Idiopathic recurrent acute pericarditis: familial Mediterranean fever mutations and disease evolution in a large cohort of Caucasian patients

IL-1 and autoinflammatory disease: biology, pathogenesis and therapeutic targeting

Over 20 years ago, it was first proposed that autoinflammation underpins a handful of rare monogenic disorders characterized by recurrent fever and systemic inflammation. The subsequent identification of novel, causative genes directly led to a better understanding of how the innate immune system is regulated under normal conditions, as well as its dysregulation associated with pathogenic mutations. Early on, IL-1 emerged as a central mediator for these diseases, based on data derived from patient cells, mutant mouse models and definitive clinical responses to IL-1 targeted therapy. Since that time, our understanding of the mechanisms of autoinflammation has expanded beyond IL-1 to additional innate immune processes. However, the number and complexity of IL-1-mediated autoinflammatory diseases has also multiplied to include additional monogenic syndromes with expanded genotypes and phenotypes, as well as more common polygenic disorders seen frequently by the practising clinician. In order to increase physician awareness and update rheumatologists who are likely to encounter these patients, this review discusses the general pathophysiological concepts of IL-1-mediated autoinflammation, the epidemiological and clinical features of specific diseases, diagnostic challenges and approaches, and current and future perspectives for therapy.

Primary Sjögren's Syndrome and Cardiovascular Disease

Sjögren's syndrome is a rheumatic autoimmune disease that primarily affects middle-aged women and runs a slowly progressing course with sicca symptoms being the prevalent manifestation. Premature atherosclerosis and increased cardiovascular (CV) morbidity and mortality are frequently encountered in rheumatic diseases characterized by significant systemic inflammation, such as the inflammatory arthritides, systemic vasculitides and systemic lupus erythematosus. In the same context, chronic inflammation and immune aberrations underlying Sjögren's syndrome are also reported to be associated with augmented risk of atherosclerosis. Increased CV disease (CVD) frequency has been found in recent meta-analyses. The involvement of the CV system is not a common feature of Sjögren's syndrome; however, specific manifestations, such as autoantibody-mediated heart block, pericarditis, pulmonary arterial hypertension and dysautonomia, have been described. This review focuses on studies addressing CV morbidity in Sjögren's syndrome and presents current data regarding distinct CV features of the disease.

Acute recurrent pericarditis: from pathophysiology towards new treatment strategy

Acute idiopathic or so-called viral pericarditis is a frequent and usually benign disease, although recurrences are frequent. Data strongly suggest the presence of underlying autoinflammatory and/or autoimmune disorders. It has been reported that there is an inflammatory response of the innate immune system typical of 'autoinflammatory diseases', predominantly mediated by interleukin-1 (IL-1). This may result from the activation of the inflammasome by a cardiotropic virus or a non-specific agent. The inflammatory response of the adaptive immune system, typical of 'autoimmune diseases'-mainly mediated by autoantibodies or autoreactive T lymphocytes-seems also involved as anti-heart or anti-intercalated disk autoantibodies were associated with a higher number of recurrences and hospitalisations. Current guidelines recommend that aspirin/non-steroidal anti-inflammatory drugs for a few weeks should be associated to colchicine for 6 months in recurrent pericarditis. In refractory cases, low-dose corticosteroids or immunosuppressive drugs have been proposed with limited efficacy. Growing evidences suggest a place of IL-1 receptor antagonists in the treatment of recurrent pericarditis. Many retrospective studies, one recent randomised placebo-controlled study and data of a real-life large international registry showed the good efficacy of anakinra with a good safety profile. Other IL-1 receptor antagonists showed promising results (canakinumab, rilonacept). However, IL-1 receptor antagonists' position in the treatment algorithm of recurrent pericarditis needs further evaluation in larger prospective clinical trials to replicate initial findings as well as to assess safety, cost-effectiveness and long-term efficacy.

Recurrent pericarditis: still idiopathic? The pros and cons of a well-honoured term

In developed countries, more than 80% of cases of acute pericarditis remain without an established diagnosis after a conventional and standard diagnostic approach. These cases are generally labelled as 'idiopathic', i.e. without a known cause. This lack of information is a matter of concern for both patients and clinicians. Some years ago, this term reflected the state of the art of scientific knowledge on the topic. Advances have changed this point of view, in light of available molecular techniques like polymerase chain reaction able to identify viral cardiotropic agents in pericardial fluid and biopsies. Furthermore, the remarkable efficacy of interleukin-1 antagonists, a therapy targeting the innate immune response, suggests clinical and pathogenic similarity between a proportion of patients with idiopathic recurrent pericarditis and classical autoinflammatory diseases. So, it seems useful to discuss the pros and cons of using the term "idiopathic" in light of the new knowledge.

Management of idiopathic recurrent pericarditis in adults and in children: a role for IL-1 receptor antagonism

Recurrent pericarditis is one of the most frequent pericardial diseases, affecting up to 30% of the patients who have experienced acute pericarditis. While the diagnosis of acute pericarditis is sometime straight forward, its etiology and therapeutic management are still a challenge for physicians. In developed countries, the idiopathic form is the most frequent, and the search for an infectious etiology is almost invariably negative. Nevertheless, since standard treatment with nonsteroidal anti-inflammatory drugs and colchicine is not always able to neutralize pericardial inflammation in recurrent pericarditis, anakinra, an IL-1 receptor antagonist, has been proposed as a possible therapeutic alternative for refractory forms. IL-1 is a cytokine that exerts a pivotal role in innate immunity and in the pathogenesis of some autoimmune diseases, such as rheumatoid arthritis, and in autoinflammatory disorders, as familial Mediterranean fever and cryopyrin-associated periodic syndromes. The successful management of patients with acute idiopathic recurrent pericarditis (IRP) needs a teamwork approach, where cardiologists, rheumatologists, clinical immunologists and internists are involved. In this review, we will discuss the clinical and therapeutical challenges of IRP both in adults and children from a clinical practice standpoint. We will also briefly illustrate the main pathogenic mechanisms of IRP to provide internists and cardiologists with the rationale for approaching the use of anakinra in selected clinical cases.

The Therapeutic Role of Interleukin-1 Inhibition in Idiopathic Recurrent Pericarditis: Current Evidence and Future Challenges

Recurrent pericarditis is a common complication of acute pericarditis (15–30%) for which, in most cases, no underlying etiology is found [idiopathic recurrent pericarditis (IRP)]. IRP is currently viewed as an autoinflammatory disease with characteristic recurrent episodes of sterile inflammation. According to the most recent Guidelines, the initial treatment regimen consists of a combination of aspirin or non-steroidal anti-inflammatory drugs with colchicine followed by the addition of corticosteroids in resistant or intolerant cases. Despite this treatment approach, a number of patients either do not respond or cannot tolerate the above therapies. For this refractory group, small case series and a recent randomized controlled trial have shown that interleukin-1 inhibition with anakinra is a rapidly acting, highly efficient, steroid-sparing, and safe therapeutic intervention. In this perspective, we discuss the available clinical evidence and our own clinical experience as well as the future prospects of this novel therapeutic approach for patients with IRP.

Usefulness of cardiac magnetic resonance-guided management in patients with recurrent pericarditis

Recurrent pericarditis (RP) affects 10% to 50% of patients with acute pericarditis. The use of steroids has been associated with increased recurrence rate of pericarditis, along with known major side effects. Cardiac magnetic resonance imaging (CMR) is more frequently used to assess pericardial inflammation and less commonly to guide therapy. The aim of this study was to assess the utility of CMR in the management of RP compared with standard therapy. A total of 507 consecutive patients with RP after the first attack, all of whom were treated with colchicine and nonsteroidal anti-inflammatory drugs as first-line therapy, were retrospectively evaluated. There were 257 patients who were treated with medications and received CMR-guided therapy (group 1) and 250 patients who were treated with medications without CMR (group 2). The 2 groups had similar baseline characteristics and follow-up periods (17 ± 7.9 vs 16.3 ± 16.2 months, respectively, p = 0.97). CMR was used to assess the presence of pericardial inflammation, and on the basis of the results, the clinician made changes to the steroid dose dictated by the severity of inflammation. There was no significant difference in the incidence of constrictive pericarditis, pericardial window, or pericardiectomy between groups during the follow-up. However, group 2 patients had a larger number of steroid pulse therapies (defined as prednisone 50 mg/day orally for 10 days and tapering to none over 4 weeks), and higher overall total milligrams of steroid administered compared with the CMR group (p = 0.003 and p = 0.001, respectively). Recurrence and pericardiocentesis rates were lower in group 1 (p <0.0001). In conclusion, CMR-guided therapy modulates the management of RP. This approach decreased pericarditis recurrence and exposure to steroids.

Autoimmunity and autoinflammation as the yin and yang of idiopathic recurrent acute pericarditis

Autoimmunity and autoinflammation are generally considered as mutually exclusive mechanisms of diseases but may concur to specific syndromes. Idiopathic recurrent acute pericarditis (IRAP) is defined as the recurrence of pericardial symptoms at any point following the prior cessation of acute pericarditis, and the latency is generally 6 weeks. Manifestations of pericarditis such as pericardial friction rub, electrocardiographic changes, and pericardial effusion are less frequent in the subsequent episodes compared to the index attack, and in some cases the only clinical sign is represented by a suggestive chest pain. Several autoimmune diseases may manifest with pericarditis which is often related to viral infections, while postviral pericarditis may in turn display a nonspecific autoimmune background. Similarly, autoinflammatory syndromes such as familial Mediterranean fever and tumor necrosis factor receptor-associated periodic syndrome are characterized by self-limiting pericardial symptoms. Corticosteroids are generally effective, thus supporting the autoimmune nature of IRAP, but dramatic results are obtained with interleukin-1 blocking agents in corticosteroid-dependent cases, pointing to a pathogenic role for the inflammasome. Based on these observations, we submit that IRAP represents a paradigmatic example of the putative coexistence of autoimmunity and autoinflammation: the main aim of this review is to critically discuss the hypothesis as well as the current understanding of this enigmatic clinical condition.

Idiopathic recurrent pericarditis as an immune-mediated disease: current insights into pathogenesis and emerging treatment options

Idiopathic recurrent pericarditis affects 30-50% of patients with a previous attack of pericarditis. The etiopathogenesis is incompletely understood and most cases remain idiopathic with a presumed immune-mediated pathogenesis. The mainstay of therapy is aspirin or a nonsteroidal anti-inflammatory drug plus colchicine and the possible adjunct of a low-to-moderate dose of a corticosteroid in more difficult cases. Colchicine as an adjunct to anti-inflammatory therapy reduces by 50% the subsequent recurrent rate. For true refractory cases with failure of standard combination therapies, new and emerging options especially include human intravenous immunoglobulins and biological agents (i.e., anakinra). The outcome of idiopathic recurrent pericarditis is good with a negligible risk of developing constrictive pericarditis. Thus, it is important to reassure patients on their prognosis, explaining the nature of the disease and the likely course. Moreover, therapeutic choices should include less toxic agents and favor cheaper drugs whenever possible.

Efficacy of an interleukin-1β receptor antagonist (anakinra) in idiopathic recurrent pericarditis

Pericarditis may recur in up to 30 % of adult patients, but recurrent pericarditis is a rare disease in childhood. The etiology of the initial attack and the causes of recurrences often remain unknown. Recurrent pericarditis is accompanied by a high morbidity rate and may represent a challenge to the clinician due to problems in management. Therapeutic strategies are not specific and include nonsteroidal antiinflammatory drugs, corticosteroids, immunosuppressive drugs, colchicine, and pericardiectomy. Controlled trials have demonstrated that colchicine can reduce the recurrent rate of pericarditis, whereas early corticosteroid therapy promotes recurrences. Anakinra, a recombinant human interleukin-1β receptor antagonist, is a promising new biologic agent for the treatment of autoinflammatory diseases such as cryopyrinopathies, tumor necrosis factor receptor-associated periodic syndrome, and hyperimmunoglobulinemia D with periodic fever syndrome. This report describes an 11-year-old boy successfully treated with anakinra for a steroid-dependent recurrent pericarditis unresponsive to conventional treatment.

Long-term efficacy of interleukin-1 receptor antagonist (anakinra) in corticosteroid-dependent and colchicine-resistant recurrent pericarditis

OBJECTIVE

To evaluate the long-term response and safety of interleukin-1 receptor antagonist (anakinra) in recurrent pericarditis.

STUDY DESIGN

Fifteen patients (12 children, 3 adults) were enrolled in a multicenter retrospective study. All the patients were corticosteroid-dependent and 14 had received colchicine. Anakinra was given at 1-2 mg/kg/d. The primary outcome of the study was a reduction of at least 70% of disease flares after anakinra treatment compared with the pretreatment period. Secondary outcomes were: (1) number of complete or partial responders to anakinra and time for complete response; (2) number of patients who discontinued other ongoing treatments (non-steroidal anti-inflammatory drugs, corticosteroid, colchicine) and time needed for discontinuation; (3) number of relapses during continuous anakinra treatment; and (4) number of relapses during anakinra tapering or discontinuation.

RESULTS

All patients treated had a complete response within a few days and were able to rapidly withdraw concomitant treatments, including corticosteroids. During daily treatment, no patient had a relapse of the disease; 14 patients started tapering and 6 of them experienced a relapse, with a prompt response after anakinra reintroduction. Overall, after a median follow-up of 39 months (range 6-57), a 95% reduction of flares was observed compared with pretreatment period.

CONCLUSION

The long-term use of anakinra in monotherapy is associated with persistent control of recurrent pericarditis.

Role of autoimmunity and autoinflammation in the pathogenesis of idiopathic recurrent pericarditis

Idiopathic recurrent pericarditis is the most common and troublesome complication of acute pericarditis affecting about one third of such patients. The pericardium may be involved in different systemic autoimmune diseases (i.e., systemic lupus erythematosus, rheumatoid arthritis, progressive systemic sclerosis, mixed connective tissue disease, Sjogren's Syndrome, polyarteritis, giant cell arteritis, other systemic vasculitides) either in a symptomatic form (usually during the active phase of the disease) or as asymptomatic pericardial effusion. Moreover, idiopathic recurrent pericarditis mimicks hereditary periodic fever syndromes (HPFSs). HPFSs are a group of disorders characterized by primary dysfunction of the innate immune system mostly caused by mutations of genes involved in the regulation or activation of the inflammatory response, without any apparent involvement of antigen-specific T cells or significant production of autoantibodies. These disorders usually manifest in the pediatric population, with onset ranging from the first hours to the first decade of life, however a limited number of patients experience disease onset during adulthood.

Recurrent pericarditis: autoimmune or autoinflammatory?

Idiopathic recurrent acute pericarditis (IRAP) represents the most troublesome complication of acute pericarditis and occurs in up to 20-50% of patients. It is generally idiopathic or postcardiac injury. IRAP is a disease of suspected immune-mediated pathogenesis. On the other hand, it has been suggested that some of these patients might have an atypical or subclinical form of an autoinflammatory disease, e.g. genetic disorders characterized by primary dysfunction of the innate immune system and caused by mutations of genes involved in the inflammatory response. We found that IRAP patients were negative for mutations associated with familial Mediterranean fever, but 6% (8/131 patients) carry a mutation in the TNFRSF1A gene, encoding the receptor for tumor necrosis factor-alfa. C-reactive protein (CRP) may be useful to follow the disease activity and guide the appropriate length of therapy, with continuation of the attack doses of the drugs until CRP normalization, at which time tapering may be considered. IRAP often needs a multidrug therapy: NSAIDs or aspirin at high dosages every 6-8h, corticosteroids only rarely, at low dosages and with a very gradual tapering (months) and colchicine at low dosages if tolerated. Anakinra could be a solution for patients who do not tolerate other therapies.

Idiopathic recurrent pericarditis refractory to colchicine treatment can reveal tumor necrosis factor receptor-associated periodic syndrome

Recurrences develop in up to 20-50% of patients with acute pericarditis. Although different causes of recurrent pericarditis have been identified, the etiology remains obscure in most cases which are therefore labelled as idiopathic. Autoinflammatory syndromes include familial Mediterranean fever (FMF), due to mutations in the MEFV gene, and tumor necrosis factor receptor-associated periodic syndrome (TRAPS), due to mutations in the TNFRSF1A gene. Recurrent pericarditis is a common feature of both conditions, but it rarely occurs alone. Colchicine is the standard treatment for FMF, while patients with TRAPS do not respond to colchicine therapy, but are responsive to corticosteroids. Based on the proven efficacy of colchicine in preventing polyserositis in FMF, colchicine has been proposed for the treatment of recurrent pericarditis and is able to decrease the recurrence rate. Our aim was to investigate the possible involvement of TNFRSF1A mutations in a group of patients with idiopathic recurrent pericarditis who were refractory to colchicine treatment. Thirty consecutive patients (17 males, 13 females) diagnosed with idiopathic recurrent pericarditis, who were characterized by a poor response to colchicine treatment, were enrolled in the study. Mutations of the TNFRSF1A gene were searched for by amplifying, using polymerase chain reaction (PCR), genomic DNA, and direct sequencing. TNFRSF1A mutations were found in 4 of the 30 patients. None of these 4 patients had a family history of recurrent inflammatory syndromes or history of pericarditis. One of the 4 patients had a novel heterozygous deletion (DeltaY103-R104) and three patients carried a heterozygous low-penetrance R92Q mutation. Our data suggest that TRAPS should be kept in mind in the differential diagnosis of recurrent pericarditis, and mutation analysis of the TNFRSF1A gene should be considered, in addition to MEFV analysis, in patients of Mediterranean origin. A poor response to colchicine treatment and/or a steroid-dependence may be the clue to investigate TNFRSF1A mutations in patients with idiopathic recurrent pericarditis.

Innate versus acquired immune response in the pathogenesis of recurrent idiopathic pericarditis

The pathogenesis of recurrent pericarditis is still poorly understood and may be related either to viral infections or autoimmune and autoinflammatory disorders. The immune system plays a major role in the pathogenesis of the disease, modulating individual responses to different noxa and explaining the variable reported recurrence rate (ranging from 20% to 50% of patients) following an attack of acute or recurrent pericarditis. Increasing interest is currently being devoted to autoinflammatory disorders, a group of conditions characterized by spontaneously relapsing and remitting bouts of systemic inflammation without apparent involvement of antigen-specific T cells or significant production of auto-antibodies. Ongoing basic and clinical research is needed to provide further evidence for the understanding of this common and troublesome disease, and to develop targeted and more efficacious therapies.

Long-term outcomes in difficult-to-treat patients with recurrent pericarditis

Patients with many recurrences of acute pericarditis are commonly alarmed by the fear of constriction. We studied their long-term outcome and the possible presence of systemic diseases. Sixty-one Italian patients (36 men) were followed for an average of 8.3 years according to a predefined protocol, including testing for autoimmune diseases and familial Mediterranean fever. Symptomatic pericarditis lasted from 1 to 43 years (mean 5.4 years). Fifty-two patients had been referred to us after failure of previous therapies, including steroids. We observed 378 attacks with a mean of 1.6 per patient per year and 156 hospital admissions. Thirteen patients had a post-cardiac injury syndrome. In 43 (70.5%), the pericarditis remained idiopathic, whereas we made a new diagnosis of rheumatoid arthritis in 1 and of Sjogren's syndrome in 4 patients, but in these patients pericarditis represented the dominant clinical manifestation. Cardiac tamponade occurred during the initial attacks in 4 patients (6.5%) but never recurred. Pleural effusions were present during the first attack in 22 patients (36.0%) and liver involvement in 5 (8%). No patients developed constrictive pericarditis. Echocardiographic examination produced no evidence of chronic myocardial disease. Response to therapy was good. Thirty-one patients (50.8%) are in sustained remission, without any therapy; their total observation period has averaged 10.3 years. In idiopathic patients, antinuclear antibodies were present in 56.2% and anti-Ro/SSA in 8.3%. Mutations linked to familial Mediterranean fever were absent. In conclusion, in this large series of difficult patients with recurrent acute pericarditis and a very long follow-up, the long-term prognosis is good.

Intrafamilial segregation analysis of the p.E148Q MEFV allele in familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF) is the most frequent of the recurrent inherited fevers. This autosomal recessive disorder is characterised by periodic episodes of fever and serositis that commonly affect the people of Arab, Armenian, Sephardic Jewish and Turkish origin. Most of the described MEFV gene anomalies responsible for the disease are missense mutations. In the absence of any functional test, epidemiological studies or pedigree analyses are the only means of proving the deleterious character of these sequence variations. Evidence was provided by our recent study using a population-based approach, that the p.E148Q allele is probably a benign polymorphism and not a disease-causing mutation. Its implication in FMF remains, however, controversial.

OBJECTIVE

To evaluate the segregation of the p.E148Q MEFV allele with FMF disease by using pedigree analysis.

PARTICIPANTS

21 patients and 48 unaffected relatives belonging to 18 independent families with FMF.

RESULTS

Segregation analysis of the p.E148Q allele was compatible with a Mendelian autosomal recessive transmission of the disease phenotype in only three families. In 15 of 18 families, segregation was partly or completely defective. The p.E148Q allele was not transmitted to 14 of 19 (74%) affected children.

CONCLUSIONS

No evidence of preferential transmission of p.E148Q from heterozygous parents to their affected offspring was observed. MEFV is not associated with the clinical manifestations of several patients carrying this variant. Considering p.E148Q to be a benign polymorphism should reduce the possibility of false-positive diagnoses, while highlighting genetic heterogeneity in FMF.