting their first biologic were compared between therapies. Patients starting etanercept before 2010 were included to analyse changes in etanercept prescribing. The pathway of patients starting a second biologic was recorded in all patients.

RESULTS

To 26 August 2014, 931 patients were recruited starting a first-line biologic (142 Biologics for Children with Rheumatic Diseases; 789 British Society for Paediatric and Adolescent Rheumatology Etanercept Cohort Study). From 2010, patients with systemic JIA (sJIA) were almost exclusively prescribed anakinra or tocilizumab. Choice between anti-TNF therapies was largely driven by history of chronic anterior uveitis (CAU). When investigating trends in patients starting etanercept over time, disease duration at etanercept start, patients with sJIA, a history of CAU, and those who received concomitant oral corticosteroids decreased over time. Patients who started a second biologic from 1 January 2010 showed a similar stratification.

CONCLUSION

Although etanercept remains the most common biologic prescribed for JIA, there has been a clear shift towards the use of alternative biologics, largely driven by disease subtype and history of CAU. This channelling of children towards specific therapies should be considered carefully in future studies and in clinical guidelines and ongoing research.

Impact of Antiinflammatory Treatment on the Onset of Uveitis in Juvenile Idiopathic Arthritis: Longitudinal Analysis From a Nationwide Pediatric Rheumatology Database

Objective

Based on a nationwide database, this study analyzed the influence of methotrexate (MTX), tumor necrosis factor (TNF) inhibitors, and a combination of the 2 medications on uveitis occurrence in juvenile idiopathic arthritis (JIA) patients.

Methods

Data from the National Paediatric Rheumatological Database in Germany were used in this study. Between 2002 and 2013, data from JIA patients were annually documented at the participating pediatric rheumatologic sites. Patients with a JIA disease duration of <12 months at initial documentation and ≥2 years of followup were included in this study. The impact of antiinflammatory treatment on the occurrence of uveitis was evaluated by discrete‐time survival analysis.

Results

A total of 3,512 JIA patients (mean ± SD age 8.3 ± 4.8 years, 65.7% female, 53.2% antinuclear antibody positive, and mean ± SD age at arthritis onset 7.8 ± 4.8 years) fulfilled the inclusion criteria. Mean ± SD total followup time was 3.6 ± 2.4 years. Uveitis developed in a total of 180 patients (5.1%) within 1 year after arthritis onset. Uveitis onset after the first year was observed in another 251 patients (7.1%). Disease‐modifying antirheumatic drug (DMARD) treatment in the year before uveitis onset significantly reduced the risk for uveitis as follows: MTX: hazard ratio (HR) 0.63, P = 0.022; TNF inhibitors: HR 0.56, P < 0.001; and a combination of the 2 medications: HR 0.10, P < 0.001. Patients treated with MTX within the first year of JIA had an even a lower uveitis risk (HR 0.29, P < 0.001).

Conclusion

The use of DMARDs in JIA patients significantly reduced the risk for uveitis onset. Early MTX use within the first year of disease and the combination of MTX with a TNF inhibitor had the highest protective effect.

Biological treatment in systemic juvenile idiopathic arthritis: achievement of inactive disease or clinical remission on a first, second or third biological agent

OBJECTIVES

To analyse the effect of biological agents (BAs) in terms of achieving inactive disease (ID) or clinical remission (CR) in patients with systemic juvenile idiopathic arthritis (SJIA), to describe effects of switching or discontinuing a BA and to assess the proportion of patients able to maintain ID or CR off steroids and after withdrawing BA therapy.

METHODS

Retrospective study in a French paediatric rheumatology reference centre using the CEMARA (CEntre des MAladies RAres) register.

RESULTS

Seventy-seven patients were included with a cumulative follow-up of 245.5 patient-years (median 1.1, range 0.5-8.0). On a first BA, ID was achieved in 37 patients, including 1 patient out of 12 patients on etanercept, 26 patients out of 51 on anakinra and 7 out of 10 on canakinumab. One patient on abatacept and two patients on tocilizumab also achieved ID. Switching of BA was common. The switch to a second (n=34), third (n=18) or fourth (n=4) BA resulted in ID in a further 13 patients, either on canakinumab (n=6) or tocilizumab (n=7). At last follow-up, 40 patients were in CR (27 patients off steroids, 5 patients having never received steroid treatment), either on (n=29) or off (n=11) BA.

CONCLUSIONS

In this series of patients with SJIA, interleukin-1 inhibitors were associated with a higher proportion of ID than tumour necrosis factor inhibitors when used as first BA. Switching allowed some patients to achieve ID when treated with canakinumab or tocilizumab. CR was eventually achieved in more than half of the patients.

Efficacy and safety of adalimumab as the first and second biologic agent in juvenile idiopathic arthritis: the German Biologics JIA Registry

OBJECTIVE

To evaluate the efficacy and safety of adalimumab in patients with juvenile idiopathic arthritis (JIA).

METHODS

Baseline demographic and clinical characteristics and disease activity parameters were prospectively documented in the German Biologics JIA Registry. Efficacy was determined using the American College of Rheumatology (ACR) Pediatric (Pedi) response criteria and the Juvenile Arthritis Disease Activity Score based on a 10-joint count (JADAS-10). Safety assessments were based on adverse event reports from the responsible physician.

RESULTS

Two hundred eighty-nine patients with a total of 1,046 visits were identified (435.7 patient-years). A high proportion of patients demonstrated a significant response to treatment, with a marked decrease in the JADAS-10 score in both the biologics-naive group (which consisted of patients who had not received therapy with a biologic agent prior to initiation of adalimumab) and the biologic-switcher group (which consisted of patients who had been treated with a different biologic agent prior to initiation of adalimumab). The median JADAS-10 score at treatment start was significantly higher in the biologics-naive group than in the biologic-switcher group (12.9 versus 8.5; P = 0.00044), although the score in the biologics-naive group was lower over the course of adalimumab treatment. ACR Pedi 30, 50, 70, and 90 scores were achieved in 63.4%, 61.0%, 48.8%, and 34.2% of biologics-naive patients, respectively, at 6 months of treatment, while ACR Pedi 30, 50, 70, and 90 scores were achieved in 47.6%, 38.1%, 21.9%, and 15.2% of biologic-switcher patients, respectively. Forty-eight patients experienced 222 adverse events (50.9 per 100 patient-years). Eleven were reported as serious (2.5 per 100 patient-years). No malignancies were observed during adalimumab exposure. There were 16 uveitis flares in 11 patients. Treatment was discontinued in 58 patients for the following reasons: inefficacy 11.1%, adverse events 5.2%, remission 4.5%, patient request 11.8%, and other reasons 7.9%.

CONCLUSION

Adalimumab appears to be highly effective in children and adolescents with JIA who have been previously treated with biologic agents and in children and adolescents who switched biologic agents. The treatment is safe and its efficacy is similar to that of other biologic agents used to treat JIA. Few patients discontinued therapy due to intolerance or inefficacy.

What does an adult rheumatologist need to know about juvenile idiopathic arthritis?

JIA is the most common chronic inflammatory arthritis in children and young people and an estimated one-third of individuals will have persistent active disease into adulthood. There are a number of key differences in the clinical manifestations, assessment and management of JIA compared with adult-onset arthritis. Transition and transfer to adult services present significant challenges for many patients, their families and health care professionals. We describe key clinical issues relevant to adult rheumatology health care teams responsible for ongoing care of these young people.

Effectiveness of first-line treatment with recombinant interleukin-1 receptor antagonist in steroid-naive patients with new-onset systemic juvenile idiopathic arthritis: results of a prospective cohort study

OBJECTIVE

To conduct a prospective cohort study using anakinra, a recombinant IL-1 receptor antagonist (IL-1Ra), as first-line therapy in patients with new-onset systemic juvenile idiopathic arthritis (JIA).

METHODS

Therapy with recombinant IL-1Ra (2 mg/kg) was initiated in 20 patients who fulfilled the International League of Associations for Rheumatology criteria for systemic JIA, before systemic steroid treatment was administered. Patients were monitored clinically and immunologically. The protocol contained a stop strategy for patients who met at least the adapted American College of Rheumatology 90% criteria for improvement in JIA (ACR Pediatric 90 [ACR Pedi 90]) after 3 months.

RESULTS

We included consecutive patients with new-onset systemic JIA. The mean followup period was 32 months (range 12-54 months). At the 3-month time point, 85% of the patients showed an adapted ACR Pedi 90 response or had inactive disease; 75% of the patients achieved this response while receiving recombinant IL-1Ra alone. After 1 year, 17 of the 20 patients met the criteria for clinically inactive disease, and 13 of these patients met these criteria while receiving monotherapy with recombinant IL-1Ra. However, because of persistent disease activity, 7 of the 20 patients required additional therapy besides recombinant IL-1Ra. According to our stop strategy, 73% of patients with at least an adapted ACR Pedi 90 response at 3 months could stop recombinant IL-1Ra treatment within 1 year. After 2 years, 12 (86%) of 14 patients met the criteria for disease remission, either while receiving (n = 4) or not receiving (n = 8) medication. After 3 years, 10 (91%) of 11 patients met the criteria for disease remission, either while receiving (n = 2) or not receiving (n = 8) medication.

CONCLUSION

This is the first prospective study in which recombinant IL-1Ra was used as first-line therapy in patients with systemic JIA. We observed excellent responses in nearly all patients within 3 months. In the majority of responding patients, treatment with recombinant IL-1Ra could be stopped within 1 year, with remission being preserved during followup. In approximately one-third of patients, concomitant therapy was required for maintenance of clinical response.

Efficacy and safety of tocilizumab in patients with polyarticular-course juvenile idiopathic arthritis: results from a phase 3, randomised, double-blind withdrawal trial

Objective

To evaluate the interleukin-6 receptor inhibitor tocilizumab for the treatment of patients with polyarticular-course juvenile idiopathic arthritis (pcJIA).

Methods

This three-part, randomised, placebo-controlled, double-blind withdrawal study (NCT00988221) included patients who had active pcJIA for ≥6 months and inadequate responses to methotrexate. During part 1, patients received open-label tocilizumab every 4 weeks (8 or 10 mg/kg for body weight (BW) <30 kg; 8 mg/kg for BW ≥30 kg). At week 16, patients with ≥JIA-American College of Rheumatology (ACR) 30 improvement entered the 24-week, double-blind part 2 after randomisation 1:1 to placebo or tocilizumab (stratified by methotrexate and steroid background therapy) for evaluation of the primary end point: JIA flare, compared with week 16. Patients flaring or completing part 2 received open-label tocilizumab.

Results

In part 1, 188 patients received tocilizumab (<30 kg: 10 mg/kg (n=35) or 8 mg/kg (n=34); ≥30 kg: n=119). In part 2, 163 patients received tocilizumab (n=82) or placebo (n=81). JIA flare occurred in 48.1% of patients on placebo versus 25.6% continuing tocilizumab (difference in means adjusted for stratification: −0.21; 95% CI −0.35 to −0.08; p=0.0024). At the end of part 2, 64.6% and 45.1% of patients receiving tocilizumab had JIA-ACR70 and JIA-ACR90 responses, respectively. Rates/100 patient-years (PY) of adverse events (AEs) and serious AEs (SAEs) were 480 and 12.5, respectively; infections were the most common SAE (4.9/100 PY).

Conclusions

Tocilizumab treatment results in significant improvement, maintained over time, of pcJIA signs and symptoms and has a safety profile consistent with that for adults with rheumatoid arthritis.

Trial registration number:

NCT00988221.

Natural killer cell activity and frequency of killer cell immunoglobulin-like receptors in children with different forms of juvenile idiopathic arthritis

BACKGROUND

Juvenile idiopathic arthritis (JIA) has three major onset types with widely varying clinical features: systemic, polyarticular and pauciarticular. We assessed natural killer (NK) cell function and killer cell immunoglobulin-like receptor (KIR) genotypes in patients with different JIA subtypes.

METHODS

Peripheral blood samples from 72 children with active JIA (systemic, 25; polyarticular, 24; pauciarticular, 23) and 25 controls were used for flow cytometric assessments of NK cell count, cytotoxicity, perforin, granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α. Samples from 220 children with JIA (systemic, 84; polyarticular, 72; pauciarticular, 64) and 150 controls were used for KIR2DS2, KIR2DS4, KIR3DS1, KIR2DL1, KIR2DL2, KIR2DL3 and KIR3DL1 typing by polymerase chain reaction with sequence-specific oligonucleotide probes.

RESULTS

Compared with the controls, the patients with systemic JIA showed lower NK cell counts, cytotoxicity and perforin and granzyme B expression (p < 0.05), while the patients with pauci- and polyarticular JIA showed higher perforin and granzyme B expression (p < 0.05). NK cells produced higher level of TNF-α while lower level of IFN-γ in the pauci- and polyarticular JIA groups than in the systemic JIA group (p < 0.05). No significant differences in KIR gene frequencies were found between the JIA subgroups and healthy controls, except for the positive frequency and locus frequency of KIR2DS4, which were lower in the systemic JIA group.

CONCLUSIONS

Compared with poly- and pauciarticular JIA, systemic JIA is associated with decreased NK cell function, more IFN-γ and less TNF-α secretion of NK cell and lower KIR2DS4 frequency.