Update in familial Mediterranean fever

The pyrin inflammasome, a leading actor in pediatric autoinflammatory diseases

The activation of the pyrin inflammasome represents a highly intriguing mechanism employed by the innate immune system to effectively counteract pathogenic agents. Despite its key role in innate immunity, pyrin has also garnered significant attention due to its association with a range of autoinflammatory diseases (AIDs) including familial Mediterranean fever caused by disruption of the MEFV gene, or in other genes involved in its complex regulation mechanisms. Pyrin activation is strictly dependent on homeostasis-altering molecular processes, mostly consisting of the disruption of the small Ras Homolog Family Member A (RhoA) GTPases by pathogen toxins. The downstream pathways are regulated by the phosphorylation of specific pyrin residues by the kinases PKN1/2 and the binding of the chaperone 14-3-3. Furthermore, a key role in pyrin activation is played by the cytoskeleton and gasdermin D, which is responsible for membrane pores in the context of pyroptosis. In addition, recent evidence has highlighted the role of steroid hormone catabolites and alarmins S100A8/A9 and S100A12 in pyrin-dependent inflammation. The aim of this article is to offer a comprehensive overview of the most recent evidence on the pyrin inflammasome and its molecular pathways to better understand the pathogenesis behind the significant group of pyrin-related AIDs.

Effectiveness of Colchicine or Canakinumab in Japanese Patients with Familial Mediterranean Fever: A Single-Center Study

Background: To investigate the clinical features of Japanese patients with Familial Mediterranean Fever (FMF), we evaluated the frequency of attacks, treatment responses, and adverse effects in 27 patients with FMF treated with colchicine or canakinumab in a real-world clinical setting. Methods: We retrospectively reviewed 27 Japanese patients with FMF treated at our institute between April 2012 and June 2023. All patients were diagnosed with FMF according to the Tel-Hashomer criteria. We performed genetic analyses of the MEFV gene using targeted next-generation sequencing. The clinical response was monitored through the number of attacks, and inflammatory markers were monitored through the C-reactive protein (CRP), and serum amyloid A (SAA) concentrations. Colchicine resistance was defined as the presence of at least one attack/month despite administration of the maximum tolerated dose of colchicine for at least 6 months, and C-reactive protein and serum amyloid A levels above the normal range between attacks. Results: A total of 27 patients diagnosed with FMF were enrolled in this study and the median follow-up period was 36.4 months. The median attack frequency was 1.0 (interquartile range: 0.33-1.0) every 3 months before treatment initiation. All the patients (n = 27) were treated with colchicine. Among the 27 patients, 20 (71.8%) showed a clinical response and 7 (25.9%) showed an incomplete response with sufficient doses of colchicine (n = 5) and non-sufficient doses (n = 2). Two patients on non-sufficient doses were unable to increase colchicine to the maximum dose due to diarrhea and liver dysfunction. All seven patients achieved a reduction in attack frequency after the initiation of canakinumab. No serious adverse events associated with canakinumab treatment were observed. In these seven patients with colchicine-resistant FMF (crFMF), the MEFV exon 10 variant was not detected, and the absence ratio of the MEFV variant was significantly higher compared to those without crFMF. Conclusions: Colchicine was effective in 71.8% (20/27) of Japanese patients with FMF; however, the remaining patients (7/27) had crFMF. Canakinumab effectively controlled febrile attacks in crFMF, even in the absence of pathogenic MEFV exon 10 variants.

Monogenic autoinflammatory disease-associated cardiac damage

INTRODUCTION

Autoinflammatory diseases (AIDs) constitute several disorders that are characterized by the presence of recurrent episodes of unprovoked inflammation due to dysregulated innate immune system in the absence of autoantibodies or infections. Most of them have a strong genetic background, with mutations in single genes involved in inflammation referred to monogenic AIDs. In this article, we will review the cardiac manifestations in various monogenic AIDs.

AREAS COVERED

Various cardiac manifestations can be seen in various monogenic AIDs, including pericarditis, valvular diseases, coronary diseases, cardiomyopathies, and pulmonary hypertension, especially in Familial Mediterranean fever (FMF).

EXPERT COMMENTARY

Monogenic AIDs can manifest a variety of cardiac lesions, the most common of which is pericardial effusion, which may be local pericardial inflammation secondary to systemic inflammatory responses. While, the pathogenesis and incidence are still unclear. More research is still needed to explore the relationship between monogenic AIDs and cardiac damage for better understanding these diseases.

VEXAS syndrome: Current clinical, diagnostic and treatment approaches

VEXAS syndrome, is a hemato-inflammatory chronic disease characterized with predominantly rheumatic and hematologic systemic involvement. It was first described in 2020 by a group of researchers in the United States. VEXAS syndrome is a rare condition that primarily affects adult males and is caused by a mutation in the UBA1 gene located on the X chromosome. Its pathogenesis is related to the somatic mutation affecting methionine-41 (p.Met41) in UBA1, the major E1 enzyme that initiates ubiquitylation. Mutant gene lead to decreased ubiquitination and activated innate immune pathways and systemic inflammation occur. The specific mechanism by which the UBA1 mutation leads to the clinical features of VEXAS syndrome is not yet fully understood. VEXAS is a newly define adult-onset inflammatory syndrome manifested with treatment-refractory fevers, arthritis, chondritis, vasculitis, cytopenias, typical vacuoles in hematopetic precursor cells, neutrophilic cutaneous and pulmonary inflammation. Diagnosing VEXAS syndrome can be challenging due to its rarity and the overlap of symptoms with other inflammatory conditions. Genetic testing to identify the UBA1 gene mutation is essential for definitive diagnosis. Currently, there is no known cure for VEXAS syndrome, and treatment mainly focuses on managing the symptoms. This may involve the use of anti-inflammatory medications, immunosuppressive drugs, and supportive therapies tailored to the individual patient's needs. Due to the recent discovery of VEXAS syndrome, ongoing research is being conducted to better understand its pathogenesis, clinical features, and potential treatment options. In this review article, the clinical, diagnostic and treatment approaches of VEXAS syndrome were evaluated in the light of the latest literature data.

New Developments in the Management of Recurrent Pericarditis

Recurrent pericarditis is a common and troublesome complication that affects 15%-30% of patients with a previous episode of pericarditis. However, the pathogenesis of these recurrences is not well understood, and most cases remain idiopathic. Recent advances in medical therapy, including the use of colchicine and anti-interleukin-1 agents like anakinra and rilonacept, have suggested an autoinflammatory rather than an autoimmune mechanism for recurrences with an inflammatory phenotype. As a result, a more personalized approach to treatment is now recommended. Patients with an inflammatory phenotype (fever and elevated C-reactive protein level) should receive colchicine and anti-interleukin-1 agents as first-line therapy, whereas those without systemic inflammation should receive low to moderate doses of corticosteroids (eg, prednisone 0.2-0.5 mg/kg/d as an initial dose) and consider azathioprine and intravenous human immunoglobulins in the case of corticosteroid failure. Tapering of corticosteroids should be slow after achieving clinical remission. In this article, we review the new developments in the management of recurrent pericarditis.

Renal involvement in monogenic autoinflammatory diseases: A narrative review

Autoinflammatory diseases (AIDs) are mostly caused by dysfunctions in single genes encoding for proteins with a prominent role in the regulation of innate immunity, such as complement factors, inflammasome components, tumour necrosis factor (TNF)-α, and proteins belonging to type I-interferon (IFN) signalling pathways. Due to the deposition of amyloid A (AA) fibrils in the glomeruli, unprovoked inflammation in AIDs frequently affects renal health. In fact, secondary AA amyloidosis is the most common form of amyloidosis in children. It is caused by the extracellular deposition of fibrillar low-molecular weight protein subunits resulting from the degradation and accumulation of serum amyloid A (SAA) in numerous tissues and organs, primarily the kidneys. The molecular mechanisms underlying AA amyloidosis in AIDs are the elevated levels of SAA, produced by the liver in response to pro-inflammatory cytokines, and a genetic predisposition due to specific SAA isoforms. Despite the prevalence of amyloid kidney disease, non-amyloid kidney diseases may also be responsible for chronic renal damage in children with AIDs, albeit with distinct characteristics. Glomerular damage can result in various forms of glomerulonephritis with distinct histologic characteristics and a different underlying pathophysiology. This review aims to describe the potential renal implications in patients with inflammasomopathies, type-I interferonopathies, and other rare AIDs in an effort to improve the clinical course and quality of life in paediatric patients with renal involvement.

Biologics and JAK inhibitors for the treatment of monogenic systemic autoinflammatory diseases in children

Systemic autoinflammatory diseases (SAIDs) are caused by aberrant activation of 1 or more inflammatory pathways in an antigen-independent manner. Monogenic forms of SAIDs typically manifest during childhood, and early treatment is essential to minimize morbidity and mortality. On the basis of the mechanism of disease and the dominant cytokine(s) that propagates inflammation, monogenic SAIDs can be grouped into major categories including inflammasomopathies/disorders of IL-1, interferonopathies, and disorders of nuclear factor-κB and/or aberrant TNF activity. This classification scheme has direct therapeutic relevance given the availability of biologic agents and small-molecule inhibitors that specifically target these pathways. Here, we review the experience of using biologics that target IL-1 and TNF as well as using Janus kinase inhibitors for the treatment of monogenic SAIDs in pediatric patients. We provide an evidence-based guide for the use of these medications and discuss their mechanism of action, safety profile, and strategies for therapeutic monitoring.

Familial Mediterranean Fever in Spain: Time Trend and Spatial Distribution of the Hospitalizations

Familial Mediterranean Fever (FMF) is a rare, hereditary, auto-inflammatory disease. The aims of this study were to explore the time trend and geographical distribution of hospitalizations in Spain from 2008 to 2015. We identified hospitalizations of FMF from the Spanish Minimum Basic Data Set at hospital discharge, using ICD-9-CM code 277.31. Age-specific and age-adjusted hospitalization rates were calculated. The time trend and the average percentage change were analyzed using Joinpoint regression. Standardized morbidity ratios were calculated and mapped by province. A total of 960 FMF-related hospitalizations (52% men) were identified across the period 2008-2015, with an increase in hospitalizations of 4.9% per year being detected (p < 0.05). The risk of hospitalization was higher than expected for the national total (SMR > 1) in 13 provinces (5 in the Mediterranean area), and lower (SMR < 1) in 14 provinces (3 in the Mediterranean area). There was an increase in hospitalizations of patients with FMF in Spain throughout the study period, with a risk of hospitalization that was higher, though not exclusively so, in provinces along the Mediterranean coast. These findings contribute to the visibility of FMF and provide useful information for health planning. Further research should take into account new population-based information, in order to continue monitoring this disease.

Pathophysiology, clinical manifestations and current management of IL-1 mediated monogenic systemic autoinflammatory diseases, a literature review

BACKGROUND

Systemic autoinflammatory diseases (SAIDs) are hyperinflammatory and immune-dysregulation conditions that present in childhood. This kind of disease is a rare disease with early-onset, severe condition and difficult diagnosis, which seriously affects the growth and development of children. Most children need a genetic diagnosis. However, with the limitation of access to genetic testing and the detection of somatic mutations, the diagnosis of SAIDs remains challenging. IL-1 is one of the important cytokines involved in the pathogenesis of SAIDs. Here we briefly review monogenic SAIDs mediated by aberrant IL-1 production, with the aim to further understand the pathogenesis, clinical manifestations and treatments of IL-1 mediated SAIDs.

METHODS

Literature reviews were performed using "PubMed" and "Web of Science" by searching for the terms "autoinflammatory diseases" and "IL-1".

RESULTS

Monogenic SAIDs mediated by IL-1 include MKD, FMF, TRAPS, PAAND, PAPA, CAPS, DIRA, Majeed syndrome, NAIAD, NLRC4-MAS, PFIT, APLAID. Monogenic SAIDs have early onset, various clinical manifestations and difficult diagnosis, so early recognition and early treatment can reduce the complications and enhance the quality of life.

CONCLUSIONS

There are many kinds of IL-1 mediated SAIDs. Pediatricians should be alert to SAIDs in the face of the patients with repeated fever, repeated rash and poor effect of routine treatment. The patients should be carried out with gene testing and treatment in time.

Does Pyroptosis Play a Role in Inflammasome-Related Disorders?

Inflammasomes are multiprotein complexes orchestrating intracellular recognition of endogenous and exogenous stimuli, cellular homeostasis, and cell death. Upon sensing of certain stimuli, inflammasomes typically activate inflammatory caspases that promote the production and release of the proinflammatory cytokines IL-1β, IL-1α, and IL-18 and induce a type of inflammatory cell death known as “pyroptosis”. Pyroptosis is an important form of regulated cell death executed by gasdermin proteins, which is largely different from apoptosis and necrosis. Recently, several signaling pathways driving pyroptotic cell death, including canonical and noncanonical inflammasome activation, as well as caspase-3-dependent pathways, have been reported. While much evidence exists that pyroptosis is involved in the development of several inflammatory diseases, its contribution to inflammasome-related disorders (IRDs) has not been fully clarified. This article reviews molecular mechanisms leading to pyroptosis, and attempts to provide evidence for its possible role in inflammasome-related disorders, including NLR pyrin domain containing 3 (NLRP3) inflammasome disease, NLR containing a caspase recruitment domain 4 (NLRC4) inflammasome disease, and pyrin inflammasome disease. Although the specific mechanism needs further investigations, these studies have uncovered the role of pyroptosis in inflammasome-related disorders and may open new avenues for future therapeutic interventions.

Clinical impact and disease evolution of SARS-CoV-2 infection in familial Mediterranean fever

The innate immune system is critically involved in the pathogenesis of familial Mediterranean fever (FMF), characterized by dysregulated inflammasome activity and recurrent inflammatory attacks: this is the most common among monogenic autoinflammatory diseases, which shares some biochemical pathways with the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection. In this short review we explore the overlap in the pathophysiology of FMF and SARS-CoV-2 infection, discussing how to understand better the interaction between the two diseases and optimize management. A poorer outcome of SARS-CoV-2 infection seems not to be present in infected FMF patients in terms of hospitalization time, need for oxygen support, need for intensive care, rate of complications and exitus. Long-term surveillance will confirm the relatively low risk of a worse prognosis observed so far in SARS-CoV-2-infected people with FMF. In these patients COVID-19 vaccines are recommended and their safety profile is expected to be similar to the general population.

Familial Mediterranean Fever: How to Interpret Genetic Results? How to Treat? A Quarter of a Century After the Association with the Mefv Gene

PURPOSE OF REVIEW

To provide an up-to-date approach to diagnosis and management of FMF patients.

RECENT FINDINGS

Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease and prototype monogenic autoinflammatory recurrent fever syndrome. Although it is one of the well-known autoinflammatory disorders, evaluations in the etiopathogenesis and genetics of the disease have shown that FMF is more complex than previously known. Since the number of reported MEFV variants increased, evaluating the genetic test results has become more challenging. Here, we suggest a roadmap for clinicians to facilitate their decisions regarding diagnosis, treatment, and follow-up in FMF patients with different genotype-phenotype combinations. The correct interpretation of genetic test results is crucial for timely diagnosis, appropriate treatment, and follow-up of FMF patients.

Muscle and Bone Impairment in Infantile Nephropathic Cystinosis: New Concepts

Cystinosis Metabolic Bone Disease (CMBD) has emerged during the last decade as a well-recognized, long-term complication in patients suffering from infantile nephropathic cystinosis (INC), resulting in significant morbidity and impaired quality of life in teenagers and adults with INC. Its underlying pathophysiology is complex and multifactorial, associating complementary, albeit distinct entities, in addition to ordinary mineral and bone disorders observed in other types of chronic kidney disease. Amongst these long-term consequences are renal Fanconi syndrome, hypophosphatemic rickets, malnutrition, hormonal abnormalities, muscular impairment, and intrinsic cellular bone defects in bone cells, due to CTNS mutations. Recent research data in the field have demonstrated abnormal mineral regulation, intrinsic bone defects, cysteamine toxicity, muscle wasting and, likely interleukin-1-driven inflammation in the setting of CMBD. Here we summarize these new pathophysiological deregulations and discuss the crucial interplay between bone and muscle in INC. In future, vitamin D and/or biotherapies targeting the IL1β pathway may improve muscle wasting and subsequently CMBD, but this remains to be proven.