OBJECTIVES:The temporomandibular joint (TMJ) is a small, yet complex joint. MRI interpretation of TMJ involvement in children with juvenile idiopathic arthritis (JIA) is challenging but essential for the diagnosis and treatment monitoring. We propose a simplified and reproducible MRI scoring system to facilitate both initial diagnosis as well as longitudinal follow-up. METHODS:Two pediatric radiologists independently scored 139 TMJ MRIs from 66 children with JIA using a detailed literature-based score (Score A) and a newly developed simplified score (Score B). For all 278 TMJs, reading time was recorded, and interrater reliability was assessed using intraclass correlation coefficients (ICCs). The primary objective was to assess interrater reliability, with construct validity evaluated in an exploratory manner. RESULTS:The mean patient age was 12.0 years (SD: 3.7). For Score A, interrater agreement showed moderate agreement for the acute score with an ICC of 0.67-0.77 and good agreement for the chronic score (ICC: 0.75-0.86). In contrast, Score B demonstrated excellent agreement for the acute score (ICC: 0.94-0.99) and good agreement for the chronic score (ICC: 0.85-0.90). Both scores showed similar associations with relevant clinical criteria, including the decision to treat. Image interpretation using Score B required 83% less time than with Score A. CONCLUSION:These findings support the reproducibility and feasibility of the simplified score (Score B) for evaluating TMJ involvement in children with JIA, although further studies are required to evaluate its diagnostic performance, external validity, and impact on clinical decision-making.

BACKGROUND AND OBJECTIVE:Juvenile-onset Inflammatory Rheumatisms (JIR) are rare systemic inflammatory diseases that begin in childhood or adolescence. Numerous recommendations have been developed to support physicians, but implementation may vary in real-life. The JIR-Clinical Practice Strategies (CliPS) project investigates clinical practices for JIR diseases. This article describes the rationale of the JIR-CliPS project to serve as methodological foundation for future publications on disease-specific findings. METHODS:The JIR-CLiPS network was launched in 2020 to collect CliPS in real-life on five medical conditions: lupus nephritis, vasculitis (including IgA vasculitis and Kawasaki disease), use of biologicals for hereditary autoinflammatory diseases, periodic fever with aphthous stomatitis, pharyngitis and adenitis (PFAFA) / systemic undefined recurrent fevers (SURF) syndrome, and Still's disease. Specific questionnaires were developed, covering physician demographics, disease-specific approaches, and local healthcare constraints. RESULTS:From June 2022 to April 2024, 534 physicians from 66 countries across six continents participated, completing in 1,193 questionnaires. Respondents were primarily pediatricians and rheumatology specialists, working both at universities and in local hospitals; although most participants reported at least 10 years' experience, younger doctors also took part. Participants from only a few countries shared the development of local or national JIR-specific recommendations, with variable awareness and adherence. CONCLUSION:The JIR-CliPS network has achieved broad international physician participation. Thanks to the knowledge gathered, a library with CliPS adapted to various local and country-specific constraints is currently under development, bridging the gap between published recommendations and achievable everyday practice. This robust methodology ensures a comprehensive and globally representative dataset for future disease-specific publications.

OBJECTIVE:Data on the long-term outcome of patients with childhood-onset SLE (cSLE) are scarce. Aims of this study were to describe the long-term outcomes of cSLE and to identify factors associated with the development of damage and persistent disease activity. METHODS:We conducted a retrospective multicentre study using data from the PEDIALUP registry of the Juvenile Inflammatory Rheumatism (JIR) cohort database. Demographic characteristics, clinical manifestations, laboratory, radiological, histological and treatment data were collected from medical records during follow-up. RESULTS:A total of 138 patients with cSLE, diagnosed between 1971 and 2015, were included. With a median follow-up of 15.4 [9.6-22.4] years, 51% of patients had a SLICC-damage index (DI) score ≥1 at last follow-up with the musculoskeletal, cutaneous, renal, neurological and cardiovascular damage being the most common manifestations. The proportion of patients with a SLICC-DI score ≥1 increased significantly with the duration of the follow-up (P < 0.001). On multivariate analysis, duration of follow-up was associated with increased risk of cumulative damage (OR 1.08, 95% CI 1.01, 1.15, P = 0.035). At the last visit, 34% of patients still had active disease with a SLEDAI score of ≥6. On multivariate analysis, sub-Saharan African ethnicity was associated with 7-fold increased odds of having active disease at the last visit compared with Caucasians (OR 7.44, 95% CI 2.24, 24.74, P = 0.0002). CONCLUSION:The prevalence of damage remains high in patients with cSLE even when the diagnosis of cSLE has been made in the recent decades.

OBJECTIVES:CS are used to abort disease flares in periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome. We aimed to obtain a global overview of physicians' CS usage strategies and analyse the data in the literature regarding CS use in PFAPA syndrome. METHODS:The Juvenile Inflammatory Rheumatism Clinical Practice Strategies (JIR-CliPS) PFAPA questionnaire included nine questions on CS use in addition to the demographic data questions. The survey was distributed via e-mail to potential respondents. The MEDLINE/PubMed and Scopus databases were searched systematically to extract the data regarding CS use in PFAPA syndrome. RESULTS:From 47 countries, 144 physicians (female/male = 2.6; 67.4% paediatric rheumatologists) answered the survey. Most respondents (n = 133; 92.4%) prescribe CS in PFAPA flares. The most frequently prescribed CS was prednisolone (63.2%). The definition of response to CS was indicated as 'response within 12 h' by the highest number of respondents (n = 61; 42.4%). When CS cause an increase in attack frequency, most (57.9%) consider another treatment if this causes a decrease in quality of life. Forty-four (30.6%) respondents were 'routinely' prescribing CS to PFAPA patients, and this practice was more frequent among more experienced physicians (P < 0.001). We identified 46 articles in the literature describing 4564 PFAPA patients treated with CS. Prednisone was the most frequently preferred CS (48.2%). Response to CS was around 95%, although an increase in attack frequency was noted in almost 35% of the patients. CONCLUSION:Physicians frequently use CS for PFAPA in their routine clinical practice. Regarding treatment modification, the quality of life was a prominent consideration for physicians.

OBJECTIVES:We aimed to analyse the strategies of physicians regarding corticosteroid use in syndrome of undifferentiated recurrent fever (SURF) and examine the published data on this topic. METHODS:The JIR-CliPS questionnaire which addresses physicians' practices about on-demand corticosteroid use in SURF was distributed via e-mail to potential respondents. We systematically reviewed the MEDLINE and Scopus databases and extracted the data about on-demand corticosteroid use in SURF. RESULTS:One hundred thirty-seven physicians (F/M=2.5; 66.4% paediatric rheumatologists) from 45 countries responded to the survey. Around 70% of physicians prescribe corticosteroids for SURF flares. Most physicians (81.9%) do not use corticosteroids in SURF patients routinely, and this practice is more common among less experienced physicians (p<0.001). Prednisolone at a dose of 1 mg/kg (54.4%) was the most commonly preferred corticosteroid. The most common definition of response to corticosteroids was 'response within 12 hours' (51.6%). Most respondents (59.5%) consider changing treatment if corticosteroids cause a decrease in quality of life. We found 10 articles in the literature describing 239 SURF patients treated with on-demand corticosteroids. The most frequently preferred corticosteroid was prednisolone (63.8%). The response to corticosteroids was 70.8% and an increase in attack frequency was observed in almost 40% of patients. CONCUSIONS:On-demand corticosteroid use is not uncommon in the acute management of SURF attacks. However, most physicians do not use corticosteroids routinely and there is no consensus regarding the definition of response to treatment and when to change treatment neither in our survey results nor in the literature.

OBJECTIVES:Childhood-onset systemic lupus erythematosus (cSLE) is a rare autoimmune disease with significant morbidity. Although B cell-depleting agents show promise for refractory cSLE, there is limited research on rituximab therapy in children. This study aimed to retrospectively assess the indications, efficacy, and safety of RTX in cSLE, using data from the Juvenile Inflammatory Rheumatism (JIR) cohort database. METHODS:A national retrospective study analysed data from the JIR cohort for cSLE patients treated with RTX from July 2009 to June 2023. RESULTS:Forty-one patients received RTX over 14 years; 85.4% were girls and mean age at diagnosis was 11.7 years. RTX was administered on average 16 months post-diagnosis. At treatment initiation, 87% either had received or were receiving corticosteroids, 21% NSAIDs and 82% immunosuppressants. Main indications for RTX were lupus nephritis (51.2%), persistent polyarthritis (19.5%) and refractory cytopenias (12.2%). Significant improvements in disease activity were observed at 3 and 6 months post-RTX infusion, indicated by the SLEDAI-2K score (P < 0.001), along with a notable reduction in corticosteroid usage (from 0.93 mg/kg to 0.39 mg/kg; P = 0.001) and improvements in relevant biomarkers. Adverse effects occurred in 17% of patients, with 7.3% experiencing anaphylactic reactions. One year following the last infusion, 52.5% of the paediatric subjects did not necessitate an increase in their baseline immunosuppressive therapy or the initiation of a novel treatment modality. CONCLUSIONS:RTX in refractory cSLE reduced disease activity and steroid dependence with an acceptable safety profile. Further research and international collaboration are needed to validate these findings.

BACKGROUND:Although colchicine is the mainstay of familial Mediterranean fever (FMF) treatment, 5-10% of patients are considered to have colchicine resistance (CR). However, there is no globally agreed CR definition or indications for biological disease-modifying anti-rheumatic drugs (bDMARDs). METHODS:A survey on 'Biologics in Monogenic Autoinflammatory Diseases', part of the 'Clinical Practice Strategies' (CLiPS) initiative, was conducted by a JIR cohort-initiated eCOST network among expert participants worldwide. Our primary aim was to provide a flowchart reflecting the different CR definitions and present data regarding bDMARD indications. The secondary aim was to determine how specific biases influence clinical approaches. We analysed the CliPS according to the experience levels of physicians, country-specific FMF prevalence, countries' gross domestic product, bDMARD availability and reimbursement policies of the countries. RESULTS:A total of 223 responses from 46 countries were included in the study. Almost half of the respondents (73/160, 45.6%) indicated that three to four attacks within the preceding 6 months were necessary for their CR definition. The most frequently used acute-phase reactant was C-reactive protein (157/164, 95.7%). Almost three-fourths of the respondents (74%, n=165) considered that supplementary factors, including complications of FMF, attack severity, elevated activity scores, patient-reported outcome and quality of life scales, influenced their CR definition. CONCLUSION:We present a novel flowchart describing physicians' general attitudes and unique findings regarding management strategies for colchicine-resistant FMF and shifting trends influenced by epidemiological and socioeconomic factors.

BACKGROUND:Juvenile idiopathic arthritis (JIA) is the most common rheumatologic disease of childhood. The Existing guidelines for polyarticular JIA are typically based on data from non-African populations and may not fully address the unique challenges faced in African settings. We aimed to produce updated African guidelines for the diagnosis and treatment of children and adolescents with polyarticular juvenile idiopathic arthritis (poly-JIA). METHODS:This study was conducted with the aim of reaching a consensus among African experts on the diagnosis and treatment of poly-JIA using the Delphi technique. The first scientific committee identified a total of 15 key clinical questions according to the PICO (Patient/Population, Intervention, Comparison, Outcome) approach. A systematic review of the evidence-based literature was conducted for this work. The core steering group identified researchers and clinicians with expertise in pediatric rheumatology. A Delphi process was used to reach consensus. RESULTS:An online questionnaire was sent to the expert panel that participated in the survey (100% response rate). A total of 15 recommendation points were identified, divided into two parts: five recommendations for diagnosis and ten recommendations for management. The percentage of those who agreed with the recommendations (fourth and fifth place) ranged from 80 to 100%. All 15 clinical recommendation statements that the scientific committee had identified had been agreed upon in wording (i.e., 75% of respondents agreed or strongly agreed). CONCLUSIONS:We successfully developed guidelines for children with polyarticular JIA, taking into consideration the African specific nature of limited resources and low income, also on the same time incorporating newly released data and using a treat to target approach.

BACKGROUND:Systemic autoinflammatory disorders (SAIDs) represent a growing spectrum of diseases characterized by dysregulation of the innate immune system. The most common pediatric autoinflammatory fever syndrome, Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis (PFAPA), has well defined clinical diagnostic criteria, but there is a subset of patients who do not meet these criteria and are classified as undefined autoinflammatory diseases (uAID). This project, endorsed by PRES, supported by the EMERGE fellowship program, aimed to analyze the evolution of symptoms in recurrent fevers without molecular diagnosis in the context of undifferentiated AIDs, focusing on PFAPA and syndrome of undifferentiated recurrent fever (SURF), using data from European AID registries.METHODS:Data of patients with PFAPA, SURF and uSAID were collected from 3 registries including detailed epidemiological, demographic and clinical data, results of the genetic testing and additional laboratory investigations with retrospective application of the modified Marshall and PRINTO/Eurofever classification criteria on the cohort of PFAPA patients and preliminary SURF criteria on uSAID/SURF patients.RESULTS:Clinical presentation of PFAPA is variable and some patients did not fit the conventional PFAPA criteria and exhibit different symptoms. Some patients did not meet the criteria for either PFAPA or SURF, highlighting the heterogeneity within these groups. The study also explored potential overlaps between PFAPA and SURF/uAID, revealing that some patients exhibited symptoms characteristic of both conditions, emphasizing the need for more precise classification criteria.CONCLUSIONS:Patients with recurrent fevers without molecular diagnoses represent a clinically heterogeneous group. Improved classification criteria are needed for both PFAPA and SURF/uAID to accurately identify and manage these patients, ultimately improving clinical outcomes.

Gain-of-function mutations in NLRP3 are linked to cryopyrin-associated periodic syndromes (CAPS). Although NLRP3 autoinflammasome assembly triggers inflammatory cytokine release, its activation mechanisms are not fully understood. Our study used a functional genetic approach to identify regulators of NLRP3 inflammasome formation. We identified the HSP90β-SGT1 chaperone complex as crucial for autoinflammasome activation in CAPS. A deficiency in HSP90β, but not in HSP90α, impaired the formation of ASC specks without affecting the priming and expression of inflammasome components. Conversely, activating NLRP3 with stimuli such as nigericin or alum bypassed the need for SGT1 and HSP90β, suggesting the existence of alternative inflammasome assembly pathways. The role of HSP90β was further demonstrated in PBMCs derived from CAPS patients. In these samples, the pathological constitutive secretion of IL-1β could be suppressed using a pharmacological inhibitor of HSP90β. This finding underscores the potential of SGT1-HSP90β modulation as a therapeutic strategy in CAPS while preserving NLRP3's physiological functions.

Mevalonate kinase deficiency (MKD), a rare auto-inflammatory disorder, arises from mutations in the MVK gene, disrupting isoprenoid biosynthesis, and affecting cellular processes. This comprehensive review provides an updated perspective on MKD, including its aetiology, pathogenesis, diagnostic modalities, and therapeutic strategies. Based on recent research and clinical advances, our objective is to bridge the knowledge gaps in the 2015 SHARE guidelines. By describing molecular mechanisms, diagnostic dilemmas, and emerging therapies, this article should serve as a resource for clinicians and researchers, promoting a deeper understanding of MKD and guiding optimal patient care.

Background Systemic juvenile idiopathic arthritis (systemic JIA) is a severe disease with both systemic and joint inflammation. This study aims to identify predictors of disease evolution within the systemic JIA population enrolled in the Juvenile Inflammatory Rheumatism cohort (JIRcohort). Methods Observational patient cohort study with 201 recruited children from 4 countries (3 European, 1 North Africa) from 2005 until 2019, using retrospectively (2005–2015) and prospectively (2015–2019) routine care collected data. Results Sixty-five patients with complete follow-up data for 24 months after first diagnosis were classified as monophasic ( n = 23), polyphasic ( n = 6) or persistent group ( n = 36) corresponding to their evolution (unique flare, recurrent flares, or persistent disease activity respectively). The patients of the persistent group were more likely to have an earlier disease onset, before the age of 6 (OR 2.57, 95%-CI 0.70–9.46), persistence of arthritis at 12-months post-diagnosis (OR 4.45, 95%-CI 0.58–34.20) and higher use of synthetic DMARD (sDMARD, OR 5.28, 95%-CI 1.39–20.01). Other variables like global assessment by physician and by patient and C Reactive Protein levels at 12-months post-diagnosis were assessed but without any predictive value after adjusting for confounding factors. Conclusions Our results suggest that the earlier disease onset, the persistence of arthritis throughout the first year of disease evolution and the need of sDMARD might predict a persistent disease course.

PSTPIP1 (proline-serine-threonine phosphatase-interactive protein 1)-associated myeloid-related proteinemia inflammatory (PAMI) syndrome, previously known as Hyperzincemia/Hypercalprotectinemia (Hz/Hc) syndrome, is a recently described, rare auto-inflammatory disorder caused by specific deleterious variants in the PSTPIP1 gene (p.E250K and p.E257K). The disease is characterized by chronic systemic inflammation, cutaneous and osteoarticular manifestations, hepatosplenomegaly, anemia, and neutropenia. Increased blood levels of MRP 8/14 and zinc distinguish this condition from other PSTPIP1-associated inflammatory diseases (PAID). The aim of this systematic review is to provide a comprehensive overview of the disease phenotype, course, treatment, and outcome based on reported cases. This systematic review adheres to the PRISMA guidelines (2020) for reporting. A literature search was performed in Embase, Medline, and Web of Science on 13 October 2022. The quality of the case reports and case series was assessed using the JBI checklists. Out of the 43 included patients with PAMI syndrome, there were 24 females and 19 males. The median age at onset was 3.9 years. The main clinical manifestations included anemia (100%), neutropenia (98%), cutaneous manifestations (74%), osteoarticular manifestations (72%), splenomegaly (70%), growth failure (57%), fever (51%), hepatomegaly (56%), and lymphadenopathy (39%). Systemic inflammation was described in all patients. Marked elevation of zinc and MRP 8/14 blood levels were observed in all tested patients. Response to treatment varied and no consistently effective therapy was identified. The most common therapeutic options were corticosteroids (N = 30), anakinra (N = 13), cyclosporine A (N = 11), canakinumab (N = 6), and anti-TNF (N = 14). Hematopoietic stem cell transplantation has been recently reported to be successful in five patients. Our review highlights the key characteristics of PAMI syndrome and the importance of considering this disease in the differential diagnosis of patients presenting with early-onset systemic inflammation and cytopenia.

Background: The cryopyrin-associated periodic syndromes (CAPS) comprise a group of rare autoinflammatory diseases caused by gain-of-function mutations in the NLRP3 gene. NLRP3 contains a leucine-rich repeats (LRR) domain with a highly conserved exonic organization that is subjected to extensive alternative splicing. Aberrant NLRP3 inflammasome assembly in CAPS causes chronic inflammation; however, the mechanisms regulating inflammasome function remain unclear.Objective: We aimed to elucidate the mechanisms regulating NLRP3-mediated autoinflammation in human disease, characterizing the role of LRR in inflammasome activation.Methods: We analyzed sequence read archive data to characterize the pattern of NLRP3 splicing in human monocytes and investigated the role of each LRR-coding exon in inflammasome regulation in genetically modified U937 cells representing CAPS and healthy conditions.Results: We detected a range of NLRP3 splice variants in human primary cells and monocytic cell lines, including 2 yet-undescribed splice variants. We observe that lipopolysaccharides affect the abundance of certain splice variants, suggesting that they may regulate NLRP3 activation by affecting alternative splicing. We showed that exons 4, 5, 7, and 9 are essential for inflammasome function, both in the context of wild-type NLRP3 activation by the agonist molecule nigericin and in a model of CAPS-mediated NLRP3 inflammasome assembly. Moreover, the SGT1-NLRP3 interaction is decreased in nonfunctional variants, suggesting that alternative splicing may regulate the recruitment of proteins that facilitate inflammasome assembly. Conclusion: These findings demonstrate the contribution of the LRR domain in inflammasome function and suggest that navigating LRR exon usage within NLRP3 is sufficient to dampen inflammasome assembly in CAPS. (J Allergy Clin Immunol 2023;151:222-32.)

Background Despite guidelines, poor access to appropriate care for juvenile idiopathic arthritis (JIA) patients remains a global issue. Prompt referral to a pediatric rheumatology (PR) center and effective care is known to be critical for changing the natural history of the disease and improving long-term prognosis. This project assesses socio-economic factors of delayed referral to a pediatric rheumatologist (PRst) for JIA patients in France and Switzerland within the Juvenile Inflammatory Rheumatism (JIR) Cohort. Methods All patients diagnosed with JIA, presenting at one center of the JIRcohort in France or Switzerland with additional data on referral pathway were included. Patient characteristics at first visit to the PR center, dates of visits to healthcare providers during referral, and parent characteristics were extracted from the JIRcohort database. Results Two hundred fifty children were included. The overall median time to first PR assessment was 2.4 months [1.3; 6.9] and ranged widely across the JIA subtypes, from 1.4 months [0.6; 3.8] for children with systemic juvenile idiopathic arthritis (sJIA) to 5.3 months [2.0; 19.1] for children with enthesitis-related arthritis (ERA). A diagnosis of ERA and an appointment with an orthopedist during the referral pathway were significantly associated with a longer time before the first PR visit (hazard ratio HR 0.50 [95% CI: 0.29; 0.84]) and HR 0.68 [95% CI: 0.49; 0.93], respectively) in multivariable analysis. Having a mother with a post-graduate educational attainment level was tendentially associated with a shorter time before the first PR visit, (HR 1.32 [95% CI: 0.99; 1.78]). Conclusions Time to first PRst visit was most often short compared to other studies and close to the British recommendations. However, this time remained too long for many patients. We observed no social inequities in access to a PRst, but we show the need to improve effective pathway and access to a PR center for JIA patients.

Pediatric immune disorders encompass an array of disorders with either a systemic or tissue-specific expression, whose phenotype and therapeutic approach often depend on age. More recently, genotypic traits and knowledge of the underlying pathophysiological processes have facilitated a more individualized clinical approach. Molecular characterization in primary immune disorders has provided molecular targets for immunotherapies. In immune-mediated disorders of the CNS, better recognition of pediatric characteristics has enabled earlier diagnosis and treatment initiation. For rhumatismal disorders, like all rare immune disorders, the setting up of multi-centre registers and collaborative studies provide the framework for targeted clinical strategies.

BACKGROUND: Paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) may occur 4 to 8 weeks after SARS-CoV-2 infection. The acute presentation of PIMS-TS has been well described, but data on longer-term outcomes, particularly cardiac, is scarce. METHODS: This prospective nationwide surveillance study included children and adolescents less than 18 years of age who were hospitalised with PIMS-TS in Switzerland between March 2020 and March 2022. Data was collected from all 29 paediatric hospitals through the Swiss Paediatric Surveillance Unit (SPSU) during hospitalisation and approximately six weeks after discharge. The data was analysed after categorising the participants into three groups based on their admission status to the intensive care unit (ICU) (non-ICU, ICU-moderate) and the requirement for invasive ventilatory and/or inotropic support (ICU-severe). RESULTS: Overall, 204 children were included of whom 194 (95.1%) had follow-up data recorded. Median age was 9.0 years (interquartile range [IQR] 6.0-11.5) and 142 (69.6%) were male. In total, 105/204 (51.5%) required ICU admission, of whom 55/105 (52.4%) received inotropic support and 14/105 (13.3%) mechanical ventilation (ICU-severe group). Echocardiography was performed in 201/ 204 (98.5%) children; 132 (64.7%) had a cardiac abnormality including left ventricular systolic dysfunction (73 [36.3%]), a coronary artery abnormality (45 [22.4%]), pericardial effusion (50 [24.9%]) and mitral valve regurgitation (60 [29.9%]). Left ventricular systolic dysfunction was present at admission in 62/201 (30.8%) children and appeared during hospitalisation in 11 (5.5%) children. A coronary artery abnormality was detected at admission in 29/ 201 (14.2%) children and developed during hospitalisation or at follow-up in 13 (6.5%) and 3 (1.5%) children, respectively. None of the children had left ventricular systolic dysfunction at follow-up, but a coronary abnormality and pericardial effusion were found in 12 (6.6%) and 3 (1.7%) children, respectively. School absenteeism at the time of follow-up was more frequent in children who had been admitted to the ICU (2.5% in the non-ICU group compared to 10.4% and 17.6% in the ICU-moderate and ICU-severe group, respectively) (p = 0.011). CONCLUSION: Cardiac complications in children presenting with PIMS-TS are common and may worsen during the hospitalisation. Irrespective of initial severity, resolution of left ventricular systolic dysfunction is observed, often occurring rapidly during the hospitalisation. Most of the coronary artery abnormalities regress; however, some are still present at follow-up, emphasising the need for prolonged cardiac evaluation after PIMS-TS.

OBJECTIVES:Hip involvement remains a predictor of severe juvenile idiopathic arthritis (JIA) course and carries a high risk of disability. This study aims to determine the factors of poor prognosis of hip involvement in patients with JIA and to assess the treatment response.METHODS:This is a multicenter observational cohort study. Patients were selected from the JIR Cohort database. Hip involvement was defined as clinically suspected and confirmed by an imaging tool. Follow-up data were collected during 5 years.RESULTS:Among the 2223 patients with JIA, 341(15%) patients had hip arthritis. Male gender, enthesitis-related arthritis, and North African origin were factors associated with hip arthritis. Hip inflammation was associated with disease activity parameters during the first year, particularly Physician Global Assessment, joint count, and inflammatory marks. Structural hip progression was associated with early onset of the disease, a longer time to diagnosis, geographic origin, and JIA subtypes. Anti-TNF therapy was found to be the only treatment able to effectively reduce structural damage progression.CONCLUSION:The early onset diagnostic delay, origin, and systemic subtype of JIA predict a poor prognosis of hip arthritis in children with JIA. The use of anti-TNF was associated with a better structural prognosis.