Taper versus discontinuation of tocilizumab in patients with giant cell arteritis: Real-world experience from a tertiary center.

INTRODUCTION: Following the approval of tocilizumab (TCZ) for giant cell arteritis (GCA), recent studies have shown a high relapse frequency after abrupt discontinuation of TCZ. However, a thorough exploration of TCZ tapering compared to abrupt discontinuation has never been undertaken. Likewise, adverse events have only been scarcely investigated in routine care. This study aimed to compare the incidence of relapses in GCA patients undergoing TCZ tapering compared to abrupt discontinuation. METHODS: We performed a single-center retrospective cohort study from 2012 to 2022. Data from GCA patients treated with TCZ was obtained from the Electronic Patients Record. Relapse-free survival is reported in Kaplan-Meier plots and tapering versus abrupt discontinuation were compared using a Wilcoxon-Brewlos-Gehan test. RESULTS: We included 155 patients receiving TCZ treatment for GCA, of which 104 discontinued TCZ. Among the 104 patients discontinuing TCZ, 42 (40 %) experienced a relapse within the first year. A total of 57 patients underwent taper with 6/38 (16 %) and 2/19 (11 %) relapsing while receiving TCZ every second or third week, respectively. In comparison, 59 patients underwent abrupt discontinuation with 27 (46 %) relapsing during follow-up. The patients undergoing abrupt TCZ discontinuation demonstrated a significantly shorter time to relapse compared to all tapered patients (p = 0.02) as well as patients tapered from weekly TCZ treatment to every second week (p < 0.01). Furthermore, 15 % of patients discontinued TCZ due to adverse events. CONCLUSION: This is the first study indicating that TCZ taper induced longer relapse-free survival than abrupt discontinuation, implying that taper may be favored over discontinuation in patients with GCA.

The effect of prednisolone and a short-term prednisolone discontinuation for the diagnostic accuracy of FDG-PET/CT in polymyalgia rheumatica-a prospective study of 101 patients.

PURPOSE: 2-[18F]Fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has been suggested as an imaging modality to diagnose polymyalgia rheumatica (PMR). However, the applicability of FDG-PET/CT remains unclear, especially following glucocorticoid administration. This study aimed to investigate the diagnostic accuracy of FDG-PET/CT before and during prednisolone treatment, as well as following short-term prednisolone discontinuation. METHODS: Treatment naïve suspected PMR patients were clinically diagnosed at baseline and subsequently had an FDG-PET/CT performed. Patients diagnosed with PMR were administered prednisolone following the first FDG-PET/CT and had a second FDG-PET/CT performed after 8 weeks of treatment. Subsequently, prednisolone was tapered with short-term discontinuation at week 9 followed by a third FDG-PET/CT at week 10. An FDG-PET/CT classification of PMR/non-PMR was applied, utilizing both the validated Leuven score and a dichotomous PMR score. The final diagnosis was based on clinical follow-up after 1 year. RESULTS: A total of 68 and 27 patients received a final clinical diagnosis of PMR or non-PMR. A baseline FDG-PET/CT classified the patients as having PMR with a sensitivity/specificity of 86%/63% (Leuven score) and 82%/70% (dichotomous score). Comparing the subgroup of non-PMR with inflammatory diseases to the PMR group demonstrated a specificity of 39%/54% (Leuven/dichotomous score). After 8 weeks of prednisolone treatment, the sensitivity of FDG-PET/CT decreased to 36%/41% (Leuven/dichotomous score), while a short-term prednisolone discontinuation increased the sensitivity to 66%/60%. CONCLUSION: FDG-PET/CT has limited diagnostic accuracy for differentiating PMR from other inflammatory diseases. If FDG-PET/CT is intended for diagnostic purposes, prednisolone should be discontinued to enhance diagnostic accuracy. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04519580). Registered 17th of August 2020.

The one-year infection risk among patients diagnosed with giant cell arteritis: use of antibiotics and hospitalisations.

OBJECTIVES: Patients with giant cell arteritis (GCA) primarily have their infections managed by primary care providers and hospitalisation is rarely necessary. Existing studies in GCA focus on infection-related hospitalisations only, whereas the use of antibiotic prescriptions is largely unknown. This study aims to examine the one-year overall infection risk among patients with GCA. METHODS: This nationwide observational cohort study included patients aged ≥50 years with a first-time GCA diagnosis in the Danish National Patient Registry (1996-2022). Patients with GCA were matched 1:10 by sex and date of birth with general population individuals and followed from date of diagnosis. Overall infections were defined as redeemed antibiotic prescriptions or infection-related hospitalisations. Utilising a pseudo-observation approach, we assessed 1-year cumulative incidence proportions (CIP), risk differences (RD), and relative risks (RR) of infections. RESULTS: The study included 17 773 incident patients with GCA and 177 730 reference individuals. Patients with GCA had a 1-year CIP of 52.4% (95% CI: 51.7-53.2) for overall infections and 17.6% (95% CI: 17.1-18.2) for infection-related hospitalisations. Compared with the reference cohort, patients with GCA had a RR of 1.40 (95% CI: 1.38-1.42) for overall infections and 2.71 (95% CI: 2.61-2.82) for infection-related hospitalisations. Additionally, higher cumulative glucocorticoid doses, advanced age (≥70 years), and higher comorbidity were associated with an increased risk of infections among patients with GCA. CONCLUSIONS: The use of antibiotic prescriptions and infection-related hospitalisations in the first year after a GCA diagnosis is high compared with the background population. The cumulative glucocorticoid dose is associated with the infection risk.

A rare case of sarcoid myelitis complicating Löfgren's syndrome.

Neurosarcoidosis is a rare and serious condition. Rapid diagnosis and treatment are crucial to prevent morbidity and mortality. When neurological symptoms are not present at the time of diagnosis, CNS involvement can be undetected. We present a case of neurosarcoidosis complicating Löfgren's syndrome and discus the challenges in diagnostics and treatment, that can be encountered.

An international survey of current management practices for polymyalgia rheumatica by general practitioners and rheumatologists.

OBJECTIVES: To explore current management practices for PMR by general practitioners (GPs) and rheumatologists including implications for clinical trial recruitment. METHODS: An English language questionnaire was constructed by a working group of rheumatologists and GPs from six countries. The questionnaire focused on: 1: Respondent characteristics; 2: Referral practices; 3: Treatment with glucocorticoids; 4: Diagnostics; 5: Comorbidities; and 6: Barriers to research. The questionnaire was distributed to rheumatologists and GPs worldwide via members of the International PMR/Giant Cell Arteritis Study Group. RESULTS: In total, 394 GPs and 937 rheumatologists responded to the survey. GPs referred a median of 25% of their suspected PMR patients for diagnosis and 50% of these were returned to their GP for management. In general, 39% of rheumatologists evaluated patients with suspected PMR >2 weeks after referral, and a median of 50% of patients had started prednisolone before rheumatologist evaluation. Direct comparison of initial treatment showed that the percentage prescribing >25 mg prednisolone daily for patients was 30% for GPs and 12% for rheumatologists. Diagnostic imaging was rarely used. More than half (56%) of rheumatologists experienced difficulties recruiting people with PMR to clinical trials. CONCLUSION: This large international survey indicates that a large proportion of people with PMR are not referred for diagnosis, and that the proportion of treatment-naive patients declined with increasing time from referral to assessment. Strategies are needed to change referral and management of people with PMR, to improve clinical practice and facilitate recruitment to clinical trials.

Metabolic features and glucocorticoid-induced comorbidities in patients with giant cell arteritis and polymyalgia rheumatica in a Dutch and Danish cohort.

OBJECTIVES: Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are age-associated inflammatory diseases that frequently overlap. Both diseases require long-term treatment with glucocorticoids (GCs), often associated with comorbidities. Previous population-based cohort studies reported that an unhealthier metabolic profile might prevent the development of GCA. Here, we report metabolic features before start of treatment and during treatment in patients with GCA and PMR. METHODS: In the Dutch GCA/PMR/SENEX (GPS) cohort, we analysed metabolic features and prevalence of comorbidities (type 2 diabetes, hypercholesterolaemia, hypertension, obesity and cataract) in treatment-naïve patients with GCA (n=50) and PMR (n=42), and compared those with the population-based Lifelines cohort (n=91). To compare our findings in the GPS cohort, we included data from patients with GCA (n=52) and PMR (n=25) from the Aarhus cohort. Laboratory measurements, comorbidities and GC use were recorded for up to 5 years in the GPS cohort. RESULTS: Glycated haemoglobin levels tended to be higher in treatment-naïve patients with GCA, whereas high-density lipoprotein, low-density lipoprotein and cholesterol levels were lower compared with the Lifelines population. Data from the Aarhus cohort were aligned with the findings obtained in the GPS cohort. Presence of comorbidities at baseline did not predict long-term GC requirement. The incidence of diabetes, obesity and cataract among patients with GCA increased upon initiation of GC treatment. CONCLUSION: Data from the GCA and PMR cohorts imply a metabolic dysregulation in treatment-naïve patients with GCA, but not in patients with PMR. Treatment with GCs led to the rise of comorbidities and an unhealthier metabolic profile, stressing the need for prednisone-sparing targeted treatment in these vulnerable patients.

The provisional OMERACT ultrasonography score for giant cell arteritis.

OBJECTIVES: To develop an Outcome Measures in Rheumatology (OMERACT) ultrasonography score for monitoring disease activity in giant cell arteritis (GCA) and evaluate its metric properties. METHODS: The OMERACT Instrument Selection Algorithm was followed. Forty-nine members of the OMERACT ultrasonography large vessel vasculitis working group were invited to seven Delphi rounds. An online reliability exercise was conducted using images of bilateral common temporal arteries, parietal and frontal branches as well as axillary arteries from 16 patients with GCA and 7 controls. Sensitivity to change and convergent construct validity were tested using data from a prospective cohort of patients with new GCA in which ultrasound-based intima-media thickness (IMT) measurements were conducted at weeks 1, 3, 6, 12 and 24. RESULTS: Agreement was obtained (92.7%) for the OMERACT GCA Ultrasonography Score (OGUS), calculated as follows: sum of IMT measured in every segment divided by the rounded cut-off values of IMTs in each segment. The resulting value is then divided by the number of segments available. Thirty-five members conducted the reliability exercise, the interrater intraclass correlation coefficient (ICC) for the OGUS was 0.72-0.84 and the median intrareader ICC was 0.91. The prospective cohort consisted of 52 patients. Sensitivity to change between baseline and each follow-up visit up to week 24 yielded standardised mean differences from -1.19 to -2.16, corresponding to large and very large magnitudes of change, respectively. OGUS correlated moderately with erythrocyte sedimentation rate, C reactive protein and Birmingham Vasculitis Activity Score (corrcoeff 0.37-0.48). CONCLUSION: We developed a provisional OGUS for potential use in clinical trials.

Ultrasonography in the assessment of disease activity in cranial and large-vessel giant cell arteritis: a prospective follow-up study.

OBJECTIVES: We evaluated sensitivity to change and discriminative abilities of vascular US scores in disease monitoring in the follow-up of a prospective cohort of new-onset cranial and large-vessel (LV) GCA patients. METHODS: Baseline and follow-up (8 weeks, 24 weeks and 15 months) US of temporal arteries (TA), carotid and axillary arteries (LV) included assessment of halo and measurement of the intima media complex (IMC). Max IMC, max halo IMC, sum IMC, sum halo IMC, mean IMC, halo count and the Southend halo score were calculated. The provisional OMERACT US score, OGUS, was obtained, taking the average of temporal arteries and axillary arteries IMCs divided by their normal cut-off values. RESULTS: Baseline US was positive in 44/47 patients (72% TA, 72% LV). Sensitivity to change of all composite US scores containing TAs was evident by week 8 onward. LVs responded poorly and new axillary US lesions emerged in six patients despite clinical remission. The OGUS showed a large magnitude of change and is considered the score least prone to potential bias. All TA-based US scores showed moderate-strong correlation with disease activity markers. OGUS, TA halo count, Southend TA halo score, TA sum IMC and TA mean IMC showed potential to discriminate remission and relapse with area under the curve ≥0.8. CONCLUSIONS: The OGUS is suggested as an outcome measurement for the assessment of treatment response in clinical trials. The abilities of US scores to discriminate remission and relapse are encouraging and should be further explored.

A nationwide study of ocular manifestations leading to hospital contacts among patients with giant cell arteritis.

OBJECTIVES: To investigate the risk of ocular manifestations leading to hospital contacts among patients with giant cell arteritis (GCA). METHODS: A Danish, nationwide, register-based cohort study including 14,574 GCA patients diagnosed 1996-2018 and 145,740 general population referents, matched on sex and date of birth. Cumulative incidence proportions (CIPs) and relative risks (RRs) of ocular manifestations with 95% confidence intervals (CIs) were calculated using a pseudo-observation approach. RESULTS: A total of 1026/14,574 (7.0%) GCA patients were registered with ocular manifestations within ±1 year of the diagnosis; 392/1026 (38%) being before and 634/1026 (62%) after the GCA diagnosis, and 744/1026 (73%) were registered within ±1 month of the diagnosis. The diagnoses were 336/1026 (33%) retinal vascular occlusions, 300/1026 (29%) disorders of the optic nerve, 177/1026 (17%) visual impairment, 90/1026 (9%) diplopia, and 123/1026 (12%) amaurosis fugax. The CIP for ocular manifestations among GCA patients after 3, 6, and 12 months following the diagnosis were 4.0% (95% CI: 3.6-4.3), 4.2% (95% CI: 3.9-4.6), and 4.6% (95% CI: 4.2-4.9). The 1-year RR of ocular manifestations among GCA patients was 28.0 (95% CI: 24.0-32.7), with age above 70 years, male sex, and a positive temporal artery biopsy being risk factors. Treatment with low-dose aspirin was not associated with a reduced 1-year RR of incident ocular manifestations. CONCLUSIONS: In GCA, most cases of ocular manifestations leading to hospital contacts occur close to the time of diagnosis, with over one-third of cases occurring before the diagnosis, emphasizing the need for early recognition and treatment.

Angiopoietin-2/-1 ratios and MMP-3 levels as an early warning sign for the presence of giant cell arteritis in patients with polymyalgia rheumatica.

BACKGROUND: Diagnosing patients with giant cell arteritis (GCA) remains difficult. Due to its non-specific symptoms, it is challenging to identify GCA in patients presenting with symptoms of polymyalgia rheumatica (PMR), which is a more common disease. Also, commonly used acute-phase markers CRP and ESR fail to discriminate GCA patients from PMR and (infectious) mimicry patients. Therefore, we investigated biomarkers reflecting vessel wall inflammation for their utility in the accurate diagnosis of GCA in two international cohorts. METHODS: Treatment-naïve GCA patients participated in the Aarhus AGP cohort (N = 52) and the Groningen GPS cohort (N = 48). The AGP and GPS biomarker levels and symptoms were compared to patients presenting phenotypically as isolated PMR, infectious mimicry controls and healthy controls (HCs). Serum/plasma levels of 12 biomarkers were measured by ELISA or Luminex. RESULTS: In both the AGP and the GPS cohort, we found that weight loss, elevated erythrocyte sedimentation rate (ESR) and higher angiopoietin-2/-1 ratios but lower matrix metalloproteinase (MMP)-3 levels identify concomitant GCA in PMR patients. In addition, we confirmed that elevated platelet counts are characteristic of GCA but not of GCA mimicry controls and that low MMP-3 and proteinase 3 (PR3) levels may help to discriminate GCA from infections. CONCLUSION: This study, performed in two independent international cohorts, consistently shows the potential of angiopoietin-2/-1 ratios and MMP-3 levels to identify GCA in patients presenting with PMR. These biomarkers may be used to select which PMR patients require further diagnostic workup. Platelet counts may be used to discriminate GCA from GCA look-alike patients.

All-cause and cause-specific mortality in patients with giant cell arteritis: a nationwide, population-based cohort study.

OBJECTIVES: To investigate whether GCA is associated with increased all-cause and cause-specific mortality. METHODS: A nationwide, population-based cohort study in Denmark using medical and administrative registries. GCA cases were defined as patients aged ≥50 years from 1996-2018 with a first-time discharge diagnosis of GCA and ≥3 prescriptions for prednisolone within 6 months following diagnosis. Each GCA patient was matched based on age, sex and calendar time to 10 persons without a history of GCA. Index date was the date for the third prednisolone prescription. We used a pseudo-observation approach to calculate all-cause and cause-specific mortality, adjusted risk differences (RDs) and relative risks (RRs). RESULTS: We included 9908 GCA patients and 98 204 persons from the general population. The median time for GCA patients to redeem the third prednisolone prescription was 74 days [interquartile range (IQR: 49-106)]. Among GCA patients, the overall mortality was 6.4% (95% CI: 5.9, 6.9) 1 year after index date and 45% (95% CI: 44, 47) after 10 years. Compared with the reference cohort, adjusted RDs and RRs of deaths in the GCA cohort were 2.2% (95% CI: 1.7, 2.7) and 1.49 (95% CI: 1.36, 1.64) after 1 year, and 2.1% (95% CI: 1.0, 3.3) and 1.03 (95% CI: 1.00, 1.05) 10 years after index date. GCA patients had a higher risk of death due to infectious, endocrine, cardiovascular and gastrointestinal diseases. CONCLUSIONS: GCA is associated with increased all-cause mortality, particularly within the first year following the diagnosis. Cause-specific mortality indicates that mortality in GCA may in part be due to glucocorticoid-related complications.

Increased risk of thoracic aortic complications among patients with giant cell arteritis: a nationwide, population-based cohort study.

OBJECTIVE: To assess the risk of aortic aneurysms (AA), aortic dissections (AD) and peripheral arterial disease (PAD) among patients with GCA. METHODS: In this nationwide, population-based cohort study using Danish national health registries, we identified all incident GCA patients ≥50 years between 1996 and 2018 who redeemed three or more prescriptions for prednisolone. Index date was the date of redeeming the third prednisolone prescription. Case definition robustness was checked through sensitivity analysis. We included general population referents matched 1:10 by age, sex and calendar time. Using a pseudo-observation approach, we calculated 5-, 10- and 15-year cumulative incidence proportions (CIP) and relative risks (RR) of AA, AD and PAD with death as a competing risk. RESULTS: We included 9908 GCA patients and 98 204 referents. The 15-year CIP of thoracic AA, abdominal AA, AD and PAD in the GCA cohort were 1.9% (95% CI 1.5, 2.2), 1.8% (1.4-2.2), 1.0% (0.7-1.2) and 4.8% (4.2-5.3). Compared with the referents, the 15-year RR were 11.2 (7.41-16.9) for thoracic AA, 6.86 (4.13-11.4) for AD, 1.04 (0.83-1.32) for abdominal AA and 1.53 (1.35-1.74) for PAD. Among GCA patients, female sex, age below 70 years and positive temporal artery findings were risk factors for developing thoracic AA. The median time to thoracic AA was 7.5 years (interquartile range 4.4-11.2) with a number needed to be screened of 250 (167-333), 91 (71-111) and 53 (45-67) after 5, 10 and 15 years. CONCLUSION: Patients with GCA have a markedly increased risk of developing thoracic AA and AD, but no increased risk of abdominal AA.

OMERACT definition and reliability assessment of chronic ultrasound lesions of the axillary artery in giant cell arteritis.

OBJECTIVES: To define chronic ultrasound lesions of the axillary artery (AA) in long-standing giant cell arteritis (GCA) and to evaluate the reliability of the new ultrasound definition in a web-based exercise. METHODS: A structured Delphi, involving an expert panel of the Large Vessel Vasculitis subgroup of the Outcome Measures in Rheumatology (OMERACT) Ultrasound Working Group was carried out. The reliability of the new definition was tested in a 2-round web-based exercise involving 23 experts and using 50 still images each from AA of long-standing and acute GCA patients, as well as 50 images from healthy individuals. RESULTS: The final OMERACT ultrasound definition of chronic changes was based on measurement and appearance of the intima-media complex. The overall reliability of the new definition for chronic ultrasound changes in longstanding GCA of the AA was good to excellent with Light's kappa values of 0.79-0.80 for inter-reader reliability and mean Light's-kappa of 0.88 for intra-reader reliability. The mean inter-rater and intra-rater agreements were 86-87% and 92%, respectively. Good reliabilities were observed comparing the vessels with longstanding versus acute GCA with a mean agreement and kappa values of 81% and 0.63, respectively. CONCLUSION: The new OMERACT ultrasound definition for chronic vasculitis of the AA in GCA revealed a good to excellent inter- and intra-reader reliability in a web-based exercise of experts.

Giant cell arteritis: A nationwide, population-based cohort study on incidence, diagnostic imaging, and glucocorticoid treatment.

AIM: The study investigated the development over time of the incidence, diagnostic imaging, and treatment of giant cell arteritis (GCA). METHOD: This nationwide, population-based cohort study was conducted in Denmark using medical and administrative registries. Incident GCA cases from 1996-2018 were defined as patients aged ≥50 years registered with a first-time GCA diagnosis and ≥3 prescriptions for glucocorticoids (GCs) within 6 months after diagnosis. We determined incidence rates of GCA, the proportion of patients still receiving GCs >2 years after diagnosis, the proportion of patients receiving temporal artery biopsies (TAB) and diagnostic imaging including ultrasound, positron emission tomography, magnetic resonance, and/or computed tomography angiography at the time of diagnosis. RESULTS: We identified 9908 incident GCA cases. The incidence rates of GCA remained stable at 19-25 per 100,000 people aged >50 years from 1996-2018. The proportion of GCA patients receiving a TAB remained constant until 2016, after which it promptly declined from 70-80% to 29-39%. In contrast, the proportion of patients receiving diagnostic imaging increased from 2% to 66% from 2000-2018. The proportion of GCA patients remaining in GC treatment has steadily decreased from 1996-2016, but remains high at 64%, 40%, and 34% after 2, 5, and 10 years following the diagnosis, respectively. The cumulative GC dose has remained relatively stable. CONCLUSION: Incidence rates of GCA have remained stable since 1996 despite increasing use of diagnostic imaging. There is a clear discrepancy between current international GCA treatment guidelines and the clinical practice up to 2018.

Positive Predictive Value of the Giant Cell Arteritis Diagnosis in the Danish National Patient Registry: A Validation Study.

PURPOSE: To investigate the positive predictive value (PPV) of the giant cell arteritis (GCA) diagnosis in the Danish National Patient Registry (DNPR). PATIENTS AND METHODS: A total of 293 patients aged ≥50 years with a first-time diagnosis of GCA in the DNPR between January 2012 and December 2017 were included. Patients were sampled from two secondary and one tertiary care hospitals in the Central Region Denmark. Two independent investigators (PH & PT) reviewed all medical files, including medical records, treatment, biochemistry, histopathology and imaging, and either confirmed or dismissed the diagnosis of GCA. In case of disagreement, a consensus agreement was reached. Sub-analyses including number of redeemed prescriptions performed temporal artery biopsies (TABs), and number of GCA-related hospital contacts were performed. RESULTS: We confirmed the diagnosis of GCA in 183/293 patients resulting in a PPV of 62% (95% CI: 57-68). In patients with ≥3 redeemed prescriptions of glucocorticoids (GCs), we confirmed the diagnosis in 166/214 resulting in a PPV of 78% (95% CI: 71-83). In patients with ≥3 redeemed prescriptions of GCs and ≥3 GCA-related hospital contacts, we confirmed the diagnosis in 88/95 resulting in a PPV of 93% (95% CI: 85-96); however, this only included 88/183 confirmed GCA patients. CONCLUSION: This is the first study to validate the diagnostic code of GCA in the DNPR. The overall PPV of GCA in the DNPR was 62%. Requiring redeemed prescriptions of GCs and/or GCA-related hospital contacts increase the PPV, but also excludes a significant number of GCA patients.

Endovascular Treatment of Intracerebral Giant Cell Arteritis.

Background: Giant cell arteritis (GCA) is the most common primary systemic vasculitis predominantly affecting large and medium sized vessels. In rare cases, the vasculitis can affect the vessels of the brain. Results: We describe four cases of GCA with involvement of the cerebral vessels causing stroke. These cases were unresponsive to aggressive immunosuppression and we opted to treat with endovascular balloon dilatation of the stenotic areas. The procedure was safe. The four patients were treated in nine sessions and a total of 16 vessels were treated. We observed two dissections with no clinical influence on the patients. Discussion: In patients with stroke due to progressive GCA that is non-responsive to immunosuppression, endovascular therapy is feasible.

Diagnostic accuracy of ultrasound for detecting large-vessel giant cell arteritis using FDG PET/CT as the reference.

OBJECTIVES: The diagnostic accuracy of axillary artery US in the diagnosis of large-vessel (LV)-GCA using 18F-fluorodeoxyglucose (FDG) PET/CT as reference standard was prospectively evaluated in GCA-suspected patients. As an exploratory analysis, the diagnostic accuracy of cranial artery FDG PET/CT was evaluated. METHODS: Briefly, the inclusion criteria were age ≥50 years, raised inflammatory markers and potential GCA symptoms. Patients in immunosuppressive therapy or with a previous diagnosis of GCA or PMR were excluded. Examinations were performed pre-treatment. LV-GCA reference diagnosis was a clinical diagnosis of GCA and PET-proven LV inflammation. GCA patients fulfilling ACR criteria were considered as cranial-GCA (c-GCA). Patients without GCA were considered controls. Receiver operating characteristic curve analysis of the US-measured axillary intima-media thickness was performed. FDG uptake in temporal, maxillary and vertebral arteries was also assessed. RESULTS: Forty-six patients were diagnosed with LV-GCA, 10 with isolated c-GCA, and in 34 patients GCA was dismissed. Axillary US yielded a sensitivity of 76% and a specificity of 100% for LV-GCA. An axillary intima-media thickness cut-off of 1.0 mm yielded a sensitivity of 74% and a specificity of 92%. Adding LV US to temporal assessment increased sensitivity from 71% to 97% (all GCA patients). Cranial artery PET showed a diagnostic sensitivity of 78% and specificity of 100% for c-GCA. CONCLUSION: Axillary artery US shows high accuracy for the LV-GCA diagnosis. Building upon the recent EULAR recommendations, we propose a diagnostic algorithm with US as the first-line confirmatory test, not only in c-GCA-suspected patients, but in all patients suspected of GCA.

Acetylcholinesterase-associated inflammation in patients with giant cell arteritis. Evaluation by histology and 11C-donepezil PET/CT.

OBJECTIVES: To investigate the in-situ expression of acetylcholinesterase (AChE) in the inflamed vessel wall of patients with biopsy-positive giant cell arteritis (GCA) as compared to biopsy-negative non-GCA patients, and to evaluate the in-vivo expression of AChE in patients with large-vessel GCA (LVGCA) by 11C-donepezil (AChE inhibitor) positron emission tomography/computed tomography (PET/CT). METHODS: Twenty-four biopsy-positive GCA and 44 biopsy-negative non-GCA patients were included for AChE histology. Immunohistochemical methods were used to determine the AChE expression. The histological inflammation and the AChE expression were assessed by an experienced pathologist on a 3-point scale. Two patients with newly diagnosed 18F-fluorodeoxyglucose (18F-FDG) PET/CT verified LVGCA were included for 11C-donepezil PET/CT. PET images were assessed by an experienced nuclear medicine physician. RESULTS: AChE was expressed in all 24 positive temporal artery biopsies, 10/24 showed high AChE expression (grade 2) and 14/24 showed moderate AChE expression (grade 1). No AChE expression was observed outside the media smooth muscle cells (grade 0) in any of the biopsy-negative non-GCA patients. The AChE expression was in 86% agreement with the histological inflammation. The AChE expression was not associated with any clinical or biochemical findings. In both LV-GCA patients, PET/CT revealed extensive vascular FDG uptake but no 11C-donepezil uptake. CONCLUSIONS: AChE is highly expressed in the inflamed vessel wall of patients with GCA. Although, 11C-donepezil PET/CT showed no vascular uptake in the FDG PET/CT verified LV-GCA patients, histological findings raise the possibility that AChE can be used in the development of new diagnostic and disease monitoring tools for GCA.

PR3-ANCA-associated vasculitis is associated with a specific motif in the peptide-binding cleft of HLA-DP molecules.

OBJECTIVES: This study aimed to characterize the association between HLA alleles and ANCA-associated vasculitis (AAV) in a genetically homogeneous population, and to analyse the contribution of specific HLA molecule amino acid sequences to the risk of AAV. METHODS: We included 187 Danish patients with AAV and 1070 healthy controls. All were HLA typed at two-field resolution. The association of HLA alleles to PR3- or MPO-AAV was analysed. The contribution of the dominant molecular motifs of the HLA-DPB1 molecule to the risk of AAV was investigated by association studies that included specific amino acid sequences of the hypervariable regions in exon 2. RESULTS: Ninety-four percent of patients with PR3-AAV were carriers of HLA-DPB1*04:01 while all patients with PR3-AAV were carriers of an HLA-DPB1*04 allele, and 85% were homozygous. This was significantly more than in the control group (P < 0.0001). The association was even stronger when HLA-DPB1*04:02 and -DPB1*23:01 were included. HLA-DPB1*04:01, -DPB1*04:02 and -DPB1*23:01 share amino acids in positions 8-9, 69, 76 and 84-87 within the hypervariable regions, but only positions 69 and 84-87 contributed significantly to the disease risk. HLA-DRB1*15 was associated with an increased risk of developing PR3-AAV, while HLA-DRB1*04, -DRB1*07 and -DQB1*03 were associated with a reduced risk of kidney involvement in PR3-AAV. MPO-AAV was only weakly associated with HLA class I alleles. CONCLUSION: PR3-AAV is strongly associated with the HLA-DPB1 alleles HLA-DPB1*04:01, -DPB1*04:02 and -DPB1*23:01, which share amino acid sequences crucial for the peptide-binding groove.