Two susceptibility loci to Takayasu arteritis reveal a synergistic role of the IL12B and HLA-B regions in a Japanese population

Genetics of vasculitis

Systemic vasculitis encompasses a wide range of conditions characterized by varying degrees of inflammation in blood vessels. Although the etiology of vasculitis remains unclear, accumulated data suggest that it is triggered in genetically predisposed individuals by the concurrence of certain environmental factors. The importance of the genetic component has been consistently supported by evidence of familial aggregation, differential prevalence by ethnicity, and multiple genetic associations with disease susceptibility and severity reported in recent years. The strongest association signals in most vasculitides correspond to genetic variants within the HLA region, suggesting an important role of the immune system in its pathophysiology. However, each type of vasculitis has distinct defining HLA association markers, likely due to disease-specific differences in antigenic drivers. Furthermore, other genetic polymorphisms located outside the HLA region play an important role in susceptibility to different vasculitides. More recent research has assessed the shared genetic susceptibility evident across different vasculitides. Future studies should focus on the identification of genetic markers that can serve as reliable biomarkers for early diagnosis, prognosis, and treatment response in systemic vasculitis.

[Takayasu arteritis after COVID-19 infection in a 26-year-old female patient with Crohn's disease]

Extraintestinal manifestations, e.g. of the skin, joints or liver, are frequently found in Crohn's disease. We report about a 26-year-old female patient with longstanding Crohn's disease, who was admitted to our hospital with suspicion of an acute attack with suggestive symptoms and increased significantly inflammatory parameters. Shortly before, symptomatic COVID-19 disease (SARS-CoV-2 variant omicron) had been made. Comprehensive endoscopic and imaging diagnostics ruled out active Crohn's disease. However, inflammatory thickening of the aortic arch was seen, and a diagnosis of Takayasu arteritis (type II b) was made. Steroid therapy resulted in a rapid and sustained improvement of clinical symptoms. The occurrence of Takayasu arteritis is extremely rare outside Japan. An coincidence has been described in chronic inflammatory bowel diseases and is discussed as a possible extraintestinal manifestation. The occurrence of immune-mediated disease after COVID-19 disease has been described and may be triggered by the infection. Patients with inflammatory bowel disease may represent a special risk population.

Successful pregnancies in a patient with Takayasu arteritis and antiphospholipid syndrome, maintained on infliximab corticosteroid-free regimen: case-based review

Takayasu arteritis (TA) is a large vessel vasculitis affecting predominantly females below the age of 40. Patients with TA seem to be at increased risk for adverse pregnancy outcomes, resulting in mother or child complications. Although few studies analyzed the presence of antiphospholipid antibodies (APLA) in TA patients, an association between antiphospholipid syndrome (APS) and TA is rarely reported in the literature, mainly in the form of case reports. In fact, very few data regarding pregnancy outcomes in patients with TA and APS are available. An active form of Crohn's disease (CD) might be another risk factor strongly affecting the fertility rate. Here, we would like to present a 33-year-old woman with TA, double-positive APS and Crohn's disease (CD). The report is followed by the literature review of the association of APLA and/or APS with TA, focusing on analyzing the pregnancy outcomes. To our knowledge, this is the first case describing two successful, naturally occurring pregnancies, in a patient suffering from TA, APS and CD, and maintained on infliximab, azathioprine, and a corticosteroid-free regimen.

A Glimpse into Humoral Response and Related Therapeutic Approaches of Takayasu's Arteritis

Takayasu's arteritis (TAK) manifests as an insidiously progressive and debilitating form of granulomatous inflammation including the aorta and its major branches. The precise etiology of TAK remains elusive, with current understanding suggesting an autoimmune origin primarily driven by T cells. Notably, a growing body of evidence bears testimony to the widespread effects of B cells on disease pathogenesis and progression. Distinct alterations in peripheral B cell subsets have been described in individuals with TAK. Advancements in technology have facilitated the identification of novel autoantibodies in TAK. Moreover, emerging data suggest that dysregulated signaling cascades downstream of B cell receptor families, including interactions with innate pattern recognition receptors such as toll-like receptors, as well as co-stimulatory molecules like CD40, CD80 and CD86, may result in the selection and proliferation of autoreactive B cell clones in TAK. Additionally, ectopic lymphoid neogenesis within the aortic wall of TAK patients exhibits functional characteristics. In recent decades, therapeutic interventions targeting B cells, notably utilizing the anti-CD20 monoclonal antibody rituximab, have demonstrated efficacy in TAK. Despite the importance of the humoral immune response, a systematic understanding of how autoreactive B cells contribute to the pathogenic process is still lacking. This review provides a comprehensive overview of the biological significance of B cell-mediated autoimmunity in TAK pathogenesis, as well as insights into therapeutic strategies targeting the humoral response. Furthermore, it examines the roles of T-helper and T follicular helper cells in humoral immunity and their potential contributions to disease mechanisms. We believe that further identification of the pathogenic role of autoimmune B cells and the underlying regulation system will lead to deeper personalized management of TAK patients. We believe that further elucidation of the pathogenic role of autoimmune B cells and the underlying regulatory mechanisms holds promise for the development of personalized approaches to managing TAK patients.

Anti-integrin αvβ6 antibody in Takayasu arteritis patients with or without ulcerative colitis

Background

It has been well documented that Takayasu arteritis (TAK) and ulcerative colitis (UC) coexist in the same patients. HLA-B*52 characterizes the co-occurrence, which is one of the common genetic features between these two diseases, indicating shared underlying pathologic mechanisms. Anti-integrin αvβ6 antibody (Ab) is present in sera of UC patients in a highly specific manner. We investigated if there were any associations between anti-integrin αvβ6 Ab and TAK, considering the risk HLA alleles.

Methods

A total of 227 Japanese TAK patients were recruited in the current study and their serum samples were subjected to measurement of anti-integrin αvβ6 Ab by ELISA. The clinical information, including the co-occurrence of UC, was collected. The HLA allele carrier status was determined by Luminex or genotype imputation.

Results

The information about the presence of UC was available for 165 patients, among which eight (4.84%) patients had UC. Anti-integrin αvβ6 antibody was identified in 7 out of 8 TAK subjects with UC (87.5%) while only 5 out of 157 (3.18%) TAK subjects without UC had the antibody (OR 121, p=7.46×10-8). A total of 99 out of 218 (45.4%) patients were HLA-B*52 carriers. There was no significant association between the presence of anti-integrin αvβ6 Ab and HLA-B*52 carrier status in those without UC (OR 2.01, 95% CI 0.33-12.4, p = 0.189).

Conclusions

The prevalence of anti-integrin αvβ6 Ab was high in TAK patients with UC, but not in the absence of concomitant UC. The effect of HLA-B*52 on anti-integrin αvβ6 Ab production would be minimal.

Frequency and the effects of spondyloarthritis-spectrum disorders on the clinical course and management of Takayasu arteritis: an observational retrospective study

OBJECTIVES

Extravascular findings of Takayasu arteritis (TAK) often share features with the spondyloarthritis (SpA) spectrum of disorders. However, the characteristics of this overlap and its effect on the vascular manifestations of TAK are not fully known. Therefore, we aimed to investigate the frequency of SpA-related features in TAK patients.

MATERIAL AND METHODS

In this observational retrospective study, 350 patients with TAK classified according to ACR 1990 criteria, from 12 tertiary rheumatology clinics, were included and evaluated for the presence of axSpA, IBD, or psoriasis. Demographic, clinical features, angiographic involvement patterns, disease activity, and treatments of TAK patients with or without SpA were analyzed.

RESULTS

Mean age was 45.5 ± 13.6 years and mean follow-up period was 76.1 ± 65.9 months. Among 350 patients, 31 (8.8%) had at least one additional disease from the SpA spectrum, 8 had IBD, 8 had psoriasis, and 20 had features of axSpA. In the TAK-SpA group, TAK had significantly earlier disease onset, compared to TAK-without-SpA (p = 0.041). SpA-related symptoms generally preceded TAK symptoms. Biological treatments, mostly for active vasculitis, were higher in the TAK-SpA group (70.9%) compared to TAK-without-SpA (27.9%) (p < 0.001). Vascular involvements were similar in both.

CONCLUSION

Our study confirmed that diseases in the SpA spectrum are not rare in TAK. Vascular symptoms appeared earlier in such patients, and more aggressive therapy with biological agents was required in the TAK-SpA group, suggesting an association between TAK and SpA spectrum. Key Points • The pathogenesis of Takayasu arteritis is mediated by an MHC class I alelle (HLA-B*52), similar to spondyloarthritis-disorders. • Extravascular findings of Takayasu arteritis are in the spectrum of spondyloarthritis disease. • This frequent coexistence between Takayasu arteritis and spondyloarthritic disorders suggests a relationship rather than a coincidence.

Baricitinib for refractory Takayasu arteritis: a prospective cohort study in a tertiary referral centre

OBJECTIVE

To investigate the treatment efficacy and safety of baricitinib in patients with refractory Takayasu arteritis (TAK).

METHODS

We performed a prospective cohort study in which baricitinib 4 mg daily was prescribed to patients with refractory TAK, combined with oral glucocorticoids (GCs).

RESULTS

10 patients with refractory TAK were enrolled with a median age of 28 (IQR=22-37) years, median disease duration of 50 (IQR=24-65) months. The median dose of GCs was 10 (IQR=8.1-22.5) mg prednisone or equivalence dosage at baseline. At 6 months of baricitinib treatment, 6/10 (60%) patients had an overall treatment response. During an average follow-up of 15.3 (range 4-31) months, 4/10 (40%) patients maintained overall treatment response. 8/10 (80%) patients tapered or maintained the same dose of GCs with no change of the combined classical synthetic disease-modifying antirheumatic drugs. Two patients discontinued GCs at 18 and 24 months and were in continuous remission till the end of the study. One patient withdrew baricitinib due to liver dysfunction.

CONCLUSION

Baricitinib 4 mg daily is effective for refractory TAK and is well tolerated.

A retrospective study of infantile-onset Takayasu arteritis: experience from a tertiary referral center in China

Objective

Takayasu artery (TAK) is a chronic inflammatory disease that mainly affects the aorta and its major branches and is rarely reported in infants. We aimed to summarize the clinical features of infant TA (I-TA) in a tertiary care center.

Methods

We performed a retrospective study involving 10 infants diagnosed with TAK. A comprehensive evaluation of clinical, laboratory, radiographic features, disease activity, treatment and outcomes was carried out.

Results

A consecutive cohort was composed of 8 girls and 2 boys, with an age at diagnosis of 11.1 (1.7-36) months. The median time to diagnosis and the average time to follow-up were 9.5 days (2-235 days) and 10.9 (1-21) months, respectively. The most common initial manifestations were malaise (80%), fever (70%), hypertension (50%) and rash (30%). The mean Pediatric Vasculitis Activity Score (PVAS), Takayasu Clinical Activity Score (ITAS-2010) and ITAS-A scores were 2.8/63, 2.6/51, and 5.6/54, respectively. All patients had aberrant laboratory parameters. The most common lesions were in the thoracic aorta (60%) and abdominal aorta (60%). Corticosteroids combined with cyclophosphamide followed by long-term mycophenolate mofetil were initiated in most cases (70%). Biologics were attempted in 5 cases. Mortality was 40%.

Conclusions

It is challenging to diagnose TAK in infants in a timely manner. Considering the more vessels involved, more severe inflammation and higher mortality, aggressive treatment is warranted in infants. GCs and CYC treatment seem to be effective.

New Therapeutic Approaches to Large-Vessel Vasculitis

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are large-vessel vasculitides affecting the aorta and its branches. Arterial damage from these diseases may result in ischemic complications, aneurysms, and dissections. Despite their similarities, the management of GCA and TAK differs. Glucocorticoids are used frequently but relapses are common, and glucocorticoid toxicity contributes to significant morbidity. Conventional immunosuppressive therapies can be beneficial in TAK, though their role in the management of GCA remains unclear. Tumor necrosis factor inhibitors improve remission rates and appear to limit vascular damage in TAK; these agents are not beneficial in GCA. Tocilizumab is the first biologic glucocorticoid-sparing agent approved for use in GCA and also appears to be effective in TAK. A better understanding of the pathogenesis of both conditions and the availability of targeted therapies hold much promise for future management.

Angiogenesis related genes in Takayasu Arteritis (TAK): robust association with Tag SNPs of IL-18 and FGF-2 in a South Asian Cohort

We performed genetic association study for genes encoding angiogenic and angiostatic proteins in patients with Takayasu arteritis (TAK). A total of 96 SNPs involving 60 genes were studied. Genotyping was performed in Fluidigm 96.96 Dynamic Array chip. All statistical analysis for SNP evaluation was performed using PLINK software. Initial analyses revealed five SNPs from three genes [IL-18 (encodes Interleukin-18), FGF2 (encodes Fibroblast Growth Factor-2), and ANGPT1 (encodes Angiopoietin-1)] as significantly different between controls and cases (uncorrected p < 0.05). After permutation-based analysis, two tag SNPs on the promoter region of IL-18 (rs187238 and rs1946518) and one 3'UTR tag SNP (rs1476217) of FGF2 were significantly associated with susceptibility to TAK, with p and OR (95% CI) of 0.0006 and 1.64 (1.25-2.17), 0.03 and 1.28 (1.02-1.64) & 0.016 and 1.33 (1.05-1.67), respectively; while, the two tag SNPs of ANGPT1 gene (rs6469101 and rs16875900) showed a trend (p = 0.055 & p = 0.051, respectively after permutation based correction). There is robust linkage disequilibrium between the two tag SNPs of IL-18 gene as validated by 1000 genome data of South Asian population; the eQTL effects of these tag SNPs of IL-18 and FGF2 genes on adjacent genes further suggest that these tag SNPs act as genetic risks for development of TAK in South Asians, with possible functional implications towards future biomarker development. Genotype phenotype study by genetic model-based analysis also revealed associations between genotype subsets and clinical features like fever, visual loss, left subclavian and coronary artery involvement in our TAK patients.

Pathophysiology, Diagnosis, and Management of Takayasu Arteritis: A Review of Current Advances

Takayasu arteritis (TA) is a rare, chronic, inflammatory vasculitis that primarily affects large arteries, causing significant morbidity and mortality. This review provides an overview of the pathophysiology, diagnosis, and management of TA based on current advances in the field. TA is characterized by autoimmune-mediated inflammation, vascular remodeling, and endothelial dysfunction. The disease progresses through three stages (active, chronic, and healing phase) each presenting distinct clinical features. Diagnosis of TA can be challenging due to non-specific clinical manifestations and the lack of specific diagnostic tests. Various imaging modalities, such as angiography, ultrasound, and Doppler techniques, play a crucial role in the diagnosis of TA by visualizing arterial involvement and assessing disease extent. Management of TA involves a multidisciplinary approach, with disease-modifying anti-rheumatic drugs (DMARDs) as the cornerstone of medical therapy. Synthetic and biologic DMARDs are used to induce remission, control inflammation, and prevent complications. Non-pharmacologic interventions, such as resistance exercises and curcumin supplementation, show potential benefits. Invasive interventions, including endovascular therapy and open surgery, are used for managing vascular lesions. However, challenges remain in disease understanding and management, including the heterogeneity of disease presentation and the lack of standardized treatment guidelines. The future of TA management lies in precision medicine, utilizing biomarkers and molecular profiling to personalize treatment approaches and improve patient outcomes. Further research is needed to unravel the underlying mechanisms of TA and develop targeted therapies.

Arterial wall fibrosis in Takayasu arteritis and its potential for therapeutic modulation

Arterial wall damage in Takayasu arteritis (TAK) can progress despite immunosuppressive therapy. Vascular fibrosis is more prominent in TAK than in giant cell arteritis (GCA). The inflamed arterial wall in TAK is infiltrated by M1 macrophages [which secrete interleukin-6 (IL-6)], which transition to M2 macrophages once the inflammation settles. M2 macrophages secrete transforming growth factor beta (TGF-β) and glycoprotein non-metastatic melanoma protein B (GPNMB), both of which can activate fibroblasts in the arterial wall adventitia. Mast cells in the arterial wall of TAK also activate resting adventitial fibroblasts. Th17 lymphocytes play a role in both TAK and GCA. Sub-populations of Th17 lymphocytes, Th17.1 lymphocytes [which secrete interferon gamma (IFN-γ) in addition to interleukin-17 (IL-17)] and programmed cell death 1 (PD1)-expressing Th17 (which secrete TGF-β), have been described in TAK but not in GCA. IL-6 and IL-17 also drive fibroblast activation in the arterial wall. The Th17 and Th1 lymphocytes in TAK demonstrate an activation of mammalian target organ of rapamycin 1 (mTORC1) driven by Notch-1 upregulation. A recent study reported that the enhanced liver fibrosis score (derived from serum hyaluronic acid, tissue inhibitor of metalloproteinase 1, and pro-collagen III amino-terminal pro-peptide) had a moderate-to-strong correlation with clinically assessed and angiographically assessed vascular damage. In vitro experiments suggest the potential to target arterial wall fibrosis in TAK with leflunomide, tofacitinib, baricitinib, or mTORC1 inhibitors. Since arterial wall inflammation is followed by fibrosis, a strategy of combining immunosuppressive agents with drugs that have an antifibrotic effect merits exploration in future clinical trials of TAK.

Animal models for large vessel vasculitis - The unmet need

Our understanding of the pathogenesis of large vessel vasculitis (LVV) are mainly achieved by studying the arteries taken from temporal artery biopsy in giant cell arteries (GCA) or surgical or autopsy specimens in Takayasu arteritis (TAK). These artery specimens provide invaluable information about pathological changes in these conditions that GCA and TAK are similar but are distinctly different in immune cell infiltrate and distribution of inflammatory cells in anatomical locations. However, these specimens of established arteritis do not provide information of the arteritis initiation and early events which are impossible to obtain in human artery specimens. Animal models for LVV are needed but not available. Here, several approaches are proposed for experimentation to generate animal models to aid in delineating the interaction of immune reaction with arterial wall components.

Cardiovascular Disease in Large Vessel Vasculitis: Risks, Controversies, and Management Strategies

Takayasu's arteritis (TAK) and giant cell arteritis (GCA) are the 2 most common primary large vessel vasculitides (LVV). They share common vascular targets, clinical presentations, and histopathology, but target a strikingly different patient demographic. While GCA predominantly affects elderly people of northern European ancestry, TAK preferentially targets young women of Asian heritage. Cardiovascular diseases (CVD), including ischemic heart disease, cerebrovascular disease, aortic disease, and thromboses, are significantly increased in LVV. In this review, we will compare and contrast the issue of CVD in patients with TAK and GCA, with respect to prevalence, risk factors, and mechanisms of events to gain an understanding of the relative contributions of active vasculitis, vascular damage, and accelerated atherosclerosis. Controversies and possible mitigation strategies will be discussed.

A Case Report of Differential Diagnosis of Causes of Severe Valvular Heart Disease (Takayasu's Arteritis, Infective Endocarditis and Myxomatous Degeneration) with the Key Role of Histological and PCR Examination

Aortic valve lesion is a common and may have diverse causes, from degenerative, congenital and infectious diseases to autoimmune conditions. We present a rare case of Takayasu arteritis and severe heart lesion due to the myxomatous degeneration of the aortic and mitral valves associated with development of infective endocarditis (IE) complicated by abscess, fistula, valve perforation and recurrent acute decompensated heart failure in a young female patient. A combined use of histopathological and PCR analyses of valve tissues was critically important for differential diagnosis of the valve lesions, as it made it possible to identify the true cause of the disease. The presence of Takayasu arteritis has played an indirect role by creating conditions for the development of immunosuppression and determining the disease severity and its progression.

Clinical profile and outcome of large-vessel giant cell arteritis in Japanese patients: A single-centre retrospective cohort study

OBJECTIVES

Recent advances in imaging revealed that giant cell arteritis (GCA) is frequently associated with large vessel involvement (LVI), but they may also contribute to earlier diagnosis and treatment of LV-GCA. We aimed to compare the clinical characteristics of GCA with or without LVI and evaluate its association with clinical outcomes.

METHOD

We retrospectively reviewed the medical records of 36 patients with GCA in Kyoto University Hospital.

RESULTS

Eighteen patients each were assigned to the LVI(+) and LVI(-) groups. Five-year survival rates in the LVI(+) group were better than in the LVI(-) group (p = .034), while five-year relapse-free survival rates were similar between the groups (p = .75). The LVI(+) group required lower doses of glucocorticoid at month 6 (p = .036). Disease activity evaluated with the Birmingham Vasculitis Activity Score at disease onset was higher in the LVI(-) group (p = .014), and the Vasculitis Damage Index score examined at the last visit was higher in the LVI(-) group (p = .011).

CONCLUSION

GCA without LVI had more active disease, severer vascular damage, and worse survival, possibly because of ophthalmic complications and their greater glucocorticoid requirement. Our results revisit the impact of cranial manifestations on disease severity and morbidity.

Current Diagnosis and Management of Takayasu Arteritis

Takayasu arteritis (TA or TAK) is a chronic large vessel vasculitis with predilection to affect the aorta and its branches. The new 2022 ACR/EULAR classification criteria for Takayasu arteritis incorporated imaging characteristics as an absolute requirement. ESR and CRP fails in accuracy as disease activity markers. Pentraxin 3 appears to be a relatively superior biomarker, which correlates with ITAS 2010 as per several studies. PET-CT is also increasingly being studied for assessing disease activity with variable results. The management of TAK involves use of steroids with upfront steroid sparing immunosuppressive agents. MMF is one such conventional DMARD/immunosuppressant with good efficacy and better safety profile, as reported in various cohort studies. Tocilizumab is proved to be a rapid remission inducing agent in refractory Takayasu arteritis in observational studies. TNF inhibitors in many uncontrolled studies showed good responses, and there is a need for good RCTs for confirmation. JAK inhibitors have also been used with success in a few reports.

Takayasu Arteritis: JACC Focus Seminar 3/4

Takayasu arteritis is a rare idiopathic large-vessel vasculitis that typically affects young women. An early "prepulseless" stage is often missed, associated with nonspecific constitutional symptoms (fever, malaise, and weight loss) and elevated inflammatory markers. Unchecked disease progression leads to the "pulseless" stage, manifest clinically by missing pulses, vascular tenderness, and ischemic symptoms (limb claudication, dizziness, angina, and renovascular hypertension), and is characterized pathologically by arterial wall thickening and stenotic/occlusive lesions or aneurysm formation. Vascular complications (stroke, blindness, heart failure, and aneurysm rupture) could follow unless disease progression is halted by immunosuppressive therapy and critical lesions are palliated by timely endovascular therapy or open surgery. Early diagnosis, effective therapy, and lifelong surveillance for disease activity relapses and vascular disease progression are critical to successful long-term outcomes. The outlook for patients has improved significantly in recent years with the establishment of diagnostic and classification criteria, better investigational modalities, and more effective medical and invasive therapy.

Successful treatment of a patient with Takayasu's arteritis complicated with Crohn's disease with ustekinumab: A case report

A 17-year-old woman was referred to our department with fever, general malaise, and weight loss. She was diagnosed with Takayasu arteritis (TAK) and Crohn's disease (CD) following positron emission tomography-computed tomography (PET-CT) and colonoscopy, respectively. Serological human leukocyte antigen (HLA) typing revealed HLA-B52 positivity. Initial treatment with prednisolone (0.5mg/kg) was insufficient; therefore, ustekinumab and 5-aminosalicylic acid were added. This treatment achieved prednisolone free remission for both diseases, as confirmed by PET-CT and colonoscopy. Although treatment guidelines for TAK and CD have been previously established, treatment of patients with TAK with coexisting CD is controversial. Our case suggests that ustekinumab has the ability to achieve TAK remission in addition to its therapeutic effect on CD.

Outcome Measures and Biomarkers for Disease Assessment in Takayasu Arteritis

Takayasu arteritis (TAK) is a less common large vessel vasculitis where histopathology of involved arteries is difficult to access except during open surgical procedures. Assessment of disease activity in TAK, therefore, relies on surrogate measures. Clinical disease activity measures such as the National Institutes of Health (NIH) score, the Disease Extent Index in TAK (DEI.TAK) and the Indian TAK Clinical Activity Score (ITAS2010) inconsistently associate with acute phase reactants (APRs). Computerized tomographic angiography (CTA), magnetic resonance angiography (MRA), or color Doppler Ultrasound (CDUS) enables anatomical characterization of stenosis, dilatation, and vessel wall characteristics. Vascular wall uptake of 18-fluorodeoxyglucose or other ligands using positron emission tomography computerized tomography (PET-CT) helps assess metabolic activity, which reflects disease activity well in a subset of TAK with normal APRs. Angiographic scoring systems to quantitate the extent of vascular involvement in TAK have been developed recently. Erythrocyte sedimentation rate and C-reactive protein have a moderate performance in distinguishing active TAK. Numerous novel biomarkers are under evaluation in TAK. Limited literature suggests a better assessment of active disease by combining APRs, PET-CT, and circulating biomarkers. Validated damage indices and patient-reported outcome measures specific to TAK are lacking. Few biomarkers have been evaluated to reflect vascular damage in TAK and constitute important research agenda.

Whole Exome Sequencing Revealed Variants That Predict Pulmonary Artery Involvement in Patients with Takayasu Arteritis

Purpose

To conduct the first whole exome sequencing (WES) on Takayasu arteritis (TAK) to identify common and rare variants responsible for disease susceptibility.

Patients and Methods

A total of 200 patients and 1675 healthy controls from China were recruited for this study. Site-based association analysis for common variants and gene-based burden analysis for rare variants were conducted. A weighted genetic risk score (wGRS) was calculated for each patient with TAK based on the independent risk alleles identified in the association analyses. The ability of the patient wGRS to discriminate between different phenotypes was evaluated.

Results

In the site-based analysis, the top association signal was CCHCR1 (rs1265067, p = 8.27 × 10^-12, OR = 2.41), a proxy for HLA-B*52:01. HLA-DQB1 (rs9273902), HLA-DQB2 (rs34109750), and a haplotype block in the human leukocyte antigen (HLA) class III region (represented by rs3130618) also exhibited significant associations independently. In addition, four novel non-HLA susceptibility loci were identified: PRRT4, TLL2, LRP1B, and DLGAP2. Twelve independently associated single nucleotide polymorphisms were used to calculate the wGRS. TAK patients with a higher wGRS were found to have an increased risk of pulmonary artery involvement compared with those with a lower wGRS (p = 5.76 × 10^-7, OR = 13.92). The wGRS algorithm showed good predictive capability for pulmonary artery involvement in TAK (sensitivity, 92.1%; specificity, 59.9%). In the gene-based analysis, risk genes that reached exome-wide significance were not identified.

Conclusion

This WES study on TAK supports a previously reported association within the HLA region. Moreover, novel susceptibility loci were identified outside the HLA region. These risk alleles showed potential associations with pulmonary artery involvement in TAK. However, additional studies are warranted to verify our findings.

Advances in Takayasu arteritis: An Asia Pacific perspective

Takayasu Arteritis (TA) is a rare form of chronic granulomatous large vessel vasculitis that is more common in Asia compared to other parts of the world. There have been several developments in the field of Takayasu arteritis in relation to genetics, classification, clinical features, imaging, disease activity assessment and management and much of these works have been done in the Asia Pacific region. We will be discussing selected few in the current review.

Comparing treatment options for large vessel vasculitis

INTRODUCTION

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are the major forms of large vessel vasculitis (LVV).Glucocorticoids represent the cornerstone of LVV treatment, however, relapses and recurrences frequently occur when they are tapered or stopped, determining a prolonged exposure to glucocorticoids and a subsequent increased risk of glucocorticoid-related side effects. Therefore, conventional and biologic immunosuppressive drugs have been proposed to obtain a glucocorticoid-sparing effect.

AREAS COVERED

We searched PubMed® using the keywords "giant cell arteritis/drug therapy" and "Takayasu Arteritis/drug therapy" OR "Takayasu Arteritis/surgery". This review focuses on the management of LVV, based on the current evidence while highlighting the differences in terms of therapeutic management of TAK and GCA.

EXPERT OPINION

Conventional disease modifying anti-rheumatic drugs, such as methotrexate or azathioprine, are recommended in association to glucocorticoids for selected GCA and all TAK patients. Two randomized placebo-controlled trials recently demonstrated the efficacy of tocilizumab in reducing relapses and cumulative prednisone dosage in GCA patients with newly diagnosed or relapsing disease. Observational evidence and two small randomized controlled trials support the use of TNF-alpha inhibitors and tocilizumab as glucocorticoid-sparing agents in relapsing TAK, albeit high-quality evidence regarding the management of TAK is still lacking.

Vasculitogenic T Cells in Large Vessel Vasculitis

Vasculitis is an autoimmune disease of unknown etiology that causes inflammation of the blood vessels. Large vessel vasculitis is classified as either giant cell arteritis (GCA), which occurs exclusively in the elderly, or Takayasu arteritis (TAK), which mainly affects young women. Various cell types are involved in the pathogenesis of large vessel vasculitis. Among these, dendritic cells located between the adventitia and the media initiate the inflammatory cascade as antigen-presenting cells, followed by activation of macrophages and T cells contributing to vessel wall destruction. In both diseases, naive CD4⁺ T cells are polarized to differentiate into Th1 or Th17 cells, whereas differentiation into regulatory T cells, which suppress vascular inflammation, is inhibited. Skewed T cell differentiation is the result of aberrant intracellular signaling, such as the mechanistic target of rapamycin (mTOR) or the Janus kinase signal transducer and activator of transcription (JAK-STAT) pathways. It has also become clear that tissue niches in the vasculature fuel activated T cells and maintain tissue-resident memory T cells. In this review, we outline the most recent understanding of the pathophysiology of large vessel vasculitis. Then, we provide a summary of skewed T cell differentiation in the vasculature and peripheral blood. Finally, new therapeutic strategies for correcting skewed T cell differentiation as well as aberrant intracellular signaling are discussed.

Perspectives of JAK Inhibitors for Large Vessel Vasculitis

Vasculitis is an inflammation of the blood vessels caused by autoimmunity and/or autoinflammation, and recent advances in research have led to a better understanding of its pathogenesis. Glucocorticoids and cyclophosphamide have long been the standard of care. However, B-cell depletion therapy with rituximab has become available for treating antineutrophil cytoplasmic antibody-associated vasculitis (AAV). More recently, avacopan, an inhibitor of the complement 5a receptor, was shown to have high efficacy in remission induction against AAV. Thus, treatment options for AAV have been expanded. In contrast, in large vessel vasculitis (LVV), including giant cell arteritis and Takayasu arteritis, tocilizumab, an IL-6 receptor antagonist, was shown to be effective in suppressing relapse and has steroid-sparing effects. However, the relapse rate remains high, and other therapeutic options have long been awaited. In the last decade, Janus kinase (JAK) inhibitors have emerged as therapeutic options for rheumatoid arthritis (RA). Their efficacy has been proven in multiple studies; thus, JAK inhibitors are expected to be promising agents for treating other rheumatic diseases, including LVV. This mini-review briefly introduces the mechanism of action of JAK inhibitors and their efficacy in patients with RA. Then, the pathophysiology of LVV is updated, and a rationale for treating LVV with JAK inhibitors is provided with a brief introduction of our preliminary results using a mouse model. Finally, we discuss the newly raised safety concerns regarding JAK inhibitors and future perspectives for treating LVV.

The prevalence of sacroiliitis on abdominal MRI examinations of patients with Takayasu arteritis

BACKGROUND

Takayasu arteritis (TA), a systemic large-vessel vasculitis, was reported to have high incidence of spondyloarthropathy.

PURPOSE

To evaluate the prevalence of inflammatory sacroiliitis in patients with TA that underwent abdominal/pelvic magnetic resonance imaging (MRI) examinations as part of their vasculitis work-up.

MATERIAL AND METHODS

Consecutive abdominal/pelvic MRI examinations of 34 patients with TA fulfilling the 1990 ACR criteria and 34 age- and gender-matched controls performed between 2008 and 2020 were retrospectively reviewed for the presence sacroiliitis. The presence of active and structural lesions was scored twice (with a one-month interval between reads) by one reader. Structural lesions were also evaluated on computed tomography, when available, and correlated to MRI findings. Clinical data were extracted from the patients' clinical files. MRI scores were compared between the study and control groups and correlated with the clinical data.

RESULTS

Sacroiliitis was evident in 11.7% of the TA group examinations compared to 0.3% in the control group (P = 0.6). Participants with TA had significantly more erosions and fat deposition compared to the control group (Study: 0.01/0.03, Control: 0/0, P = 0.03/0.003, respectively). However, mean sacroiliitis score was not significantly different (Study: 1.06, Control: 0.78, P = 0.015). Of the four patients with TA and sacroiliitis, 3 (75%) had a diagnosis of inflammatory bowel disease (IBD).

CONCLUSION

Sacroiliitis was detected in 11.7% of abdominal MRI examinations of patients with TA, 75% of which had associated IBD, suggesting that both IBD and sacroiliitis should be routinely screened in the TA population as their presence may influence treatment decisions.

Changes in Colonic Inflammation Related with Takayasu Arteritis during a 10-year Observation Period

Takayasu arteritis (TA) sometimes presents with colitis, which may be diagnosed as inflammatory bowel disease unclassified (IBDU) because of atypical or mixed findings of ulcerative colitis (UC) and Crohn's disease. We herein report an 18-year-old girl presenting with colitis with an occasional high fever eventually diagnosed as TA with IBDU. Colonic inflammation was initially discontinuous and stronger in the proximal colon, atypical of UC. However, over 10-year observation, the distribution of colonic inflammation varied and became UC-like. Variations in TA-related colonic inflammations over time have been unclear. Our long-term observation might help clarify the details of TA-related colonic inflammation.

Genetic variants involved in innate immunity modulate the risk of inflammatory bowel diseases in an understudied Malaysian population

BACKGROUND AND AIM

Inflammatory bowel diseases (IBD) are chronic gastrointestinal inflammatory conditions comprising two major subtypes: Crohn's disease (CD) and ulcerative colitis (UC). The incidence of IBD is increasing in Asian countries including Malaysia. The aim of this study was to determine whether 32 single nucleotide polymorphisms (SNPs) strongly associated with IBD from genome-wide association studies, performed mainly in Caucasian populations, are associated with IBD in a Malaysian population, correlating these findings with local and systemic inflammation.

METHODS

Selected SNPs were investigated in a Malaysian cohort comprising 36 IBD patients and 75 controls using customized matrix-assisted laser desorption ionization time-of-flight genotyping. Local mRNA and/or systemic protein levels of IL-10, IL-12, IL-22, IL-23, and TNF-α were measured in these same subjects.

RESULTS

ATG16L2 rs11235667 and LINC00824 rs6651252 was significantly associated with increased CD risk while IL12B rs56167332 was a significant protective factor. Three SNPs (SBNO2 rs2024092, CARD9 rs10781499, and rs17085007 between GPR12-USP12) were significantly associated with increased UC risk while NKX2-3 rs4409764 was a significant protective factor. After adjusting for age, gender, and ethnicity, SBNO2 rs2024092, ATG16L2 rs11235667, CARD9 rs10781499, and LINC00824 rs6651252 remained associated with IBD. Interestingly, the risk alleles of IL10 rs3024505, CARD9 rs1078149, and IL12 rs6556412 were associated with higher levels of IL-10, IL-22, and IL-23 in these same subjects, respectively.

CONCLUSIONS

This study identified eight SNPs associated with IBD and/or its subtypes in the Malaysia population, significantly advancing our understanding of the genetic contribution to IBD in this understudied population. Three of these SNPs modulated relevant cytokine levels and thus, may directly contribute to IBD pathogenesis.

Concurrent Takayasu Arteritis and Vascular Ehlers–Danlos Syndrome: A Case Report

Takayasu arteritis (TAK) is a rare primary systemic inflammatory vasculopathy. It is classified as a large-vessel vasculitis and is known to cause inflammatory aneurysms and vascular stenosis. Vascular Ehlers–Danlos syndrome (vEDS) is an autosomal dominant condition known to cause multiple aneurysms and arterial dissection at a young age owing to a mutation in the gene for type III collagen, COL3A1. Here, we present a case of TAK associated with vEDS with the development of multi-organ infarction of the brain, kidney, and spleen owing to multiple arterial aneurysms and stenosis of the internal carotid artery. The patient was successfully treated using anti-inflammatory agents, glucocorticoids, and tocilizumab with the addition of interventional radiology. In our case, a high inflammatory response led to vasculitis being the main cause of the disease with concurrent vEDS. When patients develop multiple aneurysms, stenosis, and dissections leading to multiple organ infarctions, a systemic differential diagnosis to consider concurrent vasculitis syndrome and non-inflammatory vasculopathy, including hereditary disorders, is important even with time constraints.

Large-vessel vasculitis

Large-vessel vasculitis (LVV) manifests as inflammation of the aorta and its major branches and is the most common primary vasculitis in adults. LVV comprises two distinct conditions, giant cell arteritis and Takayasu arteritis, although the phenotypic spectrum of primary LVV is complex. Non-specific symptoms often predominate and so patients with LVV present to a range of health-care providers and settings. Rapid diagnosis, specialist referral and early treatment are key to good patient outcomes. Unfortunately, disease relapse remains common and chronic vascular complications are a source of considerable morbidity. Although accurate monitoring of disease activity is challenging, progress in vascular imaging techniques and the measurement of laboratory biomarkers may facilitate better matching of treatment intensity with disease activity. Further, advances in our understanding of disease pathophysiology have paved the way for novel biologic treatments that target important mediators of disease in both giant cell arteritis and Takayasu arteritis. This work has highlighted the substantial heterogeneity present within LVV and the importance of an individualized therapeutic approach. Future work will focus on understanding the mechanisms of persisting vascular inflammation, which will inform the development of increasingly sophisticated imaging technologies. Together, these will enable better disease prognostication, limit treatment-associated adverse effects, and facilitate targeted development and use of novel therapies.

An Update on Childhood-Onset Takayasu Arteritis

Takayasu Arteritis (TAK) is a rare large vessel vasculitis affecting the aorta and its major branches. The heterogeneous and often severe clinical manifestations result from systemic and local inflammation as well as end-organ ischemia. Disease flares are common and contribute to accrued damage over time with significant morbidity and mortality. Newer understanding of the pathogenesis in TAK has paved the way for the use of pathway targeting agents such as tumor necrosis factor (TNF)α- or interleuking (IL)-6-inhibitors with improved disease control. Nevertheless, long-term data are lacking, particularly in children; prognosis often remains guarded and the disease burden high. This article aims at providing a comprehensive review of childhood-onset TAK with a focus on recent publications.

Establishing Clinical Remission Criteria and the Framework of a Treat-To-Target Algorithm for Takayasu arteritis: Results of a Delphi Exercise Carried out by an Expert Panel of the Japan Research Committee of the Ministry of Health, Labour, and Welfare for intractable vasculitis

OBJECTIVE

To develop a proposal for remission criteria and a framework for a treat-to-target (T2T) algorithm for Takayasu arteritis (TAK).

METHODS

A study group of the large-vessel vasculitis group of the Japanese Research Committee of the Ministry of Health, Labour, and Welfare for Intractable Vasculitis (JPVAS) consists of 10 rheumatologists, 5 cardiologists, 1 nephrologist, 1 vascular surgeon, 1 cardiac surgeon, and 2 pediatric rheumatologists. A Delphi survey of remission criteria items was circulated among the study group over 4 reiterations. To develop the T2T algorithm, the study group conducted four face-to-face meetings and two rounds of Delphi together with 3 patients.

RESULTS

Initial literature review resulted in a list of 117 candidate items for remission criteria, of which 56 items with a mean score of ≥4 (0-5) were extracted including disease activity domains and treatment/comorbidity domains. The study group provided six overarching principles for the T2T algorithm, two recommendations on treatment goals, five on evaluation of disease activity and imaging findings including PET-CT, and two on treatment intensification.

CONCLUSIONS

We developed a T2T algorithm and proposals for standardized remission criteria by means of a Delphi exercise. These will guide future evaluation of different TAK treatment regimens.

A susceptibility locus in the IL12B but not LILRA3 region is associated with vascular damage in Takayasu arteritis

HLA-B*52 is an established genetic factor in Takayasu arteritis (TAK). Recently, single nucleotide polymorphisms (SNPs) in IL12B (rs6871626) and LILRA3 (rs103294) were newly identified as non-HLA susceptibility loci in TAK. Here, we examined how these SNPs contribute to clinical characteristics and vascular damage in TAK. We retrospectively reviewed the medical records of 99 TAK patients enrolled in our previous genome-wide association study, and whose genotypes for IL12B rs6871626, LILRA3 rs103294, and HLA-B*52 were available. Incidence of aortic regurgitation (AR) was significantly associated with the A allele (risk allele) of IL12B rs6871626 (CC 42%, AC 61%, AA 81%; p = 0.0052; odds ratio [OR] 2.45), as well as with the incidence of hypertension (p = 0.049; OR 1.82) and the proportion of patients who underwent aortic valve replacement (p = 0.023; OR 3.64). Regarding vascular damage, there was positive correlation between the Takayasu Arteritis Damage Score and the A allele of IL12B rs6871626 (CC 3.42 ± 2.71, AC 4.06 ± 3.25, AA 6.00 ± 2.81; p = 0.0035; β = 1.35) and between the Vasculitis Damage Index and the A allele (CC 3.47 ± 1.98, AC 4.33 ± 2.40, AA 5.37 ± 2.22; p = 0.0054; β = 0.96). Contrarily, no correlation was found between LILRA3 rs103294 and vascular damage. In the present study, IL12B rs6871626 was associated with vascular damage in TAK, whereas LILRA3 rs103294 was not. Genotyping of IL12B rs6871626 may help to identify patients at risk of disease progression.

Polymorphisms in TNFAIP3, but not in STAT4, BANK1, BLK, and TNFSF4, are associated with susceptibility to Takayasu arteritis

BACKGROUND

Takayasu arteritis (TAK) is considered a rare disease characterized by nonspecific inflammation of the large arteries, especially the aorta and its major branches. Because TAK is an autoimmune disease (AD), it could share susceptibility loci with other pathologies such as systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA), among others. Widely explored polymorphisms in non-HLA genes, including TNFAIP3, STAT4, TNFSF4, BANK1, and BLK have been consistently associated with both SLE and RA, but they have not been evaluated in TAK.

OBJECTIVE

The aim of our study was to investigate whether TNFAIP3, STAT4, BANK1, BLK, and TNFSF4 polymorphisms are associated with susceptibility to TAK.

METHODS

The TNFAIP3 rs2230926T/G and rs5029924C/T, STAT4 rs7574865G/T, BANK1 10516487G/A, BLK rs2736340T/C, rs13277113A/G, and TNFS4 rs2205960G/T polymorphisms were genotyped in 101 cases and 276 controls by using a TaqMan SNP genotyping assay. An association analysis was performed.

RESULTS

The TNFAIP3 rs2230926T/G and rs5029924C/T polymorphisms were in complete linkage disequilibrium and turned out to be risk factors for TAK (OR = 4.88, p = 0.0001). The STAT4, BANK1, BLK, and TNFSF4 polymorphisms were not associated with the disease.

CONCLUSIONS

This is the first study documenting an association of TNFAIP3 rs2230926T/G and rs5029924C/T with TAK. Our results provide new information on the genetic bases of TAK.

Vasculitis therapy refines vasculitis mechanistic classification

The primary vasculitides constitute a heterogeneous group of immune mediated diseases of incompletely understood pathogenesis currently classified by the size of blood vessels affected (Chapel Hill classification). In recent years, several drugs with well-characterized immunological targets have been tested in clinical trials in large vessel vasculitis and small vessel vasculitis. Such trials provide "reverse translational" or bedside to bench information about underlying pathogenic mechanisms. Therefore, the aim of this systematic literature review was to examine the evidence base for a more refined mechanistic immunological classification of vasculitis. A total of 40 studies (20 randomized controlled trials (RCTs), 16 prospective studies, 1 retrospective cohort study and 3 case series) were included for full qualitative assessment. RCTs concerning biologic therapy for large vessel vasculitis mainly supports interleukin 6 receptor inhibition (tocilizumab). RCTs concerning biologic therapy for granulomatosis with polyangiitis and microscopic polyangiitis mainly support anti-CD20 treatment (rituximab) and complement inhibition with a small molecule C5a receptor antagonist (avacopan) is an emerging treatment option. The biologic treatment of eosinophilic granulomatosis with polyangiitis is centered around interleukin 5 inhibition (mepolizumab). Studies on tumor necrosis factor alpha inhibition (adalimumab, infliximab, and etanercept) showed negative results in giant cell arteritis but some effect in Takayasu arteritis. Taken together, clinical studies with cytokine and cell specific drugs are dissecting the heterogeneous immunopathogenic mechanisms of vasculitis and support a mechanistic immunological classification. Especially, cytokine antagonism is pointing towards immunological distinctions between eosinophilic granulomatosis with polyangiitis and granulomatosis with polyangiitis/microscopic polyangiitis and differences between giant cell arteritis and Takayasu arteritis.

Innate and Adaptive Immunity in Giant Cell Arteritis

Autoimmune diseases can afflict every organ system, including blood vessels that are critically important for host survival. The most frequent autoimmune vasculitis is giant cell arteritis (GCA), which causes aggressive wall inflammation in medium and large arteries and results in vaso-occlusive wall remodeling. GCA shares with other autoimmune diseases that it occurs in genetically predisposed individuals, that females are at higher risk, and that environmental triggers are suspected to beget the loss of immunological tolerance. GCA has features that distinguish it from other autoimmune diseases and predict the need for tailored diagnostic and therapeutic approaches. At the core of GCA pathology are CD4⁺ T cells that gain access to the protected tissue niche of the vessel wall, differentiate into cytokine producers, attain tissue residency, and enforce macrophages differentiation into tissue-destructive effector cells. Several signaling pathways have been implicated in initiating and sustaining pathogenic CD4⁺ T cell function, including the NOTCH1-Jagged1 pathway, the CD28 co-stimulatory pathway, the PD-1/PD-L1 co-inhibitory pathway, and the JAK/STAT signaling pathway. Inadequacy of mechanisms that normally dampen immune responses, such as defective expression of the PD-L1 ligand and malfunction of immunosuppressive CD8⁺ T regulatory cells are a common theme in GCA immunopathology. Recent studies are providing a string of novel mechanisms that will permit more precise pathogenic modeling and therapeutic targeting in GCA and will fundamentally inform how abnormal immune responses in blood vessels lead to disease.

Identification of susceptibility loci for Takayasu arteritis through a large multi-ancestral genome-wide association study

Takayasu arteritis is a rare inflammatory disease of large arteries. We performed a genetic study in Takayasu arteritis comprising 6,670 individuals (1,226 affected individuals) from five different populations. We discovered HLA risk factors and four non-HLA susceptibility loci in VPS8, SVEP1, CFL2, and chr13q21 and reinforced IL12B, PTK2B, and chr21q22 as robust susceptibility loci shared across ancestries. Functional analysis proposed plausible underlying disease mechanisms and pinpointed ETS2 as a potential causal gene for chr21q22 association. We also identified >60 candidate loci with suggestive association (p < 5 × 10^-5) and devised a genetic risk score for Takayasu arteritis. Takayasu arteritis was compared to hundreds of other traits, revealing the closest genetic relatedness to inflammatory bowel disease. Epigenetic patterns within risk loci suggest roles for monocytes and B cells in Takayasu arteritis. This work enhances understanding of the genetic basis and pathophysiology of Takayasu arteritis and provides clues for potential new therapeutic targets.

Clinical characteristics and outcomes of chronic heart failure in adult Takayasu arteritis: A cohort study of 163 patients

BACKGROUND

Chronic heart failure (CHF) is a serious complication and a major cause of mortality in patients with Takayasu arteritis (TA). We aimed to explore the clinical features and long-term outcomes in TA patients with CHF.

METHODS AND RESULTS

Adult TA patients admitted to our hospital between January 2009 to April 2018 were classified as HF and non-HF group. The adverse events were defined as a composite of all-cause mortality and hospitalization for HF. The outcome of the HF-group was further analyzed. A total of 61 HF patients and 102 non-HF patients were identified. In the HF group, the median age at assessment was 41.9 years, and female was predominant (82.0%). The multivariable logistic regression model revealed that pulmonary hypertension, aortic regurgitation, mitral regurgitation, level albumin, and uric acid were independently associated with CHF. After a median follow-up of 1347 days, 25 adverse events occurred in HF patients, and the 5-year event-free rate was 54.7%. The Cox model showed that coronary artery involvement, aortic regurgitation, without interventional treatment were related to adverse events.

CONCLUSIONS

The 5-year event-free rate was not satisfying. Aggressive intervention may decreased the likelihood of adverse events in patients with CHF.

Treatment of Giant Cell Arteritis and Takayasu Arteritis-Current and Future

Purpose of Review

Guidelines for the management of large vessel vasculitides have been recently updated by several scientific societies. We have evaluated the current recommendations for treatment of giant cell arteritis (GCA) and Takayasu arteritis (TA) and addressed potential future therapeutic strategies.

Recent Findings

While glucocorticoids (GCs) remain the gold standard for induction of remission, many patients relapse and acquire high cumulative GC exposure. Thus, GC-sparing therapies such as methotrexate are recommended for selected patients with GCA and all patients with TA. Recent high-quality evidence shows that tocilizumab is an effective GC-sparing agent in GCA. Non-biologic and biologic immunomodulators also appear to have GC-sparing properties in TA.

Summary

Tocilizumab is now considered to be part of the standard treatment for GCA, particularly with relapsing disease, but questions on its use such as length of treatment and monitoring of disease activity remain open. High-quality evidence to guide treatment of TA is still lacking.

Cellular Signaling Pathways in Medium and Large Vessel Vasculitis

Autoimmune and autoinflammatory diseases of the medium and large arteries, including the aorta, cause life-threatening complications due to vessel wall destruction but also by wall remodeling, such as the formation of wall-penetrating microvessels and lumen-stenosing neointima. The two most frequent large vessel vasculitides, giant cell arteritis (GCA) and Takayasu arteritis (TAK), are HLA-associated diseases, strongly suggestive for a critical role of T cells and antigen recognition in disease pathogenesis. Recent studies have revealed a growing spectrum of effector functions through which T cells participate in the immunopathology of GCA and TAK; causing the disease-specific patterning of pathology and clinical outcome. Core pathogenic features of disease-relevant T cells rely on the interaction with endothelial cells, dendritic cells and macrophages and lead to vessel wall invasion, formation of tissue-damaging granulomatous infiltrates and induction of the name-giving multinucleated giant cells. Besides antigen, pathogenic T cells encounter danger signals in their immediate microenvironment that they translate into disease-relevant effector functions. Decisive signaling pathways, such as the AKT pathway, the NOTCH pathway, and the JAK/STAT pathway modify antigen-induced T cell activation and emerge as promising therapeutic targets to halt disease progression and, eventually, reset the immune system to reestablish the immune privilege of the arterial wall.

Pathogenesis of Giant Cell Arteritis and Takayasu Arteritis-Similarities and Differences

PURPOSE OF REVIEW

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are auto-inflammatory and autoimmune diseases with a highly selective tissue tropism for medium and large arteries. In both diseases, CD4⁺ T cells and macrophages form granulomatous lesions within the arterial wall, a tissue site normally protected by immune privilege. Vascular lesions can be accompanied by an extravascular component, typically an intense hepatic acute phase response that produces well-known laboratory abnormalities, e.g., elevated ESR and CRP. It is unclear whether GCA and TAK lie on a spectrum of disease or whether they represent fundamentally different disease processes.

RECENT FINDINGS

GCA and TAK share many clinical features, but there are substantial differences in genetics, epidemiology, disease mechanisms, response to treatment, and treatment complications that give rise to different disease trajectories. A significant difference lies in the composition of the wall-infiltrating immune cell compartment, which in TAK includes a significant population of CD8⁺ T cells as well as natural killer cells, specifying disparate disease effector pathways mediating tissue damage and vessel wall remodeling. Despite the similarities in tissue tropism and histomorphology, GCA and TAK are two distinct vasculitides that rely on separate disease mechanisms and require disease-specific approaches in diagnosis and management.

Long-term outcomes of refractory Takayasu arteritis patients treated with biologics including ustekinumab

OBJECTIVES

Biologics have been used to treat refractory Takayasu arteritis (TAK), but their efficacy and safety have not been sufficiently evaluated.

METHODS

We extracted clinical information from medical records for TAK patients who were treated with biologics including ustekinumab (UST) at Kyoto University Hospital. We also analysed the patient's genetic backgrounds.

RESULTS

Of 163 cases, 12 (7.4%) were treated with infliximab, tocilizumab, or UST (n = 3). Erythrocyte sedimentation rate (ESR), C-reactive protein levels (CRP), and prednisolone (PSL) dose were significantly decreased 12 months after the initiation of biologics. When compared with the 15 patients who were only treated with immunosuppressants (IS group), the change in ESR from baseline was significantly lower in the biologics group than in the IS group (-2 mm/h, p = .005). The proportion of patients with HLA-B*52 and the risk-type alleles of the SNP were similar in both groups. Among the biologics, TCZ showed the highest continuation rate. UST exhibited marginal effects on reducing ESR, CRP levels, and PSL dose. No adverse events were observed in patients with UST for approximately 3 years.

CONCLUSIONS

Biological treatments resulted in a reduction in inflammatory markers and PSL dose in refractory TAK patients.

Roles of cytotoxic lymphocytes and MIC/LILR families in pathophysiology of Takayasu arteritis

Takayasu arteritis (TAK) affects the aorta and its primary branches, mainly in young women. In its advanced stages, it can cause severe complications, such as cerebral infarction, impaired vision, and valvular heart diseases. In the aortic tissue of TAK, there is increased infiltration of cytotoxic lymphocytes, such as natural killer (NK) cells and CD8⁺T cells, and enhanced expression of accessory molecules, such as major histocompatibility complex (MHC) and MHC class I chain-related gene (MIC) family. Genome-wide association studies on TAK have identified susceptibility genes, such as IL-12p40, MICA, MICB, leukocyte immunoglobulin-like receptor A3 (LILRA3), and LILRB3. Other studies have also shown their involvement in the pathophysiology of TAK. In addition, we reported the importance of NK cells by enhancer enrichment analysis. These results suggest that the gene polymorphisms that potentially upregulate the expression of cytokines and accessory molecules, which contribute to the activation of cytotoxic lymphocytes, are associated with the development of TAK. Based on these results, new molecular targeted therapies look promising.

[Treatment of Takayasu arteritis]

Despite advances in the diagnosis and treatment, the mortality rate of Takayasu arteritis (TAK) is still elevated even today. The diagnosis is often made after a long time delay and the course of the disease is characterized by progressive structural vascular lesions. Recently, new recommendations for the management of large vessel vasculitis were published by the European League Against Rheumatism (EULAR). For induction of remission oral glucocorticoids (GC) are administered in an initial daily dose of 40-60 mg. As experience has shown that the cumulative GC demand in TAK is high, GC-sparing treatment with moderately potent immunosuppressants, such as methotrexate, azathioprine and mycophenolate mofetil is recommended from the time of initial diagnosis. In cases of a relapsing course, tocilizumab or tumor necrosis factor (TNF)-alpha inhibitors can be used as an additive off-label treatment. If vascular stenoses persist despite supposedly sufficient inflammation control and if these stenoses are symptomatic, vascular surgery or interventional treatment procedures can be indicated. Such revascularization or even surgical procedures for the treatment of aneurysms should be performed during phases of sufficient drug control of the vasculitis. In quite a few patients progressive vascular lesions continue to develop despite clinical and laboratory analytical remission. Due to the poor correlation of clinical symptoms and acute phase markers with the progression of vascular lesions, the distinction between active and inactive diseases is often a challenge in the clinical practice. Imaging studies can then support therapeutic decisions but are not yet formally and comprehensively validated in the long-term course of TAK.

Family-based genome-wide association study of leprosy in Vietnam

Leprosy is a chronic infectious disease of the skin and peripheral nerves with a strong genetic predisposition. Recent genome-wide approaches have identified numerous common variants associated with leprosy, almost all in the Chinese population. We conducted the first family-based genome-wide association study of leprosy in 622 affected offspring from Vietnam, followed by replication in an independent sample of 1181 leprosy cases and 668 controls of the same ethnic origin. The most significant results were observed within the HLA region, in which six SNPs displayed genome-wide significant associations, all of which were replicated in the independent case/control sample. We investigated the signal in the HLA region in more detail, by conducting a multivariate analysis on the case/control sample of 319 GWAS-suggestive HLA hits for which evidence for replication was obtained. We identified three independently associated SNPs, two located in the HLA class I region (rs1265048: OR = 0.69 [0.58-0.80], combined p-value = 5.53x10-11; and rs114598080: OR = 1.47 [1.46-1.48], combined p-value = 8.77x10-13), and one located in the HLA class II region (rs3187964 (OR = 1.67 [1.55-1.80], combined p-value = 8.35x10-16). We also validated two previously identified risk factors for leprosy: the missense variant rs3764147 in the LACC1 gene (OR = 1.52 [1.41-1.63], combined p-value = 5.06x10-14), and the intergenic variant rs6871626 located close to the IL12B gene (OR = 0.73 [0.61-0.84], combined p-value = 6.44x10-8). These results shed new light on the genetic control of leprosy, by dissecting the influence of HLA SNPs, and validating the independent role of two additional variants in a large Vietnamese sample.