onset in infancy (SAVI), and another by additive loss-of-function mutations in proteasome genes causing the proteasome-associated autoinflammatory syndromes (PRAAS) (also, chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperatures [CANDLE]), presented with chronically elevated interferon (IFN) signatures, suggesting a pathogenic role for type-I IFN in autoinflammatory diseases (2, 3). Type-I IFN was first discovered as a soluble antiviral factor over 50 years ago, and a role in sterile inflammation was proposed in patients with systemic lupus erythematosus (4). However, the discovery of genetic mutations that cause the autoinflammatory type-I interferonopathies CANDLE (2, 5), SAVI (3, 6-8), and Aicardi-Goutières syndrome (AGS) (9, 10) have shed light on pathomechanisms that drive chronic IFN signaling, and recent studies blocking IFN signaling validate a critical role for type-I IFNs (11). AGS-causing loss-of-function mutations in nucleases impair self-nucleic acid homeostasis, SAVI-causing

Objective. To describe the disease characteristics, long-term course, and outcome of patients with juvenile idiopathic arthritis (JIA) in a population-based setting.Methods. Consecutive cases of JIA from defined geographic areas of Denmark, Finland, Sweden, and Norway in whom disease onset occurred in 1997-2000 were included in a prospective, multicenter cohort study. The study was designed to be as close to a population-based study as possible, with centers participating only if they were able to include in their catchment area all children in whom JIA was diagnosed.Results. Of 500 children included, 440 (88.0%) had repeated visits, with the last visit occurring at least 7 years after disease onset (median 98 months, range 84-147 months). Changes in the International League of Associations for Rheumatology category were observed in 10.8% of the children, and, in addition, extended oligoarthritis developed in 34.7% of the group with oligoarticular JIA. During the observation period, 58.0% of the children were treated with diseasemodifying antirheumatic drugs, including biologic medications. Ongoing disease activity was mostly mild, but some JIA-related damage developed in 22.9% of the children. At the last followup visit, remission off medication was observed in 42.4% of the children, 8.9% were in remission on medication, and 48.7% were not in remission. The highest rates of remission were observed in patients with persistent oligoarticular JIA and in those with systemic JIA.Conclusion. In this long-term prospective study of JIA in a population-based Nordic setting, ongoing disease was evident in a majority of the children. The present results underline the need to identify early predictors of outcome, to further improve therapy, and to continue long-term followup of patients with JIA.

The aim of this study was to determine the prevalence of self-reported chronic idiopathic pain among adolescents in relation to age and gender, and to explore how pain interferes with daily activities. The study was performed in Nord-Trøndelag County, Norway in 2006-2008. All adolescents were invited to participate; the response rate was 78%. Participants completed a comprehensive questionnaire, including questions about pain and interference with everyday life. Chronic idiopathic pain was defined as pain at least once a week during the last 3 months, not related to any known disease or injury. The final study population, with complete pain questionnaires, consisted of 7373 adolescents aged 13-18 years. Chronic pain was reported by 44.4% of the participants, and 25.5% reported pain in at least 2 locations. Chronic idiopathic musculoskeletal pain was most prevalent (33.4%), and the neck/shoulder was most commonly affected. Musculoskeletal pain in 3 or more locations was reported by 8.5%. Pain almost daily was reported by 10.2%. More girls than boys reported pain. In girls, the prevalence of pain increased with age. A high number of pain-associated disabilities were reported, and 58.5% described difficulties doing daily activities in leisure time. Subjective disabilities were higher in girls, and increased with the frequency of pain and the number of pain locations, as shown by high disability in adolescents with musculoskeletal pain in 3 or more locations. Chronic idiopathic pain, especially multisite pain, is common among adolescents, and those suffering from it report a major impact on several areas of daily living.

ObjectivesJuvenile idiopathic arthritis (JIA) is a heterogeneous group of diseases, comprising seven categories. Genetic data could potentially be used to help redefine JIA categories and improve the current classification system. The human leucocyte antigen (HLA) region is strongly associated with JIA. Fine-mapping of the region was performed to look for similarities and differences in HLA associations between the JIA categories and define correspondences with adult inflammatory arthritides.MethodsDense genotype data from the HLA region, from the Immunochip array for 5043 JIA cases and 14 390 controls, were used to impute single-nucleotide polymorphisms, HLA classical alleles and amino acids. Bivariate analysis was performed to investigate genetic correlation between the JIA categories. Conditional analysis was used to identify additional effects within the region. Comparison of the findings with those in adult inflammatory arthritic diseases was performed.ResultsWe identified category-specific associations and have demonstrated for the first time that rheumatoid factor (RF)-negative polyarticular JIA and oligoarticular JIA are genetically similar in their HLA associations. We also observe that each JIA category potentially has an adult counterpart. The RF-positive polyarthritis association at HLA-DRB1 amino acid at position 13 mirrors the association in adult seropositive rheumatoid arthritis (RA). Interestingly, the combined oligoarthritis and RF-negative polyarthritis dataset shares the same association with adult seronegative RA.ConclusionsThe findings suggest the value of using genetic data in helping to classify the categories of this heterogeneous disease. Mapping JIA categories to adult counterparts could enable shared knowledge of disease pathogenesis and aetiology and facilitate transition from paediatric to adult services.

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