Novel Th17 Lymphocyte Populations, Th17.1 and PD1+Th17, are Increased in Takayasu Arteritis, and Both Th17 and Th17.1 Sub-Populations Associate with Active Disease

Pediatric-onset Takayasu arteritis is associated with greater risk of mortality than adult-onset Takayasu arteritis-A systematic review with meta-analysis of observational cohort studies

A subset of Takayasu arteritis (TAK) has onset in the pediatric age group (≤18 years). The differences in mortality between pediatric-onset and adult-onset TAK are unclear. Therefore, we undertook a systematic review with meta-analysis to compare mortality risk in pediatric-onset with adult-onset TAK. Scopus, Pubmed (MEDLINE and Pubmed Central), recent conference abstracts, clinicaltrials.gov, and the Cochrane database were searched up to August 2023 for relevant studies. Five studies (all of moderate or high quality on the Newcastle Ottawa scale) were identified which had compared mortality between 151 pediatric-onset and 499 adult-onset TAK. Pediatric-onset TAK was associated with a significantly higher risk of death than adult-onset TAK (pooled risk ratio 2.27, 95% confidence interval 1.05 - 4.85, I2=0%). Cardiovascular disease and infections were the major causes of death in both pediatric-onset and adult-onset TAK. Sub-group analyses identified a greater mortality risk with pediatric-onset TAK in retrospective (but not prospective) studies and in studies of high quality (but not in those of moderate quality). Meta-regression did not reveal a significant influence of differences in sex distribution or age or the proportions of patients with pediatric-onset or adult-onset TAK on the pooled mortality risk. An increased mortality risk with pediatric-onset TAK on meta-analysis is consistent with more frequent severe organ manifestations of pediatric-onset TAK (heart failure, renal failure) when compared with adult-onset TAK. Future studies should systematically evaluate differences in the pathogenesis between pediatric-onset and adult-onset to understand the reasons for such observed differences in the mortality risk.

Th17 cytokines and factors modulating their activity in patients with pernicious anemia

The effects of specific cytokines produced by T cell subsets (such as Th1, Th2, and newly discovered Th17, Treg, Tfh, or Th22) are diverse, depending on interactions with other cytokines, distinct signaling pathways, phase of the disease, or etiological factor. The immunity equilibrium of the immune cells, such as the Th1/Th2, the Th17/Treg, and the Th17/Th1 balance is necessary for the maintenance of the immune homeostasis. If the balance of the T cells subsets is damaged, the autoimmune response becomes enhanced which leads to autoimmune diseases. Indeed, both the Th1/Th2 and the Th17/Treg dichotomies are involved in the pathomechanism of autoimmune diseases. The aim of the study was to determine the cytokines of Th17 lymphocytes as well as the factors modulating their activity in patients with pernicious anemia. The magnetic bead-based immunoassays used (Bio-Plex) allow simultaneous detection of multiple immune mediators from one serum sample. In our study, we showed that patients suffering from pernicious anemia develop the Th1/Th2 imbalance with a quantitative advantage of cytokines participating in Th1-related immune response, the Th17/Treg imbalance with a quantitative advantage of cytokines participating in Treg-related response, as well as the Th17/Th1 imbalance with a quantitative predominance of cytokines participating in Th1-related immune response. Our study results indicate that T lymphocytes and their specific cytokines play an role in the course of pernicious anemia. The observed changes may indicate the immune response to pernicious anemia or be an element of the pernicious anemia pathomechanism.

Systemic review and meta-analysis of the association between interleukin-10 and Takayasu arteritis

OBJECTIVE

The aim of this meta-analysis is to investigate the relationship between interleukin (IL)-10 levels and its polymorphism and Takayasu arteritis (TAK).

METHODS

Five databases including PubMed, Web of Science, Ovid, Sinomed and China National Knowledge Infrastructure (CNKI) were gone through from inception to March 31, 2022. Studies were screened according to the inclusion and exclusion criteria. Newcastle-Ottawa Scale (NOS) was applied to assess study quality. Strengths of association were evaluated by odds ratio (OR) and 95% CI. The T v. t (allele contrast), TT v. tt (homozygous contrast), Tt vs tt (heterozygous contrast), TT + Tt vs tt (dominant contrast) and TT vs Tt + tt (recessive contrast) models were adopted.

RESULTS

Seven studies were included. No significant relationship between IL-10 and TAK was detected in the included patients (P > 0.05). The levels of IL-10 were lower in the active group than those in the stable group, which was -0.47 (95% CI: -0.93, 0.00) (P = 0.05). No significant relationships between IL-10 and TAK were found under all contrasts for polymorphisms rs1800871, rs1800872 and rs1800896 (P > 0.05).

CONCLUSIONS

There was no significant difference in IL-10 levels between TAK patients and control subjects. The levels of IL-10 were lower in TAK patients in the active stage. There was no significant association between IL-10 gene polymorphisms and TAK. Further well-designed studies with larger sample sizes in patients with different stages are needed.

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.

Management of Takayasu arteritis

This review overviews the challenges in the assessment of disease activity, damage, and therapy of Takayasu arteritis (TAK). Recently developed disease activity scores for TAK are more useful for follow-up visits and require validation of cut-offs for active disease. A validated damage score for TAK is lacking. Computed tomography angiography (CTA), magnetic resonance angiography (MRA), and ultrasound enable the evaluation of vascular anatomy and arterial wall characteristics of TAK. 18-fluorodeoxyglucose (18-FDG) positron emission tomography (PET) visualizes arterial wall metabolic activity and complements the information provided by circulating C-reactive protein (CRP) levels. ESR and CRP alone moderately reflect TAK disease activity. TAK is corticosteroid-responsive but relapses upon tapering corticosteroids. Conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs) are the first-line maintenance agents, and tumor necrosis factor-alpha inhibitors, tocilizumab, or tofacitinib are second-line agents for TAK. Revascularization procedures for TAK should be used judiciously during periods of inactive disease.

The effectiveness of tocilizumab and its comparison with tumor necrosis factor alpha inhibitors for Takayasu Arteritis: A systematic review and meta-analysis

Takayasu arteritis (TAK) refractory to conventional disease-modifying anti-rheumatic drugs (DMARDs) is commonly treated with biologic DMARDs such as tocilizumab or tumor necrosis factor-alpha inhibitors (TNFi). The 2021 American College of Rheumatology (ACR) recommendations preferred TNFi to tocilizumab. Therefore, we conducted a systematic review with meta-analysis to assess the evidence base for tocilizumab in TAK by updating a previous systematic review on DMARDs in TAK through searches on MEDLINE, Pubmed Central, Scopus, major international Rheumatology conference abstracts, and clinical trial databases from January 2021 to November 2022. Thirty-five studies involving 1082 TAK [one randomized controlled trial (RCT), eleven controlled and twenty-one uncontrolled studies, most of moderate to high quality] had evaluated tocilizumab in TAK. The RCT of tocilizumab versus placebo failed to meet its primary end-point of superiority of tocilizumab on an intention-to-treat analysis (hazard ratio 0.41, 95%CI 0.15-1.10) but successfully met the secondary end-point of superiority on per-protocol analysis (hazard ratio 0.34, 95%CI 0.11-1.00). A meta-analysis of six studies identified similar rates of clinical remission [risk ratio (RR) tocilizumab vs TNFi 1.03, 95%CI 0.91-1.17)], angiographic stabilization (RR 1.00, 95%CI 0.72-1.40) or adverse events (RR 0.84, 95%CI 0.54-1.31) with tocilizumab or TNFi. A meta-analysis of three studies identified superior clinical response (RR 1.55, 95%CI 1.15-2.10) and adverse effect profile (RR 0.45, 95%CI 0.25-0.80) with tocilizumab than cyclophosphamide. Pooled data from uncontrolled studies identified clinical response in 85%(95%CI 79-91%) and angiographic stabilization in 82% (95%CI 68-94%). Our study suggests similar evidence for treating TAK with tocilizumab or TNFi, contrary to the ACR 2021 recommendations.

Design and Protocol for Beijing Hospital Takayasu Arteritis (BeTA) Biobank

BACKGROUND

Although hundreds of studies have been conducted, our understanding of the pathogenesis, indications for surgical intervention, and disease markers of Takayasu arteritis (TAK) are still limited. Collection of biological specimens, clinical data and imaging data will facilitate translational research and clinical studies. In this study, we aim to introduce the design and protocol for the Beijing Hospital Takayasu Arteritis (BeTA) Biobank.

METHODS

Based in the Department of Vascular Surgery of Beijing Hospital and Beijing Hospital Clinical Biological Sample Management Center, the BeTA Biobank is composed of clinical data and sample data from patients with TAK requiring surgical treatment. All clinical data of participants are collected, including demographic characteristics, laboratory tests, imaging results, operation information, perioperative complications, follow-up data, etc. Both blood samples including plasma, serum and cells, and vascular tissues or perivascular adipose tissue are collected and stored. These samples will promote the establishment of a multiomic database for TAK and help to identify disease markers and to explore potential targets for specific future drugs for TAK.

Impact of Geographic Location on Diagnosis and Initial Management of Takayasu Arteritis: A Tale of Two Cohorts from Italy and India

The present study compares disease characteristics, imaging modalities used, and patterns of treatment in two large cohorts of Takayasu arteritis (TAK) from Italy and India. Clinic files were retrospectively reviewed to retrieve information about initial choices of vascular imaging and immunosuppressive therapies. Unpaired t-tests compared means, and proportions were compared using Fisher’s exact test or Chi square test [Odds ratios (OR) with 95% confidence intervals (95%CI) calculated where appropriate]. The cohorts comprised 318 patients [Italy (n = 127), India (n = 191)] with similar delays to diagnosis. Ultrasound (OR Italy vs. India 9.25, 95%CI 5.02−17.07) was more frequently used in Italy and CT angiography in India (OR 0.32, 95%CI 0.20−0.51). Corticosteroid use was more prevalent and for longer duration in Italy. TAK from Italy had been more often treated with methotrexate, leflunomide or azathioprine, as opposed to tacrolimus in TAK from India (p < 0.05). Biologic or targeted synthetic disease-modifying agents were almost exclusively used in Italy. Survival on first immunosuppressive agent was longer from Italy than from India (log rank test p value 0.041). Considerable differences in the choice of initial vascular imaging modality and therapies for TAK from Italy and India could relate to prevalent socio-economic disparities. These should be considered while developing treatment recommendations for TAK.

Comparison of Presentation and Prognosis of Takayasu Arteritis with or without Stroke or Transient Ischemic Attack-A Retrospective Cohort Study

Takayasu arteritis (TAK) could cause a stroke or transient ischemic attack (TIA) in young individuals due to inflammatory vascular occlusion or intracerebral hemorrhage. We compared the clinical presentation, angiographic features, longitudinal patterns of disease activity, medical treatments, and survival in 34 TAK patients with stroke/TIA and 157 without stroke/TIA from a single-center retrospective cohort. TAK patients with stroke/TIA were older (p = 0.044) with a greater proportion of males (p = 0.022), more frequent vision loss (odds ratio (OR) for stroke/TIA vs. without stroke TIA 5.21, 95% CI 1.42-19.14), and less frequent pulse or blood pressure inequality (OR 0.43, 95% CI 0.19-0.96) than TAK patients without stroke/TIA. Hata's angiographic type IIa was more common in TAK patients with stroke/TIA (OR 11.00, 95%CI 2.60-46.58) and type V in TAK patients without stroke/TIA (OR 0.27, 95% CI 0.12-0.58). Cyclophosphamide was used more often in TAK patients with stroke/TIA (p = 0.018). Disease activity at baseline, 6, 12, and 24 months of follow-up was mostly similar for both groups. Risk of mortality was similar in TAK patients with or without stroke/TIA (hazard ratio unadjusted 0.76, 95% CI 0.15-3.99; adjusted for gender, age of disease onset, delay to diagnosis, baseline disease activity, and the number of conventional or biologic/targeted synthetic immunosuppressants used 1.38, 95% CI 0.19-10.20) even after propensity score-matched analyses. Stroke or TIA does not appear to affect survival in TAK patients adversely.

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.

Neuroinflammation: Extinguishing a blaze of T cells

Inflammation is a biological process that dynamically alters the surrounding microenvironment, including participating immune cells. As a well-protected organ surrounded by specialized barriers and with immune privilege properties, the central nervous system (CNS) tightly regulates immune responses. Yet in neuroinflammatory conditions, pathogenic immunity can disrupt CNS structure and function. T cells in particular play a key role in promoting and restricting neuroinflammatory responses, while the inflamed CNS microenvironment can influence and reshape T cell function and identity. Still, the contraction of aberrant T cell responses within the CNS is not well understood. Using autoimmunity as a model, here we address the contribution of CD4 T helper (Th) cell subsets in promoting neuropathology and disease. To address the mechanisms antagonizing neuroinflammation, we focus on the control of the immune response by regulatory T cells (Tregs) and describe the counteracting processes that preserve their identity under inflammatory challenges. Finally, given the influence of the local microenvironment on immune regulation, we address how CNS-intrinsic signals reshape T cell function to mitigate abnormal immune T cell responses.

Presentation and clinical course of pediatric-onset versus adult-onset Takayasu arteritis-a systematic review and meta-analysis

Takayasu arteritis (TAK) is a less common large-vessel vasculitis which can occur in either children or adults. However, differences between pediatric-onset and adult-onset TAK have not been systematically analyzed. We undertook a systematic review (pre-registered on PROSPERO, identifier CRD42022300238) to analyze differences in clinical presentation, angiographic involvement, treatments, and outcomes between pediatric-onset and adult-onset TAK. We searched PubMed (MEDLINE and PubMed Central), Scopus, major recent international rheumatology conference abstracts, Cochrane database, and clinicaltrials.gov, and identified seven studies of moderate to high quality comparing pediatric-onset and adult-onset TAK. Meta-analysis of 263 pediatric-onset and 981 adult-onset TAK suggested that constitutional features (fever, and in subgroup analyses, weight loss), hypertension, headache, and sinister features of cardiomyopathy, elevated serum creatinine, and abdominal pain were more frequent in pediatric-onset TAK, whereas pulse loss/pulse deficit and claudication (particularly upper limb claudication) were more frequent in adult-onset TAK. Hata's type IV TAK was more common in pediatric-onset TAK, and Hata's type I TAK in adult-onset TAK. Children with TAK also appeared to require more intense immunosuppression with more frequent use of cyclophosphamide, biologic DMARDs, tumor necrosis factor alpha inhibitors, and, in subgroup analyses, tocilizumab in pediatric-onset TAK than in adult-onset TAK. Surgical or endovascular procedures, remission, and risk of mortality were similar in both children and adults with TAK. No studies had compared patient-reported outcome measures between pediatric-onset and adult-onset TAK. Distinct clinical features and angiographic extent prevail between pediatric-onset and adult-onset TAK. Clinical outcomes in these subgroups require further study in multicentric cohorts.

Th17.1 lymphocytes: emerging players in the orchestra of immune-mediated inflammatory diseases

It is now well established that Th17 lymphocytes associate with myriad immune-mediated inflammatory diseases. Over the past one and a half decades, a subset of Th17 lymphocytes viz. Th17.1 lymphocytes has been identified in pre-clinical and clinical models of inflammatory rheumatic diseases. These lymphocytes secrete IL-17A (signature cytokine of Th17 lymphocytes) as well as IFN-γ (the signature cytokine of Th1 lymphocytes). They express the chemokine markers for Th1 (CXCR3) as well as Th17 (CCR6) lymphocytes. Th17.1 lymphocytes also express the drug efflux protein p-glycoprotein, which associates with resistance to corticosteroids and other immunosuppressive drugs. This narrative review overviews the evidence regarding Th17.1 lymphocytes in different inflammatory rheumatic diseases. It is now recognized that Th17.1 lymphocytes are increased in the synovial fluid of affected joints in rheumatoid arthritis (RA) and associate with poor treatment response to abatacept. Th17.1 lymphocytes from synovial fluid of RA are less responsive to immunosuppression than those from the peripheral blood. In sarcoidosis, Th17.1 lymphocytes are concentrated in mediastinal lymph nodes and alveolar lining. Such Th17.1 lymphocytes in sarcoidosis are the predominant source of IFN-γ in the sarcoid lung. Th17.1 lymphocytes are elevated in lupus and Takayasu arteritis and associate with disease activity. Future studies should evaluate isolated Th17.1 lymphocytes from peripheral blood or sites of pathology such as synovial fluid and assess their modulation with immunosuppressive therapy in vitro. The analysis of gene expression signature of isolated Th17.1 lymphocytes might enable the identification of newer therapeutic strategies specifically targeting these cell populations in inflammatory rheumatic diseases. Key Points • Th17.1 lymphocytes are a subset of Th17 lymphocytes secreting both IFN-γ and IL-17 • Th17.1 lymphocytes drive neutrophilic inflammation, granuloma formation, and corticosteroid resistance • Th17.1 lymphocytes are elevated in rheumatoid arthritis and sarcoidosis at sites of inflammation • Increased circulating Th17.1 lymphocytes have been identified in lupus and Takayasu arteritis and associate with active disease.

The Th17 Pathway in Vascular Inflammation: Culprit or Consort?

The involvement of IL-17A in autoimmune and inflammatory diseases has prompted the development of therapeutic strategies to block the Th17 pathway. Promising results came from their use in psoriasis and in ankylosing spondylitis. IL-17A acts on various cell types and has both local and systemic effects. Considering the premature mortality observed during chronic inflammatory diseases, IL-17A action on vascular cells was studied. Both in vitro and in vivo results suggest that this cytokine favors inflammation, coagulation and thrombosis and promotes the occurrence of cardiovascular events. These observations led to study the role of IL-17A in diseases characterized by vascular inflammation, namely allograft rejection and vasculitis. Increased circulating levels of IL-17A and histological staining reveal that the Th17 pathway is involved in the pathogenesis of these diseases. Vasculitis treatment faces challenges while the use of steroids has many side effects. Regarding results obtained in giant cell arteritis with IL-6 inhibitors, a cytokine involved in Th17 differentiation, the use of anti-IL-17 is a promising strategy. However, lessons from rheumatoid arthritis and multiple sclerosis must be learnt before targeting IL-17 in vasculitis, which may be culprit, consort or both of them.