Accumulation of lymphocytes, dendritic cells, and granulocytes in the aortic wall affected by Takayasu's disease

Effector CD4+ T-cell subsets in Takayasu arteritis-differences between the peripheral blood and the aorta

Takayasu arteritis (TAK) is a granulomatous vasculitis that affects large arteries. T cells are important in TAK pathophysiology as these cells orchestrate granulomatous infiltration in arteries. This study aims to evaluate effector CD4+ T cells in the peripheral blood and the aortic wall of TAK patients and to analyze associations with disease activity and therapy. We performed a longitudinal study including 30 TAK patients and 30 controls. CD3+ T cells, CD3+CD4- T cells, CD4+ T cells, and Th1, Th2, and Th17 cells were evaluated in peripheral blood by flow cytometry, and the expression of CD4, CD8, Tbet, GATA-3, and RORγT was analyzed in the aorta of six patients by immunohistochemistry. TAK patients presented lower CD3+ T cells and CD4+ T cells (P = 0.031 and P = 0.039, respectively) than controls. Patients with active disease and those in remission had higher proportions of Th17 cells than controls (P = 0.016 and P = 0.004, respectively). Therapy for TAK did not result in significant differences concerning CD4+ effector T-cell subpopulations. Disease duration correlated with the number and percentage of Th2 cells (rho = -0.610 and rho = -0.463, respectively) and with Th17 cells (rho = -0.365 and rho = -0.568). In the aorta, the expression of CD8 was higher than CD4, whereas GATA-3, Tbet, and RORγT were expressed in this order of frequency. In conclusion, TAK patients present an increased Th17 response in the peripheral blood regardless of disease activity, whereas in the aortic tissue CD8 cells and the Th2 response were predominant.

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.

Treatment efficacy and safety of adalimumab versus tocilizumab in patients with active and severe Takayasu arteritis: an open-label study

OBJECTIVE

This study aimed to compare the efficacy and safety of adalimumab (ADA) vs tocilizumab (TCZ) in patients with Takayasu arteritis (TAK).

METHODS

This was a randomized, controlled, open-label study. Forty patients with active and severe TAK were enrolled. They were treated with ADA (n = 21) combined with glucocorticoids (GCs) and MTX or TCZ (n = 19) combined with GCs and MTX. The planned follow-up duration was 12 months. The primary end point was the efficacy rate (ER) at 6 months. The secondary end points included ER at 9 and 12 months, relapse rate, GC tapering, adverse effects, and life quality changes during treatment.

RESULTS

In the intention-to-treat (ITT) population, the ER at 6 months was higher in the ADA group (85.71% vs 52.63%, P = 0.02). A similar direction of effect was noted in the per-protocol set (89.47% vs 62.50%, P = 0.06). The percentages of patients who achieved a GC dose of ≤10 mg/day at 6 months were similar between the ADA and TCZ groups (47.37% vs 43.75%, P = 0.83). The ERs at 9 and 12 months were similar between the two groups (P > 0.05). During the first 12 months of treatment, the relapse rate and adverse event incidence were comparable between the two groups (ADA vs TCZ: 9.52% vs 10.53%, P = 0.96; 38.10% vs 47.37%, P = 0.55, respectively).

CONCLUSION

ADA combined with GCs and MTX may be more efficacious than TCZ combined with GCs and MTX among patients with active and severe TAK.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT04300686.

The Contribution of Innate Immunity in Large-Vessel Vasculitis: Detangling New Pathomechanisms beyond the Onset of Vascular Inflammation

Large-vessel vasculitis (LVV) are autoimmune and autoinflammatory diseases focused on vascular inflammation. The central core of the intricate immunological and molecular network resides in the disruption of the "privileged immune state" of the arterial wall. The outbreak, initially primed by dendritic cells (DC), is then continuously powered in a feed-forward loop by the intimate cooperation between innate and adaptive immunity. If the role of adaptive immunity has been largely elucidated, knowledge of the critical function of innate immunity in LVV is still fragile. A growing body of evidence has strengthened the active role of innate immunity players and their key signaling pathways in orchestrating the complex pathomechanisms underlying LVV. Besides DC, macrophages are crucial culprits in LVV development and participate across all phases of vascular inflammation, culminating in vessel wall remodeling. In recent years, the variety of potential pathogenic actors has expanded to include neutrophils, mast cells, and soluble mediators, including the complement system. Interestingly, new insights have recently linked the inflammasome to vascular inflammation, paving the way for its potential pathogenic role in LVV. Overall, these observations encourage a new conceptual approach that includes a more in-depth study of innate immunity pathways in LVV to guide future targeted therapies.

The neutrophil: A key resourceful agent in immune‐mediated vasculitis

The term "vasculitis" refers to a group of rare immune-mediated diseases characterized by the dysregulated immune system attacking blood vessels located in any organ of the body, including the skin, lungs, and kidneys. Vasculitides are classified according to the size of the vessel that is affected. Although this observation is not specific to small-, medium-, or large-vessel vasculitides, patients show a high circulating neutrophil-to-lymphocyte ratio, suggesting the direct or indirect involvement of neutrophils in these diseases. As first responders to infection or inflammation, neutrophils release cytotoxic mediators, including reactive oxygen species, proteases, and neutrophil extracellular traps. If not controlled, this dangerous arsenal can injure the vascular system, which acts as the main transport route for neutrophils, thereby amplifying the initial inflammatory stimulus and the recruitment of immune cells. This review highlights the ability of neutrophils to "set the tone" for immune cells and other cells in the vessel wall. Considering both their long-established and newly described roles, we extend their functions far beyond their direct host-damaging potential. We also review the roles of neutrophils in various types of primary vasculitis, including immune complex vasculitis, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, Takayasu arteritis, and Behçet's disease.

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.

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.

Mast cells drive pathologic vascular lesions in Takayasu arteritis

BACKGROUND

Takayasu arteritis (TAK) is a large vessel vasculitis resulting in artery wall remodeling with segmental stenosis and/or aneurysm formation. Mast cells (MCs) are instrumental in bridging cell injury and inflammatory response.

OBJECTIVES

This study sought to investigate the contribution of MCs on vessel permeability, angiogenesis, and fibrosis in patients with TAK.

METHODS

MC activation and their tissue expression were assessed in sera and in aorta from patients with TAK and from healthy donors (HDs). In vivo permeability was assessed using a modified Miles assay. Subconfluent cultured human umbilic vein endothelial cells and fibroblasts were used in vitro to investigate the effects of MC mediators on angiogenesis and fibrogenesis.

RESULTS

This study found increased levels of MC activation markers (histamine and indoleamine 2,3-dioxygenase) in sera of patients with TAK compared with in sera of HDs. Marked expression of MCs was shown in aortic lesions of patients with TAK compared with in those of noninflammatory aorta controls. Using Miles assay, this study showed that sera of patients with TAK significantly increased vascular permeability in vivo as compared with that of HDs. Vessel permeability was abrogated in MC-deficient mice. MCs stimulated by sera of patients with TAK supported neoangiogenesis (increased human umbilic vein endothelial cell proliferation and branches) and fibrosis by inducing increased production of fibronectin, type 1 collagen, and α-smooth muscle actin by fibroblasts as compared to MCs stimulated by sera of HD.

CONCLUSIONS

MCs are a key regulator of vascular lesions in patients with TAK and may represent a new therapeutic target in large vessel vasculitis.

Overview of imaging in adult- and childhood-onset Takayasu arteritis

Takayasu Arteritis is an idiopathic large vessel vasculitis, that affects young adults and children and can lead to ischemia and end-organ damage. Vascular imaging is crucial for diagnosis, assessment of disease extent and management of the disease. In this article, we critically review evidence for the clinical use of the different imaging modalities conventional angiography, magnetic resonance imaging, computed tomography, Doppler ultrasound and ¹⁸fluorodeoxyglucose positron emission tomography. We thereby focus on their clinical applicability, challenges and specific use in children.

Efficacy of tocilizumab for refractory Takayasu arteritis: a retrospective study and literature review

To evaluate the efficacy and safety of tocilizumab (TCZ) in the treatment of refractory Takayasu arteritis (TAK). Eleven refractory TAK patients treated with TCZ at the First Affiliated Hospital of Anhui Medical University between 2017 July and 2020 December were respectively analyzed. We also respectively analyzed the studies on TCZ efficacy in patients with TAK, from PubMed/MEDLINE, Elsevier Science Direct between January 2010 and April 2021. The median age of 11 patients was 34(19–46) years. After 3 months of TCZ, a significant drop was found in median NIH (3[2–5] at baseline vs 1[0–2] after 6 months; p < 0.05), ITAS-2010 score (8.5[6–11] vs 6[1–10]; p < 0.05). One (9%) patient experienced relapse during TCZ treatment. After withdrawal of TCZ, one patient (9%) underwent relapse and nine patients (81%) were spared of GC use. In literature review, a total of 211 patients (mean age 35 years) were analyzed, including 80 (38%) Chinese and 169 females (80%). Among the 211 patients, (154 patients) 73% achieved remission after the last infusion of TCZ; TAK relapsed in 6% of patients during TCZ treatment and 5% of the TCZ patients after the withdrawal of TCZ. A total of 95 types of adverse events were observed in the literature. Infection was the most common adverse effect, occurring in 50% of patients. TCZ could serve as an efficacious and safe agent for refractory TAK.

Risk assessment model for heart failure in Chinese patients with Takayasu's arteritis

OBJECTIVES

We aimed to construct and validate a risk assessment model to identify risk factors for heart failure (HF) in patients with Takayasu's arteritis (TAK).

METHODS

Three hundred sixty-five patients with TAK were recruited in the East China Takayasu Arteritis Cohort from January 2012 to December 2019. Patients were assigned into training and validation sets following a 2:1 ratio according to the date of enrollment. Clinical characteristics were compared between heart failure (HF) and non-HF subgroups in the training set, and a risk assessment model for HF and its scoring algorithm was established based on logistic regression, which was tested in the validation set.

RESULTS

Among total of 74 (20.27%) TAK patients exhibited HF, and 55 cases (74.32%) were in the training set. The risk factors for HF of TAK patients included onset age >38 years, serum tumor necrosis factor (TNF)-α concentration >10 pg/ml, aortic valve involvement, coronary artery involvement, and pulmonary hypertension. We constructed the model without TNF-α (Model 1) and with TNF-α (Model 2). Patients in the training set with the score ≥ 3 appeared to be associated with an increased risk of HF with an area under curve (AUC) of 0.88 and 0.90 in Model 1 and Model 2 respectively. The AUC reached to 0.88 and 0.89 in the validation set that proved the accuracy of the model.

CONCLUSIONS

We presented a risk assessment model of HF in TAK, which may help clinicians alert the complication of HF in the patients with specifically cardiac impairments. Key Points • Heart failure was not rare in Chinese Takayasu's arteritis patients, and there were approximately 20% of patients with heart failure in ECTA cohort. • Cardiac involvements on echocardiography include pathological valvular and atrioventricular abnormalities. • The onset age >38 years, serum tumor necrosis factor (TNF)-α concentration >10 pg/ml, aortic valve involvement, coronary artery involvement, and pulmonary hypertension were risk factors for heart failure in Takayasu's arteritis patients. • We constructed the model without TNF-α (Model 1) and with TNF-α (Model 2). Patients with the risk assessment model score of ≥ 3 appeared to be associated with an increased risk of heart failure.

Role of Neutrophils in Systemic Vasculitides

Neutrophils and neutrophil extracellular traps (NETs) contribute to the pathogenesis of many autoimmune diseases, including vasculitis. Though neutrophils, and NETs, can break self-tolerance by being a source of autoantigens for autoantibodies in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, playing a key role in driving the autoimmune response, the role of neutrophils and NETs in large vessel vasculitis, including giant cell arteritis (GCA), is not well understood. In this review, we summarize the current insight into molecular mechanisms contributing to neutrophil-mediated pathology in small and medium vessel vasculitis, as well as provide potential translational perspectives on how neutrophils, and NETs, may partake in large vessel vasculitis, a rare disease entity of unclear pathogenesis.

Childhood-onset Takayasu Arteritis

Childhood-onset Takayasu Arteritis (cTAK) is a rare, large-vessel type of vasculitis seen in children, mainly affecting the aorta and its major branches. Clinical manifestations are often severe and arise as a result of systemic and local inflammation, along with end-organ ischemia. Disease flares are common and the disease burden is high, with a significant rate of morbidity and mortality. Recent advances in understanding the underlying disease pathobiology resulted in the use of pathway-targeting agents, such as TNF- or IL-6 inhibitors with improved disease control. Nonetheless, the prognosis often remains guarded and the accrued damage is significant. This review aims at summarizing the recent evidence and observations regarding this condition, with a focus on pediatric publications.

Discrepancies between vascular and systemic inflammation in large vessel vasculitis: an important problem revisited

A lack of absolute correlation between systemic inflammation parameters and ongoing vascular disease activity is an important problem in some patients with large vessel vasculitis, especially Takayasu arteritis (TAK). Systemic and vascular wall inflammation in TAK are obviously interrelated, but sometimes they may act independently. There are clear discrepancies between these two types of inflammation, including cytokine patterns and responses to treatment. Vascular and systemic inflammation may also be discordant in two subgroups of giant cell arteritis. The first subgroup is mainly characterized by severe systemic inflammation mostly associated with IL-6-driven immunity, while in the second subgroup there is less systemic inflammation but prominent neuro-ophthalmic ischaemic complications characterized mostly by IFN-γ-mediated effects. Although no definite boundaries exist, it may be suggested that the IL-6/Th17/IL-17 pathway primarily drives systemic inflammation while the IL-12/Th1/IFN-γ pathway dominates in vascular wall inflammation both in TAK and giant cell arteritis. Immunosuppressive treatment of TAK (especially corticosteroids) initially suppresses systemic inflammation, while longer treatment duration is required for the suppression of vascular inflammation. Therefore, evaluating only the systemic inflammation may be misleading. Vascular wall inflammation is currently evaluated using expensive imaging methods, which are not feasible for repetitive use. Although pentraxin-3 is superior to erythrocyte sedimentation rate and CRP, we need more reliable biomarkers to reflect vascular wall inflammation in patients with TAK.

Takayasu Arteritis

Takayasu arteritis is an idiopathic granulomatous vasculitis of the aorta and its main branches and it constitutes one of the more common vasculitides in children. Inflammation and intimal proliferation lead to wall thickening, stenotic or occlusive lesions, and thrombosis, while destruction of the elastica and muscularis layers originates aneurysms and dissection. Carotid artery tenderness, claudication, ocular disturbances, central nervous system abnormalities, and weakening of pulses are the most frequent clinical features. The diagnosis is usually confirmed by the observation of large vessel wall abnormalities: stenosis, aneurysms, occlusion, and evidence of increased collateral circulation in angiography, MRA or CTA imaging. The purpose of this revision is to address the current knowledge on pathogenesis, investigations, classification, outcome measures and management, and to emphasize the need for timely diagnosis, effective therapeutic intervention, and close monitoring of this severe condition.

Tertiary Lymphoid Organs in Takayasu Arteritis

Objective

The role of B cells in the pathogenesis of Takayasu arteritis (TA) is controversial. We aimed to study the presence of tertiary lymphoid organs (TLOs) in the aortic wall of TA patients.

Methods

Hematoxylin and eosin-stained sections from aorta specimens from patients with TA were screened for TLOs. The presence of B cell aggregates (CD20), follicular dendritic cells (FDCs, CD21), and high endothelial venules (HEVs, PNAd) was investigated by immunohistochemistry. Immune cells from the adventitial layer of one patient were characterized by flow cytometry. Demographic, medical history, laboratory, imaging, treatment, and follow-up data were extracted from medical records.

Results

Aorta specimens from Bentall procedures were available from seven patients (5 females, aged 22–57 years) with TA. Surgical treatment was performed at TA diagnosis (n = 4) or at a median of 108 months (84–156) after TA diagnosis. Disease was active at surgery in four patients according to NIH score. B cell aggregates-TLOs containing HEVs were observed in the adventitia of all but one patient. Of note, ectopic follicles containing CD21⁺ FDCs were found in all patients (4/4) with increased aortic ¹⁸F-fluoro-deoxyglucose (FDG) uptake before surgery but were absent in all but one patients (2/3) with no FDG uptake. In addition, flow cytometry analysis confirmed the accumulation of memory/germinal center-like B cells in the adventitial layer and showed the presence of antigen-experienced T follicular helper cells.

Conclusion

Ectopic lymphoid neogenesis displaying functional features can be found in the aortic wall of a subset of patients with active TA. The function of these local B cell clusters on the pathogenesis of TA remains to be elucidated.

[Pathogenesis of large vessel vasculitis]

Giant cell arteritis (GCA) and Takayasu's arteritis (TA) are two granulomatous vasculitis affecting large arteries that present specific epidemiological and clinical features. Their pathogenesis is not fully understood but major advances have been obtained during the last years, thus allowing the emergence of new therapeutic strategies. GCA and TA develop on a specific genetic background but share some similarities regarding the immunological pathways involved in their pathogenesis. The trigger of these diseases is not clearly identified but it is thought that an infectious agent could activate and lead to the maturation of dendritic cells that are localized in the adventitia of arteries. Then, the cells of the adaptative immune response are recruited and activated: CD4 T cells that polarize into Th1 and Th17 cells, cytotoxic CD8 T cells and Natural Killer cells. Furthermore, the T regulatory cells (Treg) are decreased both in GCA and TA. Humoral immune response seems also to be involved, especially in TA. Then, the cytokines produced by T lymphocytes (especially IL-17 and IFN-γ) trigger the recruitment and activation of monocytes and their differentiation into macrophages and multinuclear giant cells that produce IL-1β and IL-6 that are responsible for general symptoms of GCA and TA, and cytotoxic mediators and growth factors that trigger the remodeling of the arterial wall leading to aneurysms and ischemic manifestations of GCA an TA.

Vein graft failure

After the creation of an autogenous lower extremity bypass graft, the vein must undergo a series of dynamic structural changes to stabilize the arterial hemodynamic forces. These changes, which are commonly referred to as remodeling, include an inflammatory response, the development of a neointima, matrix turnover, and cellular proliferation and apoptosis. The sum total of these processes results in dramatic alterations in the physical and biomechanical attributes of the arterialized vein. The most clinically obvious and easily measured of these is lumen remodeling of the graft. However, although somewhat less precise, wall thickness, matrix composition, and endothelial changes can be measured in vivo within the healing vein graft. Recent translational work has demonstrated the clinical relevance of remodeling as it relates to vein graft patency and the systemic factors influencing it. By correlating histologic and molecular changes in the vein, insights into potential therapeutic strategies to prevent bypass failure and areas for future investigation are explored.

Dendritic cells and regulatory T cells in atherosclerosis

Although macrophages and other immune system cells, especially T cells, have been shown to play disease-promoting roles in atherosclerosis, less is known about the role of antigen presenting cells. Functional, immune stimulating dendritic cells (DCs) have recently been detected in aortic intima, the site of origin of atherosclerosis. We had compared DCs with macrophages in mice with experimental atherosclerosis, to clearly define cell types by developmental and functional criteria. This review summarizes recent advances in studies of DCs in humans and in mouse models of atherosclerosis, as well as providing a simple strategy to measure regulatory T (Treg) cells in the mouse aorta.

T cell costimulatory and coinhibitory pathways in vascular inflammatory diseases

A broad array of evidence indicates that T lymphocytes make significant contributions to vascular inflammation in the setting of atherosclerotic disease, hypertension, autoimmune vasculitis, and other disorders. Experimental data show that costimulatory and coinhibitory pathways involving molecules of the B7-CD28 and TNF–TNFR families regulate T cell responses that promote vascular disease. Antigen presenting cells (APCs) display both peptide–major histocompatibility complex antigen and costimulators or coinhibitors to T cells. Two major types of APCs, dendritic cells (DCs) and macrophages, are present in significant numbers in the walls of arteries affected by atherosclerosis and arteritis, and some DCs are present in normal arteries. Costimulatory and coinhibitory molecules expressed by these vascular APCs can contribute to the activation or inhibition of effector T cells within the arterial wall. Vascular DCs may also be involved in transport of antigens to secondary lymphoid organs, where they activate or tolerize naïve T cells, depending on the balance of costimulators and coinhibitors they express. Costimulatory blockade is already an approved therapeutic approach to treat autoimmune disease and prevent transplant rejection. Preclinical models suggest that costimulatory blockade may also be effective in treating vascular disease. Experiential data in mice show that DCs pulsed with the appropriate antigens and treated in a way that reduces costimulatory capacity can reduce atherosclerotic disease, presumably by inducing T cell tolerance. Progress in treating vascular disease by immune modulation will require a more complete understanding of the functions of different costimulatory and coinhibitory pathways and the different subsets of vascular APCs involved.

Anti TNF-α in refractory Takayasu's arteritis: cases series and review of the literature

Takayasu arteritis (TA) is a rare large vessels vasculitis. Conventional therapy consists of glucocorticoids which may be associated with other immunosuppressive drugs. However, some patients fail to achieve remission with conventional treatment. The use of anti-tumor necrosis factor-α (TNF-α) in patients with difficult to treat TA could be useful. We report here the main characteristics, treatment and outcome of 84 patients (5 personal cases and 79 patients from the literature) with refractory Takayasu arteritis treated with anti TNF-α. The mean age was 28.5years [median 26.0years, range 7-61years], with 74/83 (89%) of female. All patients, except one, were inadequately controlled with other immunosuppressive regimens before anti TNF-α therapy. First line of anti-TNF-α included infliximab (IFX) in 81% (68/84) and etanercept (ETA) in 19% (16/84). Most patients received IFX at 5mg/kg associated to methotrexate or azathioprine. Thirty one out of 84 (37%) patients achieved a complete remission, and 45 (53.5%) were partial responders. There were 8 (9.5%) non responders at all. Twenty seven out of 84 (32%) patients needed to increase the dose of anti TNF-α because of uncontrolled disease and 15 (18%) needed to change of anti TNF-α. Glucocorticoids have been tapered in 41/79 (52%) [from 20mg (13.1-60) to 2.5mg (0-10) daily, at baseline and after anti-TNF, respectively, p<0.0001] and discontinued in 31/77 (40%). After a median follow-up of 10months [range 3-82], 17 (20%) side effects were recorded leading to discontinuation of anti TNF-α in 8 cases. They included mainly infections, and hypersensitivity reactions. In conclusion, anti-TNF-α are an efficient therapy in refractory TA patients although side effects are observed in 20% of cases. Further studies are warranted to assess the long term efficacy and safety of anti-TNF in TA and to better define if they should be prescribed earlier in the course of TA.

[Biologic therapies in the systemic vasculitides]

Several biological therapies have been evaluated in systemic vasculitis. Anti TNF-α agents may have a role in the treatment of Takayasu's arteritis and probably in giant cell arteritis. In Kawasaki's disease, infliximab is an option in subjects with intravenous immunoglobulin-resistant disease. Anti TNF-α cannot be recommended to treat ANCA-associated vasculitis. Anti-T lymphocyte globulin and alemtuzumab could have a role in the treatment of ANCA associated vasculitis, although current information about these two biological treatments comes from conventional resistant treatment cases, so the high incidence of complications and relapses observed with these treatment may be intrinsic to the severity of the disease and not related to the biological agents.

Pathogenesis of Takayasu's arteritis: a 2011 update

While our knowledge of the pathogenesis of Takayasu's arteritis (TA) has considerably improved during the last decade, the exact pathogenic sequence remains to be elucidated. It is now hypothesised that an unknown stimulus triggers the expression of the 65kDa Heat-shock protein in the aortic tissue which, in turn, induces the Major Histocompatibility Class I Chain-Related A (MICA) on vascular cells. The γδ T cells and NK cells expressing NKG2D receptors recognize MICA on vascular smooth muscle cells and release perforin, resulting in acute vascular inflammation. Pro-inflammatory cytokines are released and increase the recruitment of mononuclear cells within the vascular wall. T cells infiltrate and recognize one or a few antigens presented by a shared epitope, which is associated with specific major Histocompatibility Complex alleles on the dendritic cells, these latter being activated through Toll-like receptors. Th1 lymphocytes drive the formation of giant cells through the production of interferon-γ, and activate macrophages with release of VEGF resulting in increased neovascularisation and PDGF, resulting in smooth muscle migration and intimal proliferation. Th17 cells induced by the IL-23 microenvironnement also contribute to vascular lesions through activation of infiltrating neutrophils. Although still controversial, dendritic cells may cooperate with B lymphocytes and trigger the production of anti-endothelial cell auto-antibodies resulting in complement-dependent cytotoxicity against endothelial cells. In a near future, novel drugs specifically designed to target some of the pathogenic mechanisms described above could be expanding the physician's therapeutic arsenal in Takayasu's arteritis.

A case of Takayasu arteritis complicated by right atrium perforation and injuries of the right common iliac artery and vein caused by cannulation for percutaneous cardiopulmonary support

We describe an autopsy case of Takayasu arteritis with right atrium perforation and injuries of the right common iliac artery and vein caused by cannulation for percutaneous cardiopulmonary support (PCPS). The decedent was an 8-year-old girl admitted for examination in respect to chest pain and syncope. During catheter angiography, she suddenly went into cardiac arrest. PCPS was attempted, whereupon bleeding into the abdominal cavity and an injury to the common iliac vein were observed. She was pronounced dead 78 hours after the initiation of PCPS. Autopsy revealed thickening of the aortic wall from the ascending aorta to the abdominal aorta, with narrowing of the proximal branches. Hemopericardium induced by right atrium perforation, and an injury of the right common iliac artery, were also found. Microscopic examinations of the aorta disclosed thickening of each layer of the vessel wall and inflammatory cell infiltration, mainly into the outer layer of the media. It was speculated that manipulation of the catheter and the underlying Takayasu arteritis caused cardiac arrest. It is also considered that hypovolemia was induced by the injuries of the right common iliac artery and vein caused during the insertion of the PCPS venous cannula. In addition, the right atrium was injured by the edge of the PCPS cannula, leading to hemopericardium. In pediatric cases involving PCPS, or in cases where cannulation is difficult, regular examination of the pericardial and abdominal cavities by echocardiography would provide useful information to prevent such accidents.

[Pathogenesis of primary large vessel arteritis]

Giant cell arteritis (GCA) and Takayasu's arteritis (TA) are the two primary large-vessel arteritides. Recent advances in cellular immunology have allowed better understanding of pathogenesis of these diseases. In GCA and TA, resident adventitial dendritic cells are activated by unidentified stimuli. This activation induces chemokine synthesis which enhances recruitment of inflammatory cells. T-cells infiltrate the vascular wall and specifically recognize one or a few antigens presented by shared epitopes associated with specific HLA molecules on dendritic cells. Activated T-cells produce IFNgamma stimulating two distinct populations of macrophages. Macrophages located in the intima produce pro-inflammatory cytokines (IL-1, IL-6). Macrophages located in the media differentiate into giant cells and/or produce reactive oxygen species, nitric oxide and matrix metallo-proteinases. Macrophages of the media also produce VEGF, which leads to neovascularization and PDGF, which induces intimal hyperplasia and vascular occlusion. In TA, cytotoxic T cells infiltrate the vascular wall and induce apoptosis of the vascular cells. Better understanding of the pathogenesis of large-vessel arteritis may lead to development of immunosuppressive drugs specifically targeting the immunological mechanisms implicated in GCA and TA.

Progressing takayasu arteritis successfully treated by common carotid-internal carotid crossover bypass grafting: technical case report

OBJECTIVE

This report describes a unique case of Takayasu arteritis with occlusion of the left common carotid artery (CCA) and the right internal carotid artery (ICA), which was successfully treated by right CCA-left ICA crossover bypass grafting using the saphenous vein. The histological findings of the original occluded prosthetic graft are also described.

CLINICAL PRESENTATION

A 63-year-old woman with a history of Takayasu arteritis was admitted to our hospital with a history of progressive dizziness, frequent syncopal attacks, and repetitive blurred vision in the left eye. She had undergone repeat transthoracic bypass surgeries, including grafting with the use of a Gore-Tex (W.L. Gore & Associates, Inc., Flagstaff, AZ) prosthesis between the left external ilioaxillary bypass and the left CCA. However, cerebral angiography demonstrated total occlusion of the left CCA, the right ICA, and the bilateral subclavian arteries. On admission, I-iodoamphetamine single-photon emission computed tomography showed a decreased cerebrovascular reactivity to acetazolamide in the bilateral cerebral hemispheres. Moreover, cerebral angiography revealed an occlusion of the Gore-Tex graft, whereas the left ICA was opacified through the retrograde filling in the left external carotid artery.

INTERVENTION

Crossover bypass grafting was performed using the saphenous vein between the right CCA and the left ICA. The Gore-Tex graft was partially removed, and myointimal hypertrophy with an inflammatory response around the wall was found histologically. The postoperative course was uneventful. A normalized cerebrovascular reserve in both cerebral hemispheres was demonstrated on I-iodoamphetamine single-photon emission computed tomography.

CONCLUSION

Although it is not frequently indicated, crossover bypass grafting using the saphenous vein between bilateral carotid arteries is considered to be a feasible alternative procedure in patients with Takayasu arteritis.

Activated myeloid dendritic cells accumulate and co-localize with CD3+ T cells in coronary artery lesions in patients with Kawasaki disease

Emerging evidence implicating the participation of dendritic cells (DCs) and T cells in various vascular inflammatory diseases such as giant cell arteritis, Takayasu's arteritis, and atherosclerosis led us to hypothesize that they might also participate in the pathogenesis of coronary arteritis in Kawasaki disease (KD). Coronary artery specimens from 4 patients with KD and 6 control patients were obtained. Immunohistochemical and computer-assisted histomorphometric analyses were performed to detect all myeloid DCs (S-100(+), fascin(+)), all plasmacytoid DCs (CD123(+)) as well as specific DC subsets (mature myeloid DCs [CD83(+)], myeloid [BDCA-1(+)] and plasmacytoid DC precursors [BDCA-2(+)]), T cells (CD3(+)), and all antigen-presenting cells (HLA-DR(+)). Co-localization of DCs with T cells was assessed using double immunostaining. Significantly more myeloid DCs at a precursor, immature or mature stage were found in coronary lesions of KD patients than in controls. Myeloid DC precursors were distributed equally in the intima and adventitia. Mature myeloid DCs were particularly abundant in the adventitia. There was a significant correlation between mature DCs and HLA-DR expression. Double immunostaining demonstrated frequent contacts between myeloid DCs and T cells in the outer media and adventitia. Plasmacytoid DC precursors were rarely found in the adventitia. In conclusion, coronary artery lesions of KD patients contain increased numbers of mature myeloid DCs with high HLA-DR expression and frequent T cell contacts detected immunohistochemically. This suggests that mature arterial myeloid DCs might be activating T cells in situ and may be a significant factor in the pathogenesis of coronary arteritis in KD.

Takayasu's arteritis: An update on physiopathology

Takayasu's arteritis (TA) is a chronic large vessel vasculitis. The physiopathology of TA has not been completely elucidated, but it appears to be multifactorial and to mainly involve cellular immunity. The pathologic sequence could implicate stimulation from an antigen that triggers heat shock protein (HSP)-65 expression in aortic tissue which, in turn, induces MHC class I-related chain A (MICA). T-cells and natural killer (NK) cells expressing NKG2D receptors could recognize MICA, resulting in acute inflammation. Pro-inflammatory cytokines released from these infiltrating cells induce matrix metalloproteinases and amplify the inflammatory response, inducing more MHC antigen and costimulatory molecule expression on vascular cells and, thus, recruiting more mononuclear cells. Alpha-beta T-cells then infiltrate and specifically recognize one or a few autoantigens presented by a shared epitope associated with specific MHC on the dendritic cells (DC). These DC simultaneously cooperate to some extent with B-cells and determine a humoral immunity mainly constituted by anti-endothelial cell autoantibodies that could trigger complement-dependent cytotoxicity against endothelial cells. The use of corticosteroids and of other immunosuppressive agents can bring TA into remission in most patients. A better understanding of the immunological mechanisms responsible for the vascular injury has led to trials of anti-TNF-alpha agents with encouraging results. In the near future, new drugs specifically designed to target some of the mechanisms described above may be able to expand the physician's therapeutic arsenal in TA.

Takayasu's arteritis: a review of the literature

Takayasu's arteritis is a rare, idiopathic, chronic inflammatory disease with cell-mediated inflammation, involving mainly the aorta and its major branches. It leads to stenosis, occlusion or aneurysmal degeneration of large arteries. The clinical presentation is characterised by an acute phase with constitutional symptoms, followed, months or years later, by a chronic phase in which symptoms relate to fibrosis or occlusion of vessels. Angiography is the gold standard for diagnosis and for topographical classification and it correlates with symptoms and prognosis. Here we focus on the pathophysiology, clinical and angiographical classification, diagnostic assessment and therapeutic approach of Takayasu's arteritis.

Serum cytokine profiles and their correlations with disease activity in Takayasu's arteritis

OBJECTIVE

To investigate serum profiles of inflammatory cytokines in patients with Takayasu's arteritis (TA) and to determine their correlations with disease activity of TA.

METHODS

Forty-nine patients with TA and 12 age- and sex-matched controls were studied. Blood samples were obtained and were divided into active and stable disease groups. Paired blood samples were available in 19 patients at the active stage before treatment and at the remitted stage after treatment. Serum tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-6, IL-12 and IL-18 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Serum TNF-alpha, IL-6 and IL-18 levels of patients with TA were significantly higher than those of controls (P<0.05), but IFN-gamma and IL-12 levels were not. Serum IL-6 and IL-18 levels were significantly higher in the active disease group than in the stable disease group (P<0.05), but the levels of TNF-alpha were not different between the groups. In the 19 patients with paired samples, serum IL-18 levels at the remitted stage after treatment were significantly decreased compared with the active stage before treatment (P<0.001). The changes in IL-18 levels between active and remitted stages correlated well with changes in erythrocyte sedimentation rate (P<0.001).

CONCLUSION

Serum IL-18 and IL-6 levels were elevated in patients with TA, especially in those with active disease. Serum IL-18 levels correlated well with disease activity of TA. These results suggest that IL-6 and IL-18 might contribute to the pathogenesis of TA and that IL-18 could be a useful marker for monitoring disease activity of TA.

Sirolimus-eluting stent for in-stent restenosis of left main coronary artery in takayasu arteritis

A 53-year-old woman with Takayasu arteritis was admitted to hospital because of worsening exertional angina. Coronary angiography revealed 90% ostial stenosis in the left main coronary artery (LMCA), which also involved the bifurcation of the relatively short LMCA. Because the patient refused coronary bypass surgery, she underwent percutaneous coronary intervention (PCI) and the stenosis was successfully dilated. However, the exertional angina recurred a few months later and again after the second PCI. Finally, a sirolimus-eluting stent was deployed in the in-stent restenotic lesion. The patient has been free from angina pectoris for 6 months after the last PCI and follow-up coronary angiography indicated no restenosis in the LMCA.

Elastic-Vessel Arteritis in Interleukin-1 Receptor Antagonist–Deficient Mice Involves Effector Th1 Cells and Requires Interleukin-1 Receptor

BACKGROUND

In mice that lack interleukin-1 receptor antagonist (IL-1ra), transmural inflammation of the elastic arteries develops at sites of turbulent flow. We described late histopathology previously. Here, we investigate the cellular events in nonlethal arteritis at the aortic root and compare them with Takayasu's arteritis and giant cell arteritis.

METHODS AND RESULTS

IL-1ra-deficient mice were inbred from the original stocks and from BALB/c backcrosses. Disease was ascertained histologically and immunohistologically postmortem at the aortic root. Onset appeared to be stochastic and was not detectably age dependent; in our local Sf3 strain, the half-time of onset was approximately 52 days. Loss of the type I IL-1 receptor suppressed the arteritis. Microvascular activation, as determined by absence of strong E-selectin expression, was absent from preaffected vessels. In mildly affected cases, infiltration was adventitial. In severely affected animals, infiltrates appeared to be active in destroying elastin, but resynthesis of disorganized elastin occurred at closely adjacent sites. Infiltrates consisted predominantly of macrophages but were rich in CD4+-interferon-gamma+ cells, which are likely to represent Th1 cells. Dendritic cells accumulated in lesional areas.

CONCLUSIONS

The arteritic phenotype of IL-1ra deficiency is mediated by the interleukin-1 receptor and involves effector Th1 cells. The destructive pattern and many of the cellular features of arteritis in IL-1ra-deficient mice resemble the human elastic-vessel arteritides, for which these mice may be a useful animal model.

Advances in the medical and surgical treatment of Takayasu arteritis

PURPOSE OF REVIEW

Takayasu arteritis remains a therapeutic challenge. In spite of current treatments, progression of vascular lesions is observed frequently. The purpose of this article is to describe advances in therapeutic strategies for Takayasu arteritis.

RECENT FINDINGS

Immunosuppressive agents including methotrexate, mycophenolate mofetil, and azathioprine added to corticosteroids can bring Takayasu arteritis into remission in many patients. Unfortunately, relapse is common when prednisone is tapered to dosages of 15 mg/day or less. A better understanding of pathogenesis has lead to trials with anti-tumor necrosis factor-alpha agents in patients with refractory disease. Preliminary results are encouraging. For patients who require revascularization intervention, both surgical and endovascular procedures can be performed that are safe, with low morbidity and mortality. The best long-term outcomes are achieved with conventional bypass grafts. Percutaneous transluminal angioplasty provides good results for short lesions. In contrast to the results in treating atherosclerosis, the use of conventional stents may not yield long-term vessel patency in Takayasu arteritis. Persistent inflammation and endothelial dysfunction may put patients with Takayasu arteritis at risk for premature atherosclerosis.

SUMMARY

In the future, greater therapeutic success may be achieved by addressing both the inflammatory and the myointimal proliferative components of Takayasu arteritis. New drugs that target intimal hyperplasia, as well as drug-eluting stents, deserve to be studied for possible utility as adjuncts to present treatments.

Takayasu's disease

Takayasu's arteritis (TA) is a chronic inflammatory disease of unknown etiology that can produce stenosis, occlusion, or aneurysmal degeneration of large arteries. TA occurs worldwide but disproportionately affects young females of Asian descent. A variable acute phase of largely constitutional symptoms is followed by a chronic phase in which symptoms related to arterial compromise predominate. Diagnosis is made using a combination of clinical and angiographic criteria. Initial therapy involves the use of corticosteroids to induce remission of acute phase activity, with the addition of cytotoxic medications for nonresponders. Angioplasty and stenting can be used in the treatment of shorter stenoses such as those encountered in the renal arteries. Surgical bypass is the preferred treatment of longer segment stenoses and occlusions. Bypass grafts should originate from unaffected arteries to ensure durable inflow. Endovascular therapy is effective initially but long-term durability data are lacking.