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OBJECTIVE: To determine whether HLA-B27 misfolding and the unfolded protein response (UPR) result in cytokine dysregulation and whether this is associated with Th1 and/or Th17 activation in HLA-B27/human beta(2)-microglobulin (Hubeta(2)m)-transgenic rats, an animal model of spondylarthritis. METHODS: Cytokine expression in lipopolysaccharide (LPS)-stimulated macrophages was analyzed in the presence and absence of a UPR induced by chemical agents or by HLA-B27 up-regulation. Cytokine expression in colon tissue and in cells purified from the lamina propria was determined by real-time reverse transcription-polymerase chain reaction analysis, and differences in Th1 and Th17 CD4+ T cell populations were quantified after intracellular cytokine staining. RESULTS: Interleukin-23 (IL-23) was found to be synergistically up-regulated by LPS in macrophages undergoing a UPR induced by pharmacologic agents or by HLA-B27 misfolding. IL-23 was also increased in the colon tissue from B27/Hubeta(2)m-transgenic rats concurrently with the development of intestinal inflammation, and IL-17, a downstream target of IL-23, exhibited robust up-regulation in a similar temporal pattern. IL-23 and IL-17 transcripts were localized to CD11+ antigen-presenting cells and CD4+ T cells, respectively, from the colonic lamina propria. Colitis was associated with a 6-fold expansion of CD4+ IL-17-expressing T cells. CONCLUSION: The IL-23/IL-17 axis is strongly activated in the colon of B27/Hubeta(2)m-transgenic rats with spondylarthritis-like disease. HLA-B27 misfolding and UPR activation in macrophages can result in enhanced induction of the pro-Th17 cytokine IL-23. These results suggest a possible link between HLA-B27 misfolding and immune dysregulation in this animal model, with implications for human disease. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To identify differences in peripheral blood gene expression between patients with different subclasses of juvenile idiopathic arthritis (JIA) and healthy controls in a multicenter study of patients with recent-onset JIA prior to treatment with disease-modifying antirheumatic drugs (DMARDs) or biologic agents. METHODS: Peripheral blood mononuclear cells (PBMCs) from 59 healthy children and 136 patients with JIA (28 with enthesitis-related arthritis [ERA], 42 with persistent oligoarthritis, 45 with rheumatoid factor [RF]-negative polyarthritis, and 21 with systemic disease) were isolated from whole blood. Poly(A) RNA was labeled using a commercial RNA amplification and labeling system (NuGEN Ovation), and gene expression profiles were obtained using commercial expression microarrays (Affymetrix HG-U133 Plus 2.0). RESULTS: A total of 9,501 differentially expressed probe sets were identified among the JIA subtypes and controls (by analysis of variance; false discovery rate 5%). Specifically, 193, 1,036, 873, and 7,595 probe sets were different in PBMCs from the controls compared with those from the ERA, persistent oligoarthritis, RF-negative polyarthritis, and systemic JIA patients, respectively. In patients with persistent oligoarthritis, RF-negative polyarthritis, and systemic JIA subtypes, up-regulation of genes associated with interleukin-10 (IL-10) signaling was prominent. A hemoglobin cluster was identified that was underexpressed in ERA patients but overexpressed in systemic JIA patients. The influence of JAK/STAT, ERK/MAPK, IL-2, and B cell receptor signaling pathways was evident in patients with persistent oligoarthritis. In systemic JIA, up-regulation of innate immune pathways, including IL-6, Toll-like receptor/IL-1 receptor, and peroxisome proliferator-activated receptor signaling, were noted, along with down-regulation of gene networks related to natural killer cells and T cells. Complement and coagulation pathways were up-regulated in systemic JIA, with a subset of these genes being differentially expressed in other subtypes as well. CONCLUSION: Expression analysis identified differentially expressed genes in PBMCs obtained early in the disease from patients with different subtypes of JIA and in healthy controls, providing evidence of immunobiologic differences between these forms of childhood arthritis. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To determine whether peripheral blood mononuclear cells (PBMCs) from children with recent-onset polyarticular juvenile idiopathic arthritis (JIA) exhibit biologically or clinically informative gene expression signatures. METHODS: Peripheral blood samples were obtained from 59 healthy children and 61 children with polyarticular JIA prior to treatment with second-line medications, such as methotrexate or biologic agents. RNA was extracted from isolated mononuclear cells, fluorescence labeled, and hybridized to commercial gene expression microarrays (Affymetrix HG-U133 Plus 2.0). Data were analyzed using analysis of variance at a 5% false discovery rate threshold after robust multichip analysis preprocessing and distance-weighted discrimination normalization. RESULTS: Initial analysis revealed 873 probe sets for genes that were differentially expressed between polyarticular JIA patients and healthy controls. Hierarchical clustering of these probe sets distinguished 3 subgroups within the polyarticular JIA group. Prototypical patients within each subgroup were identified and used to define subgroup-specific gene expression signatures. One of these signatures was associated with monocyte markers, another with transforming growth factor beta-inducible genes, and a third with immediate early genes. Correlation of gene expression signatures with clinical and biologic features of JIA subgroups suggested relevance to aspects of disease activity and supported the division of polyarticular JIA into distinct subsets. CONCLUSION: Gene expression signatures in PBMCs from patients with recent-onset polyarticular JIA reflect discrete disease processes and offer a molecular classification of disease. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To determine whether macrophages, a type of cell implicated in the pathogenesis of ankylosing spondylitis (AS), exhibit a characteristic gene expression pattern. METHODS: Macrophages were derived from the peripheral blood of 8 AS patients (median disease duration 13 years [range <1-43 years]) and 9 healthy control subjects over 7 days with the use of granulocyte-macrophage colony-stimulating factor. Cells were stimulated for 24 hours with interferon-gamma (IFNgamma; 100 units/ml), were left untreated for 24 hours, or were treated for 3 hours with lipopolysaccharide (LPS; 10 ng/ml). RNA was isolated and examined by microarray and real-time quantitative reverse transcription-polymerase chain reaction analysis. RESULTS: Microarray analysis revealed 198 probe sets detecting the differential expression of 141 unique genes in untreated macrophages from AS patients compared with healthy controls. Clustering and principal components analysis clearly distinguished AS patients and controls. Of the differentially expressed genes, 78 (55%) were IFN-regulated, and their relative expression indicated a 'reverse' IFN signature in AS patient macrophages, where IFNgamma-up-regulated genes were underexpressed and down-regulated genes were overexpressed. Treatment of macrophages with exogenous IFNgamma normalized the expression of these genes between patients and controls. In addition, the messenger RNA encoded by the IFNgamma gene was approximately 2-fold lower in AS patient macrophages at baseline (P = 0.004) and was poorly responsive to LPS (P = 0.018), as compared with healthy controls. CONCLUSIONS: Our findings reveal consistent differences in gene expression in macrophages from AS patients, with evidence of a striking 'reverse' IFN signature. Together with poor expression and responsiveness of the IFNgamma gene, these results suggest that there may be a relative defect in IFNgamma gene regulation, with autocrine consequences and implications for disease pathogenesis. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the cause of the enhanced intracellular replication of Salmonella enteritidis in HLA-B27-transfected U937 human monocytic cells and the contribution of HLA-B27 heavy chain (HC) misfolding. METHODS: U937 monocytic cell transfectants stably expressing pSV2neo resistant vector (mock), wild-type HLA-B27, or mutated HLA-B27 HCs with amino acid substitutions in the B pocket were differentiated, infected with S enteritidis, and treated with signaling pathway inhibitors or specific p38 small interfering RNA (siRNA). The numbers of living intracellular bacteria were determined with the colony-forming unit method. To visualize S enteritidis, the bacteria were transformed with green fluorescent protein, and studied by microscopy. RESULTS: Treatment with the p38 MAPK inhibitors or with p38 siRNA enhanced the replication of S enteritidis in U937 transfectants, whereas the other inhibitors had no effect. In mock-transfected cells and in cells expressing the mutated B27 HCs in which the misfolding had been corrected, p38 inhibitors impaired their ability to resist the replication of bacteria (mock, B27.A2B, B27.E45M, and B27.C67A). In contrast, the number of intracellular bacteria was not significantly increased in p38 inhibitor-treated cells expressing misfolded B27 HCs (B27g, B27cDNA, and B27.H9F). CONCLUSION: Our results show that p38 activity plays a crucial role in controlling intracellular S enteritidis in U937 cells. Enhanced replication of bacteria in B27-expressing cells requires that the HCs contain glutamic acid at position 45 and cysteine at position 67. Furthermore, in transfectants expressing misfolded B27 HCs, p38 inhibition had no significant effect on bacterial replication, suggesting that in these cells, the p38 pathway may not function properly. [ABSTRACT FROM AUTHOR]

OBJECTIVE: HLA-B27 is implicated in the pathogenesis of spondylarthritis (SpA), yet the molecular mechanisms are incompletely defined. HLA-B27 misfolding has been associated with endoplasmic reticulum stress and activation of the unfolded protein response (UPR) in macrophages from HLA-B27/human beta(2)-microglobulin-transgenic (B27-transgenic) rats. This study was performed to assess the mechanisms that drive activation of the HLA-B27-induced UPR and to determine whether splenocytes respond in a similar manner. METHODS: Splenocytes were isolated and bone marrow macrophages were derived from B27-transgenic and wild-type rats. Cells were treated for up to 24 hours with cytokines that induce class I major histocompatibility complex expression. HLA-B27 expression and misfolding were assessed by real-time reverse transcription-polymerase chain reaction, flow cytometry, and immunoblotting. Activation of the UPR was measured by quantifying UPR target gene expression and X-box binding protein 1 messenger RNA (mRNA) splicing. RESULTS: HLA-B27 mRNA up-regulation was accompanied by a dramatic increase in the accumulation of misfolded heavy chains and preceded robust activation of the UPR in macrophages. When macrophages were treated with various cytokines, the magnitude of the UPR correlated strongly with the degree of HLA-B27 up-regulation. In contrast, B27-transgenic splenocytes exhibited only low-level differences in the expression of UPR target genes after exposure to interferon-gamma or concanavalin A, which resulted in minimal HLA-B27 up-regulation. CONCLUSION: These results suggest that HLA-B27-associated activation of the UPR in macrophages is attributable to the accumulation of misfolded heavy chains, and that certain cell types may be more susceptible to the effects of HLA-B27 misfolding. Strategies that eliminate HLA-B27 up-regulation and/or the accumulation of misfolded heavy chains may be useful in evaluating the role of these events in the pathogenesis of SpA. [ABSTRACT FROM AUTHOR]

The Spondylitis Association of America (SAA) and the National Institute of Arthritis, Musculoskeletal and Skin Diseases (NIAMS) convened a conference on the campus of the National Institutes of Health (NIH) on September 28 and 29, 2023, to identify unmet needs in spondyloarthritis (SpA) research. The conference featured presentations by experts in areas of disease endotypes, pain, innovative imaging in SpA, health disparities in rheumatic diseases, and therapeutics. Members of the conference planning committee moderated the sessions and led the development of manuscripts summarizing recommendations to address unmet research needs. Early career investigators were invited to submit abstracts, which were presented at a networking session during the conference. Here, we highlight each of the sessions comprising the conference in the form of manuscripts published together as a conference summary.

Objectives: To develop and validate classification criteria for axial disease in youth with juvenile spondyloarthritis (SpA; AxJSpA)., Methods: This international initiative consisted of four phases: 1) Item generation; 2) Item reduction; 3) Criteria development; and 4) Validation of the AxJSpA criteria by an independent team of experts in an internationally representative Validation cohort., Results: These criteria are intended to be used on youth with a physician diagnosis of juvenile SpA and for whom axial disease is suspected. Item generation consisted of a systematic literature review and a free-listing exercise using input from international physicians and collectively resulted in 108 items. After the item reduction exercise and expert panel input, 37 items remained for further consideration. The final AxJSpA criteria domains included: imaging: active inflammation, imaging: structural lesions, pain chronicity, pain pattern, pain location, stiffness, and genetics. The most heavily weighted domains were active inflammation and structural lesions on imaging. Imaging typical of sacroiliitis was deemed necessary, but not sufficient, to classify a youth with AxJSpA. The threshold for classification of AxJSpA was a score of ≥55 (out of 100). When tested in the validation data set, the final criteria had a specificity of 97.5% (95% CI: 91.4-99.7), sensitivity of 64.3% (95% CI: 54.9-73.1) and Area Under the Receiver Operating Characteristic (AUROC) curve of 0.81 (95% CI: 0.76-0.86)., Conclusions: The new AxJSpA classification criteria require an entry criterion, physician diagnosis of juvenile SpA, and include seven weighted domains. The AxJSpA classification criteria are validated and designed to identify participants for research studies., (This article is protected by copyright. All rights reserved.)

Inter-reader reliability of a new scoring system for evaluating joint inflammation and enthesitis in whole body MRI (WBMRI) in juvenile idiopathic arthritis was tested. The scoring system grades 732 item-region combinations of bone marrow and soft tissue changes for commonly involved joints and entheseal sites. Five radiologists rated 17 WBMRI scans through an online rating platform. Item-wise reliability was calculated for 117 items with non-zero scores in >10 % of readings. Interquartile ranges of the five-reader Kappa reliability coefficients were 0.58-0.73 (range: 0.36-0.88) for the joints, 0.65-0.81 (range: 0.39-0.95) for the entheses, and 0.62-0.75 (range: 0.60-0.76) for chronic nonbacterial osteomyelitis-like lesions., Competing Interests: Declaration of competing interest Dr. Andrea Doria has had the following relationships unrelated to the conduct of this study: Chair and Co-Chair of the International Myositis Assessment & Clinical Studies Group (not for profit) and the OMERACT SIG in MRI in JIA (not for profit), respectively, board member of the OMERACT Technical Advisory Group (not for profit), and PI of research grants from Novo Nordisk, the Terry Fox Foundation, the PSI Foundation, the Society of Pediatric Radiology, and the Garron Family Cancer Centre. Drs. Jonathan Akikusa and Marion van Rossum are also Co-Chairs of OMERACT SIG in MRI in JIA (not for profit). The remaining authors did not express any conflicts of interest related to current study., (Copyright © 2024. Published by Elsevier Inc.)

HLA-B27 is a major risk factor for spondyloarthritis (SpA), yet the underlying mechanisms remain unclear. HLA-B27 misfolding-induced IL-23, which is mediated by endoplasmic reticulum (ER) stress has been hypothesized to drive SpA pathogenesis. Expression of HLA-B27 and human β 2 m (hβ 2 m) in rats (HLA-B27-Tg) recapitulates key SpA features including gut inflammation. Here we determined whether deleting the transcription factor CHOP (Ddit3-/-), which mediates ER-stress induced IL-23, affects gut inflammation in HLA-B27-Tg animals. ER stress-mediated Il23a overexpression was abolished in CHOP-deficient macrophages. Although CHOP-deficiency also reduced Il23a expression in immune cells isolated from the colon of B27+ rats, Il17a levels were not affected, and gut inflammation was not reduced. Rather, transcriptome analysis revealed increased expression of pro-inflammatory genes, including Il1a, Ifng and Tnf in HLA-B27-Tg colon tissue in the absence of CHOP, which was accompanied by higher histological Z-scores. RNAScope localized Il17a mRNA to the lamina propria of the HLA-B27-Tg rats and revealed similar co-localization with Cd3e (CD3) in the presence and absence of CHOP. This demonstrates that CHOP-deficiency does not improve, but rather exacerbates gut inflammation in HLA-B27-Tg rats, indicating that HLA-B27 is not promoting gut disease through ER stress-induced IL-23. Hence, CHOP may protect rats from more severe HLA-B27-induced gut inflammation., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Patients with classical melorheostosis exhibit exuberant bone overgrowth in the appendicular skeleton, resulting in pain and deformity with no known treatment. Most patients have somatic, mosaic mutations in MAP2K1 (encoding the MEK1 protein) in osteoblasts and overlying skin. As with most rare bone diseases, lack of affected tissue has limited the opportunity to understand how the mutation results in excess bone formation. The aim of this study was to create a cellular model to study melorheostosis. We obtained patient skin cells bearing the MAP2K1 mutation (affected cells), and along with isogenic control normal fibroblasts reprogrammed them using the Sendai virus method into induced pluripotent stem cells (iPSCs). Pluripotency was validated by marker staining and embryoid body formation. iPSCs were then differentiated to mesenchymal stem cells (iMSCs) and validated by flow cytometry. We confirmed retention of the MAP2K1 mutation in iMSCs with polymerase chain reaction (PCR) and confirmed elevated MEK1 activity by immunofluorescence staining. Mutation-bearing iMSCs showed significantly elevated vascular endothelial growth factor (VEGF) secretion, proliferation and collagen I and IV secretion. iMSCs were then differentiated into osteoblasts, which showed increased mineralization at 21 days and increased VEGF secretion at 14 and 21 days of differentiation. Administration of VEGF to unaffected iMSCs during osteogenic differentiation was sufficient to increase mineralization. Blockade of VEGF by bevacizumab reduced mineralization in iMSC-derived affected osteoblasts and in affected primary patient-derived osteoblasts. These data indicate that patient-derived induced pluripotent stem cells recreate the elevated MEK1 activity, increased mineralization, and increased proliferation seen in melorheostosis patients. The increased bone formation is driven, in part, by abundant VEGF secretion. Modifying the activity of VEGF (a known stimulator of osteoblastogenesis) represents a promising treatment pathway to explore. iPSCs may have wide applications to other rare bone diseases. © 2023 American Society for Bone and Mineral Research (ASBMR)., (© 2023 American Society for Bone and Mineral Research (ASBMR).)

Objective: Stakeholders met to address persistent challenges facing the development of therapeutics for polyarticular juvenile idiopathic arthritis (pJIA), which result in fewer approved therapies for children with pJIA than adults with rheumatoid arthritis (RA) and long lag times from adult RA approval to pediatric labeling. Ensuring that new medications are authorized in a timely manner to meet the needs of JIA patients worldwide is critically important to multiple stakeholders., Methods: The Food and Drug Administration in collaboration with the University of Maryland Center for Regulatory Science and Innovation held a public workshop entitled "Accelerating Drug Development for pJIA" on October 2, 2019, to address challenges surrounding access to new medications for children and adolescents with pJIA. Regulatory, academic, and industry stakeholders, as well as patient representatives, participated in the workshop, which consisted of 4 sessions, including panel discussions., Results: The workshop facilitated broad public discussion of challenges facing the development of pJIA therapeutics, highlighting areas of need and outlining opportunities to expedite development, while underscoring the necessity of close collaboration between all stakeholders, including patients and families., Conclusion: This report summarizes key aspects of the workshop, including the appropriate application of innovative approaches to the development of pJIA therapeutics, including extrapolation, to address current challenges and provide timely access to newer safe and effective treatments. Long-term safety assessment is of pressing concern to stakeholders and cannot be fully extrapolated from adult studies but requires consistent postmarketing long-term follow-up., (© 2023 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Objective: To validate the Juvenile Spondyloarthritis Disease Activity Index (JSpADA), and modified versions thereof, in a North American cohort of patients with enthesitis-related arthritis (ERA)., Methods: We utilized the Childhood Arthritis and Rheumatology Research Alliance Registry database ERA cohort to validate the JSpADA and its modifications (JSpADA6-no Schober, no C-reactive protein [CRP]/erythrocyte sedimentation rate [ESR]; JSpADA7-no Schober; and JSpADA7-no CRP/ESR) using the Outcome Measures in Rheumatology principles of face validity, discriminative validity, and responsiveness to change., Results: There were 51 subjects (64 visits) with complete JSpADA data with a mean age of 13.7 years and disease duration of 30.9 months. Subjects were predominantly White (84.3%), and 56.9% were male and 50% were HLA-B27 positive. The JSpADA showed high correlation with the clinical 10-joint Juvenile Arthritis Disease Activity Score (cJADAS10; r = 0.81), moderate-to-high correlation with physician global assessment (PGA; r = 0.69), and low-to-fair correlation with Childhood Health Assessment Questionnaire (CHAQ; r = 0.22). The modifications of the JSpADA (JSpADA7-no Schober; JSpADA7-no CRP/ESR; and JSpADA6-no Schober, no CRP/ESR) performed similarly with high correlation with cJADAS10 ( r = 0.81, 0.79, and 0.80, respectively), moderate-to-high correlation with PGA ( r = 0.65, 0.67, 0.64, respectively), and low-to-fair correlation with CHAQ ( r = 0.35, 0.34, 0.39, respectively). All modified versions of JSpADA had good responsiveness to change. All versions of JSpADA had excellent discriminative validity., Conclusion: We propose the term modified JSpADA for the modification of JSpADA with 6 elements (JSpADA6-no Schober, no CRP/ESR). This shorter disease activity index may improve implementation of JSpADA in both clinical practice and research trials., (Copyright © 2023 by the Journal of Rheumatology.)

Objective: We undertook this study to examine the functional basis for epistasis between endoplasmic reticulum aminopeptidase 1 (ERAP1) and HLA-B27 in experimental spondyloarthritis (SpA)., Methods: ERAP1-knockout rats were created using genome editing and bred with HLA-B27/human β 2 -microglobulin-transgenic (HLA-B27-Tg) rats and HLA-B7-Tg rats. The effects of ERAP1 deficiency on HLA allotypes were determined using immunoprecipitation and immunoblotting, flow cytometry, allogeneic T cell proliferation assays, and gene expression analyses. Animals were examined for clinical features of disease, and tissue was assessed by histology., Results: ERAP1 deficiency increased the ratio of folded to unfolded (β 2 m-free) HLA-B27 heavy chains, while having the opposite effect on HLA-B7. Furthermore, in rats with ERAP1 deficiency, HLA-B27 misfolding was reduced, while free HLA-B27 heavy chain dimers on the cell surface and monomers were increased. The effects of ERAP1 deficiency persisted during up-regulation of HLA-B27 and led to a reduction in endoplasmic reticulum stress. ERAP1 deficiency reduced the prevalence of arthritis in HLA-B27-Tg rats by two-thirds without reducing gastrointestinal inflammation. Dendritic cell abnormalities attributed to the presence of HLA-B27, including reduced allogeneic T cell stimulation and loss of CD103-positive/major histocompatibility complex class II-positive cells, were not rescued by ERAP1 deficiency, while excess Il23a up-regulation was mitigated., Conclusion: ERAP1 deficiency reduced HLA-B27 misfolding and improved folding while having opposing effects on HLA-B7. The finding that HLA-B27-Tg rats had partial protection against SpA in this study is consistent with genetic evidence that loss-of-function and/or reduced expression of ERAP1 reduces the risk of ankylosing spondylitis. Functional studies support the concept that the effects of ERAP1 on HLA-B27 and SpA may be a consequence of how peptides affect the biology of this allotype rather than their role as antigenic determinants., (© 2022 American College of Rheumatology. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

During inflammation, cellular glucose uptake and glycolysis are upregulated to meet an increased energy demand. For example, keratinocyte glycolysis is essential for progression of psoriasis. Therefore, understanding the regulation of glucose metabolism in keratinocytes is of importance. Here, we show that the pro-inflammatory cytokines IFNγ and TNF together rapidly induce glucose uptake, glycolysis, and glycolytic capacity in cultured keratinocytes. Furthermore, we found that acute IFNγ and TNF stimulation induces glucose transporter 4 (GLUT4) translocation to the plasma membrane and engages AMPK-dependent intracellular signaling. Together, these findings suggest acute cytokine-induced glucose metabolism in keratinocytes could contribute to inflammation in psoriatic disease, and that GLUT4 is involved in these processes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Melorheostosis is a rare sclerosing bone disease with associated vascular abnormalities in skin and bone, which is caused by somatic mosaic single nucleotide variations in the MAP2K1 gene, which encodes MAPK/extracellular signal‒regulated kinase (ERK) kinase 1. However, disease pathogenesis is poorly understood. Using patient-derived cells, we found that affected skin fibroblasts carrying the single nucleotide variations have increased activation of ERK1/2, which results in increased expression and secretion of proangiogenic factors, including VEGF. VEGF secretion was strongly reduced in affected cells after treatment with MAPK/ERK kinase 1 inhibitor trametinib. Treatment of healthy endothelial cells on matrigel with conditioned medium from affected fibroblasts induces the adoption of a proangiogenic phenotype. Direct coculture of fibroblasts and endothelial cells further shows that both secreted factors and extracellular matrix are capable of inducing a proangiogenic phenotype in healthy endothelial cells. Blocking VEGF with bevacizumab reduces the proangiogenic effect of affected fibroblasts in both the matrigel and direct coculture angiogenesis models, indicating that elevated VEGF secretion is a key mediator of increased angiogenesis in melorheostosis tissue. In conclusion, this work identifies the role of several important molecular mediators in the pathogenesis of melorheostosis, including MAPK/ERK kinase 1, phosphorylated ERK1/2, and VEGF, all of which have clinically available pharmacologic inhibitors, which could be further explored as therapeutic targets., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

This review will summarize clinical, genetic, and pathophysiologic characteristics that are shared between children with enthesitis-related arthritis (ERA) with axial involvement and adults with nonradiographic (and in some cases radiographic) axial spondyloarthritis (SpA), as well as between children with ERA and primarily peripheral disease manifestations and adults with peripheral SpA. Due to the differences in classification criteria for children with ERA and adults with axial and peripheral SpA, the US Food and Drug Administration (FDA) granted automatic full waivers of studies in children for new medications for "axial spondyloarthropathies including ankylosing spondylitis" up until July 2020. Thus, although current juvenile idiopathic arthritis treatment guidelines recommend the use of biologic disease-modifying antirheumatic drugs as part of the early treatment for patients with ERA, none of the FDA-approved therapies for peripheral SpA or nonradiographic axial SpA (certolizumab pegol, ixekizumab, and secukinumab) have been studied or are labeled for use in children with ERA. Considering the similarities between adult SpA and ERA in terms of etiology, genetics, pathogenesis, and clinical manifestations summarized in this review, medications approved for axial SpA or peripheral SpA should also be studied in children with active ERA involving axial or peripheral joints, respectively, with the intent to achieve labeling for use in children. Considering the current lack of effective FDA-approved therapies for ERA, the FDA should also consider requiring pediatric studies for medications that have already been approved for the treatment of adults with SpA., (© 2020 American College of Rheumatology.)

Objectives: To evaluate the current practices in management of patients with juvenile spondyloarthritis (JSpA) who failed anti-tumour necrosis factor agents (anti-TNF)., Methods: An online survey was distributed to Childhood Arthritis and Rheumatology Research Alliance (CARRA) members of the JIA workgroup. Data collection included estimated number of JSpA patients who have failed anti-TNF therapy over two-year period, reasons for discontinuing anti-TNF therapy and other medications used afterward. The JSpA population was de ned as the following subtypes: enthesitis-related arthritis, psoriatic arthritis, undifferentiated spondyloarthritis, juvenile ankylosing spondylitis (AS) i.e. meeting modi ed NY criteria for AS before age 16, and reactive arthritis. Findings were summarised using descriptive statistics., Results: The survey response rate was 36% (n= 60/169). The majority of participants were paediatric rheumatologists (93%). Many physicians have JSpA patients who failed anti-TNF therapy (63%). The most common reason for changing anti-TNF therapy was secondary non-response (72%). Sacroiliitis was the most important factor considered when assessing response to an anti-TNF agent and the most common reason for primary non-response (45%). When assessing anti-TNF failure for sacroiliitis, many (65%) felt imaging of the sacroiliac joints was the most important aspect in their decision making. The majority try a second anti-TNF agent after initial anti-TNF failure (87%) and switch to another medication class after 2 anti-TNF agents have failed (62%)., Conclusions: More than half of paediatric rheumatologists surveyed have at least one JSpA patient who failed anti-TNF therapy. The majority failed because of secondary non-response. Sacroiliitis is an important but challenging aspect to manage for patients with JSpA.

Objectives: Whole body-MRI is helpful in directing diagnostic and treatment approaches, and as a research outcome measure. We describe our initial consensus-driven phase towards developing a whole body-MRI scoring system for juvenile idiopathic arthritis., Methods: An iterative approach using three rounds of anonymous Delphi surveys followed by a consensus meeting was used to draft the structure of the whole body-MRI scoring system, including the relevant anatomic joints and entheses for assessment, diagnostic item selection, definition and grading, and selection of appropriate MRI planes and sequences. The surveys were completed independently by an international expert group consisting of pediatric radiologists and rheumatologists., Results: Twenty-two experts participated in at least one of three rounds of Delphi surveys and a concluding consensus meeting. A first iteration scoring system was developed which ultimately included the assessment of 100 peripheral, 23 chest, and 76 axial joints, and 64 entheses, with 2-4 diagnostic items graded in each of the items, using binary (presence/absence) and 2-3-level ordinal scores. Recommendations on anatomic MRI planes and sequences were specified as the minimally necessary imaging protocol for the scoring system., Conclusion: A novel whole body-MRI scoring system for juvenile idiopathic arthritis was developed by consensus among members of MRI in JIA OMERACT working group. Further iterative refinements, reliability testing, and responsiveness are warranted in upcoming studies., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Spondyloarthritis represents a group of disorders characterized by enthesitis and axial skeletal involvement. Juvenile spondyloarthritis begins before age 16. Joint involvement is usually asymmetric. Bone marrow edema on noncontrast MRI of the sacroiliac joints can facilitate diagnosis. The most significant risk factor for axial disease is HLA-B27. Most patients have active disease into adulthood. Enthesitis and sacroiliitis correlate with greater pain intensity and poor quality-of-life measures. Tumor necrosis factor inhibitors are the mainstay of biologic therapy. Although other biologics such as IL-17 blockers have shown benefit in adult spondyloarthritis, none are approved by the US Food and Drug Administration., (Published by Elsevier Inc.)

Objective: Somatic mutations in UBA1 cause a newly defined syndrome known as VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome). More than 50% of patients currently identified as having VEXAS met diagnostic criteria for relapsing polychondritis (RP), but clinical features that characterize VEXAS within a cohort of patients with RP have not been defined. We undertook this study to define the prevalence of somatic mutations in UBA1 in patients with RP and to create an algorithm to identify patients with genetically confirmed VEXAS among those with RP., Methods: Exome and targeted sequencing of UBA1 was performed in a prospective observational cohort of patients with RP. Clinical and immunologic characteristics of patients with RP were compared based on the presence or absence of UBA1 mutations. The random forest method was used to derive a clinical algorithm to identify patients with UBA1 mutations., Results: Seven of 92 patients with RP (7.6%) had UBA1 mutations (referred to here as VEXAS-RP). Patients with VEXAS-RP were all male, were on average ≥45 years of age at disease onset, and commonly had fever, ear chondritis, skin involvement, deep vein thrombosis, and pulmonary infiltrates. No patient with VEXAS-RP had chondritis of the airways or costochondritis. Mortality was greater in VEXAS-RP than in RP (23% versus 4%; P = 0.029). Elevated acute-phase reactants and hematologic abnormalities (e.g., macrocytic anemia, thrombocytopenia, lymphopenia, multiple myeloma, myelodysplastic syndrome) were prevalent in VEXAS-RP. A decision tree algorithm based on male sex, a mean corpuscular volume >100 fl, and a platelet count <200 ×10 3 /μl differentiated VEXAS-RP from RP with 100% sensitivity and 96% specificity., Conclusion: Mutations in UBA1 were causal for disease in a subset of patients with RP. This subset of patients was defined by disease onset in the fifth decade of life or later, male sex, ear/nose chondritis, and hematologic abnormalities. Early identification is important in VEXAS given the associated high mortality rate., (Published 2021. This article is a U.S.Government work and is in the public domain in the USA.)

Several cytokines involved in inflammatory pathologies signal via the Janus kinase-signal transducer and activator of transcription pathway. Four JAKs are known: JAK1, JAK2, JAK3 and TYK2. The specific activation of JAKs and STATs determines the biological effects of each cytokine. JAK1 is involved in the signalling of 'γc' receptor cytokines (IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21), pro-inflammatory cytokines including IL-6, as well as IFN. The critical position of JAK1 downstream of these cytokines suggests that JAK1-selective inhibitors are comparable to non-selective ones, without the unwanted consequences of JAK2- or JAK3-blockade. JAK inhibition has led to a better understanding of the biology of synovial inflammation and bone homeostasis. Moreover, the efficacy of non-selective JAK inhibitors and novel JAK1-selective drugs in RA supports a role for JAK1 in its pathogenesis. JAK1-selective drugs are also showing promise in axial spondyloarthritis, suggesting that they may target additional regulatory pathways that impact cytokines such as TNF and IL-17A, which do not use JAKs. Additionally, evidence now supports a JAK1 predominance in the signalling of IL-6 and oncostatin M, and indirectly, of TNF in synovial fibroblasts, macrophages and endothelial cells. Notably, bone homeostasis is also dependent on cytokines relying on JAK1 signalling to promote receptor activator of NF-κB ligand expression in osteoblasts and T cells, contributing to osteoclastogenesis. Here, the contribution of JAK1 over other kinases is unclear. While beneficial effects of JAK inhibitors on bone erosion are supported by preclinical and clinical data, effects on new bone formation in axial spondyloarthritis requires additional study., (Published by Oxford University Press on behalf of the British Society for Rheumatology 2021. This work is written by US Government employees and is in the public domain in the US.)

Chronic inflammatory arthritis in childhood is heterogeneous in presentation and course. Most forms exhibit clinical and genetic similarity to arthritis of adult onset, although at least one phenotype might be restricted to children. Nevertheless, paediatric and adult rheumatologists have historically addressed disease classification separately, yielding a juvenile idiopathic arthritis (JIA) nomenclature that exhibits no terminological overlap with adult-onset arthritis. Accumulating clinical, genetic and mechanistic data reveal the critical limitations of this strategy, necessitating a new approach to defining biological categories within JIA. In this Review, we provide an overview of the current evidence for biological subgroups of arthritis in children, delineate forms that seem contiguous with adult-onset arthritis, and consider integrative genetic and bioinformatic strategies to identify discrete entities within inflammatory arthritis across all ages.

Establishing a clear role for HLA-B*27 in the pathogenesis of spondyloarthritis continues to be challenging. Aberrant properties of the heavy chain as well as a potential role presenting arthritogenic peptides continue to be pursued as plausible mechanisms. Recent studies implicate HLA-B*27 in aberrant bone formation. An unanticipated cell surface interaction between HLA-B*27 and the bone morphogenetic protein pathway receptor subunit ALK2 may augment TGFβ superfamily signaling pathways, increasing responsiveness to Activin A and TGFβ. This has the potential to increase bone formation as well as Th17 T cell development, presenting an attractive model to explain several aspects of axial and peripheral spondyloarthritis. In a separate study, intracellular effects of misfolded HLA-B*27 implicate this mechanism in increased osteoblast mineralization and bone formation. HLA-B*27 expression in early osteoblasts activates unfolded protein response-mediated X-box binding protein-1 mRNA splicing and induction of the retinoic acid receptor-β gene, with downstream increases in expression of tissue non-specific alkaline phosphatase. Increased TNAP expression in osteoblasts was linked to increased mineralization in vitro and bone formation in vivo. In the ongoing search for evidence of arthritogenic peptides, high-throughput TCR (T cell receptor) sequencing has provided evidence for reduced clonal expansion and increased TCR diversity in ankylosing spondylitis. In addition to two common CD8+ TCR sequences identified in one study, similar CD8 and CD4 TCR motifs were found in another study. Further work will be needed to shed light on the nature of the peptide-HLA class I complex recognized by these T cells and its role in disease.

Here we report on the antibody and memory B cell responses of a cohort of 20 volunteers who received the Moderna (mRNA-1273) or Pfizer-BioNTech (BNT162b2) vaccine against SARS-CoV-2 1-4 . Eight weeks after the second injection of vaccine, volunteers showed high levels of IgM and IgG anti-SARS-CoV-2 spike protein (S) and receptor-binding-domain (RBD) binding titre. Moreover, the plasma neutralizing activity and relative numbers of RBD-specific memory B cells of vaccinated volunteers were equivalent to those of individuals who had recovered from natural infection 5,6 . However, activity against SARS-CoV-2 variants that encode E484K-, N501Y- or K417N/E484K/N501-mutant S was reduced by a small-but significant-margin. The monoclonal antibodies elicited by the vaccines potently neutralize SARS-CoV-2, and target a number of different RBD epitopes in common with monoclonal antibodies isolated from infected donors 5-8 . However, neutralization by 14 of the 17 most-potent monoclonal antibodies that we tested was reduced or abolished by the K417N, E484K or N501Y mutation. Notably, these mutations were selected when we cultured recombinant vesicular stomatitis virus expressing SARS-CoV-2 S in the presence of the monoclonal antibodies elicited by the vaccines. Together, these results suggest that the monoclonal antibodies in clinical use should be tested against newly arising variants, and that mRNA vaccines may need to be updated periodically to avoid a potential loss of clinical efficacy.

Background: Adult-onset inflammatory syndromes often manifest with overlapping clinical features. Variants in ubiquitin-related genes, previously implicated in autoinflammatory disease, may define new disorders., Methods: We analyzed peripheral-blood exome sequence data independent of clinical phenotype and inheritance pattern to identify deleterious mutations in ubiquitin-related genes. Sanger sequencing, immunoblotting, immunohistochemical testing, flow cytometry, and transcriptome and cytokine profiling were performed. CRISPR-Cas9-edited zebrafish were used as an in vivo model to assess gene function., Results: We identified 25 men with somatic mutations affecting methionine-41 (p.Met41) in UBA1, the major E1 enzyme that initiates ubiquitylation. (The gene UBA1 lies on the X chromosome.) In such patients, an often fatal, treatment-refractory inflammatory syndrome develops in late adulthood, with fevers, cytopenias, characteristic vacuoles in myeloid and erythroid precursor cells, dysplastic bone marrow, neutrophilic cutaneous and pulmonary inflammation, chondritis, and vasculitis. Most of these 25 patients met clinical criteria for an inflammatory syndrome (relapsing polychondritis, Sweet's syndrome, polyarteritis nodosa, or giant-cell arteritis) or a hematologic condition (myelodysplastic syndrome or multiple myeloma) or both. Mutations were found in more than half the hematopoietic stem cells, including peripheral-blood myeloid cells but not lymphocytes or fibroblasts. Mutations affecting p.Met41 resulted in loss of the canonical cytoplasmic isoform of UBA1 and in expression of a novel, catalytically impaired isoform initiated at p.Met67. Mutant peripheral-blood cells showed decreased ubiquitylation and activated innate immune pathways. Knockout of the cytoplasmic UBA1 isoform homologue in zebrafish caused systemic inflammation., Conclusions: Using a genotype-driven approach, we identified a disorder that connects seemingly unrelated adult-onset inflammatory syndromes. We named this disorder the VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. (Funded by the NIH Intramural Research Programs and the EU Horizon 2020 Research and Innovation Program.)., (Copyright © 2020 Massachusetts Medical Society.)

Objective: To document the need for additional Food and Drug Administration (FDA)-approved medications for the treatment of juvenile idiopathic arthritis (JIA)., Methods: The electronic medical records of JIA patients treated at Cincinnati Children's Hospital Medical Center (CCHMC) and data from JIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry were included in this study. Unmet medication need was defined in 2 ways: (a) the presence of chronically uncontrolled JIA, defined as a physician global assessment of JIA activity ≥3 (on a 0-10 scale, where 0 = inactive) OR ≥3 joints with active arthritis OR a patient global assessment of well-being ≥3 (on a 0-10 scale, where 0 = very well), despite sequential use of ≥2 biologic disease-modifying antirheumatic drugs (bDMARDs); and (b) the use of ≥1 bDMARD not approved for any JIA category., Results: At CCHMC, 829 of 1,599 JIA patients (52%) were treated with ≥1 bDMARD, and 304 (19%) had been exposed to ≥1 unapproved bDMARD. In the CARRA Registry, 4,766 of 7,379 children (65%) had received ≥1 bDMARD, and 1,122 (15%) had been prescribed ≥1 unapproved bDMARD. Of those children treated with ≥2 bDMARDs for whom complete data were available, 52% (255 of 487) at CCHMC and 45% (527 of 1,159) in the CARRA Registry had chronically uncontrolled JIA despite the use of ≥2 bDMARDs., Conclusion: Despite the availability of bDMARDs currently approved for JIA, there is persistent need for additional therapies to control JIA signs and symptoms. Since FDA approval is critical to ensure access to bDMARDs, the study and licensing of new medications is critical to address the unmet medication need and to further improve JIA outcomes., (© 2020, American College of Rheumatology.)

Objectives: Patients with Crohn's disease often produce antibodies against flagellated intestinal bacteria. There are mixed data as to whether such antibodies are present in patients with spondyloarthritis. Our objectives were to evaluate for the presence of antibodies against intestinal organisms in children with enthesitis related arthritis (ERA)., Methods: Children with ERA and healthy controls were recruited at three sites. Sera were plated on a nitrocellulose array and incubated with labelled antibodies to human IgA and IgG., Results: At UAB, patients and controls had similar antibody levels against the majority of the bacteria selected, with the exception of increased IgA antibodies among ERA patients against Prevotella oralis (1231 [IQR 750, 2566] versus 706 [IQR 428, 1106], p = .007.) These findings were partially validated at a second but not at a third site., Conclusions: ERA patients may produce increased IgA antibodies against P. oralis. The possible significance of this finding bears further exploration., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To assess patient-reported burden of disease in pediatric patients with relapsing polychondritis (RP) and to compare those findings to adult patients., Methods: A survey based on known clinical symptoms of RP was developed and administered to patients with a pediatric diagnosis of RP. Adult patients completed a similar survey., Results: Twenty-one pediatric patients, or their parents, completed surveys. Median age at symptom onset was 6 years (interquartile range 1.8-12). Prior to diagnosis, most pediatric patients went to the emergency room (ER; 61.9%), saw > 3 physicians (57.1%), and took > 1 year to be diagnosed (61.9%). Pediatric patients were often diagnosed with asthma (42.9%), ear infections (42.9%), or sinusitis (33.3%) prior to diagnosis of RP. Symptoms prior to diagnosis included ear pain/redness (85.7%), joint pain/swelling (61.9%), and airway symptoms (38.1%). Four pediatric patients (19%) reported tracheomalacia requiring tracheostomy. Pediatric patients frequently missed school because of their disease (71.4%). Surveys from 290 adult patients were compared to pediatric patients. Pediatric patients were significantly more likely to undergo biopsy (42.9% vs 17.4%; p < 0.01) and be treated with biologics (42.9% vs 19%; p = 0.02). Adults were significantly more likely to be female (87.8% vs 28.6%; p < 0.01) and to report airway symptoms (77.9% vs 47.6%; p = 0.01). Prevalence of disease complications was not significantly different between adult and pediatric patients., Conclusions: The burden of disease in pediatric patients with RP includes missed school, diagnostic delay, ER visits, and multisystem disease, with resultant damage to cartilaginous structures. Differences in airway involvement and treatment approaches may exist between pediatric and adult patients.

The human microbiome is impressively immense and participates in many aspects of our health and wellness, particularly involving the development and maintenance of a healthy immune system. Not only do our microbes teach the immune system to fight infection, they also teach immune tolerance and help maintain homeostasis. From this knowledge, we have learned that the loss of tolerance to microbiota in both innate and adaptive processes plays an important role in immune-mediated and autoimmune disease. In this chapter, we will be discussing about methods used to study the microbiome, both old and new methods, fundamental concepts that have taken hold within the field, and how these principles relate to rheumatology, including thoughts on how microbiome research may be focused in the next decade., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to disclose., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objective: To define inflammation-related host-microbe interactions in experimental spondyloarthritis (SpA) using novel inter-omic approaches., Methods: The relative frequency of gut microbes was determined by 16S ribosomal RNA (rRNA) gene sequencing, and gene expression using RNA-Seq of host tissue. HLA-B27/human β 2 -microglobulin-transgenic (HLA-B27-transgenic) and wild-type rats from dark agouti, Lewis, and Fischer backgrounds were used. Inter-omic analyses using Cytoscape were employed to identify relevant relationships. PICRUSt was used to predict microbial functions based on known metagenomic profiles., Results: Inter-omic analysis revealed several gut microbes that were strongly associated with dysregulated cytokines driving inflammatory response pathways, such as interleukin-17 (IL-17), IL-23, IL-17, IL-1, interferon-γ (IFNγ), and tumor necrosis factor (TNF). Many microbes were uniquely associated with inflammation in Lewis or Fischer rats, and one was relevant on both backgrounds. Several microbes that were strongly correlated with immune dysregulation were not differentially abundant in HLA-B27-transgenic compared to wild-type controls. A multi-omic network analysis revealed non-overlapping clusters of microbes in Lewis and Fischer rats that were strongly linked to overlapping dysregulated immune/inflammatory genes. Prevotella, Clostridiales, and Blautia were important in Lewis rats, while Akkermansia muciniphila and members of the Lachnospiraceae family dominated in Fischer rats. Inflammation-associated metabolic pathway perturbation (e.g., butanoate, propanoate, lipopolysaccharide, and steroid biosynthesis) was also predicted from both backgrounds., Conclusion: Inter-omic and network analysis of gut microbes and the host immune response in experimental SpA provides an unprecedented view of organisms strongly linked to dysregulated IL-23, IL-17, IL-1, IFNγ, and TNF. Functional similarities between these organisms may explain why animals of different genetic backgrounds exhibit common patterns of immune dysregulation, possibly through perturbation of similar metabolic pathways. These results highlight the power of linking analyses of gut microbiota with the host immune response to gain insights into the role of dysbiotic microbes in SpA beyond taxonomic profiling., (© 2019, American College of Rheumatology. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

Objective: To develop recommendations for the screening, monitoring, and treatment of uveitis in children with juvenile idiopathic arthritis (JIA)., Methods: Pediatric rheumatologists, ophthalmologists with expertise in uveitis, patient representatives, and methodologists generated key clinical questions to be addressed by this guideline. This was followed by a systematic literature review and rating of the available evidence according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. A group consensus process was used to compose the final recommendations and grade their strength as conditional or strong., Results: Due to a lack of literature with good quality of evidence, recommendations were formulated on the basis of available evidence and a consensus expert opinion. Regular ophthalmic screening of children with JIA is recommended because of the risk of uveitis, and the frequency of screening should be based on individual risk factors. Regular ophthalmic monitoring of children with uveitis is recommended, and intervals should be based on ocular examination findings and treatment regimen. Ophthalmic monitoring recommendations were strong primarily because of concerns of vision-threatening complications of uveitis with infrequent monitoring. Topical glucocorticoids should be used as initial treatment to achieve control of inflammation. Methotrexate and the monoclonal antibody tumor necrosis factor inhibitors adalimumab and infliximab are recommended when systemic treatment is needed for the management of uveitis. The timely addition of nonbiologic and biologic drugs is recommended to maintain uveitis control in children who are at continued risk of vision loss., Conclusion: This guideline provides direction for clinicians and patients/parents making decisions on the screening, monitoring, and management of children with JIA and uveitis, using GRADE methodology and informed by a consensus process with input from rheumatology and ophthalmology experts, current literature, and patient/parent preferences and values., (© 2019, American College of Rheumatology.)

Objective: To develop treatment recommendations for children with juvenile idiopathic arthritis manifesting as non-systemic polyarthritis, sacroiliitis, or enthesitis., Methods: The Patient/Population, Intervention, Comparison, and Outcomes (PICO) questions were developed and refined by members of the guideline development teams. A systematic review was conducted to compile evidence for the benefits and harms associated with treatments for these conditions. GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology was used to rate the quality of evidence. A group consensus process was conducted among the Voting Panel to generate the final recommendations and grade their strength. A Parent and Patient Panel used a similar consensus approach to provide patient/caregiver preferences for key questions., Results: Thirty-nine recommendations were developed (8 strong and 31 conditional). The quality of supporting evidence was very low or low for 90% of the recommendations. Recommendations are provided for the use of nonsteroidal antiinflammatory drugs, disease-modifying antirheumatic drugs, biologics, and intraarticular and oral glucocorticoids. Recommendations for the use of physical and occupational therapy are also provided. Specific recommendations for polyarthritis address general medication use, initial and subsequent treatment, and adjunctive therapies. Good disease control, with therapeutic escalation to achieve low disease activity, was recommended. The sacroiliitis and enthesitis recommendations primarily address initial therapy and adjunctive therapies., Conclusion: This guideline provides direction for clinicians, caregivers, and patients making treatment decisions. Clinicians, caregivers, and patients should use a shared decision-making process that accounts for patients' values, preferences, and comorbidities. These recommendations should not be used to limit or deny access to therapies., (© 2019, American College of Rheumatology.)

Juvenile spondyloarthritis (SpA) is a distinct form of juvenile arthritis characterized by male predominance and adolescent onset. Clinical manifestations include lower extremity and sacroiliac joint arthritis, enthesitis, and subclinical gastrointestinal inflammation. Juvenile SpA is an immune-mediated inflammatory disease long recognized as associated with HLA-B27, which may be related to the microbial environment as suggested by its coexistence with reactive arthritis and psoriasis. Treatment of peripheral arthritis includes nonsteroidal anti-inflammatory drugs, joint injections, and disease-modifying agents, whereas treatment of axial disease may necessitate a tumor necrosis factor inhibitor biologic agent. Fewer than half of children achieve remission off medication 5 years after diagnosis., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Monogenic IFN-mediated autoinflammatory diseases present in infancy with systemic inflammation, an IFN response gene signature, inflammatory organ damage, and high mortality. We used the JAK inhibitor baricitinib, with IFN-blocking activity in vitro, to ameliorate disease., Methods: Between October 2011 and February 2017, 10 patients with CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperatures), 4 patients with SAVI (stimulator of IFN genes-associated [STING-associated] vasculopathy with onset in infancy), and 4 patients with other interferonopathies were enrolled in an expanded access program. The patients underwent dose escalation, and the benefit was assessed by reductions in daily disease symptoms and corticosteroid requirement. Quality of life, organ inflammation, changes in IFN-induced biomarkers, and safety were longitudinally assessed., Results: Eighteen patients were treated for a mean duration of 3.0 years (1.5-4.9 years). The median daily symptom score decreased from 1.3 (interquartile range [IQR], 0.93-1.78) to 0.25 (IQR, 0.1-0.63) (P < 0.0001). In 14 patients receiving corticosteroids at baseline, daily prednisone doses decreased from 0.44 mg/kg/day (IQR, 0.31-1.09) to 0.11 mg/kg/day (IQR, 0.02-0.24) (P < 0.01), and 5 of 10 patients with CANDLE achieved lasting clinical remission. The patients' quality of life and height and bone mineral density Z-scores significantly improved, and their IFN biomarkers decreased. Three patients, two of whom had genetically undefined conditions, discontinued treatment because of lack of efficacy, and one CANDLE patient discontinued treatment because of BK viremia and azotemia. The most common adverse events were upper respiratory infections, gastroenteritis, and BK viruria and viremia., Conclusion: Upon baricitinib treatment, clinical manifestations and inflammatory and IFN biomarkers improved in patients with the monogenic interferonopathies CANDLE, SAVI, and other interferonopathies. Monitoring safety and efficacy is important in benefit-risk assessment., Trial Registration: ClinicalTrials.gov NCT01724580 and NCT02974595., Funding: This research was supported by the Intramural Research Program of the NIH, NIAID, and NIAMS. Baricitinib was provided by Eli Lilly and Company, which is the sponsor of the expanded access program for this drug.

Objective: To determine whether autophagy is involved in the degradation of misfolded HLA-B27 in experimental spondyloarthritis., Methods: Bone marrow-derived macrophages from HLA-B27/human β 2 -microglobulin (hβ 2 m)-transgenic rats were incubated in the presence or absence of interferon-γ and proteasome or autophagy inhibitors. Immunoprecipitation, immunoblotting, and immunofluorescence analysis were used to measure HLA-B27 heavy chains and autophagy. Autophagy was induced using rapamycin. Macrophages from HLA-B7/hβ 2 m-transgenic and wild-type rats were used as controls., Results: HLA-B27-expressing macrophages showed phosphatidylethanolamine-conjugated microtubule-associated protein 1 light chain 3B levels similar to those in both control groups, before and after manipulation of autophagy. Blocking autophagic flux with bafilomycin resulted in the accumulation of misfolded HLA-B27 dimers and oligomers as well as monomers, which was comparable with the results of blocking endoplasmic reticulum-associated degradation (ERAD) with the proteasome inhibitor bortezomib. HLA-B7 monomers also accumulated after blocking each degradation pathway. The ubiquitin-to-heavy chain ratio was 2-3-fold lower for HLA-B27 than for HLA-B7. Activation of autophagy with rapamycin rapidly eliminated ~50% of misfolded HLA-B27, while folded HLA-B27 or HLA-B7 monomeric heavy chains were minimally affected., Conclusion: This study is the first to demonstrate that both autophagy and ERAD play roles in the elimination of excess HLA class I heavy chains expressed in transgenic rats. We observed no evidence that HLA-B27 expression modulated the autophagy pathway. Our results suggest that impaired ubiquitination of HLA-B27 may play a role in the accumulation of misfolded disulfide-linked dimers, the elimination of which can be enhanced by activation of autophagy. Manipulation of the autophagy pathway should be further investigated as a potential therapeutic target in spondyloarthritis., (Published 2018. This article is a U.S. Government work and is in the public domain in the USA.)