JAK inhibitors in refractory juvenile rheumatic diseases: Efficacy, tolerance and type-I interferon profiling, a single center retrospective study.

OBJECTIVES: - Janus Kinase inhibitors (JAKi) are a new class of drugs available for pediatric rheumatic diseases. This study aimed to describe the safety and effectiveness of JAKi in these diseases, with a focus on longitudinal interferon-stimulated genes (ISG) assessment. METHODS: - We present a single-center retrospective study of children with refractory pediatric rheumatic diseases including connective tissue diseases, monogenic type I interferonopathies or juvenile idiopathic arthritis, receiving JAKi. According to physicians' assessment, treatment effectiveness was classified at 12 months as a complete response in the total absence of disease activity, partial response in case of significant (>50%) but incomplete improvement or no response in the case of non-response or improvement of less than 50% of the clinical and biological parameters. ISG were monitored longitudinally using Nanostring technology. RESULTS: - 22 children were retrospectively included in this study, treated either by baricitinib or ruxolitinib. Complete response was achieved at 12 months in 9/22 (41%) patients. 6/22 (27%) patients were non-responders and treatment had been discontinued in five of them. Within the interferon (IFN)-related diseases group, ISG-score was significantly reduced 12 months after JAKi onset (p = 0.0068). At 12 months, daily glucocorticoid doses had been reduced with a median dose of 0.16 mg/kg/day (IQR 0.11; 0.33) (p = 0.0425). 7/22 (32%) patients had experienced side effects, infections being the most common. Increase of the body mass index was also recorded in children in the first 6 months of treatment. CONCLUSION: - JAKi represent a promising treatment of immune-mediated pediatric diseases, enabling to decrease type-I IFN transcriptomic signature in responding patients, especially in the context of juvenile dermatomyositis. JAKi represent steroid-sparing drugs but they induce metabolic changes linked to weight gain, posing a concern in the treatment of young patients and teenagers. More data are required to define the efficacy and safety of JAKi in the management of refractory pediatric rheumatic diseases.

Functional diversity of NLRP3 gain-of-function mutants associated with CAPS autoinflammation.

NLRP3-associated autoinflammatory disease is a heterogenous group of monogenic conditions caused by NLRP3 gain-of-function mutations. The poor functional characterization of most NLRP3 variants hinders diagnosis despite efficient anti-IL-1 treatments. Additionally, while NLRP3 is controlled by priming and activation signals, gain-of-functions have only been investigated in response to priming. Here, we characterize 34 NLRP3 variants in vitro, evaluating their activity upon induction, priming, and/or activation signals, and their sensitivity to four inhibitors. We highlight the functional diversity of the gain-of-function mutants and describe four groups based on the signals governing their activation, correlating partly with the symptom severity. We identify a new group of NLRP3 mutants responding to the activation signal without priming, associated with frequent misdiagnoses. Our results identify key NLRP3 residues controlling inflammasome activity and sensitivity to inhibitors, and antagonistic mechanisms with broader efficacy for therapeutic strategies. They provide new insights into NLRP3 activation, an explanatory mechanism for NLRP3-AID heterogeneity, and original tools for NLRP3-AID diagnosis and drug development.

Extra-osseous manifestations in chronic recurrent multifocal osteomyelitis: a retrospective study.

OBJECTIVES: Extra-osseous (EO) manifestations are poorly characterized in chronic recurrent multifocal osteomyelitis (CRMO). This study aimed to further define the frequency, characteristics and treatment of EO events in CRMO and whether different phenotypes can be distinguished and benefit from special management. METHODS: This multicentre retrospective study included CRMO patients followed in several paediatric rheumatology departments in France, between 2015 and 2022. EO manifestations were defined as skin lesions, gastrointestinal manifestations, arthritis, enthesitis, sacroiliitis, uveitis, vasculitis, and fever. At the last visit, the physician defined CRMO as active in the presence of clinical manifestations including both osseous and EO symptoms. RESULTS: We included 133 patients; 87 (65.4%) were girls; the median age at first symptoms was 9.0 years (interquartile range 7.0-10.0). EO manifestations were described in 90 (67.7%) patients, with a predominance of skin lesions (n = 51/90; 56.7%), followed by sacroiliitis (n = 38/90; 42.2%), enthesitis (n = 21/90; 23.3%), arthritis (n = 14/90, 15.6%) and gastrointestinal manifestations (n = 6/90, 6.7%). The use of non-steroidal anti-inflammatory drugs and bisphosphonates did not differ by presence or not of EO manifestations. Biologics were taken more frequently by patients with than without EO manifestations (p< 0.001); tumour necrosis factor inhibitors were used in 33 (36.7%) EO+ patients. Under this treatment, 18 (54.5%) patients achieved complete remission of osseous and EO manifestations. At the last visit, more EO-positive than EO-negative patients were on treatment (p= 0.009), with active disease in 58 (64.4%) patients. CONCLUSION: The analysis of EO manifestations in CRMO delineates 2 groups of patients in terms of severity and treatments used. Our study opens up new pathophysiological leads that may underlie the wide range of CRMO phenotypes.

Mutations in the B30.2 and the central helical scaffold domains of pyrin differentially affect inflammasome activation.

Familial Mediterranean Fever (FMF) is the most common monogenic autoinflammatory disorder. FMF is caused by mutations in the MEFV gene, encoding pyrin, an inflammasome sensor. The best characterized pathogenic mutations associated with FMF cluster in exon 10. Yet, mutations have been described along the whole MEFV coding sequence. Exon 10 encodes the B30.2 domain of the pyrin protein, but the function of this human-specific domain remains unclear. Pyrin is an inflammasome sensor detecting RhoA GTPase inhibition following exposure to bacterial toxins such as TcdA. Here, we demonstrate that the B30.2 domain is dispensable for pyrin inflammasome activation in response to this toxin. Deletion of the B30.2 domain mimics the most typical FMF-associated mutation and confers spontaneous inflammasome activation in response to pyrin dephosphorylation. Our results indicate that the B30.2 domain is a negative regulator of the pyrin inflammasome that acts independently from and downstream of pyrin dephosphorylation. In addition, we identify the central helical scaffold (CHS) domain of pyrin, which lies immediately upstream of the B30.2 domain as a second regulatory domain. Mutations affecting the CHS domain mimic pathogenic mutations in the B30.2 domain and render the pyrin inflammasome activation under the sole control of the dephosphorylation. In addition, specific mutations in the CHS domain strongly increase the cell susceptibility to steroid catabolites, recently described to activate pyrin, in both a cell line model and in monocytes from genotype-selected FMF patients. Taken together, our work reveals the existence of two distinct regulatory regions at the C-terminus of the pyrin protein, that act in a distinct manner to regulate positively or negatively inflammasome activation. Furthermore, our results indicate that different mutations in pyrin regulatory domains have different functional impacts on the pyrin inflammasome which could contribute to the diversity of pyrin-associated autoinflammatory diseases.

[The transitional care from pediatrics to adult medicine within the rare autoimmune and autoinflammatory diseases network]. / Transition de la médecine pédiatrique à la médecine pour adultes dans les maladies autoimmunes et autoinflammatoires rares.

The committee involved in transitional care within the French network on rare autoimmune and auto-inflammatory diseases has developed tools and published recommendations for the care during the transition of adolescents and young adults suffering from these chronic diseases which often demonstrate flares. As the challenge is the compliance to the continuation of care in the adult world, the therapeutic alliance between the young patient and his/her pediatrician and then his/her adult doctor is particularly important. The working group thus carried out a survey on how doctors and young patients perceive their relationship during the period of transition in medical supervision.

Title: Transition de la médecine pédiatrique à la médecine pour adultes dans les maladies autoimmunes et autoinflammatoires rares. Abstract: La commission « Transition ¼ de la filière de santé des maladies auto-immunes et auto-inflammatoires rares a développé des outils et émis des recommandations pour la prise en charge des adolescents et jeunes adultes atteints de ces maladies chroniques évoluant souvent par poussées, durant la période de transition de la médecine pédiatrique vers la médecine pour adultes. L'enjeu de l'adhésion du jeune patient à la poursuite de son parcours de soin dans le système de santé des adultes rend particulièrement importante l'alliance thérapeutique avec son médecin pédiatre puis son médecin pour adultes. Le groupe de travail issu de cette commission a ainsi mené une enquête sur la façon dont les médecins et les jeunes patients perçoivent leur relation durant la période de la transition du suivi médical.

Case Report: Comorbid Hyper-IgD Syndrome and Hidradenitis Suppurativa - A New Syndromic Form of HS? A Report of Two Cases.

Hidradenitis Suppurativa (HS) is a chronic suppurative disease of the pilosebaceous unit. The current model of HS pathophysiology describes the condition as the product of hyperkeratinisation and inflammation at the hair follicular unit. Environmental factors (such as smoking and obesity), gender, genetic predisposition, and skin dysbiosis are considered the main pathogenic drivers of the disease. Autoinflammatory syndromes associated with HS are rare but may help to highlight the potential roles of autoinflammation and dysregulated innate immune system in HS. Therefore, it is of major relevance to increase the awareness about these diseases in order to improve the understanding of the disease and to optimize the management of the patients. Herein, we report for the first time, to our knowledge, two clinical cases of Hyper-IgD syndrome-associated HS. Hyper-IgD is an autoinflammatory syndrome caused by a mevalonate kinase deficiency (MKD), a key kinase in the sterol and isoprenoid production pathway. We describe the potentially shared pathophysiological mechanisms underpinning comorbid MKD-HS and propose therapeutic options for the management of these patients.

Therapeutic alliance is associated to treatment adherence in children with juvenile idiopathic arthritis.

OBJECTIVES: Therapeutic alliance (TA) is the agreement between caregiver and patient during the care process. Therapeutic adherence is a major issue for the management of Juvenile Idiopathic Arthritis (JIA) requiring child's strong ability to follow treatments. The aim of this study was to evaluate the relationship between TA and adherence in patients with JIA. METHODS: Observational, cross-sectional, multicenter study. Children, with JIA, aged 8-16, were included. Children, parents and physicians completed the Helping Alliance Questionnaire (HAQ-CP) for assessing TA. Adherence was measured using the Child/Parent Adherence Report Questionnaire (CARQ & PARQ). Demographic data, disease characteristics, current treatments and social environment were collected. The univariate relationship between TA and adherence, was studied by Pearson correlation coefficient. The multivariate analysis used a multiple linear regression model. RESULTS: A total of 119 patients were included: 68.9% girls, mean age (SD) 12.4 (2.9) years, disease duration 73.1 (48.2) months. JIA was in remission (52%), in low activity (32%) and active (16%). TA scores were high (≥80/100) for children, parents and physicians. HAQCP was highly correlated with CARQ (r=0.31; P<0.001) PARQ (r=0.37; P<0.001). In univariate analysis, disease activity (P<0.05), place of residence (P<0.01) and family status (P<0.01) were associated with child's TA. In multivariate analysis, only the place of residence (P<0.001) and the family status (P<0.05) remained associated with TA. CONCLUSION: TA strongly influences therapeutic adherence and therefore may be important for treatment effectiveness.

LACC1 deficiency links juvenile arthritis with autophagy and metabolism in macrophages.

Juvenile idiopathic arthritis is the most common chronic rheumatic disease in children, and its etiology remains poorly understood. Here, we explored four families with early-onset arthritis carrying homozygous loss-of-expression mutations in LACC1. To understand the link between LACC1 and inflammation, we performed a functional study of LACC1 in human immune cells. We showed that LACC1 was primarily expressed in macrophages upon mTOR signaling. We found that LACC1 deficiency had no obvious impact on inflammasome activation, type I interferon response, or NF-κB regulation. Using bimolecular fluorescence complementation and biochemical assays, we showed that autophagy-inducing proteins, RACK1 and AMPK, interacted with LACC1. Autophagy blockade in macrophages was associated with LACC1 cleavage and degradation. Moreover, LACC1 deficiency reduced autophagy flux in primary macrophages. This was associated with a defect in the accumulation of lipid droplets and mitochondrial respiration, suggesting that LACC1-dependent autophagy fuels macrophage bioenergetics metabolism. Altogether, LACC1 deficiency defines a novel form of genetically inherited juvenile arthritis associated with impaired autophagy in macrophages.

Fast diagnostic test for familial Mediterranean fever based on a kinase inhibitor.

BACKGROUND AND OBJECTIVE: Familial Mediterranean fever (FMF) is the most frequent hereditary autoinflammatory disease. Its diagnosis relies on a set of clinical criteria and a genetic confirmation on identification of biallelic pathogenic MEFV variants. MEFV encodes pyrin, an inflammasome sensor. Using a kinase inhibitor, UCN-01, we recently identified that dephosphorylation of FMF-associated pyrin mutants leads to inflammasome activation. The aim of this study was to assess whether quantifying UCN-01-mediated inflammasome activation could discriminate FMF patients from healthy donors (HD) and from patients with other inflammatory disorders (OID). METHODS: Real-time pyroptosis and IL-1ß secretion were monitored in response to UCN-01 in monocytes from FMF patients (n=67), HD (n=71) and OID patients (n=40). Sensitivity and specificity of the resulting diagnostic tests were determined by receiver operating characteristic curve analyses. RESULTS: Inflammasome monitoring in response to UCN-01 discriminates FMF patients from other individuals. Pyroptosis assessment leads to a fast FMF diagnosis while combining pyroptosis and IL-1ß dosage renders UCN-01-based assays highly sensitive and specific. UCN-01-triggered monocytes responses were influenced by MEFV gene dosage and MEFV mutations in a similar way as clinical phenotypes are. CONCLUSIONS: UCN-01-based inflammasome assays could be used to rapidly diagnose FMF, with high sensitivity and specificity.

Comparison of paediatric and adult classification criteria in juvenile idiopathic arthritis during the transition from paediatric to adult care.

OBJECTIVES: To determine the characteristics of juvenile idiopathic arthritis (JIA) patients seen during the transition period in order to compare paediatric classification criteria with those for adults. METHODS: Patients with JIA according to the ILAR classification and who had a consultation at transition between 2010 and 2017 were included in a retrospective bi-centre (Lyon, Lausanne) study. JIA classification criteria were compared to ACR/EULAR 2010 criteria for rheumatoid arthritis (RA), Yamaguchi criteria for adult-onset Still's disease (AOSD), ASAS criteria for spondyloarthritis and CASPAR criteria for psoriatic arthritis. RESULTS: One hundred and thirty patients were included: 13.9% with systemic JIA, 22.3% with polyarticular JIA, 22.3% with oligoarticular JIA, 34.6% with enthesitis-related arthritis (ERA) and 6.9% with psoriatic arthritis; 13.1% had suffered from uveitis; 14.5% of patients had erosions or carpitis, mainly those with psoriatic arthritis, polyarticular or systemic JIA; 37.5% of patients with ERA displayed radiological sacroiliitis. When comparing paediatric JIA criteria with adult classifications, we found that: 66.6% of patients with systemic JIA fulfilled the criteria for AOSD, 87.5% of rheumatoid factor-positive polyarticular JIA and 9.5% of rheumatoid factor-negative polyarticular JIA met the criteria for RA, and 34.5% of oligoarticular JIA fulfilled the criteria for spondyloarthritis. Finally, 77.7% of patients with ERA met the criteria for spondyloarthritis, and 100% of patients with psoriatic arthritis JIA met the criteria for psoriatic arthritis. CONCLUSION: Oligoarticular JIA and rheumatoid factor-negative polyarticular JIA seem to be paediatric entities, whereas the other types of JIA tended to meet the respective adult classification criteria.

The benefit-risk balance for biological agents in juvenile idiopathic arthritis: a meta-analysis of randomized clinical trials.

OBJECTIVE: To assess the net benefit of biological agents (BA) used in JIA. METHODS: We systematically searched databases up to March 2019 for randomized controlled trials (RCT) performed in JIA disease. Separate random-effects meta-analyses were conducted for efficacy (ACR paediatric score 30%, ACRpedi30) and serious adverse events for safety. In order to standardize the baseline risk, we performed a meta-analysis of baseline risk in the control group (for both efficacy and safety meta-analysis). The net benefit was determined as the risk difference of efficacy subtracted by the risk difference of safety. RESULTS: We included 19 trials: 11 parallel RCTs (754 patients) and 8 withdrawal RCTs (704 patients). The net benefit ranged from 2.4% (adalimumab) to 17.6% (etanercept), and from 2.4% (etanercept) to 36.7%, (abatacept) in parallel and withdrawal trials assessing non-systemic JIA, respectively. In the systemic JIA category, the net benefit ranged from 22.8% (rilonacept) to 70.3% (canakinumab), and from 32.3% (canakinumab) to 58.2% (tocilizumab) in parallel and withdrawal trials, respectively. CONCLUSION: The results suggest that a greater number of patients experienced therapeutic success without serious adverse events in the systemic onset JIA category compared with the BAs for non-systemic JIA categories. Baseline risk, design of trial and JIA categories impact the measure of net benefit of BAs in JIA patients.

Clinical Characteristics of Acne Fulminans Associated With Chronic Nonbacterial Osteomyelitis in Pediatric Patients.

OBJECTIVE: Acne fulminans (AF) is a rare, explosive systemic form of acne. Chronic nonbacterial osteomyelitis (CNO) or chronic recurrent multifocal osteomyelitis (CRMO) is a primarily pediatric autoinflammatory disorder characterized by sterile osteolytic bone lesions. Concomitant occurrence of CNO/CRMO and AF is very rare, and little is known about the epidemiological and clinical particularities of this association. The aim of this retrospective observational study was to describe the characteristics of pediatric patients with CNO/CRMO associated to AF. METHODS: Electronic mailing lists of French medical societies were used to call for patients with CNO/CRMO and AF. A search for published patients with CNO/CRMO and AF was performed by screening PubMed. RESULTS: We identified 5 original patients and 10 patients from the literature. All patients were adolescent boys. Mean age at disease onset was 14.8 years. Nine of 15 patients had received isotretinoin before the sudden onset of AF. Osteoarticular symptoms appeared within < 1-3 months after the onset of AF. The mean numbers of clinical and radiological bone lesions were 3.6 and 5.6, respectively. The percentages of patients with involvement of vertebrae, pelvis, chest, and cranial were 40%, 40%, 33.3%, and 6.6%, respectively. Arthritis was observed in 69.2% of patients and sacroiliac arthritis in 46.2%. CONCLUSION: CNO/CRMO associated to AF occurs predominantly in male adolescents and is characterized by frequent involvement of the axial skeleton and arthritis. Epidemiological and clinical features of these patients differ from general CNO/CRMO cohorts. Clinical management requires careful handling of isotretinoin doses.

Pyrin dephosphorylation is sufficient to trigger inflammasome activation in familial Mediterranean fever patients.

Familial Mediterranean fever (FMF) is the most frequent hereditary systemic autoinflammatory syndrome. FMF is usually caused by biallelic mutations in the MEFV gene, encoding Pyrin. Conclusive genetic evidence lacks for about 30% of patients diagnosed with clinical FMF. Pyrin is an inflammasome sensor maintained inactive by two kinases (PKN1/2). The consequences of MEFV mutations on inflammasome activation are still poorly understood. Here, we demonstrate that PKC superfamily inhibitors trigger inflammasome activation in monocytes from FMF patients while they trigger a delayed apoptosis in monocytes from healthy donors. The expression of the pathogenic p.M694V MEFV allele is necessary and sufficient for PKC inhibitors (or mutations precluding Pyrin phosphorylation) to trigger caspase-1- and gasdermin D-mediated pyroptosis. In line with colchicine efficacy in patients, colchicine fully blocks this response in FMF patients' monocytes. These results indicate that Pyrin inflammasome activation is solely controlled by Pyrin (de)phosphorylation in FMF patients while a second control mechanism restricts its activation in healthy donors/non-FMF patients. This study paves the way toward a functional characterization of MEFV variants and a functional test to diagnose FMF.

Safety of biological agents in paediatric rheumatic diseases: A real-life multicenter retrospective study using the JIRcohorte database.

OBJECTIVE: To analyse and report the incidence of side effects of biological agents in paediatric patients with inflammatory diseases using of real-life follow-up cohort. METHODS: In this international, observational, retrospective, multicentre study of children treated by biological agents and followed in the Juvenile Inflammatory Rheumatism (JIR) cohort (JIRcohorte) network, a Kaplan-Meier method was used to estimate the occurrence of adverse events. A Cox model was constructed to identify independent predictors of adverse events. RESULTS: Overall 813 patients totalling 3439 patients-year (PY) of biological agents were included. The main diagnosis was juvenile idiopathic arthritis (84%). A total of 222 patients (27.3%) had 419 adverse events, representing an incidence rate of 12.2 per 100 PY 95% CI [11.0; 13.4]. The overall incidence rate of serious adverse events was 3.9 per 100 PY 95% CI [3.2; 4.6]. Tocilizumab and infliximab were significantly associated with adverse events and canakinumab with serious adverse events. Univariate and multivariable analysis of adverse events and serious adverse events indicated that patients under biological agents with concomitant immunosuppressive drugs (excluding methotrexate) suffered from more of these events. CONCLUSION: This study suggests an overall an acceptable safety of biologic agents in children with inflammatory rheumatic diseases treated with biological agents. However, the concomitant prescription of immunosuppressive drugs with biological agents represents a substantial risk of adverse events.

Building a transitional care checklist in rheumatology: A Delphi-like survey.

OBJECTIVES: To design a transitional care checklist to be used by and facilitate the work of health professionals in providing transitional care for children with a chronic rheumatologic disease and their families. METHODS: A Delphi-like study among an international expert panel was carried out in four steps: (1) a working group of 6 specialists established a draft; (2) a web-survey among a panel of international experts evaluated it; (3) a 2-day consensus conference with an expert panel discussed items not reaching agreement; (4) a web-survey among the panel of international experts with the list of reformulated items. RESULTS: The first draft of the checklist included 38 items in 3 phases of transition and 5 age groups. Thirty-three international experts evaluated the checklist reaching≥80% agreement for 26 items and ≤80% for 12. The consensus conference of 12 experts discussed and redefined the 12 items. Twenty-five international experts filled out the web-survey and all items reached a minimum of 80% agreement except one. The final checklist was reached. CONCLUSIONS: This Delphi-like study defined what themes should be included and at what age they need to be addressed with patients with a chronic rheumatology disease and their families during transition. This checklist reached a strong international and interdisciplinary consensus while examining transition in a broad way. It should now be spread widely to health professionals to be used by all those who care for adolescents aged≥12 years at times of transition. It could be transposed to most chronic conditions. Recommendations for further research are given.

Familial Mediterranean fever mutations are hypermorphic mutations that specifically decrease the activation threshold of the Pyrin inflammasome.

Objectives: FMF is the most frequent autoinflammatory disease and is associated in most patients with bi-allelic MEFV mutations. MEFV encodes Pyrin, an inflammasome sensor activated following RhoGTPase inhibition. The functional consequences of MEFV mutations on the ability of Pyrin variants to act as inflammasome sensors are largely unknown. The aim of this study was to assess whether MEFV mutations affect the ability of Pyrin to detect RhoGTPase inhibition and other inflammasome stimuli. Methods: IL-1ß and IL-18 released by monocytes from healthy donors (HDs) and FMF patients were measured upon specific engagement of the Pyrin, NLRP3 and NLRC4 inflammasomes. Cell death kinetics following Pyrin activation was monitored in real time. Results: Monocytes from FMF patients secreted significantly more IL-1ß and IL-18 and died significantly faster than HD monocytes in response to low concentrations of Clostridium difficile toxin B (TcdB), a Pyrin-activating stimulus. Monocytes from patients bearing two MEFV exon 10 pathogenic variants displayed an increased Pyrin inflammasome response compared with monocytes from patients with a single exon 10 pathogenic variant indicating a gene-dosage effect. Using a short priming step, the response of monocytes from FMF patients to NLRP3- and NLRC4-activating stimuli was normal indicating that MEFV mutations trigger a specific hypersensitivity of monocytes to low doses of a Pyrin-engaging stimulus. Conclusion: Contrary to the NLRP3 mutations described in cryopyrin-associated periodic syndrome, FMF-associated MEFV mutations do not lead to a constitutive activation of Pyrin. Rather, FMF-associated mutations are hypermorphic mutations that specifically decrease the activation threshold of the Pyrin inflammasome without affecting other canonical inflammasomes.

MISS questionnaire in French version: a good tool for children and parents to assess methotrexate intolerance.

The aim of this study was to assess the relevance for children and parents to use the French-validated version of the methotrexate intolerance severity score (MISS), a measure of methotrexate intolerance for children suffering from juvenile idiopathic arthritis. The French-version MISS was developed following the "Guidelines for the process of cross-cultural adaptation of self-report measures." The new version was tested in families of children with juvenile idiopathic arthritis who completed the questionnaire twice at a 2-week interval. Item correlations, Cronbach's alpha, and kappa coefficients were computed to evaluate acceptability, internal consistency, and reproducibility. A culturally acceptable version to French was obtained. A total of 71 individuals were included from May 2015 to November 2015. The results show very good acceptability: good response rate (80%), few missing data (<1%) and good understanding of parents and children. The inter-item, dimension-item, and inter-dimension correlations were satisfactory (except for "vomiting" items-other items correlation). Cronbach's alpha coefficient was well higher than the usually recommended value of 0.6. The results of validity of internal and external consistencies were satisfactory. We also found good agreement between the test-retest for every family. The empirical discriminative cut-off point of 3 showed a sensitivity of 86% and a specificity of 83%. The MISS questionnaire is quick to complete, easy to use. It can be completed by children or their parents with no significant difference. This validated French-version MISS can help study prevalence and risk factors of methotrexate intolerance, better detect this intolerance, and provide better support for patients on long-term treatment.

Tocilizumab in the treatment of mixed connective tissue disease and overlap syndrome in children.

Arthritis is one of the main manifestations of mixed connective tissue disease (MCTD) and overlap syndrome in children and can be responsible for functional disability. We report on 2 children with arthritis that were dramatically improved by a treatment with interleukin-6 (IL-6) blockers in the context of connective tissue disease. However, in both cases, other systemic autoimmune symptoms were not modified by the treatment and autoantibodies tend to increase, suggesting a differential effect of IL-6 inhibition on articular inflammation and systemic autoimmunity.

Musculoskeletal symptoms in patients with cryopyrin-associated periodic syndromes: a large database study.

OBJECTIVE: To determine the type and frequency of musculoskeletal symptoms at onset and during followup of cryopyrin-associated periodic syndromes (CAPS). METHODS: We retrospectively recorded the articular and muscular symptoms of patients with CAPS followed up in French hospitals. Data were presented as frequencies or the median (range), and patient groups were compared using chi-square test, Fisher's exact test, and Mann-Whitney test. RESULTS: The study included 133 patients (33 children), 20 with familial cold autoinflammatory syndrome, 88 with Muckle-Wells syndrome, 22 with chronic infantile neurologic, cutaneous, articular syndrome, and 3 with unclassified CAPS. The median age was 35 years (range 0-78 years) at the time of the study, 1 year (range 0-41 years) at symptom onset, and 23 years (range 0-58 years) at diagnosis. The disease was sporadic in 17% of the patients. Cutaneous symptoms predominated at onset (77%), followed by articular symptoms (30%). The p.Thr348Met and p.Arg260Trp NLRP3 mutations were significantly associated with the presence and absence of articular symptoms at onset, respectively. During followup, 86% of the patients had musculoskeletal symptoms, 88% had arthralgia, and 58% had arthritis, but only 9% had joint destruction. Tendinopathies occurred in 21.5% of the patients, tender points in 16.5%, and myalgia in 33%. Only 3 patients had typical knee deformities. Radiographs were rarely obtained. Except for bone deformities, osteoarticular symptoms occurred at similar frequencies in the different CAPS phenotypes. CONCLUSION: Joint manifestations were frequent in all CAPS phenotypes. Bone deformities were rare. Musculoskeletal manifestations varied within given families but tended to worsen over time.