Infections and the risk of incident giant cell arteritis: a population-based, case-control study

Investigating interferon type I responses in patients with suspected giant cell arteritis and polymyalgia rheumatica

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are closely related inflammatory disorders. Easily measurable biomarkers defining active disease and identifying patients in need of glucocorticoid sparing treatment options are highly desired. Interferon Type I (IFN-I) might be involved in disease pathology; however, evidence is limited. This study explores a systemic IFN-I signature and expression of IFN-I markers in GCA and PMR patients. Treatment naive GCA and PMR patients, and PMR patients with glucocorticoid treatment were included. Patients suspected of but not diagnosed with GCA were used as controls. Five relevant IFN-I-stimulated genes were identified in literature, and relative expression levels were determined using quantitative reverse transcription polymerase chain reaction (RT-qPCR) in peripheral blood mononuclear cells. An IFN-I score was generated. Serum levels of IFN-I induced C-X-C motif chemokine 10 (CXCL10) and Galectin-9 were determined by multiplex immunoassay. There were no differences in IFN-I scores between the groups. An IFN-I signature was observed in 0/9 controls, 2/11 GCA patients, 4/20 treatment naive PMR patients, and 2/10 PMR patients with treatment. Serum CXCL10 and Galectin-9 were not increased in GCA or PMR patients compared to control patients. Treated PMR patients had lower CXCL10 levels [423.2 pg/ml (375.1-491.1)] compared to treatment naive PMR patients [641.8 pg/ml (552.8-830.6)]. An IFN-I signature does not distinguish GCA and PMR patients from controls. Also, IFN-I-induced serum markers are not upregulated in GCA and PMR patients. Easily measurable IFN-I-induced serum markers will therefore probably not aid in diagnosis and additional treatment options in newly diagnosed GCA and PMR patients.

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

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

Association between infection and the onset of giant cell arteritis and polymyalgia rheumatica: a systematic review and meta-analysis

OBJECTIVE

We aimed to analyse the association between infections and the subsequent risk of giant cell arteritis (GCA) and/or polymyalgia rheumatica (PMR) by a systematic review and a meta-analysis of observational studies.

METHODS

Two databases (Medline and Embase) were systematically reviewed. Epidemiological studies studying the association between any prior infection and the onset of GCA/PMR were eligible. Risk of bias was assessed using the Newcastle-Ottawa quality assessment scale. Outcomes and pooled statistics were reported as OR and their 95% CI.

RESULTS

Eleven studies (10 case-control studies and one cohort study) were analysed, seven of them were included in the meta-analysis. Eight were at low risk of bias. A positive and significant association was found between prior overall infections and prior Herpes Zoster (HZ) infections with pooled OR (95% CI) of 1.27 (1.18 to 1.37) and 1.20 (1.08 to 1.21), respectively. When analysed separately, hospital-treated and community-treated infections, were still significantly associated with the risk of GCA, but only when infections occurring within the year prior to diagnosis were considered (pooled OR (95% CI) 1.92 (1.67 to 2.21); 1.67 (1.54 to 1.82), respectively). This association was no longer found when infections occurring within the year prior to diagnosis were excluded.

CONCLUSION

Our study showed a positive association between the risk of GCA and prior overall infections (occurring in the year before), and prior HZ infections. Infections might be the reflect of an altered immunity of GCA patients or trigger the disease. However, reverse causation cannot be excluded.CRD42023404089.

Unmet need in the treatment of polymyalgia rheumatica and giant cell arteritis

For decades, aside from prednisone and the occasional use of immune suppressive drugs such as methotrexate, there was little to offer patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). However, there is a great interest in various steroid sparing treatments in both these conditions. This paper aims to provide an overview of our current knowledge of PMR and GCA, examining their similarities and distinctions in terms of clinical presentation, diagnosis, and treatment, with emphasis placed on reviewing recent and ongoing research efforts on emerging treatment. Multiple recent and ongoing clinical trials are demonstrating new therapeutics that will provide benefit and contribute to the evolution of clinical guidelines and standard of care for patients with GCA and/or PMR.

The role of autoimmunity and autoinflammation in giant cell arteritis: A systematic literature review

Giant cell arteritis is the most common form of large vessel vasculitis and preferentially involves large and medium-sized arteries in patients over the age of 50. Aggressive wall inflammation, neoangiogenesis and consecutive remodeling processes are the hallmark of the disease. Though etiology is unknown, cellular and humoral immunopathological processes are well understood. Matrix metalloproteinase-9 mediated tissue infiltration occurs through lysis of basal membranes in adventitial vessels. CD4+ cells attain residency in immunoprotected niches, differentiate into vasculitogenic effector cells and enforce further leukotaxis. Signaling pathways involve the NOTCH1-Jagged1 pathway opening vessel infiltration, CD28 mediated T-cell overstimulation, lost PD-1/PD-L1 co-inhibition and JAK/STAT signaling in interferon dependent responses. From a humoral perspective, IL-6 represents a classical cytokine and potential Th-cell differentiator whereas interferon-γ (IFN- γ) has been shown to induce chemokine ligands. Current therapies involve glucocorticoids, tocilizumab and methotrexate application. However, new agents, most notably JAK/STAT inhibitors, PD-1 agonists and MMP-9 blocking substances, are being evaluated in ongoing clinical trials.

Incidence of biopsy-proven giant cell arteritis (GCA) in South Australia 2014-2020

Objective

To determine the incidence of biopsy proven giant cell arteritis (GCA) in South Australia.

Methods

Patients with biopsy-proven GCA were identified from pathology reports of temporal artery biopsies at state-based pathology laboratories, from 1 January 2014 to 31 December 2020. Incidence rates for biopsy-proven GCA were calculated using Australian Bureau of Statistics data for South Australian population sizes by age, sex, and calendar year. Seasonality was analyzed by cosinor analysis.

Results

There were 181 cases of biopsy-proven GCA. The median age at diagnosis of GCA was 76 years (IQR 70, 81), 64% were female. The estimated population incidence for people over 50 was 5.4 (95% CI 4.7, 6.1) per 100,000-person years. The female: male incidence ratio was 1.6 (95% CI 1.2, 2.2). There was no ordinal trend in GCA incidence rates by calendar year (p = 0.29). The incidence was, on average, highest in winter, but not significantly (p = 0.35). A cosinor analysis indicated no seasonal effect (p = 0.52).

Conclusion

The incidence of biopsy-proven GCA remains low in Australia. A higher incidence was noted compared to an earlier study. However, differences in ascertainment and methods of GCA diagnosis may have accounted for the change.

Pathogenesis of giant cell arteritis with focus on cellular populations

Giant cell arteritis (GCA), the most common non-infectious vasculitis, mainly affects elderly individuals. The disease usually affects the aorta and its main supra-aortic branches causing both general symptoms of inflammation and specific ischemic symptoms because of the limited blood flow due to arterial structural changes in the inflamed arteries. The pathogenesis of the GCA is complex and includes a dysregulated immune response that affects both the innate and the adaptive immunity. During the last two decades several studies have investigated interactions among antigen-presenting cells and lymphocytes, which contribute to the formation of the inflammatory infiltrate in the affected arteries. Toll-like receptor signaling and interactions through the VEGF-Notch-Jagged1 pathway are emerging as crucial events of the aberrant inflammatory response, facilitating among others the migration of inflammatory cells to the inflamed arteries and their interactions with the local stromal milieu. The increased use of checkpoint inhibitors in cancer immunotherapy and their immune-related adverse events has fed interest in the role of checkpoint dysfunction in GCA, and recent studies suggest a dysregulated check point system which is unable to suppress the inflammation in the previously immune-privileged arteries, leading to vasculitis. The role of B-cells is currently reevaluated because of new reports of considerable numbers of plasma cells in inflamed arteries as well as the formation of artery tertiary lymphoid organs. There is emerging evidence on previously less studied cell populations, such as the neutrophils, CD8+ T-cells, T regulatory cells and tissue residing memory cells as well as for stromal cells which were previously considered as innocent bystanders. The aim of this review is to summarize the evidence in the literature regarding the cell populations involved in the pathogenesis of GCA and especially in the context of an aged, immune system.

A Case of Giant Cell Arteritis With a Normal Erythrocyte Sedimentation Rate (ESR) Post ChAdOx1 nCoV-19 Vaccination

Giant cell arteritis (GCA) has been reported post the coronavirus disease 2019 (COVID-19) vaccination, especially with the mRNA vaccine. A normal erythrocyte sedimentation rate (ESR) is seen in some GCA patients.

This report describes a 68-year-old gentleman who presented with a right-sided temporal headache for three weeks, starting three to five days after his second dose of the ChAdOx1 nCoV-19 vaccine, a viral vector vaccine, which was given seven weeks post the first dose. On presentation, he developed blurred vision in the left eye, and it progressed to complete vision loss four days later. He also had episodes of blurred vision in the right eye. The blood test showed a mildly elevated C-reactive protein of 29 mg/L and a normal erythrocyte sedimentation rate (ESR) of 4 mm/hr. Optical coherence tomography showed anterior ischaemic optic neuropathy in the left eye and retinal ischemia in the right eye. Bilateral giant cell arteritis (GCA) was confirmed on temporal artery biopsy. He was treated with methylprednisolone pulse therapy followed by prednisolone. He re-presented with intermittent blurry vision in the right eye three months later. He was treated with methylprednisolone pulse therapy again, followed by prednisolone, aspirin, and tocilizumab.

This case describes a patient who developed GCA post ChAdOx1 nCoV-19 vaccination with a normal ESR. Further studies are needed to investigate this relationship as causal or incidental and the likelihood of low-level inflammatory makers in such a situation.

New Insights into the Pathogenesis of Giant Cell Arteritis: Mechanisms Involved in Maintaining Vascular Inflammation

The giant cell arteritis (GCA) pathophysiology is complex and multifactorial, involving a predisposing genetic background, the role of immune aging and the activation of vascular dendritic cells by an unknown trigger. Once activated, dendritic cells recruit CD4 T cells and induce their activation, proliferation and polarization into Th1 and Th17, which produce interferon-gamma (IFN-γ) and interleukin-17 (IL-17), respectively. IFN-γ triggers the production of chemokines by vascular smooth muscle cells, which leads to the recruitment of additional CD4 and CD8 T cells and also monocytes that differentiate into macrophages. Recent data have shown that IL-17, IFN-γ and GM-CSF induce the differentiation of macrophage subpopulations, which play a role in the destruction of the arterial wall, in neoangiogenesis or intimal hyperplasia. Under the influence of different mediators, mainly endothelin-1 and PDGF, vascular smooth muscle cells migrate to the intima, proliferate and change their phenotype to become myofibroblasts that further proliferate and produce extracellular matrix proteins, increasing the vascular stenosis. In addition, several defects in the immune regulatory mechanisms probably contribute to chronic vascular inflammation in GCA: a defect in the PD-1/PD-L1 pathway, a quantitative and qualitative Treg deficiency, the implication of resident cells, the role of GM-CSF and IL-6, the implication of the NOTCH pathway and the role of mucosal‑associated invariant T cells and tissue‑resident memory T cells.

Phenotypic, transcriptomic and functional profiling reveal reduced activation thresholds of CD8+ T cells in giant cell arteritis

OBJECTIVES

Evidence from temporal artery tissue and blood suggests involvement of CD8+ T cells in the pathogenesis of GCA, but their exact role is poorly understood. Therefore, we performed a comprehensive analysis of circulating and lesional CD8+ T cells in GCA patients.

METHODS

Circulating CD8+ T cells were analysed for differentiation status (CD45RO, CCR7), markers of activation (CD69 and CD25) and proliferation (Ki-67) in 14 newly diagnosed GCA patients and 18 healthy controls by flow cytometry. Proliferative capacity of CD8+ T cells upon anti-CD3 and anti-CD3/28 in vitro stimulation was assessed. Single-cell RNA sequencing of peripheral blood mononuclear cells of patients and controls (n = 3 each) was performed for mechanistic insight. Immunohistochemistry was used to detect CD3, CD8, Ki-67, TNF-α and IFN-γ in GCA-affected tissues.

RESULTS

GCA patients had decreased numbers of circulating effector memory CD8+ T cells but the percentage of Ki-67-expressing effector memory CD8+ T cells was increased. Circulating CD8+ T cells from GCA patients demonstrated reduced T cell receptor activation thresholds and displayed a gene expression profile that is concurrent with increased proliferation. CD8+ T cells were detected in GCA temporal arteries and aorta. These vascular CD8+ T cells expressed IFN-γ but not Ki-67.

CONCLUSION

In GCA, circulating effector memory CD8+ T cells demonstrate a proliferation-prone phenotype. The presence of CD8+ T cells in inflamed arteries seems to reflect recruitment of circulating cells rather than local expansion. CD8+ T cells in inflamed tissues produce IFN-γ, which is an important mediator of local inflammatory responses in GCA.

Global epidemiology of vasculitis

The many forms of vasculitis are characterized by inflammation of blood vessels, leading to potentially long-term sequelae including vision loss, aneurysm formation and kidney failure. Accurate estimation of the incidence and prevalence has been hampered by the absence of reliable diagnostic criteria and the rarity of these conditions; however, much progress has been made over the past two decades, although data are still lacking from many parts of the world including the Indian subcontinent, China, Africa and South America. Giant cell arteritis occurs in those aged 50 years and over and seems to mainly affect persons of northern European ancestry, whereas Takayasu arteritis occurs mainly in those aged under 40 years. By contrast, Kawasaki disease mainly occurs in children aged under 5 years and is most common in children of Asian ancestry, and IgA vasculitis occurs in children and adolescents. Although much less common than giant cell arteritis, the different forms of antineutrophil cytoplasmic antibody-associated vasculitis are being increasingly recognized in most populations and occur more frequently with increasing age. Behçet syndrome occurs most commonly along the ancient silk road between Europe and China. Much work needs to be done to better understand the influence of ethnicity, geographical location, environment and social factors on the development of vasculitis.

Novel aspects of regulatory T cell dysfunction as a therapeutic target in giant cell arteritis

OBJECTIVES

Giant cell arteritis (GCA) is the most common primary vasculitis, preferentially affecting the aorta and its large-calibre branches. An imbalance between proinflammatory CD4+ T helper cell subsets and regulatory T cells (Tregs) is thought to be involved in the pathogenesis of GCA and Treg dysfunction has been associated with active disease. Our work aims to explore the aetiology of Treg dysfunction and the way it is affected by remission-inducing immunomodulatory regimens.

METHODS

A total of 41 GCA patients were classified into active disease (n=14) and disease in remission (n=27). GCA patients' and healthy blood donors' (HD) Tregs were sorted and subjected to transcriptome and phenotypic analysis.

RESULTS

Transcriptome analysis revealed 27 genes, which were differentially regulated between GCA-derived and HD-derived Tregs. Among those, we identified transcription factors, glycolytic enzymes and IL-2 signalling mediators. We confirmed the downregulation of forkhead box P3 (FOXP3) and interferon regulatory factor 4 (IRF4) at protein level and identified the ineffective induction of glycoprotein A repetitions predominant (GARP) and CD25 as well as the reduced T cell receptor (TCR)-induced calcium influx as correlates of Treg dysfunction in GCA. Inhibition of glycolysis in HD-derived Tregs recapitulated most identified dysfunctions of GCA Tregs, suggesting the central pathogenic role of the downregulation of the glycolytic enzymes. Separate analysis of the subgroup of tocilizumab-treated patients identified the recovery of the TCR-induced calcium influx and the Treg suppressive function to associate with disease remission.

CONCLUSIONS

Our findings suggest that low glycolysis and calcium signalling account for Treg dysfunction and inflammation in GCA.

Functionally Heterogenous Macrophage Subsets in the Pathogenesis of Giant Cell Arteritis: Novel Targets for Disease Monitoring and Treatment

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.

Cardiovascular drug treatment, statins and biopsy-confirmed giant cell arteritis: a population-based case-control study

Objective

To determine whether exposure to cardiovascular medications and statins is associated with increased risk of giant cell arteritis (GCA).

Design

The population-based case–control study comprised a cohort of patients with biopsy-confirmed GCA linked to the Swedish Prescribed Drug Register to identify all exposure to drugs prior to diagnosis of GCA. Ten controls per GCA case, matched for age, sex and residential area, were included. Using corresponding Anatomical Therapeutic Chemical codes, ACE inhibitors, angiotensin II receptor blockers, beta-blocking agents, calcium antagonists, diuretics, statins and cardiac therapy drugs were investigated from July 1, 2005 to the diagnosis/index date. A conditional logistic regression model was fitted adjusted for income, education level and marital status. We repeated the analyses including only new drug users excluding those with any prescription during the year from July 1, 2005 to July 1, 2006.

Results

574 cases (29% men) of diagnosed GCA and 5740 controls (29% men) were included. The mean age at diagnosis is 75 years (SD 8). Of the GCA cases, 71% had at least one dispensation of a cardiovascular drug prior to the index date, compared to 74% of controls. The ORs for the association of target drug exposure with GCA were <1 for most drugs, but close to 1 in the analysis of new users. Statins were consistently associated with lower risk of GCA, OR 0.74 (95% CI 0.61 to 0.90).

Conclusion

Statins may be associated with lower risk of incident biopsy-confirmed GCA. No association was evident for other studied drugs.

CD8+ T Cells in GCA and GPA: Bystanders or Active Contributors?

Vasculitis refers to inflammation of blood vessels and can cause a variety of serious complications depending on which vessels are affected. Two different forms of vasculitis are Giant Cell Arteritis (GCA) and Granulomatosis with Polyangiitis (GPA). GCA is the most common form of vasculitis in adults affecting the large arteries and can lead to visual impairment and development of aneurysms. GPA affects small- and medium-sized blood vessels predominantly in the lungs and kidneys resulting in organ failure. Both diseases can potentially be fatal. Although the pathogenesis of GCA and GPA are incompletely understood, a prominent role for CD4+ T cells has been implicated in both diseases. More recently, the role of CD8+ T cells has gained renewed interest. CD8+ T cells are important players in the adaptive immune response against intracellular microorganisms. After a general introduction on the different forms of vasculitis and their association with infections and CD8+ T cells, we review the current knowledge on CD8+ T-cell involvement in the immunopathogenesis of GCA and GPA focusing on phenotypic and functional features of circulating and lesional CD8+ T cells. Furthermore, we discuss to which extent aging is associated with CD8+ T-cell phenotype and function in GCA and GPA.

Identification of Acute Giant Cell Arteritis in Real-World Data Using Administrative Claims-Based Algorithms

Objective

The objective of this study was to validate claims‐based algorithms for identifying acute giant cell arteritis (GCA) that will help generate real‐world evidence on comparative effectiveness research and epidemiologic studies. Among patients identified by the GCA algorithm, we further investigated whether GCA flares could be detected by using claims data.

Methods

We developed five claims‐based algorithms based on a combination of International Classification of Diseases, Ninth Revision (ICD‐9) diagnosis codes, specialist visits, and dispensed medications using Medicare Parts A, B, and D linked to electronic medical records (2006‐2014). Acute cases of GCA were determined by chart review using the treating physician’s diagnosis of GCA as the gold standard. Among the patients identified with acute GCA, we assessed if a GCA flare occurred during the year after initial diagnosis.

Results

The number of patients identified by each algorithm ranged from 220 to 896. Positive predictive values (PPVs) of the algorithms ranged from 60.7% to 84.8%. Requirement for disease‐specific workups, multiple diagnosis codes, or specialist visits improved the PPVs. The highest PPV (84.8%) was noted in an algorithm that required two or more diagnosis codes of GCA from inpatient, emergency department, or outpatient rheumatology visits plus a prednisone‐equivalent dose greater than or equal to 40 mg/day occurring 14 days before or after the second ICD‐9 diagnosis date, with the cumulative days’ supply greater than or equal to 14 days. Among patients identified as having GCA, 18.2% of patients had definite evidence of a flare and 25% had a potential flare.

Conclusion

A claims‐based algorithm requiring two or more ICD‐9 diagnosis codes from inpatient, emergency department, or outpatient rheumatology visits and high‐dose glucocorticoid dispensing can be a useful tool to identify acute GCA cases in large administrative claims databases.

Assessment for varicella zoster virus in patients newly suspected of having giant cell arteritis

OBJECTIVES

There is uncertainty if varicella zoster virus (VZV) triggers GCA. This is based on discordant reports of VZV detection in GCA temporal artery biopsies. We conducted a multimodal evaluation for VZV in the inception Giant Cell Arteritis and PET Scan (GAPS) cohort.

METHODS

Consecutive patients who underwent temporal artery biopsy for suspected GCA were clinically reviewed for active and past VZV infection and followed for 6 months. Serum was tested for VZV IgM and IgG. Temporal artery biopsy (TAB) sections were stained for VZV antigen using the VZV Mouse Cocktail Antibody (Cell Marque, Rocklin, CA, USA). A selection of GCA and control tissues were stained with the VZV gE antibody (Santa Cruz Biotechnology, Dallas, TX, USA), which was used in previous studies.

RESULTS

A total of 58 patients met inclusion criteria, 12 (21%) had biopsy-positive GCA and 20 had clinically positive GCA. None had herpes zoster at enrolment and only one patient developed a VZV clinical syndrome (zoster ophthalmicus) on follow-up. There was no difference in VZV exposure between GCA and non-GCA patients. None of the 53 patients who had VZV serology collected had positive VZV IgM antibodies. VZV antigen was not convincingly demonstrated in any of the TAB specimens; 57 TABs stained negative and 1 stained equivocally positive. The Santa Cruz Biotechnology VZV antibody exhibited positive staining in a range of negative control tissues, questioning its specificity for VZV antigen.

CONCLUSION

The absence of active infection markers argues against VZV reactivation being the trigger for GCA. Non-specific immunohistochemistry staining may account for positive findings in previous studies.

Is There an Association between Herpetic Infections and Giant Cell Arteritis? A Population-Based Study

Recent data suggests that herpes zoster (HZ) and herpes simplex virus (HSV) may be one of the underlying immunological triggers for giant cell arteritis (GCA). However, there is limited population-based data to support this. Our goal was to determine if herpetic infections increase the likelihood of GCA in the British Columbia (BC) population. The background prevalence of GCA was compared to the prevalence of GCA in subjects with HZ and HSV using diagnostic billing code data from an online BC database (BC Data Scout^TM). BC residents ≥30 years old at the time of diagnosis from January 2000 to January 2019 were included. The relevant International Classification of Disease codes was used to identify patients with GCA, HZ, and HSV. Comparisons were made using two-sample Z tests. There were 4315 GCA diagnoses, from a total population of 3,026,005 subjects. The prevalence of GCA was 143 per 100,000 people. In terms of herpetic infections, 850 GCA cases were identified in 249,900 subjects with HZ versus 310 diagnoses of GCA in 163,170 subjects with HSV. The prevalence of GCA in subjects with HZ (0.340%) was significantly higher than the prevalence of GCA (0.143%) in the general population (p < 0.00001). The prevalence of GCA in HSV subjects (0.190%) was also significantly higher (p < 0.00001) than the population prevalence but lower than (p < 0.00001) the GCA with HZ prevalence. The likelihood of GCA appears to increase with herpetic infections, more significantly with HZ.

Neurological and Ophthalmological Manifestations of Varicella Zoster Virus

BACKGROUND

Approximately 1 million new cases of herpes zoster (HZ) occur in the United States annually, including 10%-20% with herpes zoster ophthalmicus (HZO). Postherpetic neuralgia, a debilitating pain syndrome occurs in 30% HZ, whereas 50% HZO develop ophthalmic complications. Diplopia from cranial nerve palsy occurs in less than 30% HZO, whereas optic neuropathy is seen in less than 1% HZO. We reviewed recent developments in the diagnosis, treatment, and prevention of HZ as well as neurological and ophthalmological complications of relevance to the neuro-ophthalmologist.

EVIDENCE ACQUISITION

We searched the English language literature on Pubmed and Google scholar for articles relevant to the various sections of this review.

RESULTS

Antiviral treatment should be initiated within 48-72 hours of onset of HZ and HZO to decrease pain and reduce complications. We recommend neuroimaging in all patients with neuro-ophthalmic manifestations such as diplopia and acute vision loss. Diagnostic confirmation using polymerase chain reaction and serology on paired serum and cerebrospinal fluid samples should be obtained in those with neurological signs and symptoms or abnormal imaging. Patients with neurological and/or retinal varicella zoster virus (VZV) infection should be treated promptly with intravenous acyclovir. Patients with isolated optic neuropathy or cranial nerve palsy can be managed with oral antivirals. The prognosis for visual recovery is good for patients with isolated optic neuropathy and excellent for patients with isolated ocular motor cranial nerve palsy.

CONCLUSIONS

HZ produces a spectrum of potentially blinding and life-threatening complications that adversely affect quality of life and increase health care costs. Individuals at risk for HZ, such as the elderly and immunocompromised, should be encouraged to receive the highly effective VZV vaccine to prevent HZ and its complications.

Infections Are Associated With Increased Risk of Giant Cell Arteritis: A Population-based Case-control Study from Southern Sweden

OBJECTIVE

To investigate the association between infections and the subsequent development of giant cell arteritis (GCA) in a large population-based cohort from a defined geographic area in Sweden.

METHODS

Patients diagnosed with biopsy-confirmed GCA between 2000 and 2016 were identified through the database of the Department of Pathology in Skåne, the southernmost region of Sweden. For each GCA case, 10 controls matched for age, sex, and area of residence were randomly selected from the general population. Using the Skåne Healthcare Register, we identified all infection events prior to patients' date of GCA diagnosis and controls' index date. With infection as exposure, a conditional logistic regression model was employed to estimate the OR for developing GCA. The types of infections contracted nearest in time to the GCA diagnosis/index date were identified.

RESULTS

A total of 1005 patients with biopsy-confirmed GCA (71% female) and 10,050 controls were included in the analysis. Infections were more common among patients subsequently diagnosed with GCA compared to controls (51% vs 41%, OR 1.78, 95% CI 1.53-2.07). Acute upper respiratory tract infection (OR 1.77, 95% CI 1.47-2.14), influenza and pneumonia (OR 1.72, 95 % CI 1.35-2.19), and unspecified infections (OR 5.35, 95 % CI 3.46-8.28) were associated with GCA. Neither skin nor gastrointestinal infections showed a correlation.

CONCLUSION

Infections, especially those of the respiratory tract, were associated with subsequent development of biopsy-confirmed GCA. Our findings support the hypothesis that a range of infections may trigger GCA.

Polymyalgia rheumatica following infective triggers or vaccinations: a different subset of disease?

Objectives

Polymyalgia rheumatica (PMR) is the commonest inflammatory disorder of the elderly; an association with environmental triggers and a deregulated immune response have been described. The aim of this study was to investigate the association of environmental triggers before the onset of PMR.

Material and methods

The database of 58 consecutive PMR patients recruited from a single rheumatology secondary care setting was retrospectively analyzed to investigate the frequency of environmental triggers and correlations with clinical characteristics, ultrasound and laboratory data.

Results

Fifteen PMR patients (26%) described a connection with environmental agents: six PMR patients reported a vaccination, 4 reported a respiratory tract infection, 5 reported seasonal influenza before the onset of the disease. The model of multivariate linear regression which better predicted a shorter time to normalize inflammatory reactants (R² = 27.46%, p = 0.0042) comprised the presence of an environmental trigger and a higher PCR. A linear regression analysis confirmed an inverse correlation between PCR at onset and time to normalize inflammatory reactant (r = –0.3031, p = 0.0208). A significant correlation was demonstrated between presence of environmental trigger and shorter time to normalize inflammation (r = –0.5215, p< 0.0001), and lesser frequency of gleno-humeral synovitis on US (r = –0.3774, p = 0.0038).

Conclusions

Our work describes a correlation between environmental triggers in PMR and higher CRP at diagnosis, faster response to therapy, and milder shoulder synovitis. We may suppose that these patients belong to a more specific subtype of PMR, in whom external stimuli, such as vaccination or infection, may lead to a deregulated response within the context of an impaired senescent immuno-endocrine system.

[Physiopathology of giant cell arteritis: From inflammation to vascular remodeling]

Giant cell arteritis (GCA) is a large-vessel vasculitis involving the aorta and its main branches, especially supra aortic branches. Although much progress has been made, the pathophysiology remains incompletely understood. An initial trigger, suspected of infectious origin, lead to the maturation and recruitment of dendritic cells (DC). The lack of migration of these DC allows the local recruitment of T-lymphocytes (LT). These LT- CD4⁺ polarize in Type 1 helper (Th1), Th17 but also Th9. A qualitative and quantitative deficit in regulatory T cells (Treg) is observed under the influence of IL-21 overproduction. In addition, an imbalance in the Th17/Treg balance is favored by IL-6. The secretion of IFN-γ, IL-17, IL-6, IL-33 is responsible for a sustained local inflammatory reaction that is organized around tertiary lymphoid follicles. Locally recruited macrophages secrete reactive forms of oxygen together with VEGF and PDGF. These growth factors, together with neurotrophins and endothelin contribute to increase the proliferation of vascular smooth muscle cells (VSMCs). The imbalance between matrix metalloproteases (MMP)-2, MMP-9 and MMP-14 and tissue inhibitors of metalloproteases (TIMP)-1 and TIMP-2 also contribute to the remodeling process occurring in the vessel wall. Finally, arterial neovascularization contribute to the perpetuation of lymphocyte recruitment. This persistent remodeling is sometimes complicated by ischemic events responsible for the initial severity of the disease.

Giant cell arteritis: is the clinical spectrum of the disease changing?

BACKGROUND

Giant cell arteritis is a vasculitis of large and middle-sized arteries that affects patients aged over 50 years. It can show a typical clinical picture consisting of cranial manifestations but sometimes nonspecific symptoms and large-vessel involvement prevail. Prompt diagnosis and treatment is essential to avoid irreversible damage.

DISCUSSION

There has been an increasing knowledge on the occurrence of the disease without the typical cranial symptoms and its close relationship and overlap with polymyalgia rheumatica, and this may contribute to reduce the number of underdiagnosed patients. Although temporal artery biopsy is still the gold-standard and temporal artery ultrasonography is being widely used, newer imaging techniques (FDG-PET/TAC, MRI, CT) can be of valuable help to identify giant cell arteritis, in particular in those cases with a predominance of extracranial large-vessel manifestations.

CONCLUSIONS

Giant cell arteritis is a more heterogeneous condition than previously thought. Awareness of all the potential clinical manifestations and judicious use of diagnostic tests may be an aid to avoid delayed detection and consequently ominous complications.

Spontaneous remission of giant cell arteritis: possible association with a preceding acute respiratory infection and seropositivity to Chlamydia pneumoniae antibodies

Recent epidemiological or immunopathological studies demonstrate the possible association between giant cell arteritis and infectious agents including Chlamydia pneumoniae. A 62-year-old Japanese man with type 1 diabetes mellitus developed biopsy-proven giant cell arteritis after acute upper respiratory infection. Serological examination indicated concurrent re-infection with C. pneumoniae. Clinical manifestations of the vasculitis subsided within a month without any immunosuppressive therapy, and no relapse was observed for the following 12 months. The natural history of this disease is unclear and spontaneous remission is rarely reported. The self-limiting nature of the infection could contribute to this phenomenon.

2018 EULAR recommendations for a core data set to support observational research and clinical care in giant cell arteritis

Giant cell arteritis (GCA) represents the most common form of primary systemic vasculitis and is frequently associated with comorbidities related to the disease itself or induced by the treatment. Systematically collected data on disease course, treatment and outcomes of GCA remain scarce. The aim of this EULAR Task Force was to identify a core set of items which can easily be collected by experienced clinicians, in order to facilitate collaborative research into the course and outcomes of GCA. A multidisciplinary EULAR task force group of 20 experts including rheumatologists, internists, epidemiologists and patient representatives was assembled. During a 1-day meeting, breakout groups discussed items from a previously compiled collection of parameters describing GCA status and disease course. Feedback from breakout groups was further discussed. Final consensus was achieved by means of several rounds of email discussions after the meeting. A three-round Delphi survey was conducted to determine a core set of parameters including the level of agreement. 117 parameters were regarded as relevant. Potential items were subdivided into the following categories: General, demographics, GCA-related signs and symptoms, other medical conditions and treatment. Possible instruments and assessment intervals were proposed for documentation of each item. To facilitate implementation of the recommendations in clinical care and clinical research, a minimum core set of 50 parameters was agreed. This proposed core set intends to ensure that relevant items from different GCA registries and databases can be compared for the dual purposes of facilitating clinical research and improving clinical care.

Does low risk of infections as a marker of effective immunity predict increased risk of subsequent giant cell arteritis or polymyalgia rheumatica? A Danish population-based case-control study

Objective

It has been suggested that a hyper-effective immune system (“hyper-immunity”) is central to the pathogenesis of giant cell arteritis and polymyalgia rheumatica (GCA/PMR). We examined if a low risk of infections, as a marker of hyper-immunity, can predict increased subsequent risk of GCA/PMR.

Patients and methods

We conducted a population-based case–control study including all patients aged ≥50 years with incident GCA/PMR diagnosed between 1997 and 2012 in Northern Denmark. For each case, we selected 10 population controls matched on gender, age, place of residence, and time spent in the region. Complete history of hospital-treated infections and community-based anti-infective prescriptions was assessed in population-based registries. We used conditional logistic regression to compute OR of GCA/PMR associated with infections while adjusting for comorbidities, immunosuppressive treatment, and other potential confounders.

Results

We included 7,225 GCA/PMR cases and 72,250 controls. When excluding all infections occurring within the last year before GCA/PMR diagnosis, there was no decreased risk for GCA/PMR in people with a history of hospital-treated infection (adjusted OR=1.04, 95% CI: 0.98–1.10) or community anti-infective treatment (adjusted OR=1.07, 95% CI: 0.99–1.16). Within the last year preceding the GCA/PMR index date, patients with hospital-treated infections (adjusted OR=1.59, 95% CI: 1.44–1.75) or community anti-infective treatment (adjusted OR=1.63, 95% CI: 1.48–1.79) had a greatly increased risk of a GCA/PMR diagnosis.

Conclusion

These results do not support the hypothesis of “hyper-immunity” leading to GCA/PMR. Instead, incident GCA/PMR is preceded by a slightly increased risk of infection, which may be related to protopathic bias or support theories that infections may be directly involved in the pathogenesis of GCA/PMR.

Prognosis and future developments in vasculitis

The prognosis of ANCA-associated vasculitis has been transformed in recent years. Once it was a set of invariably acute and fatal conditions, but these disorders are currently considered to be chronic diseases. This change is largely attributable to earlier diagnosis and the careful application of immunotherapeutics. However, patients still experience premature mortality, relapse, comorbid ill health and poor quality of life. Mortality rates in large-vessel vasculitis are not comparable; however, morbidity and poor patient outcomes prevail. Toxicity secondary to glucocorticoids represents a common driver of poor outcomes across systemic vasculitis. The main thrust of future treatment strategies is to reduce if not eliminate exposure to these agents.

Fever of unknown origin following parathyroidectomy prior to onset of typical polymyalgia rheumatica symptoms: a case report

Polymyalgia rheumatica (PMR) is a disease commonly seen in elderly individuals, however, the etiology has not been reported. Typical clinical features include bilateral shoulder pain and morning stiffness, while serologic autoantibody test findings are negative. Approximately 40%–50% of affected patients present with low-grade fever, fatigue, and appetite loss, which we often experience in the field of general medicine, and thus, the condition should not be given low priority. However, knowledge regarding such constitutional manifestations is also limited. We encountered an elderly woman with a fever of unknown origin that developed following a parathyroidectomy for a single parathyroid adenoma, after which severe shoulder pain and morning stiffness emerged, leading to a diagnosis of PMR. The fever developed several days prior to appearance of severe pain, which is an uncommon presentation in PMR cases. Our patient had low-grade inflammation without pyrexia prior to the surgery, which might have been an important reason for the accelerated immoderate immune activation leading to PMR induced by surgery in this case. Furthermore, she was infected with the influenza A virus 3 weeks before coming to us. Some reports have suggested a relationship between the influenza virus or vaccine and PMR. It is difficult to conclude regarding the definite trigger in our patient, though the details of this case should be helpful for a better understanding of the disease.

Smoking as a risk factor for giant cell arteritis: A systematic review and meta-analysis

OBJECTIVES

To investigate the association between smoking and giant cell arteritis (GCA).

METHODS

A systematic review was performed and meta-analysis conducted on observational studies that reported absolute numbers and/or statistical comparisons with 95% confidence intervals comparing smoking history and presence of GCA, among patients with GCA and non-GCA controls. Studies were reviewed in accordance with PRISMA guidelines. Point estimates and standard errors were extracted from individual studies and were combined by the generic inverse variance method of DerSimonian and Laird. A random-effects meta-analysis was performed. Statistical heterogeneity was assessed using the Cochran's Q test which was complemented with the I² statistic.

RESULTS

The initial search yielded 3312 articles. Of these, thirteen studies (8 prospective and, 5 retrospective case-control studies) with unique cohorts were identified and included in the primary analysis (ever vs. never smoking history). Patients in the GCA cohort were more likely to have a history of smoking with an odds ratio of 1.19 (95% CI, 1.01-1.39). Considerable heterogeneity was present (I²= 85%). Five of these studies included information on current smoking status. One additional study, which only reported current smoking status, was also included. The GCA cohort showed an association with current smoking with an odds ratio of 1.18 (95% CI, 1.01-1.38).

CONCLUSION

Our study demonstrated a statistically significant increased risk of GCA among both current and ever smokers compared to non-smokers.

The association of gout with incident giant cell arteritis in older adults

OBJECTIVES

To assess whether gout is associated with a higher or lower risk of a new diagnosis of giant cell arteritis (GCA) in older adults, adjusting for known risk factors of GCA.

METHODS

We used the 5% Medicare claims to conduct a multivariable Cox regression analyses to assess the association of gout with incident GCA in adults 65 years or older adjusting for age, gender, race (known risk factors for GCA) and Charlson-Romano comorbidity score, the use of medications for cardiovascular diseases (statins, beta-blockers, diuretics, ACE-inhibitors) and gout (allopurinol, febuxostat). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated.

RESULTS

There were 3004 incident cases (new diagnosis) of GCA with crude incidence rates of GCA of 28.0/100,000 person-years in patients without gout and 63.8/100,000 person-years in patients with gout. Multivariable-adjusted analyses showed that preexisting gout was associated with a higher risk of incident/new GCA diagnosis with a hazard ratio of 2.05 (95% CI: 1.76, 2.40), confirmed in sensitivity analyses that substituted continuous Charlson-Romano comorbidity score with categorized score or individual comorbidities (plus hypertension, hyperlipidemia, and coronary artery disease). Older age, female gender, white race and higher comorbidity index, were also associated with a higher hazard of GCA. Subgroup analyses did not show any significant variation of the association of preexisting gout with incident GCA by age, race or sex.

CONCLUSIONS

Gout was associated with more than 2-fold higher risk of incident GCA in older adults, independent of known risk factors of GCA. Future studies should explore the underlying mechanisms for this association.

Diagnosis and management of giant cell arteritis: an Asia-Pacific perspective

Giant cell arteritis is the commonest primary vasculitis of the elderly. However, the prevalence does vary widely between populations with highest incidence amongst Northern Europeans and lowest amongst East Asians. Preliminary studies suggest that clinical manifestations may differ between different populations. Newer diagnostic approaches including ultrasound, MR angiography and PET imaging are under review. While there have been recent advances in the diagnosis of GCA particularly with regard to imaging, there is an urgent need for improvements in methods of diagnosis, treatment and requirement for screening. Glucocorticoid treatment remain the backbone of therapy. However, glucocorticoid therapy is associated with significant adverse effects. Conventional and novel immunosuppressive agents have only demonstrated modest effects in a subgroup of steroid refractory GCA due to the different arms of the immune system at play. However, recently a study of IL-6 blockade demonstrated benefit in GCA. Newer approaches such as fast-track pathways can also result in improvements in consequences of GCA including blindness.

Infection-associated vasculitides

Vasculitides are disorders characterized by inflammation of the vessel walls, often caused by autoimmunity, but sometimes as a result of microbial invasion. Almost all types of microbes including bacteria, viruses, protozoa and fungi have been incriminated in the pathogenesis of vasculitis. Accurate etiological diagnosis is important since immunosuppressive treatment may lead to further deterioration if infection is the cause of vasculitis. Clinical features sometimes provide clues to the etiology. Further evaluation requires a focused and cost-effective plan of laboratory investigation. The investigations aim at establishing the diagnosis of vasculitis and identify the causative organism. An accurate diagnosis of vasculitis optimally requires histological examination and imaging. For infection-associated vasculitis, the identification of the organism requires studies of stained specimens, cultures, and/or detection of antigens and antibodies. Ideally, the treatment involves administration of an appropriate antimicrobial. In non-self-limiting types of vasculitides, glucocorticoids are needed when the symptoms are progressive, with vital organs involvement, and sometimes, when there is no antimicrobial agent of proven efficacy against the incriminated agent. Additional immunosuppressive agents or interventions must be considered when the disease is severe and/or post-infective immune mechanisms are involved in the pathogenesis, e.g., severe HBV- or HCV-associated vasculitides. Available preventative vaccinations are also crucial. The incidence of HBV-associated vasculitides dramatically decreased following HBV vaccination campaigns, and other infection-associated vasculitides may as well in the future.

Does herpes zoster predispose to giant cell arteritis: a geo-epidemiologic study

Purpose

Giant cell arteritis (GCA) is the most common systemic vasculitis in the elderly and can cause irreversible blindness and aortitis. Varicella zoster (VZ), which is potentially preventable by vaccination, has been proposed as a possible immune trigger for GCA, but this is controversial. The incidence of GCA varies widely by country. If VZ virus contributes to the immunopathogenesis of GCA we hypothesized that nations with increased incidence of GCA would also have increased incidence of herpes zoster (HZ). We conducted an ecologic analysis to determine the relationship between the incidence of HZ and GCA in different countries.

Methods

A literature search for the incidence rates (IRs) of GCA and HZ from different countries was conducted. Correlation and linear regression was performed comparing the disease IR of each country for subjects 50 years of age or older.

Results

We found the IR for GCA and HZ from 14 countries. Comparing the IRs for GCA and HZ in 50-year-olds, the Pearson product-moment correlation (r) was −0.51, with linear regression coefficient (β) −2.92 (95% CI −5.41, −0.43; p=0.025) using robust standard errors. Comparing the IRs for GCA and HZ in 70-year-olds, r was −0.40, with β −1.78, which was not statistically significant (95% CI −4.10, 0.53; p=0.12).

Conclusion

Although this geo-epidemiologic study has potential for aggregation and selection biases, there was no positive biologic gradient between the incidence of clinically evident HZ and GCA.

Giant cell arteritis: pathogenic mechanisms and new potential therapeutic targets

Giant cell arteritis (GCA) is the most common idiopathic systemic vasculitis in persons aged 50 years or greater. Treatment options for GCA, to-date, have been limited and have consisted primarily of glucocorticoids. Significant advances in the understanding of the genetic and cellular mechanisms in GCA are leading to identification of potential pathogenic targets. The recent success of interleukin-6 blockade in the treatment of GCA has opened the landscape to targeted biologic therapy. T cells, particularly T helper 1 and T helper 17 cell lineages have been identified as key inflammatory cells in both active and chronic vascular inflammatory lesions. Therapeutic agents, including abatacept and ustekinumab, which can impede both vasculitogenic cell lines are of particular interest. Inhibition of signalling pathways, including the janus kinase-signal tranducers and activation of transcription (JAK-STAT) and Notch pathways are evolving options. Tocilizumab has shown clear benefit in both newly diagnosed and relapsing patients with GCA and approval of this medication for treatment of GCA has led to rapid incorporation into treatment regimens. More information is required to understand the long-term outcomes of tocilizumab and other investigational targeted therapeutics in the treatment of GCA.

Decreased Immunity to Varicella Zoster Virus in Giant Cell Arteritis

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 (HCs).

Methods

Cell-mediated immunity to VZV was determined by performing interferon-γ (IFNγ) enzyme-linked immunospot and intracellular cytokine flow cytometry measurements in 11 GCA and 15 PMR patients and in 26 age/sex-matched HCs. 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 HCs by an enzyme-linked immunosorbent assay.

Results

The number of VZV-specific IFNγ spot-forming cells was significantly lower in GCA patients on treatment, than in age-matched HCs (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 HCs.

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 HCs, indicating that GCA patients did not experience herpes zoster substantially more often in the months preceding diagnosis than controls.

Herpes Zoster as a Risk Factor for Incident Giant Cell Arteritis

OBJECTIVE

Histopathologic studies have implicated herpes zoster (HZ) as a causative organism of giant cell arteritis (GCA). The purpose of this study was to assess the epidemiologic association of HZ events with incident GCA.

METHODS

We performed a retrospective cohort study in 2 large independent US administrative data sets: Medicare 5% and Truven Health Analytics MarketScan. Eligible subjects had 12 months of continuous coverage, were >50 years old, and had no history of GCA or polymyalgia rheumatica. HZ events (complicated and uncomplicated) and GCA were identified by the presence of International Classification of Diseases, Ninth Revision, Clinical Modification codes from physician visit or hospital discharge records. Antiviral therapies and vaccinations were identified from prescription claims and drug codes. Risk of incident GCA was calculated using multivariable Cox proportional hazards regression.

RESULTS

Among 16,686,345 subjects, a total of 5,942 GCA cases occurred, with 3.1% (MarketScan) and 6.0% (Medicare) having preceding HZ events. Unadjusted GCA incidence rates were highest in the groups with complicated and uncomplicated HZ. After multivariable adjustment, complicated HZ was associated with an increased risk of GCA (hazard ratio [HR] 1.99 [95% confidence interval (95% CI) 1.32-3.02] in the Medicare cohort and 2.16 [95% CI 1.46-3.18] in the MarketScan cohort), as was uncomplicated HZ (HR 1.42 [95% CI 1.02-1.99] and HR 1.45 [95% CI 1.05-2.01] in the respective cohorts). Vaccination and antiviral treatment were not consistently associated with GCA risk, although antiviral treatment was marginally associated with a decreased risk of GCA in the Medicare cohort (HR 0.67 [95% CI 0.46-0.99]).

CONCLUSION

HZ is associated with an increased risk of GCA. The infrequency of HZ in GCA patients suggests that it is only one potential trigger for GCA. Antivirals and vaccination did not consistently mitigate this risk.

Polymyalgia rheumatica

Polymyalgia rheumatica is an inflammatory disease that affects the shoulder, the pelvic girdles, and the neck, usually in individuals older than 50 years. Increases in acute phase reactants are typical of polymyalgia rheumatica. The disorder might present as an isolated condition or in association with giant cell arteritis. Several diseases, including inflammatory rheumatic and autoimmune diseases, infections, and malignancies can mimic polymyalgia rheumatica. Imaging techniques have identified the presence of bursitis in more than half of patients with active disease. Vascular uptake on PET scans is seen in some patients. A dose of 12·5-25·0 mg prednisolone daily or equivalent leads to rapid improvement of symptoms in most patients with isolated disease. However, relapses are common when prednisolone is tapered. Methotrexate might be used in patients who relapse. The effectiveness of biological therapies, such as anti-interleukin 6, in patients with polymyalgia rheumatica that is refractory to glucocorticoids requires further investigation. Most population-based studies indicate that mortality is not increased in patients with isolated disease.