Risk loci involved in giant cell arteritis susceptibility: a genome-wide association study.

BACKGROUND: Giant cell arteritis is an age-related vasculitis that mainly affects the aorta and its branches in individuals aged 50 years and older. Current options for diagnosis and treatment are scarce, highlighting the need to better understand its underlying pathogenesis. Genome-wide association studies (GWAS) have emerged as a powerful tool for unravelling the pathogenic mechanisms involved in complex diseases. We aimed to characterise the genetic basis of giant cell arteritis by performing the largest GWAS of this vasculitis to date and to assess the functional consequences and clinical implications of identified risk loci. METHODS: We collected and meta-analysed genomic data from patients with giant cell arteritis and healthy controls of European ancestry from ten cohorts across Europe and North America. Eligible patients required confirmation of giant cell arteritis diagnosis by positive temporal artery biopsy, positive temporal artery doppler ultrasonography, or imaging techniques confirming large-vessel vasculitis. We assessed the functional consequences of loci associated with giant cell arteritis using cell enrichment analysis, fine-mapping, and causal gene prioritisation. We also performed a drug repurposing analysis and developed a polygenic risk score to explore the clinical implications of our findings. FINDINGS: We included a total of 3498 patients with giant cell arteritis and 15 550 controls. We identified three novel loci associated with risk of giant cell arteritis. Two loci, MFGE8 (rs8029053; p=4·96 × 10-8; OR 1·19 [95% CI 1·12-1·26]) and VTN (rs704; p=2·75 × 10-9; OR 0·84 [0·79-0·89]), were related to angiogenesis pathways and the third locus, CCDC25 (rs11782624; p=1·28 × 10-8; OR 1·18 [1·12-1·25]), was related to neutrophil extracellular traps (NETs). We also found an association between this vasculitis and HLA region and PLG. Variants associated with giant cell arteritis seemed to fulfil a specific regulatory role in crucial immune cell types. Furthermore, we identified several drugs that could represent promising candidates for treatment of this disease. The polygenic risk score model was able to identify individuals at increased risk of developing giant cell arteritis (90th percentile OR 2·87 [95% CI 2·15-3·82]; p=1·73 × 10-13). INTERPRETATION: We have found several additional loci associated with giant cell arteritis, highlighting the crucial role of angiogenesis in disease susceptibility. Our study represents a step forward in the translation of genomic findings to clinical practice in giant cell arteritis, proposing new treatments and a method to measure genetic predisposition to this vasculitis. FUNDING: Institute of Health Carlos III, Spanish Ministry of Science and Innovation, UK Medical Research Council, and National Institute for Health and Care Research.

miR-146a and miR-146b regulate the expression of ICAM-1 in giant cell arteritis.

Giant cell arteritis (GCA) is an inflammatory disease of large/medium-sized arteries. MiRNAs are small, non-coding RNAs that inhibit gene expression at post-transcriptional level. Several miRNAs have been shown to be dysregulated in temporal artery biopsies (TABs) from GCA patients, but their role is unknown. The aims of the present work were: to gain insight into the link between inflammation and miRNA up-regulation in GCA; to identify the role of miR-146a and miR-146b. Primary cultures from TABs were treated with IL-1ß, IL-6, soluble IL-6R (sIL6R), IL-17, IL-22, IFNγ, LPS and PolyIC. Correlations between cytokine mRNA and miRNA levels were determined in inflamed TABs. Primary cultures from TABs, human aortic endothelial and smooth muscle cells and ex-vivo TAB sections were transfected with synthetic miR-146a and miR-146b to mimic miRNA activities. Cell viability, target gene expression, cytokine levels in culture supernatants were assayed. Treatment of primary cultures from TABs with IL-1ß and IL-17 increased miR-146a expression while IL-1ß, IL-6+sIL6R and IFNγ increased miR-146b expression. IFNγ and IL-1ß mRNA levels correlated with miR-146a/b levels. Following transfection, cell viability decreased only in primary cultures from TABs. Moreover, transfection of miR-146a/b mimics increased ICAM-1 gene expression and production of the soluble form of ICAM-1 by primary cultures from TABs and by ex-vivo TABs. ICAM-1 expression was higher in inflamed than normal TABs and ICAM-1 levels correlated with miR-146a/b levels. Expression of miR-146a and miR-146b in GCA appeared to be driven by inflammatory cytokines (e.g. IL-1ß, IFNγ). miR-146a and miR-146b seem responsible for the increase of soluble ICAM-1.

[Epidemiology and pathophysiology of giant cell arteritis]. / Épidémiologie et physiopathologie de l'artérite à cellules géantes.

EPIDEMIOLOGY AND PATHOPHYSIOLOGY OF GIANT CELL ARTERITIS. Giant cell arteritis (GCA) is a granulomatous vasculitis. It affects patients over 50 years of age, predominantly women. The pathophysiology of GCA involves genetic and environmental factors leading to the development of inflammation and subsequent large artery wall remodelling, the mechanisms of which are increasingly understood. The process is thought to begin with the activation of dendritic cells in the vessel wall. These then recruit and activate CD4 T cells, inducing their proliferation and polarisation into Th1 and Th17 cells, which produce interferon-gamma (IFN-γ) and interleukin-17 (IL-17) respectively. IFN-γ activates vascular smooth muscle cells, which produce chemokines that induce the recruitment of other mononuclear cells (CD4 and CD8 T cells and monocytes). This inflammatory infiltrate, the differentiation of monocytes into macrophages induce the production of other mediators that cause remodeling of the vascular wall based on destruction of the arterial wall, neoangiogenesis and intimal hyperplasia. This remodelling leads to the ischaemic manifestations of GCA by causing stenosis or even occlusion of the affected vessels. More recently, mechanisms have been identified that allow the perpetuation of inflammation and vascular remodelling, explaining the chronic evolution of GCA.

ÉPIDÉMIOLOGIE ET PHYSIOPATHOLOGIE DE L'ARTÉRITE À CELLULES GÉANTES. L'artérite à cellules géantes (ACG) est une vascularite granulomateuse affectant les patients de plus de 50 ans, préférentiellement les femmes. La physiopathologie de l'ACG fait intervenir des facteurs génétiques et environnementaux qui conduisent à l'apparition d'une inflammation, puis d'un remodelage de la paroi des artères de gros calibre dont les mécanismes sont de mieux en mieux compris. On pense que le processus débute par l'activation des cellules dendritiques de la paroi vasculaire qui recrutent ensuite les lymphocytes T CD4, les activent et induisent leur prolifération et leur polarisation en lymphocytes Th1 et Th17, qui produisent respectivement de l'interféron gamma (IFN-γ) et de l'interleukine 17 (IL-17). L'IFN-γ active les cellules musculaires lisses vasculaires qui produisent des chimiokines induisant le recrutement d'autres cellules mononucléées (lymphocytes T CD4 et CD8 ; monocytes). Cet infiltrat inflammatoire, la différenciation des monocytes en macrophages induisent la production d'autres médiateurs qui provoquent un remodelage de la paroi vasculaire reposant sur une destruction de la paroi artérielle, une néoangiogenèse et une hyperplasie intimale. Ce remodelage conduit à la sténose, voire à l'occlusion, des vaisseaux atteints et ainsi aux manifestations ischémiques de l'ACG. Plus récemment, des mécanismes permettant d'entretenir l'inflammation et le remodelage vasculaire ont été mis en évidence et permettent d'expliquer l'évolution chronique de l'ACG.

Cranial and extracranial giant cell arteritis do not exhibit differences in the IL6 -174 G/C gene polymorphism.

OBJECTIVES: Since interleukin-6 (IL-6) is a pivotal proinflammatory cytokine implicated in the pathogenesis of giant cell arteritis (GCA), we aimed to determine the potential association of the functional IL6 -174 G/C polymorphism with GCA as well as if the single base change variation at the promoter region in the human IL-6 gene may account for differences in the clinical spectrum of GCA between cranial and extracranial large vessel vasculitis (LVV)-GCA. METHODS: The IL6 -174 G/C polymorphism (rs1800795) was genotyped in 191 patients with biopsy-proven GCA who had typical cranial manifestations of the disease, 109 patients with extracranial LVV-GCA, without cranial ischaemic manifestations of GCA, and 877 ethnically matched unaffected controls. A comparative study was carried out between patients with cranial and extracranial LVV-GCA and controls. RESULTS: No significant differences in genotype and allele frequencies of IL6 -174 G/C polymorphism were found between the whole cohort of GCA patients and healthy controls. It was also the case when cranial and extracranial LVV-GCA were compared or when each of these subgroups was compared to controls. Moreover, no significant results in genotype and allele frequencies of IL6 -174 G/C polymorphism were disclosed when the whole cohort of GCA patients were stratified according to the presence of polymyalgia rheumatica, severe ischaemic manifestations, including permanent visual loss and peripheral arteriopathy, and HLA-DRB1*04:01 status. CONCLUSIONS: Our results show that the IL6 -174 G/C polymorphism does not influence the phenotypic expression of GCA.

Human monocyte-derived suppressive cells (HuMoSC) for cell therapy in giant cell arteritis.

Introduction: The pathogenesis of Giant Cell Arteritis (GCA) relies on vascular inflammation and vascular remodeling, the latter being poorly controlled by current treatments. Methods: This study aimed to evaluate the effect of a novel cell therapy, Human Monocyte-derived Suppressor Cells (HuMoSC), on inflammation and vascular remodeling to improve GCA treatment. Fragments of temporal arteries (TAs) from GCA patients were cultured alone or in the presence of HuMoSCs or their supernatant. After five days, mRNA expression was measured in the TAs and proteins were measured in culture supernatant. The proliferation and migration capacity of vascular smooth muscle cells (VSMCs) were also analyzed with or without HuMoSC supernatant. Results: Transcripts of genes implicated in vascular inflammation (CCL2, CCR2, CXCR3, HLADR), vascular remodeling (PDGF, PDGFR), angiogenesis (VEGF) and extracellular matrix composition (COL1A1, COL3A1 and FN1) were decreased in arteries treated with HuMoSCs or their supernatant. Likewise, concentrations of collagen-1 and VEGF were lower in the supernatants of TAs cultivated with HuMoSCs. In the presence of PDGF, the proliferation and migration of VSMCs were both decreased after treatment with HuMoSC supernatant. Study of the PDGF pathway suggests that HuMoSCs act through inhibition of mTOR activity. Finally, we show that HuMoSCs could be recruited in the arterial wall through the implication of CCR5 and its ligands. Conclusion: Altogether, our results suggest that HuMoSCs or their supernatant could be useful to decrease vascular in flammation and remodeling in GCA, the latter being an unmet need in GCA treatment.

Evaluation of Arterial Histopathology and microRNA Expression That Underlie Ultrasonography Findings in Temporal Arteries of Patients with Giant Cell Arteritis.

The aim of this study was to assess the interrelation between vascular ultrasonography (US) findings, histopathological data, and the expression of selected dysregulated microRNAs (miRNAs) in giant cell arteritis (GCA). The study included data on the clinical parameters, US measurements, and temporal artery biopsies (TABs) of 46 treatment-naïve patients diagnosed with GCA and 22 age-matched non-GCA patient controls. We performed a comprehensive comparative and correlation analysis along with generation of receiver operating characteristic (ROC) curves to ascertain the diagnostic performance of US examination parameters and selected miRNAs for GCA diagnosis. We showed significant differences in the US-measured intima-media thickness of the temporal arteries, the presence of a halo sign, and the presence of luminal stenosis between GCA-positive/TAB-positive, GCA-positive/TAB-negative, and non-GCA patients. Correlation analysis revealed significant associations between several histopathological parameters, US-measured intima-media thickness, and the halo sign. We found that the significant overexpression of miR-146b-5p, miR-155-5p, miR-511-5p, and miR-21-5p, and the under-expression of the miR-143/145 cluster, miR-30a-5p, and miR-125a-5p, coincides and is associated with the presence of a halo sign in patients with GCA. Notably, we determined a high diagnostic performance of miR-146b-5p, miR-21-3p, and miR-21-5p expression profiles in discriminating GCA patients from non-GCA controls, suggesting their potential utilization as putative biomarkers of GCA. Taken together, our study provides an insight into the US-based diagnostic evaluation of GCA by revealing the complex interrelation of clearly defined image findings with underlying vascular immunopathology and altered arterial tissue-specific miRNA profiles.

Cranial and extracranial large-vessel giant cell arteritis share a genetic pattern of interferon-gamma pathway.

OBJECTIVES: Two main different clinical phenotypes of giant cell arteritis (GCA) have been described, the classic cranial pattern and the extracranial large-vessel (LV) pattern. Since interferon gamma (IFNG) has shown to be a pivotal cytokine in the pathophysiology of GCA, our aim was to evaluate for the first time the influence of IFNG and IFNG receptor 1 (IFNGR1) polymorphisms in the different clinical phenotypes of GCA. METHODS: Two IFNG polymorphisms (rs2069718 G/A and rs1861493 A/G) and one polymorphism in IFNGR1 (rs1327474 G/A) were genotyped in 191 patients with biopsy-proven cranial GCA, 109 with extracranial LV-GCA and 490 healthy controls. A comparative study was conducted between patients with cranial and extracranial LV-GCA. RESULTS: No significant differences in genotype, allele, and haplotype frequencies of IFNG polymorphisms were found between GCA patients with the classic cranial pattern and the extracranial LV-GCA pattern. Similar results were found for genotype and allele frequencies of IFNGR1 polymorphism. It was also the case when patients with extracranial LV-GCA were compared with healthy controls. CONCLUSIONS: Our results show that IFNG and IFNGR1 polymorphisms do not influence the clinical phenotype of expression of GCA. Classic cranial GCA and extracranial LV-GCA seem to share a genetic pattern of IFNG pathway.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome (VEXAS syndrome) with prominent supraglottic larynx involvement: a case-based review.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome (VEXAS syndrome) is a recently described genetic disorder that gathers autoinflammatory symptoms and myeloid dysplasia. The first description was reported in 2020, and subsequently, a growing number of cases have been described worldwide. Herein, we describe a case of a 72-year-old male patient with VEXAS syndrome with p.Met41Val mutation of the UBA1 gene, prominent supraglottic larynx involvement, and costochondritis. To our knowledge, this is the first report of VEXAS syndrome in Colombia and South America. This disease could present features of relapsing polychondritis, polyarteritis nodosa, giant cell arteritis, and Sweet syndrome, associated with hematologic involvement, including cytopenias, myelodysplastic syndrome, or thromboembolic disease. Supraglottic larynx chondritis and costochondritis are atypical manifestations. These features were proposed previously to differentiate relapsing polychondritis from VEXAS syndrome but are not entirely reliable like in the case described. A diagnosis of VEXAS should be considered in male patients with incomplete or complete features of the previously described conditions, refractory to treatment, requiring high-dose glucocorticoids, and associated progressive hematologic abnormalities. Key Points • VEXAS syndrome is a recently described genetic (somatic mutations in UBA1 gene) disorder that gathers autoinflammatory and hematologic manifestations. • VEXAS syndrome should be considered in male patients with incomplete or complete features of relapsing polychondritis, polyarteritis nodosa, giant cell arteritis, and Sweet syndrome, refractory to treatment, associated with hematologic involvement, including cytopenias, myelodysplastic syndrome, or thromboembolic disease. • Glucocorticoids ameliorate symptoms effectively. However, other treatment options are limited due to a lack of evidence. Traditional immunosuppressants and biological therapy have been used empirically with limited efficacy and a transient effect. Bone marrow transplant offers a curative approach, but it has high morbidity and mortality.

Vascular endothelial growth factor haplotypes are associated with severe ischaemic complications in giant cell arteritis regardless of the disease phenotype.

OBJECTIVES: To determine whether functional vascular endothelial growth factor (VEGF) polymorphisms influence the expression of the clinical phenotype of giant cell arteritis (GCA). We also evaluated whether VEGF polymorphism is associated with the development of severe ischaemic manifestations in patients with GCA regardless of the clinical phenotype, classic cranial GCA or predominantly extracranial GCA large vessel vasculitis (LVV). METHODS: VEGF rs833061 T/C, rs2010963 G/C and rs3025039 C/T polymorphisms were genotyped in 185 patients with biopsy-proven cranial GCA, 105 with extracranial LVV-GCA and 490 healthy controls. Allelic combinations (haplotypes) of VEGF were carried out. Comparisons were performed between patients with GCA and healthy controls as well as between patients with GCA stratified according to the clinical phenotype and the presence of severe ischaemic manifestations. RESULTS: No significant differences in genotype, allele, and haplotype frequencies of VEGF were found between patients with GCA and healthy controls as well as between GCA patients with the classic cranial pattern and the extracranial LVV-GCA pattern of the disease. However, the VEGF CGC haplotype (OR= 1.63 [1.05-2.53]) and the CGT haplotype (OR= 2.55 [1.10-5.91]) were significantly more frequent in GCA patients with severe ischaemic complications compared to those patients without these complications. CONCLUSIONS: VEGF haplotypes seem to play a role in the development of severe ischaemic manifestations in GCA patients, regardless of the clinical phenotype of expression of the disease.

Myeloproliferative neoplasms and clonal haematopoiesis in patients with giant cell arteritis: a case-control and exploratory study.

OBJECTIVES: GCA is a large vessel vasculitis for which triggering factors remain unknown. Clonal haematopoiesis (CH) was associated with atherosclerosis through the induction of inflammation in myeloid cells, and data suggest that CH expansion and inflammation may support each other to induce a pro-inflammatory loop. Our objective was to describe the impact of JAK2p.V617F-mutated myeloproliferative neoplasms (MPNs) on GCA and to screen MPN-free patients for CH mutations. METHODS: We performed a retrospective case-control study comparing the characteristics of 21 GCA patients with MPN and 42 age- and gender-matched GCA patients without MPN. Also, 18 GCA patients were screened for CH through next-generation sequencing (NGS). RESULTS: The most frequent associated MPN was essential thrombocythaemia (ET; n = 11). Compared with controls, GCA patients with MPN had less-frequent cephalic symptoms (71.4 vs 97.6%; P = 0.004) and higher platelet counts at baseline [485 × 109/l (interquartile range 346-586) vs 346 (296-418); P = 0.02]. There was no difference between groups for other clinical features. Overall survival was significantly shorter in patients with MPN compared with controls [hazard ratio 8.2 (95% CI 1.2, 56.6); P = 0.03]. Finally, screening for CH using NGS in 15 GCA patients without MPN revealed CH in 33%. CONCLUSION: GCA patients with MPN display higher platelet counts and shorter overall survival than controls. This association is not fortuitous, given the possible pathophysiological relationship between the two diseases. CH was found in one-third of GCA patients, which may be higher than the expected prevalence for a similar age, and should be confirmed in a larger cohort.

The presence of both HLA-DRB1*04:01 and HLA-B*15:01 increases the susceptibility to cranial and extracranial giant cell arteritis.

OBJECTIVES: To determine if patients with the predominant extracranial large-vessel-vasculitis (LVV) pattern of giant cell arteritis (GCA) have a distinctive HLA-B association, different from that reported in biopsy-proven cranial GCA patients. In a further step we assessed if the combination of HLA-B and HLA-DRB1 alleles confers an increased risk for GCA susceptibility, either for the cranial and extracranial LVV phenotypes. METHODS: A total of 184 patients with biopsy-proven cranial GCA, 105 with LVV-GCA and 486 healthy controls were included in our study. We compared HLA-B phenotype frequencies between the three groups. RESULTS: HLA-B*15 phenotype was significantly increased in patients with classic cranial GCA compared to controls (14.7% versus 5.8%, respectively; p<0.01; OR [95% CI] =2.81 [1.54-5.11]). It was mainly due to the HLA-B*15:01 allele (12.5% versus 4.0%, respectively; p<0.01; OR [95% CI] =3.51 [1.77-6.99]) and remained statistically significant after Bonferroni correction. Similar HLA-B*15 association was observed in patients with the LVV-GCA (11.4% versus 5.8%, p=0.04, OR [95% CI] =2.11 [1.04-4.30]). This association was also mainly due to the HLA-B*15:01 allele (10.5% versus 4.0%, respectively; p=0.0054; OR [95% CI] =2.88 [1.19-6.59]). Noteworthy, the presence of HLA-B*15:01 together with HLA-DRB1*04:01 led to an increased risk of developing both cranial and extracranial LVV-GCA. CONCLUSIONS: Susceptibility to GCA is strongly related to the HLA region, regardless of the clinical phenotype of expression of the disease.

Specific Follicular Helper T Cell Signature in Takayasu Arteritis.

OBJECTIVE: Our aim was to compare transcriptome and phenotype profiles of CD4+ T cells and CD19+ B cells in patients with Takayasu arteritis (TAK), patients with giant cell arteritis (GCA), and healthy donors. METHODS: Gene expression analyses, flow cytometry immunophenotyping, T cell receptor (TCR) gene sequencing, and functional assessments of cells from peripheral blood and arterial lesions from TAK patients, GCA patients, and healthy donors were performed. RESULTS: Among the most significantly dysregulated genes in CD4+ T cells of TAK patients compared to GCA patients (n = 720 genes) and in CD4+ T cells of TAK patients compared to healthy donors (n = 1,447 genes), we identified a follicular helper T (Tfh) cell signature, which included CXCR5, CCR6, and CCL20 genes, that was transcriptionally up-regulated in TAK patients. Phenotypically, there was an increase in CD4+CXCR5+CCR6+CXCR3- Tfh17 cells in TAK patients that was associated with a significant enrichment of CD19+ B cell activation. Functionally, Tfh cells helped B cells to proliferate, differentiate into memory cells, and secrete IgG antibodies. Maturation of B cells was inhibited by JAK inhibitors. Locally, in areas of arterial inflammation, we found a higher proportion of tertiary lymphoid structures comprised CD4+, CXCR5+, programmed death 1+, and CD20+ cells in TAK patients compared to GCA patients. CD4+CXCR5+ T cells in the aortas of TAK patients had an oligoclonal α/ß TCR repertoire. CONCLUSION: We established the presence of a specific Tfh cell signature in both circulating and aorta-infiltrating CD4+ T cells from TAK patients. The cooperation of Tfh cells and B cells might be critical in the occurrence of vascular inflammation in patients with TAK.

Inflammatory Cell Composition and Immune-Related microRNA Signature of Temporal Artery Biopsies From Patients With Giant Cell Arteritis.

Objectives: The aim of this study was to quantitatively assess distinct immune cell subsets comprising inflammatory infiltrate in temporal artery biopsies (TABs) from patients with giant cell arteritis (GCA), and to link the obtained histopathological data with expression profiles of immune-related microRNAs (miRNAs). Methods: The study included 68 formalin-fixed, paraffin-embedded TABs from treatment-naïve patients, including 30 histologically positive GCA and 16 negative GCA TABs, and 22 control non-GCA TABs. Quantitative assessment of histological parameters was performed using histopathological and immunohistochemical techniques. miRNA expression analysis was performed by quantitative real-time PCR. Results: Intense transmural mononuclear inflammatory infiltrates in TAB-positive GCA arteries were predominantly composed of CD3+, CD4+ and CD8+ T lymphocytes, and CD68+ macrophages, accompanied by a strong nuclear overexpression of the nuclear factor of activated T cells, cytoplasmic 1 (NFATC) in the lymphocyte infiltrate fraction. Furthermore, TAB-positive GCA arteries were characterized by significant overexpression of nine pro-inflammatory miRNAs (miR-132-3p/-142-3p/-142-5p/-155-5p/-210-3p/-212-3p/-326/-342-5p/-511-5p) and a significant under-expression of six regulatory immune-related miRNAs (miR-30a-5p/-30b-5p/-30c-5p/-30d-5p/-30e-5p/-124-3p), whose expression levels significantly associated with most evaluated histopathological parameters. Notably, we revealed miR-132-3p/-142-3p/-142-5p/-155-5p/-212-3p/-511-5p as major promoters of arterial inflammation and miR-30a-5p/-30c-5p/-30d-5p as putative regulators of NFATC signaling in TAB-positive GCA arteries. Conclusion: Overall, we demonstrated that an altered arterial tissue-specific pro-inflammatory miRNA signature favors enhanced T cell-driven inflammation and macrophage activity in TAB-positive GCA arteries. Moreover, dysregulation of several immune-related miRNAs seems to contribute crucially to GCA pathogenesis, through impairing their regulatory activity towards T cell-mediated immune responses driven by the calcineurin (CaN)/NFAT signaling pathway, indicating their therapeutic, diagnostic and prognostic potential.

Somatic Mutations in UBA1 and Severe Adult-Onset Autoinflammatory Disease.

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.).

Cranial and extracranial giant cell arteritis share similar HLA-DRB1 association.

OBJECTIVE: To determine whether giant cell arteritis (GCA) patients with the typical pattern of cranial ischemic manifestations and those with the extracranial large-vessel-vasculitis (LVV)-GCA phenotype exhibit different HLA-DRB1 association. METHODS: 178 biopsy-proven GCA patients who had cranial ischemic features but no LVV manifestations, 100 patients with LVV-GCA without cranial ischemic manifestations and 486 ethnically matched healthy controls were recruited. All patients and controls were Spanish of European ancestry. We compared HLA-DRB1 phenotype frequencies between the three groups. RESULTS: Both GCA subgroups had well-differentiated clinical features. Patients with LVV-GCA were younger (68.0 ±â€¯10.0 years versus 74.0 ±â€¯10.4 years; p < 0.01) and presented more commonly with polymyalgia rheumatica symptoms (81% versus 39.3%; p < 0.01) than those with the classic cranial GCA phenotype. HLA-DRB1*04 phenotype frequency was significantly increased in patients with classic cranial GCA compared to controls (42.1% versus 23.5%, respectively; p < 0.01; odds ratio-OR [95% confidence interval-CI] = 2.38 [1.62-3.47]). This association was mainly due to the HLA-DRB1*04:01 allele (20.8% versus 5.3%, respectively; p < 0.01; OR [95% CI] = 4.64 [2.63-8.26]). HLA-DRB1*04 association was also observed in LVV-GCA patients when compared to controls (46.0% versus 23.5%, respectively; p < 0.01; OR [95% CI] = 2.78 [1.73-4.44]). Similar to cranial GCA, the association was also mainly due to the HLA-DRB1*04:01 allele (19.0% versus 5.3%, respectively; p < 0.01; OR [95% CI] = 4.15 [2.06-8.19]). Cranial and LVV-GCA patients did not exhibit HLA-DRB1 allele differences. CONCLUSION: Cranial and extracranial LVV-GCA share similar HLA-DRB1 association.

Identification of microRNAs and their target gene networks implicated in arterial wall remodelling in giant cell arteritis.

OBJECTIVES: To identify dysregulated microRNAs (miRNAs) and their gene targets in temporal arteries from GCA patients, and determine their association with GCA pathogenesis and related arterial wall remodelling. METHODS: We included 93 formalin-fixed, paraffin-embedded temporal artery biopsies (TABs) from treatment-naïve patients: 54 positive and 17 negative TABs from clinically proven GCA patients, and 22 negative TABs from non-GCA patients. miRNA expression analysis was performed with miRCURY LNA miRNome Human PCR Panels and quantitative real-time PCR. miRNA target gene prediction and pathway enrichment analysis was performed using the miRDB and Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) databases, respectively. RESULTS: Dysregulation of 356 miRNAs was determined in TAB-positive GCA arteries, among which 78 were significantly under-expressed and 22 significantly overexpressed above 2-fold, when compared with non-GCA controls. Specifically, TAB-positive GCA arteries were characterized by a significant overexpression of 'pro-synthetic' (miR-21-3p/-21-5p/-146a-5p/-146b-5p/-424-5p) and under-expression of 'pro-contractile' (miR-23b-3p/-125a-5p/-143-3p/-143-5p/-145-3p/-145-5p/-195-5p/-365a-3p) vascular smooth muscle cell phenotype-associated regulatory miRNAs. These miRNAs targeted gene pathways involved in the arterial remodelling and regulation of the immune system, and their expression correlated with the extent of intimal hyperplasia in TABs from GCA patients. Notably, the expression of miR-21-3p/-21-5p/-146a-5p/-146b-5p/-365a-3p differentiated between TAB-negative GCA arteries and non-GCA temporal arteries, revealing these miRNAs as potential biomarkers of GCA. CONCLUSION: Identification of dysregulated miRNAs involved in the regulation of the vascular smooth muscle cell phenotype and intimal hyperplasia in GCA arterial lesions, and detection of their expression profiles, enables a novel insight into the complexity of GCA pathogenesis and implies their potential utilization as diagnostic and prognostic biomarkers of GCA.

Discovery of IL-6 and Development of Anti-IL-6R Antibody.

A series of our studies on IL-6 have revealed that it has a pleiotropic activity in various tissues and cells and its deregulated expression is responsible for several chronic inflammations and hemopoietic malignancies.Humanized antibody against 80kd IL-6R (Tocilizumab) has shown significant therapeutic effect in RA, JIA, Castleman's diseases and several other autoimmune inflammatory diseases, such as, giant cell arteritis, reactive arthritis, polymyalgia rheumatica and adult still's disease. Cytokine storm induced by CAR-T cell therapy has been shown to be controlled by Tocilizumab.Therapeutic effect of Tocilizumab confirmed that over and constitutive-production of IL-6 is responsible for the pathogenesis of autoimmune diseases.Then, the question to be asked is how is IL-6 production regulated. We identified a novel molecule called Arid5a which binds with the 3'-UTR of IL-6 mRNA and protects its degradation by competing with Regnase-1. Interestingly, this molecule is present in nuclei and inflammatory stimulation induced translocation of Arid5a from nuclei into cytoplasm and it competes with Regnase-1 for the protection of mRNA of IL-6.Our study indicates that Arid5a is one of the key molecules for inflammation as well as the development of septic shock.The results also suggest the therapeutic potential of anti-agonistic agents for Arid5a in the prevention of various inflammatory diseases and septic shock.

Gene and miRNA expression in giant cell arteritis-a concise systematic review of significantly modified studies.

Giant cell arteritis (GCA) is a systemic vasculitis in individuals older than 50 years, characterized by headaches, visual disturbances, painful scalp, jaw claudication, impairment of limb arteries, and systemic inflammation, among other symptoms. GCA diagnosis is confirmed by a positive temporal artery biopsy (TAB) or by imaging modalities. A prominent acute phase response with inflammation is the hallmark of the disease, predominantly targeting large- and medium-sized arteries leading to stenosis or occlusion of arterial lumen. To date, there are no reliable tissue markers specific for GCA. Scarce reports have indicated the importance of epigenetics in GCA. The current systematic review reports significantly changed candidate biomarkers in TABs of GCA patients compared to non-GCA patients using qPCR.