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Summary For years, clinicians and researchers working on giant cell arteritis have been battling with the conundrum of a disease that displays a short-term steroid responsiveness but is burdened by a remarkable risk of flares and chronic damage in the long term. This issue should be addressed by a change in the direction of research and clinical practice. Evidence suggests that giant cell arteritis is not a monolithic disease; it varies in extent and severity. Hence, treatment should be guided by disease stratification. The current one-size-fits-all strategy leads to overreliance on glucocorticoids and progression of glucocorticoid-related and disease-related complications. A new approach requires disease stratification using clinical, laboratory, histology, and imaging parameters. A giant cell arteritis registry might offer opportunities to scrutinise disease course and prognostic variables early; however, more studies that directly incorporate disease stratification through the above parameters are required. This Series paper also suggests that future clinical trials should be targeted at patients with different disease strata of giant cell arteritis and should incorporate ultrasound, PET-CT scanning, and other imaging modalities as key outcomes.

Background The aim of this study was to explore the feasibility of assisted diagnosis of active (peri-)aortitis using radiomic imaging biomarkers derived from [18F]-Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography (FDG PET–CT) images. Methods The aorta was manually segmented on FDG PET–CT in 50 patients with aortitis and 25 controls. Radiomic features (RF) (n = 107), including SUV (Standardized Uptake Value) metrics, were extracted from the segmented data and harmonized using the ComBat technique. Individual RFs and groups of RFs (i.e., signatures) were used as input in Machine Learning classifiers. The diagnostic utility of these classifiers was evaluated with area under the receiver operating characteristic curve (AUC) and accuracy using the clinical diagnosis as the ground truth. Results Several RFs had high accuracy, 84% to 86%, and AUC scores 0.83 to 0.97 when used individually. Radiomic signatures performed similarly, AUC 0.80 to 1.00. Conclusion A methodological framework for a radiomic-based approach to support diagnosis of aortitis was outlined. Selected RFs, individually or in combination, showed similar performance to the current standard of qualitative assessment in terms of AUC for identifying active aortitis. This framework could support development of a clinical decision-making tool for a more objective and standardized assessment of aortitis.

Several factors that influence physiologic 18F-fluorodeoxyglucose (FDG) uptake and general FDG distribution may affect PET/CT imaging in infection and inflammation. The general impact of hyperglycemia on the diagnostic performance of FDG-PET/CT is probably less in infection/inflammation than in malignancy. Patient preparation may reduce physiologic FDG uptake, but recommendations are less established than in malignancy. Local implementation of various patient preparatory measures should reflect the specific patient population and indications. This article outlines some of the challenges with physiologic FDG distribution, focusing on infectious and inflammatory diseases, and potential countermeasures and patient preparation to limit physiologic uptake before scan.

To confirm the diagnosis of large vessel vasculitis (LVV) with high accuracy, one of the recommended imaging techniques is [18F]Fluoro-2-deoxy-d-glucose positron emission tomography with computed tomography ([18F]FDG-PET/CT). Visual assessment of [18F]FDG uptake in the arterial wall compared to liver uptake is the mainstay for diagnosing LVV in routine clinical practice. To date, there is no consensus on the preferred semi-quantitative or quantitative parameter for diagnosing LVV. The aim of this review is to critically update the knowledge on the available evidence of semi-quantitative and quantitative [18F]FDG uptake parameters for diagnosing LVV and to provide future directions for methodological standardization and research.

To confirm the diagnosis of large vessel vasculitis (LVV) with high accuracy, one of the recommended imaging techniques is [F-18]Fluoro-2-deoxy-d-glucose positron emission tomography with computed tomography ([F-18]FDG-PET/CT). Visual assessment of [F-18]FDG uptake in the arterial wall compared to liver uptake is the mainstay for diagnosing LVV in routine clinical practice. To date, there is no consensus on the preferred semi-quantitative or quantitative parameter for diagnosing LVV. The aim of this review is to critically update the knowledge on the available evidence of semi-quantitative and quantitative [F-18]FDG uptake parameters for diagnosing LVV and to provide future directions for methodological standardization and research.

Giant cell arteritis (GCA) is a granulomatous large-vessel vasculitis that affects adults above 50 years of age. In GCA, circulating monocytes are recruited to the inflamed arteries. With cues from the vascular microenvironment, they differentiate into macrophages and play important roles in the pathogenesis of GCA via pro-inflammatory cytokine production and vascular remodeling. However, a deeper understanding of macrophage heterogeneity in GCA pathogenesis is needed to assist the development of novel diagnostic tools and targeted therapies. Here, we review the current knowledge on macrophage heterogeneity and diverse functions of macrophage subsets in the pathogenesis of GCA. We next discuss the possibility to exploit their heterogeneity as a source of novel biomarkers and as targets for nuclear imaging. Finally, we discuss novel macrophage-targeted therapies and future directions for targeting these cells in GCA.

White blood cells activated by either a pathogen or as part of a systemic inflammatory disease are characterized by high energy consumption and are therefore taking up the glucose analogue PET tracer FDG avidly. It is therefore not surprising that a steadily growing body of research and clinical reports now supports the use of FDG PET/CT to diagnose a wide range of patients with non-oncological diseases. However, using FDG PET/CT in patients with infectious or inflammatory diseases has some limitations and potential pitfalls that are not necessarily as pronounced in oncology FDG PET/CT. Some of these limitations are of a general nature and related to the laborious acquisition of PET images in patients that are often acutely ill, whereas others are more disease-specific and related to the particular metabolism in some of the organs most commonly affected by infections or inflammatory disease. Both inflammatory and infectious diseases are characterized by a more diffuse and less pathognomonic pattern of FDG uptake than oncology FDG PET/CT and the affected organs also typically have some physiological FDG uptake. In addition, patients referred to PET/CT with suspected infection or inflammation are rarely treatment naïve and may have received varying doses of antibiotics, corticosteroids or other immune-modulating drugs at the time of their examination. Combined, this results in a higher rate of false positive FDG findings and also in some cases a lower sensitivity to detect active disease. In this review, we therefore discuss the limitations and pitfalls of FDG PET/CT to diagnose infections and inflammation taking these issues into consideration. Our review encompasses the most commonly encountered inflammatory and infectious diseases in head and neck, in the cardiovascular system, in the abdominal organs and in the musculoskeletal system. Finally, new developments in the field of PET/CT that may help overcome some of these limitations are briefly highlighted.

BackgroundRheumatic and musculoskeletal immune-related adverse events (irAEs) are observed in about 10% of patients with cancer receiving checkpoint inhibitors (CPIs). Given the recent emergence of these events and the lack of guidance for rheumatologists addressing them, a European League Against Rheumatism task force was convened to harmonise expert opinion regarding their identification and management.MethodsFirst, the group formulated research questions for a systematic literature review. Then, based on literature and using a consensus procedure, 4 overarching principles and 10 points to consider were developed.ResultsThe overarching principles defined the role of rheumatologists in the management of irAEs, highlighting the shared decision-making process between patients, oncologists and rheumatologists. The points to consider inform rheumatologists on the wide spectrum of musculoskeletal irAEs, not fulfilling usual classification criteria of rheumatic diseases, and their differential diagnoses. Early referral and facilitated access to rheumatologist are recommended, to document the target organ inflammation. Regarding therapeutic, three treatment escalations were defined: (1) local/systemic glucocorticoids if symptoms are not controlled by symptomatic treatment, then tapered to the lowest efficient dose, (2) conventional synthetic disease-modifying antirheumatic drugs, in case of inadequate response to glucocorticoids or for steroid sparing and (3) biological disease-modifying antirheumatic drugs, for severe or refractory irAEs. A warning has been made on severe myositis, a life-threatening situation, requiring high dose of glucocorticoids and close monitoring. For patients with pre-existing rheumatic disease, baseline immunosuppressive regimen should be kept at the lowest efficient dose before starting immunotherapies.ConclusionThese statements provide guidance on diagnosis and management of rheumatic irAEs and aim to support future international collaborations.

Tocilizumab (TCZ), an IL-6 receptor blocker, is approved for relapsing, refractory giant cell arteritis (GCA). We report real-life clinical experience with TCZ in GCA including assessment of responses on imaging (ultrasound (US) and 18F-Fluorodeoxyglucose Positron Emission Tomography-computed Tomography (18FDG-PET-CT)) during the first year of treatment. We included 22 consecutive patients with GCA treated with TCZ where EULAR core data set on disease activity, quality of life (QoL) and treatment-related complications were collected. Pre-TCZ US and 18FDG-PET/CT findings were available for 21 and 4 patients, respectively, where we determined the effect on US halo thickness, temporal and axillary artery Southend Halo Score and Total Vascular Score on 18FDG-PET-CT. The 22 patients with GCA (10 cranial, 10 large vessel, 2 both) had a median disease duration of 58.5 (range, 1–370) weeks prior to initiation of TCZ. Half had used prior conventional synthetic disease-modifying antirheumatic drug (csDMARDs). TCZ was initiated for refractory (50%), ischaemic (36%) or relapsing (14%) disease. Median follow-up was 43 (12–52) weeks. TCZ was discontinued due to serious adverse events (SAEs) in two patients. On treatment with TCZ, 4 discontinued prednisolone, 11 required doses ≤2.5 mg, 2 required daily dose of 2.5–5 mg and 5 needed prednisolones ≥5 mg daily. QoL improved by 50%. Total US halo thickness decreased in 38 arterial segments, median temporal artery Halo Score decreased from 11 to 0, axillary artery Halo Score remained stable. Median Total Vascular Score on FDG-PET/CT reduced from 11.5 to 6.5. In our experience, TCZ showed an excellent response with acceptable safety in GCA, with improvement on US and FDG-PET/CT imaging.

Background and aimGiant cell arteritis (GCA) remains a medical emergency because of the risk of sudden irreversible sight loss and rarely stroke along with other complications. Because headache is one of the cardinal symptoms of cranial GCA, neurologists need to be up to date with the advances in investigation and management of this condition. The aim of this document by the European Headache Federation (EHF) is to provide an evidence-based and expert-based recommendations on GCA.MethodsThe working group identified relevant questions, performed systematic literature review and assessed the quality of available evidence, and wrote recommendations. Where there was not a high level of evidence, the multidisciplinary (neurology, ophthalmology and rheumatology) group recommended best practice based on their clinical experience.ResultsAcross Europe, fast track pathways and the utility of advanced imaging techniques are helping to reduce diagnostic delay and uncertainty, with improved clinical outcomes for patients. GCA is treated with high dose glucocorticoids (GC) as a first line agent however long-term GC toxicity is one of the key concerns for clinicians and patients. The first phase 2 and phase 3 randomised controlled trials of Tocilizumab, an IL-6 receptor antagonist, have been published. It is now been approved as the first ever licensed drug to be used in GCA.ConclusionThe present article will outline recent advances made in the diagnosis and management of GCA.

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.

Macrophages are key players in the pathogenesis of large-vessel vasculitis (LVV) and may serve as a target for diagnostic imaging of LVV. The radiotracer, 18F-FDG has proven to be useful in the diagnosis of giant cell arteritis (GCA), a form of LVV. Although uptake of 18F-FDG is high in activated macrophages, it is not a specific radiotracer as its uptake is high in any proliferating cell and other activated immune cells resulting in high non-specific background radioactivity especially in aging and atherosclerotic vessels which dramatically lowers the diagnostic accuracy. Evidence also exists that the sensitivity of 18F-FDG PET drops in patients upon glucocorticoid treatment. Therefore, there is a clinical need for more specific radiotracers in imaging GCA to improve diagnostic accuracy. Numerous clinically established and newly developed macrophage targeted radiotracers for oncological and inflammatory diseases can potentially be utilized for LVV imaging. These tracers are more target specific and therefore may provide lower background radioactivity, higher diagnostic accuracy and the ability to assess treatment effectiveness. However, current knowledge regarding macrophage subsets in LVV lesions is limited. Further understanding regarding macrophage subsets in vasculitis lesion is needed for better selection of tracers and new targets for tracer development. This review summarizes the development of macrophage targeted tracers in the last decade and the potential application of macrophage targeted tracers currently used in other inflammatory diseases in imaging LVV.

Macrophages are key players in the pathogenesis of large-vessel vasculitis (LVV) and may serve as a target for diagnostic imaging of LVV. The radiotracer, 18F-FDG has proven to be useful in the diagnosis of giant cell arteritis (GCA), a form of LVV. Although uptake of 18F-FDG is high in activated macrophages, it is not a specific radiotracer as its uptake is high in any proliferating cell and other activated immune cells resulting in high non-specific background radioactivity especially in aging and atherosclerotic vessels which dramatically lowers the diagnostic accuracy. Evidence also exists that the sensitivity of 18F-FDG PET drops in patients upon glucocorticoid treatment. Therefore, there is a clinical need for more specific radiotracers in imaging GCA to improve diagnostic accuracy. Numerous clinically established and newly developed macrophage targeted radiotracers for oncological and inflammatory diseases can potentially be utilized for LVV imaging. These tracers are more target specific and therefore may provide lower background radioactivity, higher diagnostic accuracy and the ability to assess treatment effectiveness. However, current knowledge regarding macrophage subsets in LVV lesions is limited. Further understanding regarding macrophage subsets in vasculitis lesion is needed for better selection of tracers and new targets for tracer development. This review summarizes the development of macrophage targeted tracers in the last decade and the potential application of macrophage targeted tracers currently used in other inflammatory diseases in imaging LVV.

To develop evidence-based recommendations for the use of imaging modalities in primary large vessel vasculitis (LVV) including giant cell arteritis (GCA) and Takayasu arteritis (TAK). European League Against Rheumatism (EULAR) standardised operating procedures were followed. A systematic literature review was conducted to retrieve data on the role of imaging modalities including ultrasound, MRI, CT and [F-18]-fluorodeoxyglucose positron emission tomography (PET) in LVV. Based on evidence and expert opinion, the task force consisting of 20 physicians, healthcare professionals and patients from 10 EULAR countries developed recommendations, with consensus obtained through voting. The final level of agreement was voted anonymously. A total of 12 recommendations have been formulated. The task force recommends an early imaging test in patients with suspected LVV, with ultrasound and MRI being the first choices in GCA and TAK, respectively. CT or PET may be used alternatively. In case the diagnosis is still in question after clinical examination and imaging, additional investigations including temporal artery biopsy and/or additional imaging are required. In patients with a suspected flare, imaging might help to better assess disease activity. The frequency and choice of imaging modalities for long-term monitoring of structural damage remains an individual decision; close monitoring for aortic aneurysms should be conducted in patients at risk for this complication. All imaging should be performed by a trained specialist using appropriate operational procedures and settings. These are the first EULAR recommendations providing up-to-date guidance for the role of imaging in the diagnosis and monitoring of patients with (suspected) LVV.

International audience; Giant cell arteritis (GCA) is a large-vessel vasculitis whose diagnosis is confirmed by temporal artery biopsy. However, involvement of large vessels, especially the aorta, can be shown by imaging, which plays an increasing role in GCA diagnosis. The threshold above which aortic wall thickening, as measured by computed tomography (CT), is considered pathological is controversial, with values ranging from 2 to 3 mm. This study assessed aortic morphology by CT scan and its diagnostic value in GCA. Altogether, 174 patients were included (64 with GCA, 43 with polymyalgia rheumatica and 67 controls). All patients had a CT scan at diagnosis or at inclusion for controls. Aortic wall thickness, aortic diameter and scores for atheroma were measured. Assessor was blinded to each patient's group. Aortic diameters and atheroma scores were similar between groups. Aortic wall thickness was greater in the GCA group, even after the exclusion of GCA patients with aortic wall thickness >= 3 mm. The receiver operating characteristic (ROC) curve showed that a wall thickness of 2.2 mm was the optimal threshold to diagnose GCA (sensitivity, 67%; specificity, 98%). Measuring aortic wall thickness by CT scan is effective to diagnose GCA. The optimal threshold to regard aortic wall thickening as pathological was >= 2.2 mm. aEuro cent Imaging, including CT scan, plays an increasing role in GCA diagnosis aEuro cent CT measurement of aortic wall thickness is useful to diagnose GCA aEuro cent A 2.2-mm threshold allows the diagnosis of thickened aortic wall in GCA.

BACKGROUND: Giant-cell arteritis commonly relapses when glucocorticoids are tapered, and the prolonged use of glucocorticoids is associated with side effects. The effect of the interleukin-6 receptor alpha inhibitor tocilizumab on the rates of relapse during glucocorticoid tapering was studied in patients with giant-cell arteritis.METHODS: In this 1-year trial, we randomly assigned 251 patients, in a 2:1:1:1 ratio, to receive subcutaneous tocilizumab (at a dose of 162 mg) weekly or every other week, combined with a 26-week prednisone taper, or placebo combined with a prednisone taper over a period of either 26 weeks or 52 weeks. The primary outcome was the rate of sustained glucocorticoid-free remission at week 52 in each tocilizumab group as compared with the rate in the placebo group that underwent the 26-week prednisone taper. The key secondary outcome was the rate of remission in each tocilizumab group as compared with the placebo group that underwent the 52-week prednisone taper. Dosing of prednisone and safety were also assessed.RESULTS: Sustained remission at week 52 occurred in 56% of the patients treated with tocilizumab weekly and in 53% of those treated with tocilizumab every other week, as compared with 14% of those in the placebo group that underwent the 26-week prednisone taper and 18% of those in the placebo group that underwent the 52-week prednisone taper (PCONCLUSIONS: Tocilizumab, received weekly or every other week, combined with a 26-week prednisone taper was superior to either 26-week or 52-week prednisone tapering plus placebo with regard to sustained glucocorticoid-free remission in patients with giant-cell arteritis. Longer follow-up is necessary to determine the durability of remission and safety of tocilizumab. (Funded by F. Hoffmann-La Roche; ClinicalTrials.gov number, NCT01791153 .).

Whereas in the past the term "vasculitis" was most frequently used in context with systemic vasculitides, such as the large vessel vasculitides (LVV) Takayasa arteritis and giant cell arteritis, characterized by inflammation of blood vessel walls, it nowadays comprises also inflammatory changes of the vessel wall as a substantial part of the atherosclerotic disease process. Implementing non-invasive imaging techniques, such as computed tomography angiography (CTA), magnetic resonance angiography (MRA) as well as positron emission tomography (PET) in the diagnostic algorithm of atherosclerosis and LVV, depicts a promising step towards an earlier detection with a, consecutively, improved therapeutic approach and potentially prognostic benefit in patients suffering from vasculitis. Mainly molecular imaging with 18F-fluorodeoxyglucose (FDG) PET seems to be promising in offering an early and sensitive identification of inflammatory changes in both, atherosclerosis and LVV. This review will therefore provide an overview on the diagnostic performance and clinical relevance of FDG-PET in monitoring vasculitis in atherosclerosis and LVV, with a focus on LVV.

To develop evidence-based recommendations for the use of imaging modalities in primary large vessel vasculitis (LVV) including giant cell arteritis (GCA) and Takayasu arteritis (TAK). European League Against Rheumatism (EULAR) standardised operating procedures were followed. A systematic literature review was conducted to retrieve data on the role of imaging modalities including ultrasound, MRI, CT and [18F]-fluorodeoxyglucose positron emission tomography (PET) in LVV. Based on evidence and expert opinion, the task force consisting of 20 physicians, healthcare professionals and patients from 10 EULAR countries developed recommendations, with consensus obtained through voting. The final level of agreement was voted anonymously. A total of 12 recommendations have been formulated. The task force recommends an early imaging test in patients with suspected LVV, with ultrasound and MRI being the first choices in GCA and TAK, respectively. CT or PET may be used alternatively. In case the diagnosis is still in question after clinical examination and imaging, additional investigations including temporal artery biopsy and/or additional imaging are required. In patients with a suspected flare, imaging might help to better assess disease activity. The frequency and choice of imaging modalities for long-term monitoring of structural damage remains an individual decision; close monitoring for aortic aneurysms should be conducted in patients at risk for this complication. All imaging should be performed by a trained specialist using appropriate operational procedures and settings. These are the first EULAR recommendations providing up-to-date guidance for the role of imaging in the diagnosis and monitoring of patients with (suspected) LVV. ispartof: ANNALS OF THE RHEUMATIC DISEASES vol:77 issue:5 pages:636-643 ispartof: location:England status: published

Age-associated changes in the immune system including alterations in surface protein expression are thought to contribute to an increased susceptibility for autoimmune diseases. The balance between the expression of coinhibitory and costimulatory surface protein molecules, also known as immune checkpoint molecules, is crucial in fine-tuning the immune response and preventing autoimmunity. The activation of specific inhibitory signaling pathways allows cancer cells to evade recognition and destruction by the host immune system. The use of immune checkpoint inhibitors (ICIs) to treat cancer has proven to be effective producing durable antitumor responses in multiple cancer types. However, one of the disadvantages derived from the use of these agents is the appearance of inflammatory manifestations termed immune-related adverse events (irAEs). These irAEs are often relatively mild, but more severe irAEs have been reported as well including several forms of vasculitis. In this article, we argue that age-related changes in expression and function of immune checkpoint molecules lead to an unstable immune system, which is prone to tolerance failure and autoimmune vasculitis development. The topic is introduced by a case report from our hospital describing a melanoma patient treated with ICIs and who subsequently developed biopsy-proven giant cell arteritis. Following this case report, we present an in-depth review on the role of immune checkpoint pathways in the development and progression of autoimmune vasculitis and its relation with an aging immune system.

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.

We conducted a large-scale genetic analysis on giant cell arteritis (GCA), a polygenic immune-mediated vasculitis. A case-control cohort, comprising 1,651 case subjects with GCA and 15,306 unrelated control subjects from six different countries of European ancestry, was genotyped by the Immunochip array. We also imputed HLA data with a previously validated imputation method to perform a more comprehensive analysis of this genomic region. The strongest association signals were observed in the HLA region, with rs477515 representing the highest peak (p = 4.05 x 10(-40), OR = 1.73). A multivariate model including class II amino acids of HLA-DR beta 1 and HLA-DQ alpha 1 and one class I amino acid of HLA-B explained most of the HLA association with GCA, consistent with previously reported associations of classical HLA alleles like HLA-DRB1*04. An omnibus test on polymorphic amino acid positions highlighted DR beta 1 13 (p = 4.08 x 10(-43)) and HLA-DQ alpha 1 47 (p = 4.02 x 10(-46)), 56, and 76 (both p = 1.84 x 10(-45)) as relevant positions for disease susceptibility. Outside the HLA region, the most significant loci included PTPN22 (rs2476601, p = 1.73 x 10(-6), OR = 1.38), LRRC32 (rs10160518, p = 4.39 x 10(-6), OR = 1.20), and REL (rs115674477, p = 1.10 x 10(-5), OR = 1.63). Our study provides evidence of a strong contribution of HLA class I and II molecules to susceptibility to GCA. In the non-HLA region, we confirmed a key role for the functional PTPN22 rs2476601 variant and proposed other putative risk loci for GCA involved in Th1, Th17, and Treg cell function.

Introduction. Herpes zoster, which can have a major impact on quality of life, results from reactivation of a latent varicella-zoster virus (VZV) infection. We hypothesized that giant cell arteritis (GCA) patients are at increased risk of herpes zoster because of treatment with high-dose glucocorticoids and advanced age. Aim of the study therefore was to determine cell-mediated and humoral immunity to VZV in patients with GCA, patients with closely related disease polymyalgia rheumatica (PMR; treated with lower doses of glucocorticoids) and healthy controls. Methods. Cell-mediated immunity to VZV was determined by performing interferon-γ (IFNγ) enzyme-linked immunospot (ELISpot) and intracellular cytokine flow cytometry measurements in 11 GCA and 15 PMR patients, and in 26 age/sex-matched healthy controls. Immunoglobulin G antibodies to VZV glycoprotein (VZV-IgG) were measured in serum samples of 35 GCA and 26 PMR patients at different times of follow-up, and in 58 age and sex matched healthy controls by an enzyme-linked immunosorbent assay (ELISA). Results. The number of VZV-specific IFNγ spot-forming cells was significantly lower in GCA patients on treatment, than in age-matched healthy controls (p=0.029), but was not different in PMR patients on treatment. Similar levels of VZV-IgG were found in GCA and PMR patients at baseline, compared to healthy controls. Conclusion. The finding of a decreased cell-mediated immunity to VZV, known to be of great importance in defense to the virus, indicates an increased herpes zoster risk in GCA patients compared to an already at-risk elderly population. Herpes zoster vaccination is therefore of special importance in GCA patients, and would ideally be administered at time of diagnosis. Interestingly, as VZV was suggested to be the trigger in GCA pathogenesis, similar levels of VZV-IgG were found in GCA patients at time of diagnosis and age matched healthy controls, indicating that GCA patients did not experience herpes zoster substantially more often in the months preceding diagnosis than controls.

Monocytes/macrophages are critical in systemic and local inflammation in giant cell arteritis (GCA) and possibly in clinically overlapping polymyalgia rheumatica (PMR). Therefore, we aimed to understand the contribution of monocyte subsets and the CX3CR1-CX3CL1 and CCR2-CCL2 migratory pathways, to the pathology of GCA. Peripheral blood monocytes were enumerated in samples from newly-diagnosed, untreated GCA and PMR patients and after prednisone-induced remission. The distribution of classical (CD14brightCD16neg) and the more pro-inflammatory, intermediate (CD14brightCD16+) and non-classical (CD14dimCD16+) monocyte subsets was analysed by flow cytometry. The phenotype of macrophages in temporal artery biopsies (TABs) from GCA patients was studied by immunohistochemistry and immunofluorescence. A clear monocytosis was seen in newly diagnosed GCA and PMR patients caused by elevated numbers of classical monocytes. Prednisone treatment suppressed numbers of non-classical monocytes. Both chemokine CX3CL1 and CCL2 were highly expressed in the TAB. Most macrophages in the TAB of GCA patients expressed non-classical monocyte markers CD16 and CX3CR1 whereas co-localisation of CD16 with classical monocyte marker CCR2 was infrequent. In conclusion, we report an altered distribution of monocyte subsets in both GCA and PMR patients. The majority of macrophages in TABs of GCA patients were CD68 + CD16 + CX3CR1 + CCR2− and thereby resembled the phenotype of non-classical monocytes.

Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P = 7.54E-07; ORGCA = 1.19, ORTAK = 1.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA = 5.52E-04, ORGCA = 1.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus., This work was supported by SAF2012– 34435 from the Spanish Ministry of Economy and Competitiveness, BIO-1395 from Junta de Andalucía, and RD12/0009/0004 from the RETICS Program (RIER) of Instituto de Salud Carlos III (ISCIII). FDC was recipient of a grant from the ‘Ramón y Cajal’ programme of the Spanish Ministry of Economy and Competitiveness (RYC-2014–16458). MCC and JHR are supported by Ministerio de Economía y Competitividad (SAF 14/57708R), cofunded by “Fondo Europeo de Desarrollo Regional, Unión Europea, Una manera de hacer Europa” [Instituto de Salud Carlos III and Fondo Europeo de desarrollo regional (FEDER) (PIE 13/00033)]. The Vasculitis Clinical Research Consortium has received support from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (U54AR057319), the National Center for Research Resources (U54 RR019497), the Office of Rare Diseases Research, and the National Center for Advancing Translational Science. The VCRC is part of the Rare Diseases Clinical Research Network (RDCRN).

Whereas in the past the term "vasculitis" was most frequently used in context with systemic vasculitides, such as the large vessel vasculitides (LVV) Takayasa arteritis and giant cell arteritis, characterized by inflammation of blood vessel walls, it nowadays comprises also inflammatory changes of the vessel wall as a substantial part of the atherosclerotic disease process. Implementing non-invasive imaging techniques, such as computed tomography angiography (CTA), magnetic resonance angiography (MRA) as well as positron emission tomography (PET) in the diagnostic algorithm of atherosclerosis and LVV, depicts a promising step towards an earlier detection with a, consecutively, improved therapeutic approach and potentially prognostic benefit in patients suffering from vasculitis. Mainly molecular imaging with 18F-fluorodeoxyglucose (FDG) PET seems to be promising in offering an early and sensitive identification of inflammatory changes in both, atherosclerosis and LVV. This review will therefore provide an overview on the diagnostic performance and clinical relevance of FDG-PET in monitoring vasculitis in atherosclerosis and LVV, with a focus on LVV.

IF 7.760; International audience; CD8(+) T cells participate in the pathogenesis of some vasculitides. However, little is known about their role in Giant Cell Arteritis (GCA). This study was conducted to investigate CD8(+) T cell involvement in the pathogenesis of GCA.Analyses were performed at diagnosis and after 3 months of glucocorticoid treatment in 34 GCA patients and 26 age-matched healthy volunteers . Percentages of CD8(+) T-cell subsets, spectratype analysis of the TCR v beta families of CD8(+) T cells, levels of cytokines and chemokines and immunohistochemistry of temporal artery biopsies (TAB) were assessed.Among total CD8+ T cells, percentages of circulating cytotoxic CD8 T lymphocytes (CTL, CD3(+)CD8(+)perforin(+)granzymeB(+)), Tc17 (CD3(+)CD8(+)IL-17(+)), CD63(+)CD8(+) T cells and levels of soluble granzymes A and B were higher in patients than in controls, whereas the percentage of Tc1 cells (CD3(+)CD8(+)IFN-gamma(+)) was similar. Moreover, CD8+ T cells displayed a restricted TCR repertoire in GCA patients. Percentages of circulating CTL, Tc17 and soluble levels of granzymes A and B decreased after treatment. CXCR3 expression on CD8(+) T cells and its serum ligands (CXCL9, -10, -11) were higher in patients. Analyses of TAB revealed high expression of CXCL9 and -10 associated with infiltration by CXCR3(+)CD8(+) T cells expressing granzyme B and TiA1. The intensity of the CD8 T-cell infiltrate in TAB was predictive of the severity of the disease.This study demonstrates the implication and the prognostic value of CD8(+) T-cells in GCA and suggests that CD8(+) T-cells are recruited within the vascular wall through an interaction between CXCR3 and its ligands. (C) 2016 Elsevier Ltd. All rights reserved.

The human complement factor H-related protein-3 (FHR-3) is a soluble regulator of the complement system. Homozygous cfhr3/1 deletion is a genetic risk factor for the autoimmune form of atypical hemolytic-uremic syndrome (aHUS), while also found to be protective in age-related macular degeneration (AMD). The precise function of FHR-3 remains to be fully characterized. We generated four mouse monoclonal antibodies (mAbs) for FHR-3 (RETC) without cross-reactivity to the complement factor H (FH)-family. These antibodies detected FHR-3 from human serum with a mean concentration of 1 μg/mL. FHR-3 levels in patients were significantly increased in sera from systemic lupus erythematosus, rheumatoid arthritis, and polymyalgia rheumatica but remained almost unchanged in samples from AMD or aHUS patients. Moreover, by immunostaining of an aged human donor retina, we discovered a local FHR-3 production by microglia/macrophages. The mAb RETC-2 modulated FHR-3 binding to C3b but not the binding of FHR-3 to heparin. Interestingly, FHR-3 competed with FH for binding C3b and the mAb RETC-2 reduced the interaction of FHR-3 and C3b, resulting in increased FH binding. Our results unveil a previously unknown systemic involvement of FHR-3 in rheumatoid diseases and a putative local role of FHR-3 mediated by microglia/macrophages in the damaged retina. We conclude that the local FHR-3/FH equilibrium in AMD is a potential therapeutic target, which can be modulated by our specific mAb RETC-2.

The purpose of this study was to identify clinical and laboratory parameters that may improve the effectiveness of the use of fluorodeoxyglucose positron emission tomography ((18) F-FDG PET)(/CT) for diagnosing large vessel vasculitis (LVV), and secondarily to assess the contribution of (18) F-FDG PET/CT in finding other diagnoses for patients without signs of LVV on the scan. A multicenter retrospective study of (18) F-FDG PET(/CT) scans performed between January 2000 and December 2009 for clinical suspicion of LVV was conducted. A total of 304 (18) F-FDG PET(/CT) scans were included, of which 62 (20%) were positive and 242 (80%) were negative for LVV. Univariate analysis showed that patients with a positive scan were older (65.9 +/- 13.4 versus 58.6 +/- 16.5 years, p = 0.002), were more frequently female (76% versus 55%, p = 0.002), more often had a history of temporal arteritis (10% versus 3%, p = 0.044), less frequently had artralgia (31% versus 67%, p = 0.000), and had higher thrombocyte counts (434 +/- 161 versus 373 +/- 168 x 10(9)/l, p = 0.049) and a higher erythrocyte sedimentation rate (ESR) (72.6 +/- 31.0 versus 51.4 +/- 30.5 mm/h, p = 0.001) than patients with a negative scan. In the multivariate analysis, only artralgia (OR 0.091; 95% CI 0.023-0.366) and ESR (OR 1.024; 95% CI 1.002-1.046) remained statistically significant predictors. The presence of artralgia is a statistically significant negative predictor and an elevated ESR a statistically significant positive predictor of LVV showing up on (18) F-FDG PET(/CT). A reliable prediction of the outcome of the scan, based on these two parameters, is not possible however. (18) F-FDG PET(/CT) allows early diagnosis of LVV and may discover occult inflammatory or neoplastic disorders.

Objectives: To develop European League Against Rheumatism (EULAR) recommendations for the management of large vessel vasculitis.Methods: An expert group (10 rheumatologists, 3 nephrologists, 2 immunolgists, 2 internists representing 8 European countries and the USA, a clinical epidemiologist and a representative from a drug regulatory agency) identified 10 topics for a systematic literature search through a modified Delphi technique. In accordance with standardised EULAR operating procedures, recommendations were derived for the management of large vessel vasculitis. In the absence of evidence, recommendations were formulated on the basis of a consensus opinion.Results: Seven recommendations were made relating to the assessment, investigation and treatment of patients with large vessel vasculitis. The strength of recommendations was restricted by the low level of evidence and EULAR standardised operating procedures.Conclusions: On the basis of evidence and expert consensus, management recommendations for large vessel vasculitis have been formulated and are commended for use in everyday clinical practice.

Objectives:To develop European League Against Rheumatism (EULAR) recommendations for the management of large vessel vasculitis.Methods:An expert group (10 rheumatologists, 3 nephrologists, 2 immunolgists, 2 internists representing 8 European countries and the USA, a clinical epidemiologist and a representative from a drug regulatory agency) identified 10 topics for a systematic literature search through a modified Delphi technique. In accordance with standardised EULAR operating procedures, recommendations were derived for the management of large vessel vasculitis. In the absence of evidence, recommendations were formulated on the basis of a consensus opinion.Results:Seven recommendations were made relating to the assessment, investigation and treatment of patients with large vessel vasculitis. The strength of recommendations was restricted by the low level of evidence and EULAR standardised operating procedures.Conclusions:On the basis of evidence and expert consensus, management recommendations for large vessel vasculitis have been formulated and are commended for use in everyday clinical practice.

Background. Nuclear medicine imaging differs from other imaging modalities by showing physiological processes instead of anatomical details.Objective. To describe the current applications of positron emission tomography (PET) and single photon emission computed tomography (SPECT) as a diagnostic tool for vascular disease as relevant to vascular surgeons.Methods. A literature search identified articles focussing on vascular disease and PET or SPECT using the Pubmed database. Manual cross referencing was also performed.Results. PET and SPECT may be used to assess plaque vulnerability, biology of aneurysm progression, prosthetic graft infection, and vasculitis. The ability to combine computerized tomography scanning or magnetic resonance imaging with PET or SPECT adds detailed anatomical information and enhances the potential of nuclear medicine imaging in the investigation of vascular disease.Discussion. Considerable further information will be needed to define whether and where PET or SPECT will fit in a clinical strategy. The necessary validation studies represent an exciting challenge for the future but also may require the development of interdisciplinary imaging groups to integrate expertise and optimize nuclear diagnostic potential. (C) 2007 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Background. Nuclear medicine imaging differs from other imaging modalities by showing physiological processes instead of anatomical details. Objective. To describe the current applications of positron emission tomography (PET) and single photon emission computed tomography (SPECT) as a diagnostic tool for vascular disease as relevant to vascular surgeons. Methods. A literature search identified articles focussing on vascular disease and PET or SPECT using the Pubmed database. Manual cross referencing was also performed. Results. PET and SPECT may be used to assess plaque vulnerability, biology of aneurysm progression, prosthetic graft infection, and vasculitis. The ability to combine computerized tomography scanning or magnetic resonance imaging with PET or SPECT adds detailed anatomical information and enhances the potential of nuclear medicine imaging in the investigation of vascular disease. Discussion. Considerable further information will be needed to define whether and where PET or SPECT will fit in a clinical strategy. The necessary validation studies represent an exciting challenge for the future but also may require the development of interdisciplinary imaging groups to integrate expertise and optimize nuclear diagnostic potential. (C) 2007 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Giant cell arteritis (GCA) is the most frequent form of vasculitis in persons older than 50 years. Cranial and systemic large vessels can be involved. [F-18] fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is increasingly used to diagnose inflammation of the large arteries in GCA. Unfortunately, no consensus exists on the preferred scoring method. In the present study, we aim to define the optimal FDG PET/CT scoring method for GCA diagnosis using temporal artery biopsy and clinical diagnosis as the reference method.FDG PET/CT scans of GCA patients (12 glucocorticoid-naive, 6 on glucocorticoid treatment) and 3 control groups (inflammatory, atherosclerotic, and normal controls) were evaluated. We compared 2 qualitative visual methods (i.e. (1a) first impression and (1b) vascular uptake versus liver uptake) and 4 semiquantitative methods ((2a) SUVmax aorta, (2b) SUVmax aorta-to-liver ratio, (2c) SUVmax aorta-to-superior-caval-vein ratio, and (2d) SUVmax aorta-to-inferior-caval-vein ratio). FDG uptake pattern (diffuse or focal) and presence of arterial calcifications were also scored.Diagnostic accuracy of the visual method vascular versus liver uptake (1b) was highest when the cut-off point vascular uptake higher than liver uptake (sensitivity 83%, specificity 91%) was used. Sensitivity increased to 92% when patients on glucocorticoids were excluded from the analysis. Regarding the semiquantitative methods, the aorta-to-liver ratio (2b) with a cutoff of 1.03 had the highest diagnostic accuracy, with a sensitivity and specificity of 69% and 92%, respectively. Sensitivity increased to 90% when patients on glucocorticoids were excluded. The number of vascular segments with diffuse FDG uptake pattern was significantly higher in GCA patients without glucocorticoid use compared with all control patient groups. CRP was not significantly different between positive and negative FDG PET scans in the GCA group.Visual vascular uptake higher than liver uptake resulted in the highest diagnostic accuracy for the detection of GCA, especially in combination with a diffuse FDG uptake pattern. Of the semiquantitative methods, the aorta-to-liver SUVmax ratio (cutoff point=1.03) had the highest diagnostic accuracy. The diagnostic accuracy increased when patients using glucocorticoids were excluded from the analyses.

We conducted a large-scale genetic analysis on giant cell arteritis (GCA), a polygenic immune-mediated vasculitis. A case-control cohort, comprising 1,651 case subjects with GCA and 15,306 unrelated control subjects from six different countries of European ancestry, was genotyped by the Immunochip array. We also imputed HLA data with a previously validated imputation method to perform a more comprehensive analysis of this genomic region. The strongest association signals were observed in the HLA region, with rs477515 representing the highest peak (p = 4.05 x 10(-40), OR = 1.73). A multivariate model including class II amino acids of HLA-DR beta 1 and HLA-DQ alpha 1 and one class I amino acid of HLA-B explained most of the HLA association with GCA, consistent with previously reported associations of classical HLA alleles like HLA-DRB1*04. An omnibus test on polymorphic amino acid positions highlighted DR beta 1 13 (p = 4.08 x 10(-43)) and HLA-DQ alpha 1 47 (p = 4.02 x 10(-46)), 56, and 76 (both p = 1.84 x 10(-45)) as relevant positions for disease susceptibility. Outside the HLA region, the most significant loci included PTPN22 (rs2476601, p = 1.73 x 10(-6), OR = 1.38), LRRC32 (rs10160518, p = 4.39 x 10(-6), OR = 1.20), and REL (rs115674477, p = 1.10 x 10(-5), OR = 1.63). Our study provides evidence of a strong contribution of HLA class I and II molecules to susceptibility to GCA. In the non-HLA region, we confirmed a key role for the functional PTPN22 rs2476601 variant and proposed other putative risk loci for GCA involved in Th1, Th17, and Treg cell function.

Introduction.18F-FDG-PET visualises inflammation. Both atherosclerosis and giant cell arteritis cause vascular inflammation, but distinguishing the two may be difficult. The goal of this study was to assess interobserver agreement and diagnostic accuracy of18F-FDG-PET for the detection of large artery involvement in giant cell arteritis (GCA).Methods. 3118F-FDG-PET/CT scans were selected from 2 databases. Four observers assessed vascular wall18F-FDG uptake, initially without and subsequently with predefined observer criteria (i.e., vascular wall18F-FDG uptake compared to liver or femoral artery18F-FDG uptake). External validation was performed by two additional observers. Sensitivity and specificity of18F-FDG-PET were determined by comparing scan results to a consensus diagnosis.Results. The highest interobserver agreement (kappa: 0.96 in initial study and 0.79 in external validation) was observed when vascular wall18F-FDG uptake higher than liver uptake was used as a diagnostic criterion, although agreement was also good without predefined criteria (kappa: 0.68 and 0.85). Sensitivity and specificity were comparable for these methods. The criterion of vascular wall18F-FDG uptake equal to liver18F-FDG uptake had low specificity.Conclusion. Standardization of image assessment for vascular wall18F-FDG uptake promotes observer agreement, enables comparative studies, and does not appear to result in loss of diagnostic accuracy compared to nonstandardized assessment.

Introduction: Takayasu arteritis (TA) and giant cell arteritis (GCA) are large vessel vasculitides (LVV) that usually present as granulomatous inflammation in arterial walls. High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released by dying or activated cells. This study aims to evaluate whether serum HMGB1 can be used as a biomarker in LVV.Methods: Twenty-nine consecutive TA patients with 29 healthy controls (HC) were evaluated in a cross-sectional study. Eighteen consecutive GCA patients with 16 HC were evaluated at the onset of disease and some of them during follow-up. Serum HMGB1 levels were measured by enzyme-linked immunosorbent assay.Results: In GCA patients at disease onset mean serum HMGB1 levels did not differ from HC (5.74 +/- 4.19 ng/ml vs. 4.17 +/- 3.14 ng/ml; p = 0.230). No differences in HMGB1 levels were found between GCA patients with and without polymyalgia rheumatica (p = 0.167), ischemic manifestations (p = 0.873), systemic manifestations (p = 0.474) or relapsing disease (p = 0.608). During follow-up, no significant fluctuations on serum HMGB1 levels were observed from baseline to 3 months (n = 13) (p = 0.075), 12 months (n = 6) (p = 0.093) and at the first relapse (n = 4) (p = 0.202). Serum HMGB1 levels did not differ between TA patients and HC [1.19 (0.45-2.10) ng/ml vs. 1.46 (0.89-3.34) ng/ml; p = 0.181] and no difference was found between TA patients with active disease and in remission [1.31 (0.63-2.16) ng/ml vs. 0.75 (0.39-2.05) ng/ml; p = 0.281]. HMGB1 levels were significantly lower in 16 TA patients on statins compared with 13 patients without statins [0.59 (0.29-1.46) ng/ml vs. 1.93 (0.88-3.34) ng/ml; p = 0.019]. Age was independently associated with higher HMGB1 levels regardless of LVV or control status.Conclusions: Patients with TA and GCA present similar serum HMGB1 levels compared with HC. Serum HMGB1 is not useful to discriminate between active disease and remission. In TA, use of statins was associated with lower HMGB1 levels. HMGB1 is not a biomarker for LVV.

Objectives. To determine the value of Positron Emission Tomography (PET) in the diagnosis of Takayasu arteritis (TA) and giant cell arteritis (GCA) and its value in the assessment of disease activity and response to therapy. Methods. In 5 consecutive patients diagnosed with TA or GCA, PET using the tracer F18-deoxyglucose (FDG) was performed when disease activity was suspected based on clinical and laboratory parameters. PET was repeated after therapeutic intervention when disease remission was achieved. PET,findings were compared with angiography, MRA and clinical parameters. Results. PET visualised inflamed arteries in all 5 patients, but there was a discrepancy between PET and angiography or MRA. In 8 arteries of 4 patients only PET showed disease involvement, while in 5 arteries of 2 patients only angiography or MRA showed involvement. After treatment and the disappearance of clinical symptoms, FDG uptake was clearly reduced compared to the initial scan in all patients. In all but one the acute phase response declined. In that patient a urinary tract injection explained the elevated acute phase response, as this normalised after antibiotic treatment. Conclusion. PET is a promising new technique for the diagnosis of large vessel vasculitides. Furthermore, PET appears to be a valuable tool for the assessment of disease activity during follow-up and of the response to therapy.

Objectives. To determine the value of Positron Emission Tomography (PET) in the diagnosis of Takayasu arteritis (TA) and giant cell arteritis (GCA) and its value in the assessment of disease activity and response to therapy.Methods. In 5 consecutive patients diagnosed with TA or GCA, PET using the tracer F18-deoxyglucose (FDG) was performed when disease activity was suspected based on clinical and laboratory parameters. PET was repeated after therapeutic intervention when disease remission was achieved. PET,findings were compared with angiography, MRA and clinical parameters.Results. PET visualised inflamed arteries in all 5 patients, but there was a discrepancy between PET and angiography or MRA. In 8 arteries of 4 patients only PET showed disease involvement, while in 5 arteries of 2 patients only angiography or MRA showed involvement. After treatment and the disappearance of clinical symptoms, FDG uptake was clearly reduced compared to the initial scan in all patients. In all but one the acute phase response declined. In that patient a urinary tract injection explained the elevated acute phase response, as this normalised after antibiotic treatment.Conclusion. PET is a promising new technique for the diagnosis of large vessel vasculitides. Furthermore, PET appears to be a valuable tool for the assessment of disease activity during follow-up and of the response to therapy.

Giant cell (GCA) and Takayasu's arteritis (TAK) are 2 forms of large-vessel vasculitis (LVV) that involve the aorta and its major branches. GCA has a predilection for the cranial branches, while TAK tends to affect the extracranial branches. Both disorders may also cause nonspecific constitutional symptoms. Although some clinical features are more common in one or the other disorder and the ages of initial presentation differ substantially, there is enough clinical and histopathologic overlap between these disorders that some investigators suggest GCA and TAK may be 2 processes within the spectrum of a single disease. There have been few randomized therapeutic trials completed in GCA, and none in TAK. The lack of therapeutic trials in LVV is only partially explained by the rarity of these diseases. It is likely that the lack of well validated outcome measures for LVV and uncertainties regarding trial design contribute to the paucity of trials for these diseases. An initiative to develop a core set of outcome measures for use in clinical trials of LVV was launched by the international OMERACT Vasculitis Working Group in 2009 and subsequently endorsed by the OMERACT community at the OMERACT 10 meeting. Aims of this initiative include: (1) to review the literature and existing data related to outcome assessments in LVV; (2) to obtain the opinion of experts and patients on disease content; and (3) to formulate a research agenda to facilitate a more data-based approach to outcomes development. (J Rheumatol 2011;38:1471-9; doi: 10.3899/jrheum.110275)

Objectives. To determine the value of Positron Emission Tomography (PET) in the diagnosis of Takayasu arteritis (TA) and giant cell arteritis (GCA) and its value in the assessment of disease activity and response to therapy. Methods. In 5 consecutive patients diagnosed with TA or GCA, PET using the tracer F18-deoxyglucose (FDG) was performed when disease activity was suspected based on clinical and laboratory parameters. PET was repeated after therapeutic intervention when disease remission was achieved. PET,findings were compared with angiography, MRA and clinical parameters. Results. PET visualised inflamed arteries in all 5 patients, but there was a discrepancy between PET and angiography or MRA. In 8 arteries of 4 patients only PET showed disease involvement, while in 5 arteries of 2 patients only angiography or MRA showed involvement. After treatment and the disappearance of clinical symptoms, FDG uptake was clearly reduced compared to the initial scan in all patients. In all but one the acute phase response declined. In that patient a urinary tract injection explained the elevated acute phase response, as this normalised after antibiotic treatment. Conclusion. PET is a promising new technique for the diagnosis of large vessel vasculitides. Furthermore, PET appears to be a valuable tool for the assessment of disease activity during follow-up and of the response to therapy.

Giant cell arteritis (GCA) is a granulomatous large-vessel vasculitis that affects adults above 50 years of age. In GCA, circulating monocytes are recruited to the inflamed arteries. With cues from the vascular microenvironment, they differentiate into macrophages and play important roles in the pathogenesis of GCA via pro-inflammatory cytokine production and vascular remodeling. However, a deeper understanding of macrophage heterogeneity in GCA pathogenesis is needed to assist the development of novel diagnostic tools and targeted therapies. Here, we review the current knowledge on macrophage heterogeneity and diverse functions of macrophage subsets in the pathogenesis of GCA. We next discuss the possibility to exploit their heterogeneity as a source of novel biomarkers and as targets for nuclear imaging. Finally, we discuss novel macrophage-targeted therapies and future directions for targeting these cells in GCA.