Takayasu's arteritis: An update on physiopathology

Elevated serum immunoglobulin level predicts high risk of 1-year recurrence in patients with Takayasu arteritis

BACKGROUND

The mechanism of humoral immunity to Takayasu arteritis (TAK) is not clear. In our study, we aimed to investigate the correlation between immunoglobulins and disease activity and the relationship between immunoglobulins and the prognosis of TAK patients.

METHODS

One hundred ninety TAK patients divided into two groups according to whether they had elevated immunoglobulins or not. We compared the demographic data and the clinical data between the two groups. Pearson correlation was used to analyze the relationship between immunoglobulin and disease activity, as well as the relationship between their changes. Immunohistochemical staining was used to compare the expression of humoral immune cells in TAK and atherosclerotic patients. One hundred twenty TAK patients who achieved remission within 3 months after discharge were followed up for 1 year. Logistic regression was used to explore the relationship between elevated immunoglobulins and recurrence.

RESULTS

Disease activity and inflammatory factors were significantly higher in the group with elevated immunoglobulins than in the normal group [NIH (3.0 vs. 2.0, P = 0.001), ITAS-A (9.0 vs. 7.0, P = 0.006)]. Compared with atherosclerotic patients, CD138 + plasma cells were significantly increased in the aortic wall of patients with TAK (P = 0.021). Changes in IgG correlated well with CRP and ESR [CRP (r = 0.40, P = 0.027), ESR (r = 0.64, P < 0.001)]. For patients with TAK in remission, elevated immunoglobulins was associated with 1-year recurrence [OR95%, CI: 2.37 (1.03, 5.47), P = 0.042].

CONCLUSIONS

Immunoglobulins is of clinical value in evaluating disease activity in TAK patients. Moreover, the dynamic changes of IgG were correlated with the changes in inflammatory indicators in TAK patients.

Biomarkers in Takayasu arteritis

Takayasu arteritis (TA) is a rare large vasculitis with unknown etiology, which affects the aorta and its primary branches, as well as the pulmonary and coronary arteries. Cellular and humoral immunity, chronic inflammation, and genetic factors are involved into TA pathogenesis. Several biomarkers, such as MMPs, TIMPs, cytokines, cell adhesion molecules, autoantibodies, complements, PTX3, sRAGE, NT-proBNP, 8-isoPGF_2α, NO₂^-, acute-phase and immunology-related proteins, thrombogenicity markers, ghrelin leptin and adipokines, endothelial damage and repair factors, genetic markers etc., related to the pathogenesis could be observed in patients with TA. These biomarkers have revealed great values in early diagnosis, evaluating disease activity, guiding clinical treatment options, and thus demonstrated significant clinical application values in TA. The combination of biomarkers assay and imaging examination may detect TA more accurately. The aim of this review is to systemically observe the clinical significance of these biomarkers in TA.

Childhood-onset Takayasu arteritis and immunodeficiency: case-based review

Takayasu arteritis (TAK) has been rarely reported in patients with immunodeficiency. In this review, we present two cases with childhood-onset TAK (c-TAK) and primary immunodeficiency while reviewing similar cases in the literature. We reviewed the data for our two pediatric patients with c-TAK and primary immunodeficiency. We also reviewed the literature for patients with c-TAK and immunodeficiency from the inceptions of the databases up to November 2021. A 14-year-old patient had lipopolysaccharide-sensitive beige-like anchor (LRBA) deficiency, and a 16-year-old had X-linked severe combined immunodeficiency (X-linked SCID). During the follow-up, they developed findings suggestive of vasculitides such as hypertension, elevation in acute phase reactants, weakness, and weight loss. Thoracoabdominal computed tomography angiography revealed findings consistent with vasculitis involving the aorta and its major branches. Patients were diagnosed with c-TAK, and corticosteroids were given to both patients in the treatment. We identified 11 articles describing 17 TAK patients with immunodeficiency in our literature search. Two of the patients with c-TAK were infected with human immunodeficiency virus (HIV), another patient had Wiskott-Aldrich syndrome, and the other had idiopathic CD4 + T lymphocytopenia. Nine adult patients with TAK were infected with HIV, three patients had common variable immunodeficiency disorder (CVID), and the other had STAT1 gain-of-function mutation. Clinicians should consider that immunodeficiencies may be accompanied by vasculitic conditions such as TAK. Hypertension, increased inflammatory markers, and constitutional symptoms may be red flags for the development of TAK.

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.

Acute myocardial infarction with left main coronary artery ostial negative remodelling as the first manifestation of Takayasu arteritis: a case report

Background

Takayasu arteritis is a chronic inflammatory disease involving the aorta and its major branches. Acute myocardial infarction rarely but not so much presents in patients with Takayasu arteritis, and the preferable revascularization strategy is still under debate.

Case presentation

A 22-year-old female with Takayasu arteritis presented with acute myocardial infarction. Coronary angiography and intravenous ultrasound (IVUS) showed that the right coronary artery (RCA) was occluded and that there was severe negative remodelling at the ostium of the left main coronary artery (LMCA). The patient was treated by primary percutaneous transluminal coronary angioplasty (PTCA) with a scoring balloon in the LMCA, without stent implantation. After 3 months of immunosuppressive medication, the patient received RCA revascularization by stenting. There was progressive external elastic membrane (EEM) enlargement of the LMCA ostium demonstrated by IVUS at 3 and 15 months post-initial PTCA.

Conclusion

Here, we report a case of Takayasu arteritis with involvement of the coronary artery ostium. Through PTCA and long-term immunosuppressive medication, we found that coronary negative remodelling might be reversible in patients with Takayasu arteritis.

Elevated chemokines concentration is associated with disease activity in Takayasu arteritis

BACKGROUND

Chemokines were seldom investigated in Takayasu arteritis (TA) patients. This study aimed to evaluate the plasma levels of chemokines and their association with disease activity, including C-C chemokine ligand (CCL) 2, CCL3, CCL11, CCL20, C-X-C chemokine ligand (CXCL) 8 and CXCL10.

METHODS

Chemokines were measured in 85 TA patients, and 28 age- and gender-matched healthy controls. The disease activity of these TA patients was assessed according to the National Institute of Health (NIH) criteria. The relationship between the plasma levels of chemokines and disease activity was analyzed.

RESULTS

Among the 85 TA patients, 24 (28.2%) patients had active disease according to the NIH criteria. Significantly increased levels of CCL2, CCL3, CCL20, CXCL8 and CXCL10 were observed in TA patients when compared to healthy controls, while increased levels of CCL2, CCL20, CXCL8 and CXCL10 in TA patients with active disease when compared to those with inactive disease (all p < 0.05). The plasma cut-off values of CCL2, CCL20, CXCL8 and CXCL10 were 309.6 pg/ml, 131.4 pg/ml, 4.7 pg/ml, and 282.1 pg/ml, which maximized the ability of disease activity assessment and had a sensitivity/specificity of 66.7%/67.2%, 54.2%/77.1%,70.8%/72.1%,83.3%/54.1%, respectively (p < 0.05). Among patients with negative erythrocyte sedimentation rate, C-reactive protein or high-sensitivity C-reactive protein, CCL2, CCL20, CXCL8, and CXCL10 still had a high-sensitivity to recognize patients in the active phase.

CONCLUSIONS

This study showed that the expression level of CCL2, CCL20, CXCL8 and CXCL10 was elevated in active TA patients, indicating that these chemokines might act as potential biomarkers in evaluating the disease activity.

Efficacy and safety of tocilizumab in treatment of Takayasu arteritis: A systematic review of randomized controlled trials

BACKGROUND

Takayasu arteritis (TAK) is a chronic immune vasculitis in which Interleukin-6 (IL-6) receptors play a key role in pathogenesis. Tocilizumab (TCZ), an IL-6 receptor antagonist with a favorable safety and efficacy profile, has been tried as an option for patients with TAK. This systematic review analyzed the evidence from randomized control trials (RCT) assessing the safety and efficacy of TCZ in patients with TAK.

METHODS

MEDLINE, Embase, the Cochrane Library, and clinical trial registries were searched from inception to July 2018. We included RCT assessing the efficacy and safety of TCZ versus placebo/other comparators for the treatment of patients with TAK. The risk of bias (RoB) was assessed using Cochrane RoB tool.

RESULTS

2799 identified articles were screened as per abstract and title; 42 selected full-texts articles were assessed for the potential inclusion. One trial, reported in two publications, comparing subcutaneous TCZ (162 mg/week) versus matching placebo in 36 patients with TAK was included. The relapse-free rate at 24 weeks was 50.6% and 22.9% in TCZ and placebo arm, respectively. The hazard ratio (HR) for time to first relapse was statistically significant in the per-protocol population (HR 0.34 [95.41% CI, 0.11-1.00]; p = .0345), while non-significant in the intention-to-treat population (HR 0.41 [95.41% CI, 0.15-1.10]; p = .0596). The serious adverse events were higher in the placebo arm.

CONCLUSIONS

This systematic review finds the existing evidence from RCT on efficacy and safety profile of TCZ in TAK to be promising but limited. Additional evidence is required to draw a stronger conclusion.

A Case Report of Takayasu's Arteritis and Ulcerative Colitis in a Pediatric Patient with Chronic Recurrent Multifocal Osteomyelitis Successfully Treated with Infliximab: Diagnostic Clues in Disease Associations and Immune Dysregulation

Background

Takayasu's arteritis with comorbid chronic recurrent multifocal osteomyelitis and ulcerative colitis is rare in the pediatric population. Treatment with anti-TNF alpha agents such as infliximab has been a successful treatment strategy in adults and can be used effectively in the pediatric population.

Case Presentation

We present the case of a 15-year-old Caucasian girl with a history of chronic recurrent multifocal osteomyelitis and ulcerative colitis presenting with hypertensive emergency secondary to Takayasu's arteritis with middle aortic syndrome. She was treated with corticosteroids and methotrexate and ultimately required infliximab infusions of 15 mg/kg every 4 weeks to successfully control her symptoms and normalize her inflammatory markers.

Conclusions

In this case, we discuss the use of infliximab in an adolescent patient with chronic recurrent multifocal osteomyelitis, ulcerative colitis, and Takayasu's arteritis. The significance of this case is determined by the unique occurrence of all three conditions in a pediatric patient, the important consideration of vasculitis in the differential of a pediatric patient presenting with hypertensive emergency, the need for vigilance for detecting diagnostic clues, signs, and symptoms, knowledge of disease associations when evaluating a patient with a predisposition for autoinflammatory conditions, and the use of increasing doses of infliximab to control symptoms.

Certolizumab Pegol Treatment in Three Patients With Takayasu Arteritis

Although glucocorticoids are the mainstay of treatment in Takayasu arteritis (TA), anti-tumor necrosis factor agents are other treatment options in refractory disease. The onset of TA is generally observed in females of reproductive age. Certolizumab pegol (CZP) lacks a fragment crystallizable region and this gives advantage of minimal transfer through the placenta, which makes CZP a safer option in pregnancy. Although there are case reports and trials about use of infliximab, etanercept, and adalimumab in TA, there are scarce data about use of CZP. In this article, we present three TA cases treated with CZP. While two patients benefited from CZP, one patient was refractory to CZP.

[Hypertension during Takayasu's disease: An Algerian single center experience of 279 patients]

INTRODUCTION

Takayasu arteritis (TA) is an uncommon large vessel arteritis. Lesions produced by the inflammatory process can be stenotic, occlusive, or aneurysmal. Vascular changes lead to the main complications, including hypertension, most often due to renal artery stenosis or, more rarely, stenosis of the suprarenal aorta.

AIM OF STUDY

Our study will assess the prevalence of hypertension during TA and describe its clinical profile.

MATERIAL AND METHODS

Among 279 patients with TA resulting from single center study over a period of 35 years, we collected 128 hypertensive patients. All have benefited from a vascular exploration. Renal angiography was performed in 85 patients. The classification of Lupi Herrera allowed us to distribute our patients according to the topography of their lesions. Patients are classified according to the degree of severity of their hypertension. Results are statistically analyzed with SPSS 10.0 database.

RESULTS

The prevalence of hypertension is 45.8%, mainly affecting young women (87%). It is indicative of arteritis in 24.7%. Its diagnosis is difficult and delayed when arterial stenosis exist: inter-arm blood pressure difference (53.8%), inverse coarctation (30.4%) or unmeasurable blood pressure at the 4 limbs (6.8%). In 54% of cases, hypertension was due to a renal artery stenosis. The presence of arterial hypertension was associated to a poor prognosis: it was severe in 54% of patients and was linked to 70% of deaths observed.

CONCLUSION

Arterial hypertension is common during TA. It remains a factor of bad prognosis specially when renovascular hypertension is present.

Acknowledged signatures of matrix metalloproteinases in Takayasu's arteritis

Takayasu's arteritis (TA) was reported as an eye disease in the year 1905 and later was confirmed as a vasculitis. Since then, the etiology of the disease remains unknown; however, characteristic clinical features suggest multiple causative factors. Recent progress in vascular biology and other disciplines enlightens the pathophysiology of TA and demonstrated induction of various nonspecific inflammatory symptoms and destruction of the arterial wall, which leads to aneurysms and rupture of the affected arteries. Matrix metalloproteinases (MMPs) as an enzyme family have well-established roles in several vascular pathologies including intima formation, atherosclerosiss and aneurysms. MMPs have been proposed to be one of the molecules with a potential of having dual role in the course of TA, first as an active participant in pathophysiology and secondly as a diagnostic biomarker for TA disease. The desire to improve our understanding of the importance of MMPs and their endogenous inhibitors (TIMPs) in TA disease and for the development of therapeutic agents has inspired basic and clinical scientists for over a decade. In the present paper, we summarized the scientific rationale which highlights the signatures of matrix metalloproteinases and their endogenous inhibitors in pathophysiology as well as their being a potential candidate as biomarker for Takayasu's arteritis.

Takayasu arteritis: diagnosis, treatment and prognosis

Takayasu arteritis (TA) is a chronic nonspecific granulomatous vasculitis affecting aorta and its main branches, coronary and pulmonary arteries. TA often occurs in young women and has a characteristic heterogeneity depending on ethnicity and geographical location. Although the pathogenesis of TA remains unclear, the interaction of many factors, such as autoimmunity, inflammation, genetic and environmental factors and so on, is involved in the occurrence and development of TA. Angiography, which is recognized as the gold standard in evaluating vascular lesions in TA, combined with computer tomography angiography (CTA), magnetic resonance angiography (MRA), ultrasonography, (18)Fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) could not only provide important information for early diagnosis but also detect disease activity, and thus further guide the treatment in TA. In addition, beside the commonly used corticosteroids, immunosuppressive agents, percutaneous transluminal angioplasty (PTA) and surgical revascularization, anti-tumor necrosis factor (TNF) agent has been more widely used in refractory cases of TA. The objective of this review is to systemically describe the pathogenesis, clinical characteristics, diagnosis, treatment and prognosis of TA.

Takayasu's arteritis is associated with HLA-B*52, but not with HLA-B*51, in Turkey

Introduction

HLA-B*51 and HLA-B*52 are two close human leukocyte antigen (HLA) allele groups with minor amino acid differences. However, they are associated with two different vasculitides (HLA-B*51 in Behçet's disease and HLA-B*52 in Takayasu's arteritis (TAK)) and with major clinical and immunological differences. In this study, we aimed to screen a large cohort of TAK patients from Turkey for the presence of HLA-B*51 and HLA-B*52 as susceptibility and severity factors.

Methods

TAK patients (n = 330) followed at a total of 15 centers were included in the study. The mean age of the patients was 37.8 years, and 86% were women. DNA samples from the patients and healthy controls (HC; n = 210) were isolated, and the presence of HLA-B*51 or HLA-B*52 was screened for by using PCR with sequence-specific primers.

Results

We found a significant association of HLA-B*52 with TAK (20.9% vs HC = 6.7%, P = 0.000, OR = 3.7, 95% CI = 2.02 to 6.77). The distribution of HLA-B*51 did not differ between TAK patients and HCs (22.7% vs 24.8%, OR = 0.9, 95% CI = 0.60 to 1.34). The presence of HLA-B*52 decreased in late-onset patients (> 40 years of age; 12.0%, P = 0.024, OR = 0.43, 95% CI = 0.20 to 0.91). Patients with angiographic type I disease with limited aortic involvement also had a lower presence of HLA-B*52 compared to those with all other disease subtypes (13.1% vs 26%, P = 0.005, OR = 0.43, 95% CI = 0.23 to 0.78).

Conclusions

In this study, the previously reported association of TAK with HLA-B*52 in other populations was confirmed in patients from Turkey. The functional relevance of HLA-B*52 in TAK pathogenesis needs to be explored further.

Outcomes after endovascular treatment of symptomatic patients with Takayasu's arteritis

We report our experience with endovascular treatment of supra-aortic arteries and follow-up results in patients with Takayasu's arteritis (TA) presenting with neurological symptoms. Of the 20 patients with TA who underwent cerebral angiography for neurological manifestations between May 2002 and May 2009, 12 (11 females, one male; mean age, 39 years; range 31-56 years) underwent endovascular treatment and evaluated outcome for 21 lesions, including nine common carotid arteries, four vertebral arteries, four subclavian arteries, two internal carotid arteries, and one brachiocephalic artery. Eight patients underwent multiple endovascular procedures for different lesions in single or multiple stages. Mean angiographic and clinical follow-up durations were 34 months (range, 11-79 months) and 39 months (range 11-91 months), respectively. Technical success was achieved for 20 procedures in 11 patients. One procedure failed, with 50% residual stenosis after stenting due to dense calcification of vessel walls. There were no procedure-related complications. Restenosis occurred at two lesions in two patients were treated by re-stenting. Asymptomatic occlusion occurred at two lesions in one patient. Ten patients remained in 0-1 on the modified Rankin scale (mRs) during mean 39 months. One patient, however, had a score of 3 on mRs due to a traumatic contusion during follow-up. One patient died from cardiac failure 36 months after successful angioplasty.Our data suggest that endovascular treatment of symptomatic supra-aortic lesions of TA is effective and durable in selected patients with neurologic symptoms.

Cerebral arterial stenoses and stroke: novel features of Aicardi-Goutières syndrome caused by the Arg164X mutation in SAMHD1 are associated with altered cytokine expression

Aicardi-Goutières syndrome (AGS) is a rare inborn multisystemic disease, resembling intrauterine viral infection and resulting in psychomotor retardation, spasticity and chilblain-like skin lesions. Diagnostic criteria include intracerebral calcifications and elevated interferon-alpha and pterin levels in cerebrospinal fluid (CSF). We report on four adult siblings with unknown neurodegenerative disease presenting with cerebrovascular stenoses, stroke and glaucoma in childhood, two of whom died at the age of 40 and 29 years. Genome-wide homozygosity mapping identified 170 candidate genes embedded in a common haplotype of 8Mb on chromosome 20q11-13. Next generation sequencing of the entire region identified the c.490C>T (p.Arg164X) mutation in SAMHD1, a gene most recently described in AGS, on both alleles in all affected siblings. Clinical diagnosis of AGS was then confirmed by demonstrating intracerebral calcifications on cranial computed tomography in all siblings and elevated pterin levels in CSF in three of them. In patient fibroblasts, lack of SAMHD1 protein expression was associated with increased basal expression of IL8, while stimulated expression of IFNB1 was reduced. We conclude that cerebrovascular stenoses and stroke associated with the Arg164X mutation in SAMHD1 extend the phenotypic spectrum of AGS. The observed vascular changes most likely reflect a vasculitis caused by dysregulated inflammatory stress response. © 2010 Wiley-Liss, Inc.

Takayasu arteritis in children and adolescents

Takayasu arteritis is a devastating vasculitis of the aorta and its major branches. The clinical manifestations in paediatric patients are less specific than in adults: in children the disease presents with fever, arthralgias and hypertension. Intramural inflammation results in narrowing of the blood vessel lumen and therefore hypoperfusion of the parenchyma. Conventional angiography is the gold standard diagnostic procedure. Corticosteroids, cyclophosphamide, MTX and biological therapies such as TNF-α blocking agents are treatment options.

Fatal subarachnoid hemorrhage due to ruptured vertebrobasilar aneurysm associated with giant cell arteritis in a child

A 3 ½-year-old previously healthy female experienced an episode of sudden unresponsiveness witnessed by her mother. Upon arrival to the local hospital, imaging studies of the still unresponsive child revealed severe bilateral "flash" pulmonary edema and diffuse anoxic brain injury. Aggressive resuscitative efforts were unsuccessful, and she was pronounced dead. External examination at autopsy was essentially unremarkable. Internal examination of the head revealed diffuse basilar subarachnoid blood originating from a collapsed, 2 cm irregular aneurysm arising from the junction of the vertebral and basilar arteries. Additionally, multiple calcified subpleural, parenchymal, and hilar nodal pulmonary granulomas were identified. The remaining internal examination, including that of the aorta and its major branches, was unremarkable. Histologic examination of the aneurysm revealed alternating mural attenuation and thickening, the latter resulting from prominent intimal proliferation with active fibroplasia. Most notably, numerous isolated and clustered multinucleated giant cells were seen, most prominently in areas of more intense inflammation. Specific immunolabeling and silver staining of the pulmonary granulomas revealed evidence of histoplasmosis, but both were negative for fungal elements in the aneurysm, as was ultrastructural examination. The cause of death is fatal subarachnoid hemorrhage due to rupture of a vertebrobasilar artery aneurysm caused by isolated intracranial giant cell arteritis.

Takayasu arteritis in France: a single-center retrospective study of 82 cases comparing white, North African, and black patients

We conducted a single-center retrospective study to compare the characteristics of Takayasu arteritis (TA) among white, North African, and black patients in a French tertiary care center (Hospital Pitié-Salpêtrière, Paris). Eighty-two patients were studied (82.9% female) during a median follow-up of 5.1 years (range, 1 mo to 30 yr). Among these 82 patients, 39 (47.6%) were white, 20 (24.4%) were North African, and 20 (24.4%) were black patients. Median age at diagnosis was 39.3 years (range, 14-70 yr) in white patients vs. 28.4 years (range, 12-54 yr) in North African (p = 0.02), and 28.0 years (range, 13-60 yr) in black patients (p = 0.08). Patients aged >40 years at TA onset were more frequently white than non-white (40.0% vs. 18.6%, p = 0.03). North African patients had more frequent occurrence of ischemic stroke (p = 0.03) and poorer survival (p = 0.01) than white patients. Type V of the Hata classification was the most frequent type among white (38.5%), North African (65.0%), and black patients (40.0%). Corticosteroids were used in 96.1% of patients. Fifty-three percent of white and North African patients, and 44% of black patients required a second line of immunosuppressive treatment (p = 0.60). Vascular surgical procedures were respectively performed in 46.1%, 50.0%, and 55.0% of white, North African, and black patients, p = 0.81. The 5-year and 10-year survival rates were 100% and 95.0%, respectively, in white patients; 67.4% at both 5 years and 10 years in North African patients; and 100% at both 5 years and 10 years in black patients. This study is one of the first direct comparisons of TA profiles among patients of distinct ethnic backgrounds. Our data support the idea that late-onset TA or an overlap between TA and large-vessel giant cell arteritis may be observed in white patients. North African patients have a higher occurrence of ischemic stroke and poorer survival than white patients.

Absence ofMycobacterium tuberculosisin Arterial Lesions from Patients with Takayasu’s Arteritis

Objective.

Previous studies have suggested thatMycobacterium tuberculosis(MT) could be involved in the pathogenesis of Takayasu’s arteritis (TA). The search for MT in arterial lesions of TA has never been assessed directly by sensitive methods. Our aim was to assess the presence of MT in arterial samples obtained in patients with TA.

Methods.

Fresh arterial samples were collected from 10 consecutive patients (9 women and 1 man, median age 42 yrs, range 19–67 yrs) with a diagnosis of TA according to the American College of Rheumatology criteria who underwent vascular surgical procedures for their disease. Three patients had recent onset of TA and 7 had longstanding disease. No patient had evidence of active tuberculosis. Arterial biopsies were collected during vascular surgical procedures, and were systematically studied by a pathologist specializing in vascular diseases. Presence of MT was assessed in the biopsies by acid-fast and auramine-fluorochrome stainings, mycobacterial cultures, and direct amplification test (DAT) for MT.

Results.

Histological examination showed active (n = 5) and inactive (n = 5) arterial lesions. MT was not detected in arterial lesions of either active or inactive TA, by acid-fast and auramine-fluorochrome staining, mycobacterial cultures, or DAT. No DAT inhibitors were found.

Conclusion.

Our study does not support a direct role of MT in the pathogenesis of arterial lesions in either recent or longstanding TA, but does not exclude the possibility of a cross-reaction between mycobacterial and arterial antigens.

[Takayasu arteritis: a French single centre experience]

Takayasu arteritis (TA) is an uncommon large-vessel arteritis. We report our French single-center experience in the management of patients with TA (Pitié-Salpêtrière Hospital, Paris). TA is diagnosed in patients presenting with a large-vessel arteriopathy, in whom several inflammatory and non-inflammatory differential diagnoses are ruled out by appropriate investigations. Treatment of active disease is primarily based on corticosteroids but other immunosuppressive drugs are frequently needed. Anti-platelets agents, statins and antihypertensive drugs are frequently considered. There is no validated disease activity criterion in TA; thus, we generally consider the disease as being active in the presence of the following criteria: firstly, the presence of constitutional or ischemic symptoms; secondly, the increased acute phase reactants; thirdly, the mural contrast enhancement in CT-scan or fourthly, the mural contrast enhancement or signal abnormalities in MRI; fifthly, the abnormal vascular uptake in PET-scan. When TA is active, our follow-up recommendation is to perform an ultrasonography of the supra-aortic vessels and an aortic MRI or CT-scan twice a year. When TA appears to be inactive, we recommend to perform these investigations once a year. Surgical treatment of TA is limited to a few indications. The overall prognosis of TA is good but the quality of life is altered. Management of TA patients is difficult because of the lack of reliable diagnostic criteria, consensual therapeutic strategies and validated disease activity criteria. Further studies should focus on the pathogenesis of the disease and help define better disease activity criteria.

[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.

Treatment of Takayasu's arteritis with tumor necrosis factor antagonists

Four children with Takayasu's arteritis were treated with tumor necrosis factor antagonists because of disease relapse during conventional therapy or as a first-line agent. Two patients went into remission; in the other 2, the response was partial. Anti-tumor necrosis factor agents can have a role in the treatment of Takayasu's arteritis; further controlled studies are required.

EAE tolerance induction with Hsp70-peptide complexes depends on H60 and NKG2D activity

Inflammation leads to induction of tissue stress conditions that might contribute to the generation of mechanisms limiting ongoing immune responses. We have shown previously that peptides derived from brain tissue of mice with experimental autoimmune encephalomyelitis (EAE) complexed with the chaperone heat shock protein 70 (Hsp70-pc) induce an NK-cell-dependent tolerance for subsequent EAE sensitization. We now present data that showed that the MHC class I-related glycoprotein H60 determines Hsp70-pc-induced EAE inhibition. Hsp70-pc led to significant and selective up-regulation of H60 expression in SJL/J mice, and Ab-blocking of H60 expression led to loss of EAE tolerance. Similarly, blocking of the NK cell receptor for H60, NKG2D, also reversed the Hsp70-pc-induced EAE inhibition. In contrast, in C57BL/6 mice H60 was not expressed, and Hsp70-pc-induced tolerance was not detected. The NK cell mediated Hsp70-pc-induced tolerance to EAE was dependent on modulation of dendritic cells function leading to diminished T cell reactivity to PLP. As, no increase of H60 expression on T cells from EAE mice immunized with PLP was detected, and no enhanced loss of CD3+ H60+ over CD3+ H60- cells in Hsp70-pc-induced EAE tolerance was found direct killing of H60+ PLP-reactive cells seems not to be involved in the Hsp70-pc-induced tolerance induction. We have provided evidence that Hsp70-pc-induced tolerance for EAE, mediated by NK cells, involves induction of H60 ligand and its interaction with NKG2D receptor. NK cells tolerization of EAE depends on altered dendritic cells activity leading to enhanced death of Ag reactive cells.

Giant cell and Takayasu arteritis

PURPOSE OF REVIEW

Giant cell arteritis and Takayasu arteritis are well known large vessel vasculitides with an unknown etiology. As they have similar clinical features, this short article reviews recent advances in clinical and pathophysiological findings, focusing in particular on papers published in the past year.

RECENT FINDINGS

Delayed gadolinium-enhanced magnetic resonance imaging showed delayed hyperenhancement in the aortic wall in Takayasu arteritis. This technique may be useful in monitoring disease activity or inflammation in the arterial wall and can be used for small vessels such as temporal arteries in giant cell arteritis with high-resolution imaging. Evidence is accumulating that antitumor necrosis factor-alpha monoclonal antibody therapy can be useful for patients refractory to corticosteroid and/or immunosuppressant treatment. Functional promoter polymorphisms of genes encoding inducible nitric oxide synthase and I-kappaB-like protein were suggested to be associated with susceptibility to giant cell arteritis and Takayasu arteritis, respectively.

SUMMARY

Advances in imaging technique will make it possible to evaluate inflammatory activity of the vascular lesions and provide a useful guide for treatment of giant cell arteritis and Takayasu arteritis. Further understanding of the pathophysiological mechanism may contribute to the development of new medicine targeting critical factors in the pathogenesis, such as antitumor necrosis factor-alpha agents.