Small-vessel vasculitis surrounding an uninflamed temporal artery: A new diagnostic criterion for polymyalgia rheumatica?

Large vessel involvement in antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVES

ANCA-associated vasculitis (AAV) is currently categorized under the small vessel vasculitides. There is limited knowledge about large vessel involvement in AAV (L-AAV), mainly described in case reports and small series. L-AAV can involve temporal arteries (TA-AAV), aorta (A-AAV), and periaortic soft tissue (PA-AAV). We sought to characterize the features of patients with L-AAV.

METHODS

Patients older than 18 years at diagnosis of TA-AAV, A-AAV and PA-AAV seen at the Mayo Clinic, Rochester between 1 January 2000 and 31 December 2021 were identified through a proprietary medical text search algorithm. Patients were included if diagnosed with L-AAV, fulfilled 2022 ACR/EULAR classification criteria for GPA, MPA or EGPA, had positive ANCA test results, and had more than one outpatient or inpatient visit.

RESULTS

The study cohort consists of 36 patients with L-AAV. Of those, 23 had p-ANCA and/or MPO-ANCA, and 13 had c-ANCA and/or PR3-ANCA. Mean (s.d.) age at AAV diagnosis was 63.4 (12.79) years; 20 (56%) were male. Seventeen patients had TA-AAV, 10 had A-AAV and 9 had PA-AAV. Most patients (n = 25, 69%) were diagnosed with large vessel vasculitis and AAV within a 1-year timespan. Twenty-five (69%) patients had histopathological confirmation of AAV diagnosis in a location other than temporal artery, aorta or periaortic soft tissue. Glucocorticoids (36/36), rituximab (19/36) and methotrexate (18/36) were the most frequent treatments.

CONCLUSION

This is the largest single-centre cohort of patients with L-AAV to date. AAV can involve large arteries, albeit infrequent. AAV-targeted therapy should be considered in patients with L-AAV.

Accuracy of self-reported diagnoses of polymyalgia rheumatica and giant cell arteritis in the French prospective E3N- EPIC cohort: A validation study

OBJECTIVES

To assess the accuracy of self-reported giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) diagnoses in a large French population-based prospective cohort, and to devise algorithms to improve their accuracy.

METHODS

The E3N-EPIC cohort study (Etude Epidémiologique auprès des femmes de la Mutuelle Générale de l'Education Nationale) includes 98,995 French women born between 1925 and 1950, recruited in 1990 to study risk factors of cancer and chronic diseases. They completed biennially mailed questionnaires to update their health-related information and lifestyle characteristics. In three questionnaires, women could self-report a diagnosis of GCA/PMR. Those women were additionally sent a specific questionnaire, designed to ascertain self-reported diagnoses of GCA/PMR. Four algorithms were then devised to improve their identification. Accuracies of self-reported diagnoses and of each algorithm were calculated by comparing the diagnoses with a blinded medical chart review.

RESULTS

Among 98,995 participants, 1,392 women self-reported GCA/PMR. 830 women sent back the specific questionnaire, and 202 women provided medical charts. After independent review of the 202 medical charts, 87.6 % of the self-reported diagnoses of GCA/PMR were accurate. Using additional data from a specific questionnaire (diagnosis confirmation by a physician, and self-report of >3-month of glucocorticoids), and from a reimbursement database (at least two deliveries of glucocorticoids in less than 3 consecutive months) improved their accuracy (91.8 % to 92.8 %).

CONCLUSION

The accuracy of self-reported diagnosis of GCA/PMR was high in the E3N-cohort but using additional data as a specific GCA/PMR questionnaire and/or corticosteroid reimbursement database further improved this accuracy. With nearly 600 detected cases of GCA/PMR, we will be able to investigate risk factors for GCA/PMR in women.

Polymyalgia rheumatica

Polymyalgia rheumatica is an inflammatory disease producing pain and stiffness, mainly in the shoulders and pelvic girdle, in people older than 50 years. Elevation of acute phase reactants is common due to the inflammatory nature of the disease. Since there are no specific diagnostic tests, diagnosis requires the exclusion of other diseases with similar presentations. Imaging has helped to identify the pathological substrate of polymyalgia rheumatica and it is increasingly used to support clinical diagnosis or to detect coexistent giant cell arteritis. Although polymyalgia rheumatica does not clearly impair survival or organ function, it can have a detrimental effect on quality of life. Glucocorticoids at 12·5-25·0 mg prednisone per day are effective in inducing remission in most individuals but, when tapered, relapses occur in 40-60% of those affected and side-effects are common. Assessment of disease activity can be difficult because pain related to common comorbidities such as osteoarthritis and tendinopathies, can return when glucocorticoids are reduced, and acute phase reactants are increased less during flares in individuals undergoing treatment or might increase for other reasons. The role of imaging in assessing disease activity is not yet completely defined. In the search for more efficient and safer therapies, tocilizumab and sarilumab have shown efficacy in randomised controlled trials and additional targeted therapies are emerging. However, judicious risk-benefit balance is essential in applying therapeutic innovations to people with polymyalgia rheumatica.

Giant cell arteritis: reviewing the advancing diagnostics and management

Giant Cell Arteritis (GCA) is well known to be a critical ischaemic disease that requires immediate medical recognition to initiate treatment and where one in five people still suffer visual loss. The immunopathophysiology has continued to be characterised, and the influencing of ageing in the development of GCA is beginning to be understood. Recent national and international guidelines have supported the directed use of cranial ultrasound to reduce diagnostic delay and improve clinical outcomes. Immediate high dose glucocorticoids remain the standard emergency treatment for GCA, with a number of targeted agents that have been shown in clinical trials to have superior clinical efficacy and steroid sparing effects. The aim of this review was to present the latest advances in GCA that have the potential to influence routine clinical practice.

[Hearing loss in giant cell arteritis: A case report]

INTRODUCTION

Hearing loss is a rare manifestation in giant cell arteritis. The different types of deafness are possible with a predominance of sensorineural deafness.

CASE REPORT

We report a 75-year-old woman who presented with typical manifestations of giant cell arteritis associated concomitantly with the occurrence of bilateral mixed hearing loss confirmed on the audiogram. Corticosteroids allowed a rapidly favorable clinical and biological outcome. The follow-up audiogram at 3 months was markedly improved and showed a decrease in sensorineural hearing loss and disappearance of conductive hearing loss.

CONCLUSION

Any rapid onset deafness in an inflammatory context in the elderly should lead to a search for giant cell arteritis. The diagnosis can be difficult in the absence of other typical manifestations, especially since the biopsy of the temporal artery most often comes back negative. Corticosteroids are usually effective.

Concurrent baseline diagnosis of giant cell arteritis and polymyalgia rheumatica - A systematic review and meta-analysis

INTRODUCTION

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) can be concurrent diseases. We aimed to estimate the point-prevalence of concurrent GCA and PMR. Additionally, an incidence rate (IR) of GCA presenting after PMR diagnosis in patients was estimated.

METHODS

Two authors performed a systematic literature search, data extraction and risk of bias assessment independently. Studies assessing cohorts of patients presenting with both GCA and PMR were included. The outcomes were point-prevalence of concurrent GCA and PMR and IR for development of GCA after PMR diagnosis. A meta-analysis was performed to calculate a pooled prevalence of concurrent PMR and GCA.

RESULTS

We identified 29 studies investigating concurrent GCA and PMR. Only two studies applied imaging systematically to diagnose GCA and none to diagnose PMR. GCA presenting after PMR diagnosis was assessed in 12 studies but imaging was not applied systematically. The point-prevalence of concurrent GCA present at PMR diagnosis ranged from 6%-66%. The pooled estimate of the point-prevalence from the meta-analysis was 22%. The point-prevalence of PMR present at GCA diagnosis ranged from 16%-65%. The pooled estimate of the point-prevalence from the meta-analysis was 42%. The IR ranged between 2-78 cases of GCA presenting after PMR per 1000 person-years.

CONCLUSION

This review and meta-analysis support that concurrent GCA and PMR is frequently present at the time of diagnosis. Additionally, we present the current evidence of GCA presenting in patients after PMR diagnosis. These results emphasize the need for studies applying imaging modalities to diagnose GCA.

The Clinical Significance of Small Vessel Vasculitis on Temporal Artery Biopsies

BACKGROUND

Giant cell arteritis (GCA) is the most common type of systemic vasculitis in the elderly. Untreated, it can lead to irreversible blindness. Its diagnosis relies on a temporal artery biopsy (TAB). However, a proportion of patients have small vessel vasculitis (SVV) on biopsy; the prognosis of which remains unclear. The aim of this study is to compare the clinical presentation and long-term outcomes of those with SVV with negative and positive biopsies to determine whether long-term corticosteroid therapy can be avoided in these patients.

METHODS

Post hoc analysis of patients with suspected GCA who underwent TAB and fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan as part of a prospective GCA and PET cohort. Patients were divided in to 3 groups based on TAB result: positive (inflammation in the main artery wall), negative (no inflammation), and SVV (isolated vasa vasorum or periadventitial SVV). Clinical, serological, and PET/CT data of patients with SVV were compared with those with positive and those with negative biopsies.

RESULTS

For the 58 eligible patients recruited between May 2016 and December 2017, 11 had SVV, 12 had positive, and 35 had negative biopsies. Patients with SVV had similar clinical, serological, and PET/CT findings to those with negative biopsies. Compared with those with positive biopsies, patients with SVV had lower erythrocyte sedimentation rate (25 vs 78 mm/hour; P = 0.02), platelet count (296 vs 385 ×109/L; P = 0.03), and a lower median total vascular score on PET/CT scan (1.0 vs 13.5; P = 0.01). Median prednisone dose was lower (4.8 vs 11.7 mg; P = 0.015) and fewer were on steroid-sparing agents (20% vs 67%; P = 0.043) at 6 months. The percentage of patients with a clinical diagnosis of GCA was similar between those with SVV (3/11, 27.3%) and those with negative biopsies (5/35, 14.3%; P = 0.374).

CONCLUSIONS

Patients with SVV on TAB had similar clinical features, PET/CT findings, and 6-month outcomes to those with negative biopsies. Small vessel vasculitis can be treated as equivalent to a negative biopsy when being considered for diagnosis and treatment of GCA.

Significance of inflammation restricted to adventitial/periadventitial tissue on temporal artery biopsy

OBJECTIVE

To evaluate the characteristics and significance of inflammation restricted (RI) to the adventitial and/or periadventitial tissue on temporal artery biopsy (TAB).

METHODS

We studied a retrospective cohort of 80 patients with RI, extending our earlier series of 39 patients. For comparison purposes, we collected the same data from 254 patients with transmural inflammation (TMI) and 81 TAB-negative patients. A review of the literature was also performed.

RESULTS

A final diagnosis of giant cells arteritis (GCA) and/or polymyalgia rheumatica (PMR) was observed in 86% of patients with RI. Compared to TMI, GCA diagnosis was significantly less frequently observed in patients with RI and in those TAB-negative (p < 0.0001), while cranial manifestations were significantly less frequent (p = 0.001) and ESR and CRP values at diagnosis significantly reduced (p < 0.0001). PMR, permanent visual loss, and large vessel involvement at diagnosis were equally present in the 3 subgroups. The median duration of prednisone therapy, the cumulative prednisone dosages, and the relapse and long-term remission rates were similar between patients with GCA-RI and those with TMI. The positive likelihood ratios (LRs) of pathological evidence of RI at TAB for GCA or GCA/PMR diagnoses were 0.88 (CI, 0.61-1.27) and 1.15 (CI, 0.67-1.99), while that of inflammation limited to adventitia was 1.37 (CI, 0.59-3.19) and 3.77 (CI, 0.53-26.72). In the literature review, the positive LR of RI for GCA diagnosis was 0.92 (CI, 0.68-1.25).

CONCLUSION

A large part of the patients with RI have GCA/PMR, however, the diagnostic value of RI for GCA diagnosis is not relevant.

An atypical presentation of giant cell arteritis without headache

We describe an unusual case of giant cell arteritis initially manifesting as insidiously progressive spastic quadriparesis, widespread muscle wasting and fasciculations in the absence of headache, followed by a complete left pupil-involving 3rd nerve palsy 10 months later. MRI and CSF analysis revealed evidence of intracranial involvement with established white matter lesions and intrathecal oligoclonal bands, respectively, whilst whole body FDG-PET demonstrated isolated uptake within the descending aorta. The temporal arteries were clinically and radiologically unremarkable but biopsy showed transmural inflammation and multinucleate giant cells. A rapid, complete and sustained improvement followed steroid therapy.

Clinical comparisons of patients with giant cell arteritis with versus without fever at onset

Objective

Giant cell arteritis (GCA) is the most common systemic vasculitis in individuals aged ≥50 years. Some patients with GCA who develop fever at onset without typical ischemic manifestations may be misdiagnosed with fever of unknown origin.

Methods

In the present study, we retrospectively evaluated the clinical records of patients with GCA. Patients with and without fever at onset were compared.

Results

This study included 91 patients with GCA, 55 of whom had fever at onset. The patients with fever at onset showed a lower frequency of jaw claudication and arthralgia and a higher percentage of constitutional symptoms than patients without fever. Additionally, their laboratory results revealed a lower percentage of positive anti-neutrophil cytoplasmic antibody. Furthermore, a lower proportion of affected intracranial vessels was found in patients with fever at onset. Finally, the proportion of biopsy-positive cases was higher in patients with than without fever at onset.

Conclusions

In this study, 60.4% of patients with GCA had fever at onset. Patients in this group usually had more severe inflammation with a potentially lower risk of ischemic accidents of the central nervous system than patients without fever at onset.

Comparisons of clinical manifestations and prognosis between giant cell arteritis patients with or without sensorineural hearing loss: A retrospective study of Chinese patients

Auditory manifestations has rarely been mentioned in studies concerning giant cell arteritis (GCA). This study explores the proportion of hearing loss (HL) in Chinese GCA patients and investigates the differences in clinical features between GCA patients with and without HL.The study retrospectively reviewed the clinical records of 91 patients diagnosed with GCA at Peking Union Medical College Hospital (PUMCH) from November 1998 to October 2017. GCA diagnoses were reconfirmed according to the American College of Rheumatology 1990 criteria. Diagnosis of HL was made based on a patient's symptoms combined with physical examination or ear-nose-throat (ENT) audiometry tests. Subgroup analysis was conducted according to the occurrence of HL.Totally 23 patients (25.3%) had HL. A higher percentage of males (65.2% vs 38.2%, p = 0.025) was seen in HL group. Symptoms such as headache (91.3% vs 61.2%, p = 0.011), visual loss (56.5% vs 32.4%, p = 0.039) and CNS symptoms (39.1% vs 17.6%, p = 0.035) were more frequent in HL group. Moreover, they were more likely to have smoking history (p = 0.019), lower lymphocyte count (p = 0.049), positive ANA or APL (p = 0.047, p = 0.017) or negative biopsy results (p = 0.015). Symptom like myalgia (26.1% vs 66.2%, p = 0.001) as well as comorbid disease like coronary artery disease (p = 0.037) and hypertension (p = 0.040) was more frequent in patients without HL. Either C-reactive protein (90.91 ± 65.86 vs 76.05 ± 61.15 mg/L, p = 0.347) or erythrocyte sedition rate (83.04 ± 29.61 vs 93.69 ± 26.78 mm/h, p = 0.136) was high in both groups but the differences were not significant. Meanwhile, no significant differences were found in age, disease course, vascular involvement or prognosis between the two groups. Unilateral HL tended to happen at the same side with unilateral headache, visual loss, scalp tenderness or jaw claudication.HL is probably not rare in GCA patients and is more frequently to be seen in patients presented with headache, visual loss or CNS symptoms. Differentiation of HL is necessary for specialists and GCA should be considered as a potential diagnosis especially in HL patients with high inflammatory markers. Auditory assessment should be conducted in GCA management.

Review: What Is the Current Evidence for Disease Subsets in Giant Cell Arteritis?

Giant cell arteritis (GCA) is an autoimmune vasculitis affecting large and medium‐sized arteries. Ample evidence indicates that GCA is a heterogeneous disease in terms of symptoms, immune pathology, and response to treatment. In the current review, we discuss the evidence for disease subsets in GCA. We describe clinical and immunologic characteristics that may impact the risk of cranial ischemic symptoms, relapse rates, and long‐term glucocorticoid requirements in patients with GCA. In addition, we discuss both proven and putative immunologic targets for therapy in patients with GCA who have an unfavorable prognosis. Finally, we provide recommendations for further research on disease subsets in GCA.

Development of Giant Cell Arteritis after Treating Polymyalgia or Peripheral Arthritis: A Retrospective Case-control Study

Objective.

We investigated the development of giant cell arteritis (GCA) in patients with prior diagnoses of isolated polymyalgia rheumatica and/or peripheral arthritis (PMR/PA), and the potentially relevant characteristics of both illnesses in such patients.

Methods.

We retrospectively compared the features of 67 patients at the onset of PMR/PA, and their outcomes, to those of a random group of 65 patients with PMR/PA who did not develop late GCA. We also compared the features and outcomes of patients with late GCA to those of a random sample of patients with more usual GCA (65 with concurrent PMR/PA and 65 without).

Results.

Patients with late GCA represented 7.4% of all patients with GCA included in a large hospital-based inception cohort. PMR/PA preceded overt GCA by 27 months on average. Permanent visual loss developed in 10 patients, including 8 of 48 (17%) patients featuring cranial arteritis. A questionable female predominance was the only distinguishing feature of PMR/PA evolving into GCA; late GCA more often featured subclinical aortitis (OR 6.42, 95% CI 2.39–17.23; p < 0.001), headache (OR 0.44, 95% CI 0.19–1.03; p = 0.06), and fever (OR 0.29, 95% CI 0.13–0.64; p = 0.002) less often compared to the more usual form of GCA. Patients with either form of GCA experienced similar outcomes.

Conclusion.

A cranial arteritis pattern of late GCA is associated with a significant risk for ischemic blindness. However, compared to the usual form of GCA, late GCA is often less typical, with a higher frequency of silent aortitis. Patients with relapsing/refractory PMR may not be at increased risk for late GCA.

Giant cell arteritis and polymyalgia rheumatica: current challenges and opportunities

The fields of giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) have advanced rapidly, resulting in a new understanding of these diseases. Fast-track strategies and improved awareness programmes that prevent irreversible sight loss through early diagnosis and treatment are a notable advance. Ultrasonography and other imaging techniques have been introduced into routine clinical practice and there have been promising reports on the efficacy of biologic agents, particularly IL-6 antagonists such as tocilizumab, in treating these conditions. Along with these developments, which should improve outcomes in patients with GCA and PMR, new questions and unmet needs have emerged; future research should address which pathogenetic mechanisms contribute to the different phases and clinical phenotypes of GCA, what role imaging has in the early diagnosis and monitoring of GCA and PMR, and in which patients and phases of these diseases novel biologic drugs should be used. This article discusses the implications of recent developments in our understanding of GCA and PMR, as well as the unmet needs concerning epidemiology, pathogenesis, imaging and treatment of these diseases.

Poor Predictive Value of Isolated Adventitial and Periadventitial Infiltrates in Temporal Artery Biopsies for Diagnosis of Giant Cell Arteritis

OBJECTIVE

We investigated the diagnostic value of inflammation limited to the adventitia (ILA), and isolated vasa vasorum or small-vessel vasculitis (VVV, SVV) in temporal artery biopsies (TAB) for giant cell arteritis (GCA).

METHODS

Two pathologists reviewed consecutive first TAB. Using the clinical diagnoses as the gold standard, positive predictive values (PPV) were calculated.

RESULTS

Among the 75 patients without classic TAB features of GCA, 8 had GCA diagnoses. The PPV of ILA, VVV, and SVV seen by either or both pathologists were 17%, 0%, and 7%, and 17%, 0%, and 10%, respectively.

CONCLUSION

(Peri)adventitial infiltrates in TAB poorly predict GCA.

Giant Cell Arteritis and Polymyalgia Rheumatica: 2016 Update

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are both more common among people of North European decent than among Mediterranean people. Women are 2-3 times more commonly affected. Giant cell arteritis and PMR are extremely rare before age 50 years. Polymyalgia rheumatica may be "isolated" or associated with GCA. There is increased expression of inflammatory cytokines in temporal arteries of PMR patients, without overt histological evidence of arteritis. One-third of "isolated" PMR patients have vascular uptake in positron emission tomography (PET) scans, suggesting clinically unrecognized, "hidden" GCA. Typical manifestations of GCA are headache, tenderness over temporal arteries, jaw claudication, PMR, acute vision loss, and low-grade fever. Bilateral aching of the shoulders with morning stiffness is typical for PMR. In both conditions sedimentation rate and C-reactive protein are elevated, and anemia and thrombocytosis may occur. Color duplex ultrasonography of the temporal arteries may aid in GCA diagnosis. Temporal artery biopsy showing vasculitis, often with giant cells, confirms GCA diagnosis. In cases with negative biopsy one must rely on the clinical presentation and laboratory abnormalities. The diagnosis of PMR is made primarily on clinical grounds. Other conditions that may mimic GCA or PMR must be excluded. Glucocorticoids are the treatment of choice for both conditions. Prompt treatment is crucial in GCA, to prevent irreversible complications of acute vision loss and stroke. Addition of low-dose aspirin may further prevent these complications. The average duration of treatment is 2-3 years, but some patients require a prolonged course of treatment, and some may develop disease-related or treatment-related complications. No steroid-sparing agent has been proven to be widely effective thus far, but some promising therapeutic agents are currently being studied.

Is all inflammation within temporal artery biopsies temporal arteritis?

Temporal arteritis peaks during the eighth decade, affecting patients with frequent comorbidities who are especially prone to adverse effects of corticosteroid therapy. Perivascular inflammation involving small periadventitial vessels is not uncommon in otherwise normal temporal artery biopsies (TABs). As ischemic events occur in patients with non-temporal artery--based inflammation, it has been recommended that any vascular inflammation within TABs be treated with corticosteroids. We sought to determine whether such patients are at increased risk for temporal arteritis-like adverse events compared with age-matched controls devoid of inflammatory infiltrates. TABs without transmural temporal arteritic damage accessioned between 2002 and 2012 were reviewed for inflammation (>15 perivascular lymphocytes) involving small blood vessels and/or temporal artery adventitia. Of 343 TABs, 278 (81%) were negative for transmural arteritis. Inflammation involving small vessels and/or temporal artery adventitia was present in 56 cases (20%). Age-matched controls were available for 39 cases. With a mean follow-up of 5 years (range, 1-11 years), 6/39 (15%) of patients developed stroke or cardiovascular events or died compared with 7/39 (18%) of age-matched controls. None of the patients with study-positive TAB had documented steroid therapy before or after TAB. Our results demonstrate that patients with inflammation involving only small vessels or temporal artery adventitia are not at increased risk for temporal arteritis-like adverse events, and suggest that the risks of protracted corticosteroid therapy in this elderly population likely exceed any potential benefits. We advise against diagnosing vasculitis in the absence of temporal arteritic damage.

Advances in the diagnosis of large vessel vasculitis

The diagnosis of large-vessel vasculitis has experienced substantial improvement in recent years. While Takayasu arteritis diagnosis relies on imaging, the involvement of epicranial arteries by giant-cell arteritis facilitates histopathological confirmation. When appropriately performed temporal artery biopsy has high sensitivity and specificity. However, an optimal biopsy is not always achievable and, occasionally, the superficial temporal artery may not be involved. Imaging in its various modalities including colour-duplex ultrasonography, computed tomography angiography, magnetic resonance angiography and positron emission tomography, are emerging as important procedures for the diagnosis and assessment of disease extent in large-vessel vasculitis. Recent contributions to the better performance and interpretation of temporal artery biopsies as well as advances in imaging are the focus of the present review.

NKG2D stimulated T-cell autoreactivity in giant cell arteritis and polymyalgia rheumatica

OBJECTIVE

To investigate functional expression of NKG2D on CD4 and CD8 T-cells in patients with giant cell arteritis (GCA) and polymyalgia rheumatica (PMR).

METHODS

Peripheral blood was drawn from patients with GCA (n=16), PMR (n=78) and healthy controls (HC, n=64). Tissue samples were obtained from GCA patients and controls. Proliferation and cytokine production assays were performed using CFSE and intracellular IFN-γ or TNF-α staining, respectively, and flow cytometry analysis. Immunofluorescence and immunohistology were applied to analyse the presence of NKG2D-expressing T-cells and NKG2D-ligands in temporal arteries, respectively. mRNA levels of NKG2D-ligands were determined by RT-PCR.

RESULTS

In both GCA and PMR patients, NKG2D was preferentially expressed on senescent CD4CD28(-) and CD8CD28(-), as well as on CD8CD28 T-cells. Frequencies of senescent T-cells were increased in GCA and PMR patients compared to HC. In GCA tissue samples, infiltrating T-cells were predominately CD28(-). NKG2D expressing T-cells concentrated around the vasa vasorum of the adventitia. Antigenic stimulation induced rapid up-regulation of NKG2D on CD4CD28(-) and CD4CD28 T-cells, whereas TNF-α and interleukin-15 enhanced NKG2D expression on senescent CD4 and CD8 T-cells only. NKG2D cross-linkage augmented anti-CD3 triggered proliferation, IFN-γ and TNF-α production of CD8 T-cells. In CD4CD28(-) T-cells, NKG2D ligation resulted in increased IFN-γ production only. NKG2D ligands were expressed in temporal arteries from GCA patients, particularly in the adventitial and medial layers of affected vessels.

CONCLUSIONS

NKG2D is functionally expressed on CD4CD28(-) and CD8 T-cells in GCA and PMR. NKG2D-ligands are present in temporal arteries and may co-stimulate NKG2D expressing T-cells.

Small-vessel vasculitis surrounding an uninflamed temporal artery and isolated vasa vasorum vasculitis of the temporal artery: two subsets of giant cell arteritis

OBJECTIVE

To evaluate the frequency and clinical characteristics of periadventitial small-vessel vasculitis (SVV) and isolated vasa vasorum vasculitis (VVV).

METHODS

We identified 455 temporal artery biopsies performed in residents of Reggio Emilia, Italy between 1986 and 2003. Slides of temporal artery biopsy specimens were reviewed by a pathologist who was blinded with regard to clinical data. SVV was defined as inflammation of the small vessels external to the temporal artery adventitia, and VVV was defined as isolated inflammation of temporal artery vasa vasorum. Medical records of patients with SVV and/or VVV were reviewed, and demographic, clinical, laboratory, and followup data were collected. For comparison purposes, we collected the same data from an equal number of randomly selected patients with evidence of classic giant cell arteritis (GCA).

RESULTS

Sixteen patients had SVV, 18 had isolated VVV, and 5 had both SVV and VVV. Compared with patients with classic GCA, the frequencies of headache, scalp tenderness, abnormalities of temporal arteries, jaw claudication, anorexia, and weight loss, the levels of acute-phase reactant at diagnosis, and the initial and cumulative doses prednisone were significantly lower and the frequency of peripheral synovitis was higher in the patients with SVV, and the frequency of cranial ischemic events was similar in the 2 groups. In contrast, the clinical characteristics and erythrocyte sedimentation rate at diagnosis of patients with isolated VVV were similar to those of patients with classic GCA.

CONCLUSION

Our findings indicate that isolated VVV and SVV should be considered part of the histopathologic spectrum of GCA.

The immunopathology of giant cell arteritis: diagnostic and therapeutic implications

Giant cell arteritis (GCA) is an important cause of preventable blindness, most commonly due to anterior ischemic optic neuropathy. Ischemic tissue injury is the end result of a process that begins within the walls of susceptible arteries in which local dendritic cells (DCs) recruit and activate CD4 T cells that, in turn, direct the activity of effector macrophages. In response to the immune attack, the blood vessel forms lumen-stenosing intima. Multiple cascades of excessive T-cell reactivity contribute to the autoimmune features of giant cell arteritis with TH1 and TH17 immunity responsible for the early phase and TH1 immunity promoting chronic-smoldering inflammation. These cascades are only partially overlapping, supporting the concept that a multitude of instigators induce and sustain vascular inflammation. The artery actively participates in the abnormal immune response through endogenous immune sentinels, so-called vascular DCs embedded in the adventitia. Advancing age, the strongest of all risk factors for GCA, contributes to both, the dysfunction of the immune system and the vascular system. Expansion of the therapeutic armamentarium for GCA needs to focus on approaches that mitigate the impact of the aging artery and adapt to the needs of the immunosenescent host.

Identification of target antigens of anti-endothelial cell and anti-vascular smooth muscle cell antibodies in patients with giant cell arteritis: a proteomic approach

Introduction

Immunological studies of giant cell arteritis (GCA) suggest that a triggering antigen of unknown nature could generate a specific immune response. We thus decided to detect autoantibodies directed against endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in the serum of GCA patients and to identify their target antigens.

Methods

Sera from 15 GCA patients were tested in 5 pools of 3 patients' sera and compared to a sera pool from 12 healthy controls (HCs). Serum immunoglobulin G (IgG) reactivity was analysed by 2-D electrophoresis and immunoblotting with antigens from human umbilical vein ECs (HUVECs) and mammary artery VSMCs. Target antigens were identified by mass spectrometry.

Results

Serum IgG from GCA patients recognised 162 ± 3 (mean ± SD) and 100 ± 17 (mean ± SD) protein spots from HUVECs and VSMCs, respectively, and that from HCs recognised 79 and 94 protein spots, respectively. In total, 30 spots from HUVECs and 19 from VSMCs were recognised by at least two-thirds and three-fifths, respectively, of the pools of sera from GCA patients and not by sera from HCs. Among identified proteins, we found vinculin, lamin A/C, voltage-dependent anion-selective channel protein 2, annexin V and other proteins involved in cell energy metabolism and key cellular pathways. Ingenuity pathway analysis revealed that most identified target antigens interacted with growth factor receptor-bound protein 2.

Conclusions

IgG antibodies to proteins in the proteome of ECs and VSMCs are present in the sera of GCA patients and recognise cellular targets that play key roles in cell biology and maintenance of homeostasis. Their potential pathogenic role remains to be determined.

Imaging of polymyalgia rheumatica: indications on its pathogenesis, diagnosis and prognosis

OBJECTIVES

Imaging is one of the most appealing techniques to explore PMR, a disease whose causes, development mechanisms and anatomical targets of inflammatory damage are still scarcely known. This review is concerned with an appraisal of PMR with different imaging modalities with a view to highlighting possible clues to its pathogenesis, diagnosis and prognosis.

METHODS

A systematic literature research was performed searching PubMed until July 2010. The Cochrane Library was searched for the relevant reviews, and the abstracts of the ACR and European League Against Rheumatism congresses of the period 2005-10 were reviewed.

RESULTS

A total of 1059 papers were retrieved, 46 of which were selected at the end of the review process; 6 of them were concerned with two different imaging techniques. Of these papers, 6 (11.5%) were concerned with conventional radiology; 8 (15.4%) with scintigraphy; 17 (32.7%) with ultrasonography (US); 15 (28.8%) with MRI; and 6 (11.5%) with PET. MRI, US and PET appeared to be the most promising imaging techniques. Bilateral subacromial bursitis, biceps long head tenosynovitis and trochanteric bursitis were particularly consistent findings. In addition, MRI and PET showed interspinous bursitis and PET frequently showed large-vessel vasculitis. Few papers have addressed the role of imaging for diagnosis, differential diagnosis and prognosis of PMR.

CONCLUSIONS

Imaging plays an important role in the comprehensive evaluation of PMR, including its pathogenesis, diagnosis and prognosis. Most of its potential is still unexplored, which fact should stimulate further research.

Increased muscle interstitial levels of inflammatory cytokines in polymyalgia rheumatica

OBJECTIVE

Polymyalgia rheumatica (PMR) is characterized by aching of the proximal muscles and increased blood levels of markers of inflammation. Despite the muscle complaints, the current view is that symptoms are caused by inflammation in synovial structures. The purpose of this study was to elucidate the disease mechanisms in symptomatic muscles by measuring interstitial levels of cytokines before and after prednisolone treatment.

METHODS

Twenty glucocorticoid-naive patients newly diagnosed as having PMR and 20 control subjects were studied before and after 14 days of prednisolone therapy (20 mg/day). Interstitial concentrations of interleukin-1α/β (IL-1α/β), IL-1 receptor antagonist, IL-6, IL-8, tumor necrosis factor α (TNFα), and monocyte chemoattractant protein 1 were measured in symptomatic vastus lateralis and trapezius muscles using the microdialysis technique. Plasma levels were measured simultaneously.

RESULTS

Prednisolone abolished symptoms in all of the PMR patients within 1-2 days; the erythrocyte sedimentation rate and C-reactive protein levels were normalized on day 14. In both muscles, interstitial concentrations of all cytokines were markedly higher (P < 0.05) in the PMR patients than in the controls before treatment. In both patients and controls, interstitial levels of most cytokines were higher than plasma levels, with the exception of IL-1α and TNFα, which were lower in both groups. In the PMR patients, interstitial concentrations were normalized after prednisolone treatment.

CONCLUSION

This study introduces a novel view of PMR, indicating that increased interstitial levels of inflammatory cytokines in symptomatic muscles play a role in the pathophysiology of the disease and that cytokines may be released locally. To explore the disease specificity, similar studies in other primary inflammatory conditions are warranted.

Elevated muscle interstitial levels of pain-inducing substances in symptomatic muscles in patients with polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is characterized by aching proximal muscles and systemic inflammation. We explored the pain-eliciting mechanisms by measuring interstitial levels in muscle of potentially pain-inducing substances as well as local blood flow. Twenty glucocorticoid-naive patients with newly diagnosed PMR and 20 controls were examined before and after 14 days of prednisolone (20 mg/day). Concentrations of glutamate, prostaglandin E(2) (PGE(2)), bradykinin, serotonin, adenosine triphosphate, lactate, pyruvate, and potassium as well as extraction of (3)H(2)O were measured in symptomatic vastus lateralis and trapezius muscles using microdialysis. Plasma levels were measured simultaneously. To be considered potentially pain inducing, interstitial concentrations of candidates should be higher in patients vs. controls, be normalized by prednisolone, and be higher in muscle vs. plasma. Prednisolone abolished symptoms in all patients within 2 days. Before treatment glutamate in both muscles (vastus: 60±7 vs. 38±7 μmol/L; trapezius: 60±6 vs. 43±7 μmol/L) and PGE(2) in vastus (911±200 vs. 496±122 pg/mL) were higher in patients than in controls (P<0.05), and higher in muscle than in plasma (P<0.05). Prednisolone abolished the differences between patients and controls. No other candidate completely fulfilled the predefined requirements for pain-inducing substances in PMR. (3)H(2)O extraction was identical between groups. In conclusion, local release of glutamate and PGE(2), but not ischemia, may contribute to the muscle pain in PMR. This supports the view that intramuscular mechanisms are important in PMR.

Blocking the NOTCH pathway inhibits vascular inflammation in large-vessel vasculitis

BACKGROUND

Giant cell arteritis is a granulomatous vasculitis of the aorta and its branches that causes blindness, stroke, and aortic aneurysm. CD4 T cells are key pathogenic regulators, instructed by vessel wall dendritic cells to differentiate into vasculitic T cells. The unique pathways driving this dendritic cell-T-cell interaction are incompletely understood, but may provide novel therapeutic targets for a disease in which the only established therapy is long-term treatment with high doses of corticosteroids.

METHODS AND RESULTS

Immunohistochemical and gene expression analyses of giant cell arteritis-affected temporal arteries revealed abundant expression of the NOTCH receptor and its ligands, Jagged1 and Delta1. Cleavage of the NOTCH intracellular domain in wall-infiltrating T cells indicated ongoing NOTCH pathway activation in large-vessel vasculitis. NOTCH activation did not occur in small-vessel vasculitis affecting branches of the vasa vasorum tree. We devised 2 strategies to block NOTCH pathway activation: γ-secretase inhibitor treatment, preventing nuclear translocation of the NOTCH intracellular domain, and competing for receptor-ligand interactions through excess soluble ligand, Jagged1-Fc. In a humanized mouse model, NOTCH pathway disruption had strong immunosuppressive effects, inhibiting T-cell activation in the early and established phases of vascular inflammation. NOTCH inhibition was particularly effective in downregulating Th17 responses, but also markedly suppressed Th1 responses.

CONCLUSIONS

Blocking NOTCH signaling depleted T cells from the vascular infiltrates, implicating NOTCH- NOTCH ligand interactions in regulating T-cell retention and survival in vessel wall inflammation. Modulating the NOTCH signaling cascade emerges as a promising new strategy for immunosuppressive therapy of large-vessel vasculitis.

Temporal Small-Vessel Inflammation in Patients with Giant Cell Arteritis: Clinical Course and Preliminary Immunohistopathologic Characterization

Objective.

To investigate the occurrence, clinical correlates, and immunohistochemical phenotype of temporal small-vessel inflammation (TSVI) in temporal artery biopsies from patients presenting with clinical features of giant cell arteritis (GCA).

Methods.

We retrospectively reviewed 41 temporal artery biopsy specimens for the presence of inflammatory infiltrates in small vessels external to the temporal artery adventitia (TSVI); 33 had sufficient clinical and pathological data for detailed analysis. Clinical and laboratory features at presentation and corticosteroid treatment patterns of patients with isolated TSVI were compared to those of patients with positive and negative biopsies. The cellular composition of the infiltrates was further characterized by immunohistochemistry.

Results.

Twenty-three (70%) specimens had evidence of TSVI including 10 with concurrent GCA and 13 (39%) with isolated TSVI. TSVI was found in all positive temporal artery biopsies. The proportion of macrophages and of lymphocyte subpopulations differed between infiltrates observed in TSVI and those of the main temporal artery wall. Initial erythrocyte sedimentation rate (ESR) was similar in the TSVI and positive biopsy groups and was significantly higher than in the negative biopsy group. Patients with isolated TSVI more often had symptoms of polymyalgia rheumatica compared to the positive biopsy group. Patients with TSVI received corticosteroid doses that were intermediate between patients with positive and those with negative biopsies.

Conclusion.

A significant number of patients with clinical features of GCA demonstrated isolated TSVI. Differences in the clinical presentation and cellular composition suggest that TSVI may represent a subset of GCA and should be considered in the interpretation of temporal artery biopsies and treatment decisions.

Vascular damage in giant cell arteritis

Immune-mediated damage to medium-sized arteries results in wall remodeling with intimal hyperplasia, luminal stenosis and tissue ischemia. In the case of the aorta, vasculitis may result in dissection, aneurysm or rupture. The response-to-injury program of the blood vessel is a concerted action between the immune system and wall-resident cells, involving the release of growth and angiogenic factors from macrophages and giant cells and the migration and hyperproliferation of vascular smooth muscle cells. Innate immune cells, specifically, dendritic cells (DC) positioned in the vessel wall, have been implicated in the earliest steps of vasculitis. Pathogen-derived molecular patterns are capable of activating vascular DC and initiating adaptive immune responses. The pattern of the emerging vessel wall inflammation is ultimately determined by the initial insult. Ligands to toll-like receptor (TLR) 4, such as lipopolysaccharides, facilitate the recruitment of CD4 T cells that invade deep into the wall and distribute in a panarteritic pattern. Conversely, ligands for TLR5 condition vascular DC to support perivasculitic infiltrates. In essence, both innate and adaptive immune reactions collaborate to render the arterial wall susceptible to inflammatory damage. Unique features of the tissue microenvironment, including specialized DC, shape the course of the inflammatory response. Differences in vascular damage pattern encountered in different patients may relate to distinct instigators of vasculitis.

[Pathogenesis of medium- and large-vessel vasculitis]

Giant cell arteritis (GCA), is a systemic vasculitis which preferentially targets large and medium branches of the upper-body aorta. Typical clinical manifestations result from arterial stenosis/occlusion causing blindness, stroke and aortic arch syndrome. Aortic involvement leads to dissection and aneurysm. On the cellular and molecular level, GCA is a sequel of abnormal innate and adaptive immune responses that occur in the specialized tissue niche of the arterial wall. Based on recent pathogenic studies, a novel disease model for GCA is emerging. It is now understood that the series of pathogenic events begins with dendritic cells (DC) indigenous to the artery's outer wall, leading to inflammatory vasculopathy. Placed close to the vasa vasorum, vascular DC are highly sensitive in recognizing pathogen-associated motifs assigning immune monitoring functions to blood vessels. Thus the large vessels are actively involved in immune monitoring. Each vascular territory expresses a unique profile of pathogen-sensing receptors, emphasizing functional diversity amongst structurally similar arteries. Innate immune stimulators can transform vascular DC into efficient antigen-presenting cells, attracting, activating, and instructing T lymphocytes to acquire tissue-invasive features. Macrophages provide critical tissue-damaging effector functions, directly injuring wall-residing cells and promoting a remodeling process that leads to intimal hyperplasia and luminal occlusion. Novel diagnostic and therapeutic approaches to GCA need to focus on the key position of vascular DC and the signals that break the immunoprivileged state of the vessel wall.

Toll-like receptors 4 and 5 induce distinct types of vasculitis

Large vessel vasculitides, such as Takayasu arteritis and giant cell arteritis, affect vital arteries and cause clinical complications by either luminal occlusion or vessel wall destruction. Inflammatory infiltrates, often with granulomatous arrangements, are distributed as a panarteritis throughout all of the artery's wall layers or cluster in the adventitia as a perivasculitis. Factors determining the architecture and compartmentalization of vasculitis are unknown. Human macrovessels are populated by indigenous dendritic cells (DCs) positioned in the adventitia. Herein, we report that these vascular DCs sense bacterial pathogens and regulate the patterning of the emerging arteritis. In human temporal artery-SCID chimeras, lipopolysaccharides stimulating Toll-like receptor (TLR)4 and flagellin stimulating TLR5 trigger vascular DCs and induce T-cell recruitment and activation. However, the architecture of the evolving inflammation is ligand-specific; TLR4 ligands cause transmural panarteritis and TLR5 ligands promote adventitial perivasculitis. Underlying mechanisms involve selective recruitment of functional T cell subsets. Specifically, TLR4-mediated DC stimulation markedly enhances production of the chemokine CCL20, biasing recruitment toward CCL20-responsive CCR6(+) T cells. In adoptive transfer experiments, CCR6(+) T cells produce an arteritis pattern with media-invasive T cells damaging vascular smooth muscle cells. Also, CCR6(+) T cells dominate the vasculitic infiltrates in patients with panarteritic giant cell arteritis. Thus, depending on the original danger signal, vascular DCs edit the emerging immune response by differentially recruiting specialized T effector cells and direct the disease process toward distinct types of vasculitis.