Serum interleukin-6 receptor in polymyalgia rheumatica: A potential marker of relapse/recurrence risk

Vascular-adhesion protein 1 in giant cell arteritis and polymyalgia rheumatica

Vascular adhesion protein-1 (VAP-1) is a type 2 transmembrane sialoglycoprotein with oxidative deamination functionality, encoded by the amine oxidase copper-containing 3 (AOC3) gene. VAP-1 is widely expressed across various tissues, particularly in highly vascularized tissues and organs essential for lymphocyte circulation. In the vascular system, VAP-1 is predominantly found in vascular smooth muscle cells and endothelial cells, with higher expression levels in vascular smooth muscle cells. Under inflammatory conditions, VAP-1 rapidly translocates to the endothelial cell surface, facilitating leukocyte adhesion and migration through interactions with specific ligands, such as sialic acid-binding immunoglobulin-type lectins (Siglec)-9 on neutrophils and monocytes, and Siglec-10 on B cells, monocytes, and eosinophils. This interaction is crucial for leukocyte transmigration into inflamed tissues. Furthermore, VAP-1's enzymatic activity generates hydrogen peroxide and advanced glycation end-products, contributing to cytotoxic damage and vascular inflammation. In this context, the soluble form of VAP-1 (sVAP-1), produced by matrix metalloproteinase cleavage from its membrane-bound counterpart, also significantly influences leukocyte migration. This review aims to elucidate the multifaceted pathophysiological roles of VAP-1 in vascular inflammation, particularly in giant cell arteritis (GCA) and associated polymyalgia rheumatica (PMR). By exploring its involvement in immune cell adhesion, migration, and its enzymatic contributions to oxidative stress and tissue damage, we investigate the importance of VAP-1 in GCA. Additionally, we discuss recent advancements in imaging techniques targeting VAP-1, such as [68Ga]Ga-DOTA-Siglec-9 PET/CT, which have provided new insights into VAP-1's role in GCA and PMR. Overall, understanding VAP-1's comprehensive roles could pave the way for improved strategies in managing these conditions.

Polymyalgia rheumatica

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

Biomarkers in the era of targeted therapy in giant cell arteritis and polymyalgia rheumatica: is it possible to replace acute-phase reactants?

Research into giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) has become more important in the last few decades. Physicians are facing several challenges in managing the diagnosis, treatment, and relapses of GCA and PMR patients. The search for biomarkers could provide elements to guide a physician's decision. In this review, we aim to summarize the scientific publications about biomarkers in GCA and PMR in the past decade. The first point raised by this review is the number of clinical situations in which biomarkers could be useful: differential diagnosis of either GCA or PMR, diagnosis of underlying vasculitis in PMR, prediction of relapse or complications, disease activity monitoring, choice, and modification of treatments. The second point raised by this review is the large number of biomarkers studied, from common markers like C-reactive protein, erythrocyte sedimentation rate, or elements of blood count to inflammatory cytokines, growth factors, or immune cell subpopulations. Finally, this review underlines the heterogeneity between the studies and proposes points to consider in studies evaluating biomarkers in general and particularly in the case of GCA and PMR.

[Methods for assessment of disease activity of polymyalgia rheumatica]

Polymyalgia rheumatica (PMR) is the second most frequent inflammatory rheumatic disease in old age. Remission and recurrence are frequently used as endpoints in clinical trials; however, there is as yet no international consensus on the definition of these states, which limits the comparability of published studies. The PMR activity score (PMR-AS) is the only composite score specifically developed for PMR, which together with remission is used to define low, middle and high disease activity. In recent studies the PMR-AS was often used and low disease activity was established as endpoint. The most important limitation of the PMR-AS is the potential influence of the individual variables by comorbidities. The value of C‑reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) are of restricted value in studies using drugs that influence the interleukin 6 (IL-6) axis. In these cases, calprotectin and osteopontin are promising alternative biomarkers, as they have already been shown to reflect disease activity independently of CRP in rheumatoid arthritis. Furthermore, imaging modalities including sonography, magnetic resonance imaging and fluorodeoxyglucose (FDG) positron emission tomography could also be helpful in monitoring disease activity; however, these techniques must first be validated in further studies. The PMR impact scale (PMR-IS) is a composite score to assess the impact of PMR on the patients; however, it has not yet been used in clinical studies. The development of additional patient reported outcomes (PRO) for PMR and the definition of standardized criteria for documentation of remission and recurrence are important questions in the future research agenda for PMR.

An update on polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is the most common inflammatory rheumatic disease affecting people older than 50 years and is 2-3 times more common in women. The most common symptoms are pain and morning stiffness in the shoulder and pelvic girdle and the onset may be acute or develop over a few days to weeks. General symptoms such as fatigue, fever and weight loss may occur, likely driven by systemic IL-6 signalling. The pathology includes synovial and periarticular inflammation and muscular vasculopathy. A new observation is that PMR may appear as a side effect of cancer treatment with checkpoint inhibitors. The diagnosis of PMR relies mainly on symptoms and signs combined with laboratory markers of inflammation. Imaging modalities including ultrasound, magnetic resonance imaging and positron emission tomography with computed tomography are promising new tools in the investigation of suspected PMR. However, they are still limited by availability, high cost and unclear performance in the diagnostic workup. Glucocorticoid (GC) therapy is effective in PMR, with most patients responding promptly to 15-25 mg prednisolone per day. There are challenges in the management of patients with PMR as relapses do occur and patients with PMR may need to stay on GC for extended periods. This is associated with high rates of GC-related comorbidities, such as diabetes and osteoporosis, and there are limited data on the use of disease-modifying antirheumatic drugs and biologics as GC sparing agents. Finally, PMR is associated with giant cell arteritis that may complicate the disease course and require more intense and prolonged treatment.

Immune system activation in polymyalgia rheumatica: Which balance between autoinflammation and autoimmunity? A systematic review

BACKGROUND AND AIM

Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease that is common in elderly people. Its classification in the spectrum of autoinflammatory and autoimmune diseases is difficult because of its only partially understood immune-mediated mechanisms. The literature concerning the innate and adaptive immune system activation in PMR was systematically reviewed highlighting the relative weight of autoinflammation and autoimmunity in its pathogenesis and disease progression.

METHODS

A literature search on PubMed Central and Embase scientific databases was performed by two independent reviewers. To be eligible, the studies needed to fully satisfy our initial PICO framework: a primary diagnosis of PMR as a population, the search for immune/inflammatory cells, cytokines and autoantibodies as an intervention, a control group consisting in healthy controls, patients with other inflammatory rheumatic diseases or PMR patients in remission after treatment and as outcomes the results of the investigations in the analyzed tissue samples. The most relevant data of the included papers were extracted by using a standardized template.

RESULTS

Of the 933 screened abstracts, 52 papers were included in the systematic review and categorized depending on their primary research objectives. The hyper-activity of neutrophils and monocytes, expressing toll-like receptor 7 in active disease, an impaired phagocytosis and endothelial dysfunction, as well as an increased count of innate T cells in patients with remission emerged among the major derangements of the innate immune response in PMR. Among the cytokines profile, interleukin-6 plays a key role but other pro-inflammatory mediators and angiogenesis markers such as chemokines, B-cell activating factor, vascular endothelial growth factor and angiopoietins seem to be involved in refractory or glucocorticoid-resistant PMR. The aberrant adaptive immune response was documented by tissue and serum findings of polarized T cells towards T helper 1 and 17 phenotypes, an increased expression of immunosenescent surface markers and a downregulated immunoregulatory response. The altered distribution of peripheral B cells, detected during active disease, suggested their peripheral migration towards unidentified sites. The interaction between innate and adaptive immune response was documented by a synovial infiltrate of macrophages and T cells. Despite multiple autoantibodies have been detected in PMR patients, none proved to correlate with disease activity seeming to be reactive to the marked inflammation or antigenic determinants provided by environmental triggers or tissue/cell damage.

CONCLUSIONS

The complex network between innate and adaptive immune system in PMR is supported by findings at molecular and cellular levels. By considering both the ends of the pathophysiological spectrum of immune-mediated rheumatic diseases, PMR may be regarded as an inflammatory immune-mediated disease with mixed mechanisms in a background of genetic and epigenetic factors together with immunological and endocrine senescence.

Pathogenesis, Diagnosis and Management of Polymyalgia Rheumatica

Polymyalgia rheumatica is an inflammatory rheumatic disease of the elderly characterised by pain and stiffness in the neck and pelvic girdle, and is the second most common inflammatory rheumatic condition in this age group, after rheumatoid arthritis. Polymyalgia rheumatica can occur independently or in association with giant cell arteritis, which is the most common form of primary vasculitis. The diagnosis of polymyalgia rheumatica is usually based on clinical presentation and increase of inflammatory markers. There are no pathognomonic findings that can confirm the diagnosis. However, different imaging techniques, especially ultrasonography, can assist in the identification of polymyalgia rheumatica. Glucocorticoids are the cornerstone of the treatment of polymyalgia rheumatica, but they might be associated with different adverse events. A subgroup of patients presents with a refractory disease course and, in these cases, adding methotrexate as a steroid-sparing agent could be useful. In this review, we summarise the latest findings regarding the pathogenesis, diagnosis and management of polymyalgia rheumatica and try to highlight the possible pitfalls, especially in elderly patients.

Management of difficult polymyalgia rheumatica and giant cell arteritis: Updates for clinical practice

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) represent a family of systemic inflammatory diseases occurring in adults aged 50 years and above. Clinical presentation of PMR/GCA can be variable, making diagnosis at times challenging. There has been an increased appreciation of the role of various large-vessel imaging modalities to help confirm a diagnosis of GCA. Systemic corticosteroids (CS) remain the mainstay of treatment for both PMR and GCA, yet both relapses and CS-related side effects are common. Recent research has demonstrated efficacy of certain biologic agents in these diseases, with particular emphasis on the role of interleukin-6 (IL-6) blockade in GCA. This chapter discusses the latest updates on the diagnosis and treatment of PMR/GCA, with an emphasis on clinical care.

Genetic Predispositions of Glucocorticoid Resistance and Therapeutic Outcomes in Polymyalgia Rheumatica and Giant Cell Arteritis

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are closely related chronic inflammatory diseases. Glucocorticoids (GCs) are first-choice drugs for PMR and GCA, although some patients show poor responsiveness to the initial GC regimen or experience flares after GC tapering. To date, no valid biomarkers have been found to predict which patients are at most risk for developing GC resistance. In this review, we summarize PMR- and GCA-related gene polymorphisms and we associate these gene variants with GC resistance and therapeutic outcomes. A limited number of GC resistance associated-polymorphisms have been published so far, mostly related to HLA-DRB1*04 allele. Other genes such ICAM-1, TLR4 and 9, VEGF, and INFG may play a role, although discrepancies are often found among different populations. We conclude that more studies are required to identify reliable biomarkers of GC resistance. Such biomarkers could help distinguish non-responders from responders to GC treatment, with concomitant consequences for therapeutic strategy.

Current and emerging therapies in large-vessel vasculitis

GCA shares many clinical features with PMR and Takayasu arteritis. The current mainstay of therapy for all three conditions is glucocorticoid therapy. Given the chronic, relapsing nature of these conditions and the morbidity associated with glucocorticoid therapy, there is a need for better treatment options to induce and sustain remission with fewer adverse effects. Conventional immunosuppressive treatments have been studied and have a modest effect. There is a keen interest in biologic therapies with studies showing the efficacy of IL-6 antagonists in PMR and GCA. Recently the first two randomized clinical trials in Takayasu arteritis have been completed. A major challenge for all of these conditions is the lack of standardized measures to assess disease activity. Long-term studies are needed to evaluate the impact of biologic therapies showing potential on important clinical outcomes such as vascular damage, cost-effectiveness and quality of life. The optimal duration of treatment also needs to be assessed.

Relapse of polymyalgia rheumatica after a fall

Approximately half of PMR patients have a relapse with a necessity to increase GC dosages. The role of external factors in inducing PMR relapse have been poorly investigated. We present a case-series of five PMR patients in remission with low doses of glucocorticosteroids (GC), who presented with relapse immediately after a fall. The assessment of PMR relapse was made using PMR-AS by Leeb and Bird, and a score > 9.35 was consistent with diagnosis of relapse. Gender, age, and cumulative dose of GC at the time of the fall were compared between the group of these five patients and a group of 41 PMR patients who had no PMR relapse after a fall: using the Fischer's exact test a significant difference was pointed out when the p-value was < 0.05. In our five PMR patients, the sharp worsening of clinical manifestations was always accompanied by a significant rise of the inflammatory indices and the increase of GC dosage (almost always 10 mg/day of prednisone) prompted a fast return (seven days as average) to the previous clinical and laboratory features. All other potentially responsible factors were excluded. Several months (6-10 months on average) after the fall, none of these five patients had a new relapse. No significant differences were found when we compared age, sex, and the cumulative dose of GC at the time of the fall between the group of patients with PMR relapse and the group of patients without. The possibility of PMR relapse being realised immediately after a fall should be kept in mind in daily practice, especially when typical manifestations reappear immediately after a fall and other diagnostic hypotheses have been carefully excluded. The lack of important data (genetic factors, hormonal dosages, serum levels of IL-6 and/or serum soluble IL-6 receptor) in our case-series represented important limits for clarifying the nature of our observations and should be included in any subsequent study design on this argument. If our monocentric data are confirmed by multicentric data, the assessment of the risk of falls through specific scales should be an integral part of the visit of all PMR patients.

High mRNA expression level of IL-6R was associated with better prognosis for patients with ovarian cancer: a pooled meta-analysis

Interleukin-6 acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine. IL-6/IL-6R signaling pathway, in particular, has been proposed to be a pivotal cytokine promoting ovarian cancer progression. This study aimed to elucidate potential clinical and biological function of IL-6R mRNA expression in ovarian cancer. We used the keywords “ovarian cancer” and searched through GEO database and finally a total of 7 studies together with TCGA database were incorporated in this analysis. We used Cutoff Finder to determine a cutoff point and stratified patients into two groups and found that high-expression of IL-6R mRNA in tumor tissues was a positive prognostic factor for overall survival. Simultaneously, high expression level of IL-6R mRNA correlates with better survival of patients who had additional chemotherapy treatment. These analyses suggested a possible role of tumoral expression of IL-6R in ovarian cancer. In conclusion, our results showed that mRNA levels of IL-6R in ovarian cancer was positively associated with better prognosis and sensitivity to chemotherapy and can potentially be used as a prognostic marker for this cancer.

Brief Report: A Prospective Open-Label Phase IIa Trial of Tocilizumab in the Treatment of Polymyalgia Rheumatica

OBJECTIVE

Interleukin-6 (IL-6) is a pivotal cytokine in the pathogenesis of polymyalgia rheumatica (PMR), yet the efficacy of IL-6 blockade with tocilizumab (TCZ) for the treatment of PMR is unknown. The aim of this study was to assess the efficacy and safety of TCZ in newly diagnosed PMR.

METHODS

In a single-center open-label study, patients with newly diagnosed PMR who had been treated with glucocorticoids (GCs) for <1 month were treated monthly with intravenous (IV) TCZ 8 mg/kg for 1 year, with a rapid tapering of GCs according to standardized protocol. The primary end point was the proportion of patients in relapse-free remission without GC treatment at 6 months. Secondary outcome measures included duration of GC use and cumulative GC dose. Patients were followed up for 15 months.

RESULTS

Ten patients were enrolled in the study. One patient withdrew after 2 months, leaving 9 patients in whom the primary end point was assessed. The primary end point of relapse-free remission without GC treatment at 6 months was achieved by all 9 of these patients. All patients who received TCZ treatment were able to discontinue GCs within 4 months of study entry. The cumulative mean ± SD prednisone dose was 1,085 ± 301 mg and the total duration of GC exposure was 3.9 ± 0.9 months. Remission persisted without relapse, in all 9 patients, throughout the entire 15-month study.

CONCLUSION

Our findings suggest that TCZ may be an effective, safe, and well-tolerated treatment for newly diagnosed patients with PMR, with a robust steroid-sparing effect.

Outcome Measures in Polymyalgia Rheumatica. A Systematic Review

Objective.

To identify the instruments used to assess polymyalgia rheumatica (PMR) in published studies.

Methods.

A systematic literature review of clinical trials and longitudinal observational studies related to PMR, published from 1970 to 2014, was carried out. All outcome and assessment instruments were extracted and categorized according to core areas and domains, as defined by the OMERACT (Outcome Measures in Rheumatology) Filter 2.0.

Results.

Thirty-five articles (3221 patients) were included: 12 randomized controlled trials (RCT); 3 nonrandomized trials; and 20 observational studies. More than 20 domains were identified, measured by 29 different instruments. The most frequently used measures were pain, morning stiffness, patient global assessment and physician global assessment, erythrocyte sedimentation rate, and C-reactive protein. The definition of outcomes varied considerably between studies.

Conclusion.

The outcome measures and instruments used in PMR are numerous and diversely defined. The establishment of a core set of validated and standardized outcome measurements is needed.

Glucocorticoid-resistant polymyalgia rheumatica: pretreatment characteristics and tocilizumab therapy

Treatment with glucocorticoid (GC) is the preferred therapy for polymyalgia rheumatica (PMR), but some patients show poor responses to the initial GC regimen or experience flares on GC tapering. Alternative therapies for patients with GC resistance have not yet been established. To evaluate pretreatment characteristics and therapeutic outcomes of GC-resistant PMR, we followed all patients who had been diagnosed with PMR between October 2007 and February 2013, according to our standardized protocol. GC-resistant patients were defined as those who had responded poorly to the initial GC regimen (15 mg/day of prednisolone) or those who had responded to the initial regimen but had experienced a flare upon GC tapering to 5 mg/day of the maintenance dose or within the first 6 months of maintenance therapy. Out of 23 patients, nine were found to be GC-resistant cases and the others were GC responders. Baseline values of PMR activity score and its components, especially the ability to elevate the upper limbs (EUL), were significantly higher in GC-resistant patients compared with GC responders. The additional use of methotrexate (MTX, five cases), salazosulfapyridine (one case), and tocilizumab (TCZ, three cases) was effective for GC-resistant patients, although 13 to 39 weeks were required for the achievement of remission. We report the three GC-resistant cases in which TCZ was added to GC therapy with or without MTX. We also review the medical literature on the use of TCZ as of January 31, 2014 and discuss the utility of TCZ in the treatment of GC-resistant PMR.

Tocilizumab for polymyalgia rheumatica: report of two cases and review of the literature

BACKGROUND

Glucocorticoids (GC) are the mainstay of treatment of polymyalgia rheumatica (PMR). However GC-related adverse events occur frequently, particularly in patients with relapsing disease. Several studies have demonstrated that IL-6 is a key player in the pathogenesis of PMR.

OBJECTIVES

To report 2 patients with PMR treated with the anti-IL-6 receptor monoclonal antibody tocilizumab (TCZ) and to review the published evidence on the efficacy and safety of TCZ in patients with PMR.

METHODS

We treated 2 GC-naive patients with newly diagnosed pure PMR with monthly TCZ infusions (8mg/kg body weight) for 6 months. Disease activity and drug tolerability were assessed clinically, by laboratory tests, and bilateral shoulder ultrasonography before starting the treatment and subsequently every month during TCZ therapy. We performed a systematic literature search (PubMed until July 2012) using the terms "tocilizumab," "anti-IL-6-receptor," "polymyalgia rheumatica," "giant cell arteritis", and "large-vessel vasculitis" to identify published reports of patients with PMR treated with TCZ.

RESULTS

One of our patients responded well to TCZ, while the other patient required GC therapy after the 2nd TCZ infusion because of lack of appreciable clinical response. Both patients tolerated TCZ well. The review of the literature revealed 4 reports with a total of 9 patients who received TCZ for PMR. In 7 of these 9 patients, PMR was associated with giant cell arteritis. Including our patients, 5 patients received TCZ alone and 6 TCZ plus GC. A good response to TCZ treatment was observed in all patients reported in the literature without any major adverse events.

CONCLUSIONS

TCZ both as monotherapy and in association with GC appears to be mostly effective and safe to treat patients with PMR. However, larger controlled studies are required to confirm these favorable data.

Polymyalgia rheumatica and giant cell arteritis: management of two diseases of the elderly

Both polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) present with a broad spectrum of clinical manifestations and almost exclusively occur in the population aged over 50 years. After rheumatoid arthritis, PMR is the second most common autoimmune rheumatic disorder. Visual loss is the most feared complication in temporal arteritis, and extracranial arteries and/or aorta are more often involved in GCA than previously estimated. No specific laboratory parameter exists for diagnosis of PMR. Imaging techniques such as ultrasonography, MRI or 18F-fluorodeoxyglucose PET may be helpful in the diagnosis and evaluation of the extent of vascular involvement in these diseases. This article highlights upcoming new classification criteria for PMR, recent advances of diagnostic and therapeutic procedures as well as ongoing research on biomarkers and corticosteroid-sparing medications, which should improve management of PMR and GCA.

Definition of remission and relapse in polymyalgia rheumatica: data from a literature search compared with a Delphi-based expert consensus

Objective

To compare current definitions of remission and relapse in polymyalgia rheumatica (PMR) with items resulting from a Delphi-based expert consensus.

Methods

Relevant studies including definitions of PMR remission and relapse were identified by literature search in PubMed. The questionnaire used for the Delphi survey included clinical (n=33), laboratory (n=54) and imaging (n=7) parameters retrieved from a literature search. Each item was assessed for importance and availability/practicability, and limits were considered for metric parameters. Consensus was defined by an agreement rate of ≥80%.

Results

Out of 6031 articles screened, definitions of PMR remission and relapse were available in 18 and 34 studies, respectively. Parameters used to define remission and/or relapse included history and clinical assessment of pain and synovitis, constitutional symptoms, morning stiffness (MS), physician's global assessment, headache, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), blood count, fibrinogen and/or corticosteroid therapy. In the Delphi exercise a consensus was obtained on the following parameters deemed essential for definitions of remission and relapse: patient's pain assessment, MS, ESR, CRP, shoulder and hip pain on clinical examination, limitation of upper limb elevation, and assessment of corticosteroid dose required to control symptoms.

Conclusions

Assessment of patient's pain, MS, ESR, CRP, shoulder pain/limitation on clinical examination and corticosteroid dose are considered to be important in current available definitions of PMR remission and relapse and the present expert consensus. The high relevance of clinical assessment of hips was unique to this study and may improve specificity and sensitivity of definitions for remission and relapse in PMR.