Successful treatment of resistant pseudogout with anakinra

Calcium pyrophosphate deposition disease: historical overview and potential gaps

CPPD disease can affect patients’ quality of life through its various clinical presentations. This mini-review discusses the evolution of CPPD from its discovery to current knowledge of its pathogenesis, genetic associations, diagnostics, and treatment options. Despite extensive research, the exact mechanisms of CPPD are not well understood, and there is a notable lack of knowledge about psychosocial impacts and patient experiences. This study aims to present a CPPD Disease Timeline identifying gaps in current knowledge and potential directions for future research. These findings contribute to a broader understanding of CPPD disease and emphasize the importance of continued research and innovation in this field.

Recent advances in the therapeutic management of calcium pyrophosphate deposition disease

Calcium pyrophosphate deposition (CPPD) disease is a form of crystal-induced arthropathy that arises from the accumulation of calcium pyrophosphate crystals within joints and soft tissues. This process leads to inflammation and damage to the affected joints. It can present asymptomatically or as acute or chronic inflammatory arthritis. Risk factors and comorbidities, including prior joint injury, osteoarthritis, hereditary or familial predisposition, and metabolic diseases, should be evaluated in CPPD cases. The management of CPPD remains a challenge in the sparsity of randomized controlled trials. The lack of such trials makes it difficult to establish evidence-based treatment protocols for CPPD. This review provides an overview of the current pharmacological management of CPPD, focusing on reducing inflammation, alleviating symptoms, and preventing acute flares. Non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and colchicine are effective in managing acute CPP arthritis. Colchicine may also be used prophylactically to prevent recurrent flares. In cases where other treatments have failed, anakinra, an interleukin-1 receptor antagonist, can be administered to alleviate acute flares. The management of chronic CPP inflammatory arthritis includes NSAIDs and/or colchicine, followed by hydroxychloroquine, low-dose glucocorticoids, and methotrexate, with limited data on efficacy. Tocilizumab can be used in refractory cases. In small studies, synovial destruction using intra-articular injection of yttrium 90 can decrease pain. To date, no disease-modifying therapies exist that reduce articular calcification in CPPD.

The use of Anakinra in treatment of calcium pyrophosphate crystal deposition disease: Analysis of own experience and a literature review

Calcium pyrophosphate crystal deposition disease (CPPD) is a disease caused by the deposition of calcium pyrophosphate crystals, mainly in the articular cartilage, and often manifests as severe acute or chronic arthritis. Therapy given in such cases with non-steroidal anti-inflammatory drugs, colchicine, methotrexate and glucocorticoids is often effective. In these cases, the possibility of prescribing biological drugs, primarily interleukin 1 (IL-1) inhibitors, is being considered. The article analyzes the experience of using Anakinra, an IL-1 receptor antagonist, registered in the Russian Federation in 2021, in 5 patients with persistent arthritis in CPPD. The article also presents an analysis of data from key studies on the use of the drug in patients with CPPD.

Factors Affecting Response to Anakinra in Crystalline Arthritis Flares

BACKGROUND

Interleukin 1 inhibition with anakinra has shown efficacy in the management of crystalline-induced arthritis (CIA) flares. Gout treatment guidelines recommend its use after contraindication or intolerance to first-line therapies. The aim of this study is to identify features associated with better response to anakinra when used to treat CIA flares.

METHODS

This is a medical record review study that included inpatients with acute CIA in whom anakinra was used between the years 2014 and 2019 at one tertiary center (University of Alabama at Birmingham). The primary end point was response to anakinra treatment defined as a decrease in the reported visual analog score of at least 50% within 48 hours of initiation of treatment. Demographic, clinical, and laboratory factors were compared, and factors found significant in bivariate analysis at a p value of less than 0.15 were tested in a multivariate logistic regression analysis for independent association with the response.

RESULTS

A total of 55 admission encounters were analyzed. The mean age was 60.1 years, 36 (66%) were men, and 31 (56%) were African Americans. Twenty-eight of 49 (57%) met the primary end point of response at 48 hours, but 52 of 55 (94.5%) ultimately responded to anakinra during hospital stay. Factors associated with response at 48 hours were race, reason for admission related to cardiac etiologies, not having failed steroids before trial of anakinra, and hospital admission within 48 hours of initiation of flare. On a multivariable logistic regression model, we could not find significant independent associations with response to anakinra.

CONCLUSIONS

Our study showed high response rates to anakinra. We could not identify factors associated with a more robust, early response. It is likely that anakinra is equally effective across a wide range of clinical scenarios.

Natural Products as a Novel Therapeutic Strategy for NLRP3 Inflammasome-Mediated Gout

Gout is the most common form of inflammatory arthritis. It occurs when monosodium urate crystals (MSU) are deposited within joints due to hyperuricemia and persistent elevations of serum uric acid levels. Traditional gout treatment such as urate-lowering therapy is difficult to continue for a long period of time due to the risk of side effects. Recent studies have shown that the modulation of MSU-induced inflammatory responses is dependent on the inflammatory cytokine IL-1β, which has a central role in a chain of processes involving multiple cytokines and mediators. In this regard, the NLRP3 inflammasome is known to play a crucial part and thus has been proposed as a novel target in the treatment for gout. However, the biochemical mechanism for NLRP3 inflammasome activation has not yet been clearly elucidated. Therefore, this report can provide an overview of natural extractions targeted to prevent or treat NLRP3 inflammasome-mediated gout in the MSU-induced gout model. In addition, the research and development of such natural products are suggested as a potential strategy in the treatment of gout.

The role of Interleukin-1 receptor antagonist as a treatment option in calcium pyrophosphate crystal deposition disease

Calcium Pyrophosphate Crystal Deposition (CPPD) disease is characterized by the deposition of calcium pyrophosphate crystals in the cartilage. In most cases, it can manifest as a subclinical condition named chondrocalcinosis, often revealed by joint x-ray examination. In other cases, deposition can cause flares of arthritis, known as acute CPP crystal arthritis. In the last few years, many pathogenic pathways have been discovered. Interleukin-1 (IL-1) plays a key role in the pathogenesis of CPPD disease, both as a mediator of inflammatory response to crystals and as a promoter of damage to articular cartilage. In this review, we investigated the role of IL-1R inhibitor, such as Anakinra, as an alternative to the various therapeutic strategies for CPPD disease, especially among patients resistant to traditional treatment with NSAIDs, corticosteroids and colchicine.

Off-label use of anti-IL-1 drugs in rheumatic diseases

Interleukin-1 (IL-1) plays a key role in the pathogenesis of different rheumatic diseases. There are now several agents available on the market capable of blocking IL-1. The proven effectiveness and excellent safety of these drugs makes them a possible therapeutic option in the treatment of IL-1 driven diseases, when previous therapies are contraindicated or ineffective. This article discusses the European wide off-label use of these drugs for the treatment of rheumatic diseases.

NLRP3 Inflammasome in Inflammation and Metabolism: Identifying Novel Roles in Postburn Adipose Dysfunction

Inflammasomes are multiprotein complexes that respond to pathogen or host associated damage markers, leading to caspase-1 maturation and processing of pro-inflammatory cytokines. Initially, inflammasomes were implicated primarily in inflammatory and infectious conditions. However, increasing evidence demonstrates broader roles beyond inflammation, including regulation of adipose tissue metabolism after burns. Here, we conducted a search for articles on PubMed, Web of Science, Embase, Scopus, and UpToDate with applied search strategies including a combination of "burns," "trauma," "(NLRP3) inflammasome," "metabolic conditions," "white adipose tissue," "macrophages," "browning," and "lipolysis" and included papers from 2000 to 2020. We discuss unexpected roles for NLRP3, the most characterized inflammasome to date, as a key metabolic driver in a variety of conditions. In particular, we highlight the function of NLRP3 inflammasome in burn trauma, which is characterized by both hyperinflammation and hypermetabolism. We identify a critical part for NLRP3 activation in macrophage dynamics and delineate a novel role in postburn white adipose tissue remodeling, a pathological response associated with hypermetabolism and poor clinical outcomes. Mechanistically, how inflammation and inflammasome activation is linked to postburn hypermetabolism is a novel concept to contemplate, and herein we provide evidence of an immunometabolic crosstalk between adipocytes and infiltrating macrophages.

A guide to crystal-related and nano- or microparticle-related tissue responses

Crystals and nano- and microparticles form inside the human body from intrinsic proteins, minerals, or metabolites or enter the body as particulate matter from occupational and environmental sources. Associated tissue injuries and diseases mostly develop from cellular responses to such crystal deposits and include inflammation, cell necrosis, granuloma formation, tissue fibrosis, and stone-related obstruction of excretory organs. But how do crystals and nano- and microparticles trigger these biological processes? Which pathomechanisms are identical across different particle types, sizes, and shapes? In addition, which mechanisms are specific to the atomic or molecular structure of crystals or to specific sizes or shapes? Do specific cellular or molecular mechanisms qualify as target for therapeutic interventions? Here, we provide a guide to approach this diverse and multidisciplinary research domain. We give an overview about the clinical spectrum of crystallopathies, about shared and specific pathomechanisms as a conceptual overview before digging deeper into the specialty field of interest.

Rheumatologic manifestations of hepatic diseases

The course of hepatic diseases may be complicated by a multitude of rheumatologic manifestations, which can complicate the diagnostic approach and alter the natural history of primary liver disease, sometimes worsening prognosis due to associated multiple organ dysfunction. These manifestations can occur in association with a multitude of liver diseases, including viral hepatitis, autoimmune hepatitis, alcoholic liver disease, nonalcoholic fatty liver disease, hemochromatosis, or Wilson’s disease. It is necessary not only for rheumatologists, but also for other clinicians, to be aware that these atypical manifestations may reflect an undiagnosed hepatic disease. On the other hand, it is crucial that, in a patient with known hepatic disease presenting with rheumatologic symptoms, an accurate distinction be made between the rheumatologic manifestations of hepatic disease and primary rheumatologic disease, since the treatment is often different. This review aims to summarize the current evidence regarding rheumatologic manifestations of hepatic diseases, how to distinguish them from primary rheumatologic disorders, and how to provide adequate management.

Current strategy in the treatment of calcium pyrophosphate crystal deposition disease

The paper considers currently available drugs used to treat calcium pyrophosphate crystal deposition disease. It discusses the advantages and disadvantages of the most widely used drugs, such as  nonsteroidal anti-inflammatory drugs, colchicine, glucocorticoids, traditional immunosuppressants, as well as prospects for the use of biologic agents.

Use of Anakinra in Hospitalized Patients with Crystal-associated Arthritis

OBJECTIVE

In this retrospective observational study, we assess the efficacy and safety of the interleukin 1 receptor antagonist anakinra in medically complex, hospitalized patients with acute gout and calcium pyrophosphate crystal arthritis.

METHODS

Adult inpatients treated with anakinra from 2014 to 2017 were identified for inclusion. Charts were reviewed for demographics, comorbidities, laboratory data, pain scores, joint involvement, prior treatment, dosing and response to anakinra, concurrent infections, and surgical interventions. Response to anakinra treatment was determined from review of provider documentation, as well as recorded pain scores on a numeric scale.

RESULTS

We identified 100 individuals accounting for 115 episodes of arthritis. This population was 82% male, with an average age of 60 years. Comorbidities included renal disease (45%) and history of organ transplantation (14%). Twenty-nine episodes of arthritis occurred in the perioperative setting. Concurrent infection was present in 34 episodes. Eighty-six episodes of arthritis had partial or complete response to anakinra within 4 days of treatment initiation; 66 episodes had partial or complete response within 1 day of anakinra administration. Anakinra was well tolerated.

CONCLUSION

To our knowledge, this is the largest observational study of anakinra use in the inpatient setting for the acute treatment of crystal-associated arthritis. We observed a rapid response to anakinra, with 75% of episodes significantly improving or completely resolving within 4 days of the first dose. Our data also support the use of this biologic agent in individuals with infections, as well as perioperative individuals and immunosuppressed transplant recipients.

Anakinra Therapy for Non-cancer Inflammatory Diseases

Interleukin-1 (IL-1) is the prototypical inflammatory cytokine: two distinct ligands (IL-1α and IL-1β) bind the IL-1 type 1 receptor (IL-1R1) and induce a myriad of secondary inflammatory mediators, including prostaglandins, cytokines, and chemokines. IL-1α is constitutively present in endothelial and epithelial cells, whereas IL-1β is inducible in myeloid cells and released following cleavage by caspase-1. Over the past 30 years, IL-1-mediated inflammation has been established in a broad spectrum of diseases, ranging from rare autoinflammatory diseases to common conditions such as gout and rheumatoid arthritis (RA), type 2 diabetes, atherosclerosis, and acute myocardial infarction. Blocking IL-1 entered the clinical arena with anakinra, the recombinant form of the naturally occurring IL-1 receptor antagonist (IL-1Ra); IL-1Ra prevents the binding of IL-1α as well as IL-1β to IL-1R1. Quenching IL-1-mediated inflammation prevents the detrimental consequences of tissue damage and organ dysfunction. Although anakinra is presently approved for the treatment of RA and cryopyrin-associated periodic syndromes, off-label use of anakinra far exceeds its approved indications. Dosing of 100 mg of anakinra subcutaneously provides clinically evident benefits within days and for some diseases, anakinra has been used daily for over 12 years. Compared to other biologics, anakinra has an unparalleled record of safety: opportunistic infections, particularly Mycobacterium tuberculosis, are rare even in populations at risk for reactivation of latent infections. Because of this excellent safety profile and relative short duration of action, anakinra can also be used as a diagnostic tool for undefined diseases mediated by IL-1. Although anakinra is presently in clinical trials to treat cancer, this review focuses on anakinra treatment of acute as well as chronic inflammatory diseases.

Severe calcium pyrophosphate dihydrate deposition disease of the metacarpophalangeal joints

We report a case of calcium pyrophosphate deposition disease (CPPD) with an unusual presentation of severe chondrocalcinosis with atypical large burden deposited in the metacarpophalangeal joints as well as more typical deposition in wrists and knees as demonstrated on plain radiographs. A 77-year-old African-American woman 1-year status post parathyroidectomy for hyperparathyroidism initially presented to the rheumatology clinic to treat suspected rheumatoid arthritis given her pattern of joint involvement but was found to have CPPD. The patient’s history is notable for end-stage renal disease which complicates medical management. This case illustrates radiographic findings of CPPD and explores the challenges of treating CPPD in the setting of comorbid conditions.

Review: Unmet Needs and the Path Forward in Joint Disease Associated With Calcium Pyrophosphate Crystal Deposition

Calcium pyrophosphate (CPP) crystal deposition (CPPD) is prevalent and can be associated with synovitis and joint damage. The population of elderly persons predominantly affected by CPPD is growing rapidly. Since shortfalls exist in many aspects of CPPD, we conducted an anonymous survey of CPPD unmet needs, prioritized by experts from the Gout, Hyperuricemia and Crystal-Associated Disease Network. We provide our perspectives on the survey results, and we propose several CPPD basic and clinical translational research pathways. Chondrocyte and cartilage culture systems for generating CPP crystals in vitro and transgenic small animal CPPD models are needed to better define CPPD mechanism paradigms and help guide new therapies. CPPD recognition, clinical research, and care would be improved by international consensus on CPPD nomenclature and disease phenotype classification, better exploitation of advanced imaging, and pragmatic new point-of-care crystal analytic approaches for detecting CPP crystals. Clinical impacts of CPP crystals in osteoarthritis and in asymptomatic joints in elderly persons remain major unanswered questions that are rendered more difficult by current inability to therapeutically limit or dissolve the crystal deposits and assess the consequent clinical outcome. Going forward, CPPD clinical research studies should define clinical settings in which articular CPPD does substantial harm and should include analyses of diverse clinical phenotypes and populations. Clinical trials should identify the best therapeutic targets to limit CPP crystal deposition and associated inflammation and should include assessment of intraarticular agents. Our perspective is that such advances in basic and clinical science in CPPD are now within reach and can lead to better treatments for this disorder.

Therapy for CPPD: Options and Evidence

PURPOSE OF REVIEW

Current evidence and accumulated experience for the management of calcium pyrophosphate deposition disease (CPPD) are presented.

RECENT FINDINGS

Contrary to other rheumatic inflammatory conditions that account for high interest and growing research, advances in treating CPPD are still very limited and mostly derive from those achieved in gout. Once formed, calcium pyrophosphate crystals cannot be dissolved; therefore, management relies on the control of crystal-derived inflammation. Besides classical agents-such as colchicine, glucocorticoids, or NSAIDs-the use of targeted therapies, mostly against interleukin-1, has provided a relevant relief for refractory CPPD patients in recent years. Meanwhile, former enthusiasm about conventional disease-modifying agents such as methotrexate is currently controversial.

Inflammasome Activation in Chronic Glomerular Diseases

BACKGROUND

The intracellular multiprotein complex termed the inflammasome functions as a platform of pro-inflammatory cytokine production such as IL-1β and IL-18. Under certain conditions, however, the inflammasome produces non-canonical effects such as induction of cell death, pyroptosis and cell metabolism alterations.

OBJECTIVE

In mammalian cells, several types of inflammasomes were identified, but the most widely studied one is the inflammasome containing NOD-like receptor with pyrin domain 3 (NLRP3), which has recently been reported as a central pathogenic mechanism of chronic degenerative diseases. Many activators or risk factors exert their actions through the activation of the NLRP3 inflammasome to produce a variety of functional changes in different cells including inflammatory, metabolic or survival responses. Several molecular signaling pathways are shown to mediate the activation of the NLRP3 inflammasome, and they are related to the modifications in K+ efflux, increased lysosome leakage and activation of cathepsin B or enhanced reactive oxygen species (ROS) production. In the kidney, inflammation is believed to mediate or promote the progression of glomerular sclerotic pathologies resulting in end-stage renal disease (ESRD). NLRP3 inflammasome activation may turn on glomerular inflammation and other cell damages, contributing to the onset of glomerular injury and ESRD. This inflammasome activation not only occurs in immune cells, but also in residential cells such as endothelial cells and podocytes in the glomeruli.

SUMMARY

This review briefly summarizes current evidence of NLRP3 inflammasome activation and related molecular mechanisms in renal glomeruli. The possible canonical and non-canonical effects of this inflammasome activation and its potential implication in the development of different glomerular diseases are highlighted.

Pseudogout of the cervical and thoracic spine mimicking infection after lumbar fusion: case report

Pseudogout is a form of acute calcium pyrophosphate deposition (CPPD) disease that typically afflicts the elderly. CPPD commonly involves larger joints, such as the knees, wrists, shoulders, and hips, and has been known to involve the spine. The authors report the case of a 66-year-old woman with a recent history of lumbar laminectomy and fusion who presented 5 weeks postprocedure with a clinical and radiographic picture consistent with multilevel skip lesions involving the cervical and thoracic spine, thoracic discitis, and epidural abscess. Serial blood cultures and repeat biopsy samples were sterile. Subsequent wrist and ankle erythema, pain, and swelling led to synovial fluid analysis, and pseudogout was diagnosed. She was treated with an interleukin-1 inhibitor with immediate symptom relief. To the authors' knowledge, this is only the second report of spinal pseudogout presenting with a clinical and radiographic picture consistent with discitis and epidural abscess. This report is the first to report skip lesions of pseudogout occurring throughout the spine that are uniquely remote from a recent lumbar surgery.

Anti-inflammatory panacea? The expanding therapeutics of interleukin-1 blockade

PURPOSE OF REVIEW

Blockade of interleukin (IL)-1 signaling is one of the oldest biologic therapies, yet the use of these agents is on the rise as the role of IL-1 activation is being recognized in a wide spectrum of inflammatory disorders. This review will cover established and emerging uses of IL-1 antagonism in rheumatic diseases.

RECENT FINDINGS

Expanding off-label indications for IL-1 blockade include neutrophil-dominant skin diseases, including pyoderma gangrenosum, hidradenitis supperativa, and pustular psoriasis. There is also increasing evidence for the use of IL-1 blockade in heart failure associated with rheumatic diseases. Somatic mosaicism in NLRP3 may explain the onset of later-in-life presentations of periodic fevers which are responsive to IL-1 blockade. Of importance, clinical response to anti-IL-1 therapy does not always denote protection from autoinflammatory disease complications such as macrophage activation syndrome or amyloidosis.

SUMMARY

Indications for IL-1 blocking therapies will likely continue to broaden, but given the rarity of many rheumatic diseases which respond to such treatment, rigorous, large clinical trials for each indication are unlikely to occur. Thus, recommended use of these medications will often fall to the discretion of the astute physician. However, medication cost and hurdles of insurance approval, rather than drug efficacy, may be the primary limitation for more widespread use.

Innate immune perturbations, accumulating DAMPs and inflammasome dysregulation: A ticking time bomb in ageing

Ageing has pronounced effects on the immune system, including on innate immune cells. Whilst most studies suggest that total numbers of different innate immune cell populations do not change dramatically during ageing, many of their functions such as phagocytosis, antigen presentation and inflammatory molecule secretion decline. In contrast, many endogenous damage-associated molecular patterns (DAMPs) accumulate during ageing. These include reactive oxygen species (ROS) released from damaged mitochondria, extracellular nucleotides like ATP, high mobility group box (HMGB) 1 protein, oxidized low density lipoprotein, amyloid-beta (Aβ), islet amyloid polypeptide and particulates like monosodium urate (MSU) crystals and cholesterol crystals. Some of these DAMPs trigger the activation of inflammasomes, cytosolic danger sensing signalling platforms that drive both the maturation of specific pro-inflammatory mediators such as IL-1β, as well as the initiation of pro-inflammatory pyroptotic cell death. Herein, we review the evidence that dysregulated inflammasome activation, via altered innate immune cell functions and elevated levels of DAMPs, contributes to the establishment of chronic, low-grade inflammation (characterized by elevated levels of IL-6 and C-reactive protein) and the development of age-related pathological processes.

Treating rheumatological diseases and co-morbidities with interleukin-1 blocking therapies

The inflammatory cytokines IL-1α and IL-1β orchestrate local and systemic inflammatory responses underlying a broad spectrum of diseases. Three agents for reducing IL-1 activities are currently available. Anakinra is a recombinant form of the naturally occurring IL-1 receptor antagonist. Anakinra binds to the IL-1 receptor and prevents the activity of IL-1α and IL-1β. The soluble decoy receptor rilonacept and the neutralizing mAb canakinumab block IL-1β. A mAb directed against the IL-1 receptor and a neutralizing anti-human IL-1α are in clinical trials. The availability of therapies specifically targeting IL-1 unveiled the pathological role of IL-1-mediated inflammation in a broadening list of diseases. Conditions effectively treated with agents blocking IL-1 range from classic rheumatic diseases, such as RA and gout, to autoinflammatory syndromes, such as systemic JIA and FMF. However, IL-1 antagonism is also effective against highly prevalent inflammatory diseases, namely cardiovascular diseases and type 2 diabetes, conditions that are frequently encountered as co-morbidities in patients with rheumatic diseases. Thereby, IL-1 inhibition has the potential to lift the burden of disease for patients with rheumatic conditions, but also to provide clinical benefits beyond the efficacy on osteoarticular manifestations.

Efficacy of anakinra for various types of crystal-induced arthritis in complex hospitalized patients: a case series and review of the literature

Background. There are few data on anakinra use after failure of conventional medications for crystal-induced peripheral arthritis and/or crowned dens syndrome among complex hospitalized patients. Methods. We retrospectively analyzed the outcome of six patients affected with subacute crystal-induced arthritis who had received anakinra in second or third line therapy, including three patients with crowned dens syndrome and three others with gouty arthritis. Patients' comorbidities, reasons for anakinra use and associated drugs, and outcomes were recorded. Results. All patients presented with elevated inflammatory syndrome, systemic symptoms with poly/oligoarthritis. Except for absolute contraindications, all patients were previously treated with full or decreased dose of NSAID, colchicine, and/or glucocorticoids, with unsatisfactory response. All three gouty patients exhibited complete responses in all acute involvements under anakinra within 3 to 5 days, including one of them who needed the reintroduction of colchicine treatment that was previously unsuccessful. Crowned dens syndrome patients, including two with pseudogout and one with subacute hydroxyapatite deposition disease, needed 9 to 11 days to achieve complete response. Tolerance to anakinra was good. Conclusion. In case series of complex hospitalized patients, anakinra showed good activity in crowned dens syndrome and associated crystal-induced peripheral arthritis, with longer treatment duration than in gouty arthritis.

Interleukin-1 as a common denominator from autoinflammatory to autoimmune disorders: premises, perils, and perspectives

A complex web of dynamic relationships between innate and adaptive immunity is now evident for many autoinflammatory and autoimmune disorders, the first deriving from abnormal activation of innate immune system without any conventional danger triggers and the latter from self-/non-self-discrimination loss of tolerance, and systemic inflammation. Due to clinical and pathophysiologic similarities giving a crucial role to the multifunctional cytokine interleukin-1, the concept of autoinflammation has been expanded to include nonhereditary collagen-like diseases, idiopathic inflammatory diseases, and metabolic diseases. As more patients are reported to have clinical features of autoinflammation and autoimmunity, the boundary between these two pathologic ends is becoming blurred. An overview of monogenic autoinflammatory disorders, PFAPA syndrome, rheumatoid arthritis, type 2 diabetes mellitus, uveitis, pericarditis, Behçet's disease, gout, Sjögren's syndrome, interstitial lung diseases, and Still's disease is presented to highlight the fundamental points that interleukin-1 displays in the cryptic interplay between innate and adaptive immune systems.

An expanding role for interleukin-1 blockade from gout to cancer

There is an expanding role for interleukin (IL)-1 in diseases from gout to cancer. More than any other cytokine family, the IL-1 family is closely linked to innate inflammatory and immune responses. This linkage is because the cytoplasmic segment of all members of the IL-1 family of receptors contains a domain, which is highly homologous to the cytoplasmic domains of all toll-like receptors (TLRs). This domain, termed "toll IL-1 receptor (TIR) domain," signals as does the IL-1 receptors; therefore, inflammation due to the TLR and the IL-1 families is nearly the same. Fundamental responses such as the induction of cyclo-oxygenase type 2, increased surface expression of cellular adhesion molecules and increased gene expression of a broad number of inflammatory molecules characterizes IL-1 signal transduction as it does for TLR agonists. IL-1β is the most studied member of the IL-1 family because of its role in mediating autoinflammatory disease. However, a role for IL-1α in disease is being validated because of the availability of a neutralizing monoclonal antibody to human IL-1α. There are presently three approved therapies for blocking IL-1 activity. Anakinra is a recombinant form of the naturally occurring IL-1 receptor antagonist, which binds to the IL-1 receptor and prevents the binding of IL-1β as well as IL-1α. Rilonacept is a soluble decoy receptor that neutralizes primarily IL-1β but also IL-1α. Canakinumab is a human monoclonal antibody that neutralizes only IL-1β. Thus, a causal or significant contributing role can be established for IL-1β and IL-1α in human disease.

Effectiveness and safety of infliximab in two cases of severe chondrocalcinosis: nine years of follow-up

Objectives. To investigate the efficacy of infliximab in the treatment of severe calcium pyrophosphate deposition diseases (CPPD). Methods. Two patients with severe CPPD and diffuse idiopathic skeletal hyperostosis- (DISH-) like phenotype are described. Both patients were resistant to therapy with nonsteroidal anti-inflammatory drugs (NSAIDs). Both patients were treated with infliximab, a TNF-α receptor antagonist, for nine years. Results. Treatment with infliximab resulted in major clinical and laboratory improvements without relevant side effects. Conclusions. These results suggest that infliximab may be an effective treatment of severe CPDD.

HFE-related hemochromatosis: an update for the rheumatologist

Hereditary hemochromatosis is a frequent disease in Caucasian populations. It leads to progressive iron overload in a variety of organs. The most common cause is the C282Y homozygous mutation in the HFE gene. The classical triad of skin hyperpigmentation, diabetes, and liver cirrhosis is nowadays rare but musculoskeletal symptoms are common in HFE-related hemochromatosis. Typically the second and third metacarpophalangeal joints, and the wrist, hip, and ankle joints are affected. Clinical symptoms include osteoarthritis-like symptoms, pseudogout attacks, and synovitis sometimes resembling rheumatoid arthritis. Radiographs show degenerative changes with joint space narrowing, osteophytes, and subchondral cysts. Chondrocalcinosis in the wrist and knee joints is seen in up to 50 % of patients. Although most other organ manifestations regress during phlebotomy, musculoskeletal symptoms often persist or even become worse. Importantly, patients are at an increased risk of severe large-joint arthritis necessitating joint replacement surgery. Therefore, future research should focus on the pathogenesis and treatment options for HH arthropathy.

Advances in the treatment of rheumatoid arthritis

The intense pursuit of novel therapies in rheumatoid arthritis has provided physicians with an assorted set of biologic drugs to treat patients with moderate to severe disease activity. Nine different biologic therapies are currently available: seven inhibitors of pro-inflammatory cytokines (five targeting tumor necrosis factor [TNF], one interleukin [IL]-1 and one IL-6), as well as a T- and a B-lymphocyte targeting agent. All these drugs have roughly similar efficacy profiles and are approved as first- or second-line therapy in patients who failed to respond to conventional disease-modifying anti-rheumatic drugs (DMARDs) and in most cases for first line use in rheumatoid arthritis as well. Despite the irrefutable clinical and radiological benefits of biologic therapies, there are still low rates of patients achieving stable remission. Therefore, the quest for new and more effective biologic therapies continues and every year new drugs are tested. Simultaneously, optimal use of established agents is being studied in different ways. Recently, the approval of the first small molecule targeting intracellular pathways has opened a new chapter in the treatment of rheumatoid arthritis. Other emerging treatment strategies include the activation of regulatory T cells as well as new cytokine-targeting therapies.

Current immunotherapy in rheumatoid arthritis

Rheumatoid arthritis is a common autoimmune disease primarily manifesting as chronic synovitis, subsequently leading to a change in joint integrity. Progressive disability and systemic complications are strongly associated with a decreased quality of life. To maintain function and health in patients with rheumatoid arthritis, early, aggressive and guided immunosuppressive therapy is required to induce clinical remission. Antirheumatic drugs are capable of controlling synovial inflammation and are therefore named 'disease-modifying antirheumatic drugs' (DMARDs). This article aims to bridge the beginning of DMARD therapy with agents such as methotrexate, leflunomide, sulfasalazine, injectable gold and (hydroxy)chloroquine with biological therapies, and with the new era of kinase inhibitors. Mechanisms of action, as well as advantages and disadvantages of DMARDs, are discussed with respect to the current literature and current recommendations.

Treating inflammation by blocking interleukin-1 in humans

IL-1 is a master cytokine of local and systemic inflammation. With the availability of specific IL-1 targeting therapies, a broadening list of diseases has revealed the pathologic role of IL-1-mediated inflammation. Although IL-1, either IL-1α or IL-1β, was administered to patients in order to improve bone marrow function or increase host immune responses to cancer, these patients experienced unacceptable toxicity with fever, anorexia, myalgias, arthralgias, fatigue, gastrointestinal upset and sleep disturbances; frank hypotension occurred. Thus it was not unexpected that specific pharmacological blockade of IL-1 activity in inflammatory diseases would be beneficial. Monotherapy blocking IL-1 activity in a broad spectrum of inflammatory syndromes results in a rapid and sustained reduction in disease severity. In common conditions such as heart failure and gout arthritis, IL-1 blockade can be effective therapy. Three IL-1blockers have been approved: the IL-1 receptor antagonist, anakinra, blocks the IL-1 receptor and therefore reduces the activity of IL-1α and IL-1β. A soluble decoy receptor, rilonacept, and a neutralizing monoclonal anti-interleukin-1β antibody, canakinumab, are also approved. A monoclonal antibody directed against the IL-1 receptor and a neutralizing anti-IL-1α are in clinical trials. By specifically blocking IL-1, we have learned a great deal about the role of this cytokine in inflammation but equally important, reducing IL-1 activity has lifted the burden of disease for many patients.

Treatment of acute gouty arthritis in complex hospitalized patients with anakinra

OBJECTIVE

To report our experience with the efficacy and safety of anakinra for acute gouty arthritis in medically complex hospitalized patients.

METHODS

We reviewed the hospital charts of 26 patients treated with anakinra for crystal-induced arthritis since 2007. Demographics, comorbid conditions, reason for anakinra use, response to treatment, and any adverse outcomes were recorded.

RESULTS

Twenty-six patients received 40 courses of anakinra therapy. In 67% of patients, pain improved significantly within 24 hours, and complete resolution of signs and symptoms of gout occurred by day 5 in 72.5% of patients. Seven patients received multiple courses with no decrement in response with repeated treatments. Anakinra was well tolerated and no adverse outcomes were attributed to the medication. Only 1 patient appeared to be refractory to this form of interleukin-1 inhibition.

CONCLUSION

Anakinra is an effective and safe alternative treatment for acute gouty arthritis in medically complex hospitalized patients who fail or cannot undergo more conventional therapy.

Caspase functions in cell death and disease

Caspases are a family of endoproteases that provide critical links in cell regulatory networks controlling inflammation and cell death. The activation of these enzymes is tightly controlled by their production as inactive zymogens that gain catalytic activity following signaling events promoting their aggregation into dimers or macromolecular complexes. Activation of apoptotic caspases results in inactivation or activation of substrates, and the generation of a cascade of signaling events permitting the controlled demolition of cellular components. Activation of inflammatory caspases results in the production of active proinflammatory cytokines and the promotion of innate immune responses to various internal and external insults. Dysregulation of caspases underlies human diseases including cancer and inflammatory disorders, and major efforts to design better therapies for these diseases seek to understand how these enzymes work and how they can be controlled.

Calcium oxalate crystals induce renal inflammation by NLRP3-mediated IL-1β secretion

Nephrocalcinosis, acute calcium oxalate (CaOx) nephropathy, and renal stone disease can lead to inflammation and subsequent renal failure, but the underlying pathological mechanisms remain elusive. Other crystallopathies, such as gout, atherosclerosis, and asbestosis, trigger inflammation and tissue remodeling by inducing IL-1β secretion, leading us to hypothesize that CaOx crystals may induce inflammation in a similar manner. In mice, intrarenal CaOx deposition induced tubular damage, cytokine expression, neutrophil recruitment, and renal failure. We found that CaOx crystals activated murine renal DCs to secrete IL-1β through a pathway that included NLRP3, ASC, and caspase-1. Despite a similar amount of crystal deposits, intrarenal inflammation, tubular damage, and renal dysfunction were abrogated in mice deficient in MyD88; NLRP3, ASC, and caspase-1; IL-1R; or IL-18. Nephropathy was attenuated by DC depletion, ATP depletion, or therapeutic IL-1 antagonism. These data demonstrated that CaOx crystals trigger IL-1β-dependent innate immunity via the NLRP3/ASC/caspase-1 axis in intrarenal mononuclear phagocytes and directly damage tubular cells, leading to the release of the NLRP3 agonist ATP. Furthermore, these results suggest that IL-1β blockade may prevent renal damage in nephrocalcinosis.

Calcium oxalate crystals induce renal inflammation by NLRP3-mediated IL-1β secretion

Nephrocalcinosis, acute calcium oxalate (CaOx) nephropathy, and renal stone disease can lead to inflammation and subsequent renal failure, but the underlying pathological mechanisms remain elusive. Other crystallopathies, such as gout, atherosclerosis, and asbestosis, trigger inflammation and tissue remodeling by inducing IL-1β secretion, leading us to hypothesize that CaOx crystals may induce inflammation in a similar manner. In mice, intrarenal CaOx deposition induced tubular damage, cytokine expression, neutrophil recruitment, and renal failure. We found that CaOx crystals activated murine renal DCs to secrete IL-1β through a pathway that included NLRP3, ASC, and caspase-1. Despite a similar amount of crystal deposits, intrarenal inflammation, tubular damage, and renal dysfunction were abrogated in mice deficient in MyD88; NLRP3, ASC, and caspase-1; IL-1R; or IL-18. Nephropathy was attenuated by DC depletion, ATP depletion, or therapeutic IL-1 antagonism. These data demonstrated that CaOx crystals trigger IL-1β-dependent innate immunity via the NLRP3/ASC/caspase-1 axis in intrarenal mononuclear phagocytes and directly damage tubular cells, leading to the release of the NLRP3 agonist ATP. Furthermore, these results suggest that IL-1β blockade may prevent renal damage in nephrocalcinosis.

Treatment and management of pseudogout: insights for the clinician

Pseudogout and the associated calcium pyrophosphate dihydrate (CPPD)- crystal-related arthropathies are common conditions that present particular management problems in clinical practice as they often affect older patients with multiple medical comorbidities. The epidemiology, metabolic and endocrine disease associations, and routine investigations used in the diagnostic workup are briefly reviewed. Current treatment approaches that are mainly directed at relieving the symptoms of joint inflammation are outlined. Unlike gout, there are no agents available that have been shown to decrease crystal load in CPPD-related joint disease. Recent novel insights into the pathogenesis of crystal-induced joint inflammation and subsequent joint degeneration are also discussed. The potential of colchicine as a prophylactic agent in managing recurrent attacks and the likely mechanisms of its effects on the NACHT, LRR and PYD domains-containing protein 3 (NALP-3) inflammasome of the innate immune system are highlighted. The use of agents that directly target the inflammasome, in particular drugs which inhibit the interleukin 1 pathway, in the treatment of severe, refractory pseudogout is also discussed. Finally, there is particular emphasis on the likely pathogenic role of CPPD crystal deposition in degenerative joint disease and the use of targeted anticrystal therapies as potential disease-modifying drugs.

Treating inflammation by blocking interleukin-1 in a broad spectrum of diseases

Interleukin-1 (IL-1) is a highly active pro-inflammatory cytokine that lowers pain thresholds and damages tissues. Monotherapy blocking IL-1 activity in autoinflammatory syndromes results in a rapid and sustained reduction in disease severity, including reversal of inflammation-mediated loss of sight, hearing and organ function. This approach can therefore be effective in treating common conditions such as post-infarction heart failure, and trials targeting a broad spectrum of new indications are underway. So far, three IL-1-targeted agents have been approved: the IL-1 receptor antagonist anakinra, the soluble decoy receptor rilonacept and the neutralizing monoclonal anti-IL-1β antibody canakinumab. In addition, a monoclonal antibody directed against the IL-1 receptor and a neutralizing anti-IL-1α antibody are in clinical trials.

Efficacy of anakinra for refractory acute calcium pyrophosphate crystal arthritis

Acute synovitis induced by deposition of calcium pyrophosphate (CPP) and monosodium urate crystals involves interleukin-1β production and activation. The efficacy of blocking interleukin-1β activity (with an interleukin-1 receptor antagonist [anakinra] or interleukin-1β antibody) is well documented for gout attacks but has only been reported in two single-case reports of CPP crystal-induced acute arthritis. Here we report on five cases (four males, mean age 71±27) of CPP crystal-induced inflammatory arthritis refractory and/or intolerant to usual drug therapy and efficiently treated with anakinra. Diagnosis of CPP crystal-induced arthritis was confirmed by identification of crystals in synovial fluid. CPP crystal-induced oligo-arthritis (n=4) and polyarthritis (n=1) were refractory to conventional treatments, including non-steroidal anti-inflammatory drugs, colchicine and steroids (systemic administration or intra-articular injection). After latent infection was ruled out, anakinra, 100mg/day, was administered subcutaneously for 3 days. Four patients showed rapid clinical and biological responses at a mean of 3 days after treatment. Anakinra provided good joint pain relief (baseline 0-100mm visual analog scale score 60±17mm, outcome 10±10mm) and decreased serum C-reactive protein level (58±43 to 5±2mg/L). Anakinra was well tolerated. One injection-site skin reaction was observed but no infection. Anakinra was effective and safe in this small series of patients with refractory arthritis due to acute CPP crystal deposition.

The Role of NLR-related Protein 3 Inflammasome in Host Defense and Inflammatory Diseases

Among a number of innate receptors, the nucleotide-binding domain leucine-rich repeat containing (NLR) nucleotide oligomerization domain (NOD)-like receptor families are involved in the recognition of cytosolic pathogen- or danger-associated molecules. Activation of these specific sets of receptors leads to the assembly of a multiprotein complex, the inflammasome, leading to the activation of caspase-1 and maturation of the cytokines interleukin (IL)-1β, IL-18, and IL-33. Among NLRs, NLR-related protein 3 (NLRP3) is one of the best-characterized receptors that activates the inflammasome. There is no doubt that NLRP3 inflammasome activation is important for host defense and effective pathogen clearance against fungal, bacterial, and viral infection. In addition, mounting evidence indicates that the NLRP3 inflammasome plays a role in a variety of inflammatory diseases, including gout, atherosclerosis, and type II diabetes, as well as under conditions of cellular stress or injury. Here, we review recent advances in our understanding of the role of the NLRP3 inflammasome in host defense and various inflammatory diseases.