Monogenic Autoinflammatory Syndromes Research Articles

Evidence on Hidradenitis Suppurativa as an Autoinflammatory Skin Disease.

Hidradenitis suppurativa (HS) is a chronic and debilitating inflammatory skin disease that often exhibits heterogeneity in its clinical presentation, especially in the context of its rare syndromic forms. The pathogenesis of HS results from a complex interplay of genetic predisposition, innate and adaptive immunity dysregulation, smoking, obesity and environmental factors. In the early phase of the disease, the innate immune system is hyperactivated, contributing to tissue damage and triggering the activation and amplification of the adaptive immune response, which plays a pivotal role in the chronic stages of the disease. Recent studies focused on elucidating the importance of innate immunity impairment and autoinflammation in HS and increasing evidence has emerged on the occurrence of the disease in the context of well-known monogenic and polygenic autoinflammatory syndromes (AIDs). This review provides a comprehensive examination of the current scientific background supporting the contribution of autoinflammation to HS etiology, including genetic data, molecular studies and clinical evidence, as well as the association between HS and AIDs. However, further research is needed to shed light on the pathogenic mechanism of this challenging condition and to identify potential perspectives for future therapeutic approaches.

Comment on Maghsoudlou et al. Titled “Uveitis Associated with Monogenic Autoinflammatory Syndromes in Children”

ABSTRACT The work by Maghsoudlou et al. provides a comprehensive examination of monogenic autoinflammatory syndromes (MAIS) in children, with a specific focus on uveitis as a significant clinical manifestation. It meticulously details the genetic underpinnings, clinical features, diagnostic criteria, and current therapeutic strategies, including the use of biologics. This critique highlights the strengths of the review and suggests further exploration in areas such as long-term treatment outcomes, genotype-phenotype correlations, and the impact of MAIS on quality of life. Future research could benefit from longitudinal studies and enhanced predictive models to improve management and treatment personalization.

Monogenic autoinflammatory syndromes with features of systemic vasculitis: a new field of rheumatology

The article is dedicated to a new actual problem in rheumatology: vasculitis and vasculitis-like manifestations in monogenic autoinflammatory syndromes in adult. The features of the clinical course of the rarely diagnosed VEXAS syndrome, as well as the SAVI and COPA syndromes, which sometimes occur in adults, are considered. Promising directions of future treatment are discussed.

Histiocytoid Sweet Syndrome Presenting in Two Sisters With Deficiency of Deaminase Type 2.

Deficiency of adenosine deaminase type 2 (DADA2) is an autosomal recessive monogenic autoinflammatory syndrome that is classically characterised by polyarteritis nodosa, systemic vasculitis and stroke. The spectrum of disease manifestations has broadened to encompass a range of cutaneous, vascular and haematological manifestations. We report a novel association in two sisters with heterozygous p.R169G/p.M309l mutations in ADA2 with low serum ADA2 activity who both presented similarly with clinical and histological features consistent with histiocytoid Sweet syndrome.

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

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

Azacitidine for patients with Vacuoles, E1 Enzyme, X-linked, Autoinflammatory, Somatic syndrome (VEXAS) and myelodysplastic syndrome: data from the French VEXAS registry.

Azacitidine can be effective in myelodysplastic syndromes (MDS) associated with inflammatory/autoimmune diseases. Vacuoles, E1 Enzyme, X-linked, Autoinflammatory, Somatic syndrome (VEXAS) is a new monogenic autoinflammatory syndrome caused by somatic ubiquitin-like modifier-activating enzyme 1 (UBA1) mutation, often associated with MDS, whose treatment is difficult and not yet codified. Based on a French nationwide registry of 116 patients with VEXAS, we report the efficacy and safety of azacitidine treatment in 11 patients with VEXAS with MDS. Clinical response of VEXAS to azacitidine was achieved in five patients (46%), during 6, 8+, 12, 21, 27+ months respectively, suggesting that azacitidine can be effective in selected patients with VEXAS and associated MDS.

Histologic Patterns and Clues to Autoinflammatory Diseases in Children: What a Cutaneous Biopsy Can Tell Us.

Autoinflammation is defined by aberrant, antigen-independent activation of the innate immune signaling pathways. This leads to increased, pro-inflammatory cytokine expression and subsequent inflammation. In contrast, autoimmune and allergic diseases are antigen-directed immune responses from activation of the adaptive immune system. The innate and adaptive immune signaling pathways are closely interconnected. The group of ‘complex multigenic diseases’ are a result of mutual dysregulation of both the autoinflammatory and autoimmune physiologic components. In contrast, monogenic autoinflammatory syndromes (MAIS) result from single mutations and are exclusively autoinflammatory in their pathogenesis. Studying the clinical and histopathological findings for the various MAIS explains the phenotypical correlates of their specific mutations. This review aims to group the histopathologic clues for autoinflammation into three recognizable patterns. The presence of these histologic patterns in a pediatric patient with recurrent fevers and systemic inflammation should raise suspicion of an autoinflammatory component in MAIS, or, more frequently, in a complex multigenic disease. The three major histopathological patterns seen in autoinflammation are as follows: (i) the ‘neutrophilic’ pattern, seen in urticarial neutrophilic dermatosis, pustular psoriasis, aseptic neutrophilic folliculitis, and Sweet’s syndrome; (ii) the ‘vasculitic’ pattern seen in small vessel-vasculitis (including hypersensitivity/leukocytoclastic vasculitis, thrombosing microangiopathy and lymphocytic vasculitis), and intermediate-sized vessel vasculitis, mimicking polyarteritis nodosa; and (iii) the ‘granulomatous’ pattern. Beyond these three patterns, there are additional histopathologic clues, which are detailed below. It is important for a dermatopathologist to recognize the patterns of autoinflammation, so that a diagnosis of MAIS or complex multigenic diseases may be obtained. Finally, careful histopathologic analyses could contribute to a better understanding of the various clinical manifestations of autoinflammation.

Epigenetics and familial mediterranean fever

Abstract: Throughout the last 20 years, the concept of auto-inflammation is developed, culminating with the finding of how gene mutations of Mediterranean Fever (MEFV) seemed to be causally linked to Familial Mediterranean fever (FMF). The autoinflammatory illnesses presently constitute a wide variety of disorders that have mutual signs of frequent fever, the incidence of hyper-reactive immune cells of hereditary origin, and indicators of inflammation that may occur systemically or specific to an organ with no autoimmunity specific infection.The key causes of the unregulated inflammation are the myeloid innate immune cells which mainly induced production of excessive inflammatory cytokines as IL-1β and IL-18. Deficiencies through various signalling mechanisms regulating innate immune response, especially a single and even multiple inflammasomes hyperreactivity, remain the essence of pathological autoinflammatory phenotype.While FMF would be a monogenic autoinflammatory syndrome, it is genetically complicated and affected by environmental influences. Lately, epigenetic dysregulation has appeared to be a further cause of pathogenesis. Throughout this survey, we are addressing the epigenetic involvement pathways within (FMF).

Tumor Necrosis Factor Receptor-Associated Periodic Syndrome (TRAPS) with a New Pathogenic Variant in TNFRSF1A Gene in a Family of the Adult Male with Renal AA Amyloidosis-Diagnostic and Therapeutic Challenge for Clinicians.

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) belongs to systemic autoinflammatory diseases (AIDs). Many of these syndromes are genetically conditioned and can be inherited. Diagnosis relies on clinical symptoms and should be confirmed by genetic testing. One of the most serious complications is AA amyloidosis. We present the diagnostic route of a 33-year-old male with AA amyloidosis and his children, leading to diagnosis of monogenic autoinflammatory syndrome, confirmed by genetic analysis. A novel variant of the in-frame insertion type in one allele of TNFRSF1A gene was found by whole exome sequencing and confirmed by Sanger sequencing, which allowed a diagnosis of TRAPS. Three-dimensional modeling was used to assess the structural changes introduced into TNFR1 molecule by the insertion. The analysis of the 3D model revealed that accommodation of the 4AA insert induces misalignment of three cysteine bridges (especially the C70-C96 bridge) in the extracellular domain, leading to putatively misfolded and improperly functioning TNFR1. Three of the patient’s daughters inherited the same variant of the TNFRSF1A gene and presented TRAPS symptoms. TRAPS is a very rare disease, but in the presence of suggestive symptoms the genetic diagnostic workout should be undertaken. Early diagnosis followed by appropriate clinical management can prevent irreversible complications.

Behçet disease (BD) and BD-like clinical phenotypes: NF-κB pathway in mucosal ulcerating diseases.

Behçet's disease (BD) is a heterogeneous multi-organ disorder in search of a unified pathophysiological theory and classification. The disease frequently has overlapping features resembling other disease clusters, such as vasculitides, spondyloarthritides and thrombophilias with similar genetic risk variants, namely HLA-B*51, ERAP1, IL-10, IL-23R. Many of the BD manifestations, such as unprovoked recurrent episodes of inflammation and increased expression of IL-1, IL-6 and TNFα, overlap with those of the hereditary monogenic autoinflammatory syndromes, positioning BD at the crossroads between autoimmune and autoinflammatory syndromes. BD-like disease associates with various inborn errors of immunity, including familial Mediterranean fever, conditions related to dysregulated NF-κB activation (eg TNFAIP3, NFKB1, OTULIN, RELA, IKBKG) and either constitutional trisomy 8 or acquired trisomy 8 in myelodysplastic syndromes. We review here the recent advances in the immunopathology of BD, BD-like diseases and the NF-κB pathway suggesting new elements in the elusive BD etiopathogenesis.

Autoinflammatory Mechanisms in Crystal-Induced Arthritis

Crystal-induced arthritides have been classified as “type-1 autoinflammatory diseases” for their main features which resemble those of the monogenic autoinflammatory syndromes. They are in fact characterized by spontaneous onset, recurrence of the episodes, self-limitation and resolution, inflammasome activation with huge production of IL-1β and a prevalent involvement of the innate immune system. The term “auto” refers also to the induction of IL-1β gene expression, processing and secretion by IL-1β itself. The concept of autoinflammation in crystal-induced arthritis has been finally reinforced by the efficacy of IL-1 blockade in treating acute and chronic state of this disease. The aim of this article is to review the autoinflammatory mechanisms in crystal-induced arthritis, considering both clinical and molecular aspects.

Autoinflammatory diseases in childhood, part 1: monogenic syndromes.

Autoinflammatory diseases constitute a family of disorders defined by aberrant stimulation of inflammatory pathways without involving antigen-directed autoimmunity. They may be divided into monogenic and polygenic types. Monogenic autoinflammatory syndromes are those with identified genetic mutations, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic fever syndrome (TRAPS), mevalonate kinase deficiency or hyperimmunoglobulin D syndrome, cryopyrin-associated periodic fever syndromes (CAPS), pyogenic arthritis pyoderma gangrenosum and acne (PAPA) syndrome, interleukin-10 and interleukin-10 receptor deficiencies, adenosine deaminase 2 deficiency and pediatric sarcoidosis. Those without an identified genetic mutation are known as polygenic and include systemic-onset juvenile idiopathic arthritis, idiopathic recurrent acute pericarditis, Behçet syndrome, chronic recurrent multifocal osteomyelitis and inflammatory bowel disease among others. Autoinflammatory disorders are defined by repeating episodes or persistent fever, rash, serositis, lymphadenopathy, arthritis and increased acute phase reactants, and thus may mimic infections clinically. Most monogenic autoinflammatory syndromes present in childhood. However, because of their infrequency, diverse and nonspecific presentation, and the relatively new genetic recognition, diagnosis is usually delayed. In this article, which is Part 1 of a two-part series, the authors update monogenic autoinflammatory diseases in children with special emphasis on imaging features that may help establish the correct diagnosis.

Neutrophilic Dermatoses and Their Implication in Pathophysiology of Asthma and Other Respiratory Comorbidities: A Narrative Review.

Neutrophilic dermatoses (ND) are a polymorphous group of noncontagious dermatological disorders that share the common histological feature of a sterile cutaneous infiltration of mature neutrophils. Clinical manifestations can vary from nodules, pustules, and bulla to erosions and ulcerations. The etiopathogenesis of neutrophilic dermatoses has continuously evolved. Accumulating genetic, clinical, and histological evidence point to NDs being classified in the spectrum of autoinflammatory conditions. However, unlike the monogenic autoinflammatory syndromes where a clear multiple change in the inflammasome structure/function is demonstrated, NDs display several proinflammatory abnormalities, mainly driven by IL-1, IL-17, and tumor necrosis factor-alpha (TNF-a). Additionally, because of the frequent association with extracutaneous manifestations where neutrophils seem to play a crucial role, it was plausible also to consider NDs as a cutaneous presentation of a systemic neutrophilic condition. Neutrophilic dermatoses are more frequently recognized in association with respiratory disorders than by chance alone. The combination of the two, particularly in the context of their overlapping immune responses mediated primarily by neutrophils, raises the likelihood of a common neutrophilic systemic disease or an aberrant innate immunity disorder. Associated respiratory conditions can serve as a trigger or may develop or be exacerbated secondary to the uncontrolled skin disorder. Physicians should be aware of the possible pulmonary comorbidities and apply this knowledge in the three steps of patients' management, work-up, diagnosis, and treatment. In this review, we attempt to unravel the pathophysiological mechanisms of this association and also present some evidence for the role of targeted therapy in the treatment of both conditions.

MCC950 closes the active conformation of NLRP3 to an inactive state.

NLRP3 is an innate immune sensor contributing to the development of different diseases including monogenic autoinflammatory syndromes, gout, atherosclerosis, and Alzheimer’s disease. The molecule sulfonylurea MCC950 is a NLRP3 inflammasome inhibitor with potential clinical utility. However, the mechanism of action of MCC950 remains unknown. Here, we characterize the mechanism of action of MCC950 in both wild-type and autoinflammatory-related NLRP3 mutants, demonstrating that MCC950 closes the ‘open’ conformation of active NLRP3.

New autoinflammatory diseases.

Advances in sequencing techniques and systematic cohort-analysis of patients with autoinflammatory phenotypes have enabled a burst in the recognition of new autoinflammatory diseases and contributed to the description of the mechanisms involved in autoinflammation. This review focuses on new genetic and mechanistic discoveries that have broadened the definition of autoinflammatory diseases in the context of the established landscape, providing new therapeutic opportunities and avenues for further discoveries. Mechanistic insights of inflammatory diseases open opportunities for new targeted therapies. Advances in high-throughput screening of small-molecule inhibitors accelerate the discovery of new and more specific therapeutic options. Recent evidence establishes IL-18 as a driver of macrophage activation, emerging as a new biomarker and therapeutic target. Finally, the identification of escape of nonsense-mediated decay as the genetic mechanism resulting in a monogenic immune-dysregulatory disease, unveils a possibility for future discoveries. Recent mechanistic findings in autoinflammatory diseases as well as the identification of specific biomarkers and discovery of new diseases, continue to pave the way for ever more specific targeted approaches. These therapies are not only applicable to monogenic autoinflammatory syndromes but also for other diseases in which the same pathways are dysregulated.

Monogenic autoinflammatory syndromes in children: Through the dermatologist's lens

Autoinflammatory syndromes are a group of rare disorders of innate immunity characterized by repeated episodes of inflammation without an obvious cause. Many of these disorders have a childhood onset, and present as recurrent fevers, skin lesions, joint pains and other systemic features. Newer autoinflammatory syndromes with previously undescribed clinical phenotypes are being increasingly recognized. Several of these have distinctive cutaneous manifestations, and dermatologists have an important role to play in the diagnosis of these conditions. Recently, molecular basis for many of these diseases has been identified, thus paving the way for novel targeted therapies. Interleukin-1 blockers have been found to be more effective than the conventional immunosuppressants in their treatment. In this article, we focus on the cutaneous features of well-recognized as well as some of the recently described monogenic autoinflammatory syndromes in children.

Vasculitis and vasculitis-like manifestations in monogenic autoinflammatory syndromes.

Monogenic autoinflammatory syndromes are a rare group of disorders characterized by periodic episodes of systemic inflammation of endogenous origin. Sometimes, these diseases may present with features akin to vasculitis. We conducted a literature review on such vasculitic manifestations in described monogenic autoinflammatory syndromes utilizing the Online Mendelian Inheritance in Man (OMIM), Medline, and Scopus databases. Our search identified that Familial Mediterranean fever (FMF) can manifest with features of either small, medium, large, or variable-vessel vasculitis. Stimulator of interferon gene (STING)-associated vasculopathy of infancy (SAVI) is an interferonopathy that can mimic the presentation of medium-vessel or small-vessel vasculitis, whereas deficiency of adenosine deaminase 2 (DADA2) is another such mimic of medium-vessel vasculitis, associated in a significant number of patients with features of immunodeficiency. Occasional reports exist of vasculitic manifestations in tumor necrosis factor (TNF) receptor-associated periodic fever syndrome (TRAPS) and chronic infantile neurologic cutaneous and articular disorder (CINCA), whereas mevalonate kinase deficiency can also mimic the presentation of small- or medium-vessel vasculitis. Clinicians should be aware of the possibility of autoinflammatory disease presenting as vasculitis to diagnose and treat the same appropriately.

Bone involvement in monogenic autoinflammatory syndromes

Until recently the most common autoinflammatory diseases (AIDs) associated with bone disease in childhood included a few genetically complex (chronic non-bacterial osteomyelitis, synovitis, acne, pustulosis, hyperostosis and osteitis syndrome) and monogenic (Majeed syndrome, deficiency of IL-1 receptor antagonist, cherubism) AIDs. However, the spectrum of monogenic AIDs associated with bone manifestations has markedly expanded to include both recently identified diseases such as the type I interferonopathies and also newly recognized bone dysplasias in already established AIDs. In addition, we propose that some known bone dysplasia syndromes, especially those presenting with hyperostosis and associated systemic inflammation, be classified as AIDs. Collectively, we provide an overview of the diverse bone manifestations identified in the genetically defined AIDs, discuss the hypotheses of the underlying pathophysiological mechanisms and highlight potential novel therapeutic strategies.

DNA demethylation of inflammasome-associated genes is enhanced in patients with cryopyrin-associated periodic syndromes

Inflammasomes are cytosolic multiprotein complexes in macrophages. They assemble after infection- or stress-associated stimuli, activating both caspase-1-mediated inflammatory cytokine secretion and pyroptosis. Increased inflammasome activity resulting from gene mutations is related to monogenic autoinflammatory syndromes. However, variable penetrance among patients with the same gene mutations suggests involvement of additional mechanisms associated with inflammasome gene regulation. We sought to investigate the role of DNA demethylation in activating inflammasome genes during macrophage differentiation and monocyte activation in healthy control subjects and patients with autoinflammatory syndrome. Inflammasome-related genes were tested for DNA methylation and mRNA levels by using bisulfite pyrosequencing and quantitative RT-PCR in monocytes invitro differentiated to macrophages and exposed to inflammatory conditions. The contribution of Tet methylcytosine dioxygenase 2 (TET2) and nuclear factor κB to DNA demethylation was tested by using chromatin immunoprecipitation, small interfering RNA-mediated downregulation, and pharmacologic inhibition. We observed that inflammasome-related genes are rapidly demethylated in both monocyte-to-macrophage differentiation and on monocyte activation. Demethylation associates with increased gene expression, and both mechanisms are impaired when TET2 and nuclear factor κB are downregulated. We analyzed DNA methylation levels of inflammasome-related genes in patients with cryopyrin-associated periodic syndromes (CAPS) and familial Mediterranean fever, 2 archetypical monogenic autoinflammatory syndromes. Under the above conditions, monocytes from untreated patients with CAPS undergo more efficient DNA demethylation than those of healthy subjects. Interestingly, patients with CAPS treated with anti-IL-1 drugs display methylation levels similar to those of healthy control subjects. Our study is the first to demonstrate the involvement of DNA methylation-associated alterations in patients with monogenic autoinflammatory disease and opens up possibilities for novel clinical markers.

Lights and shadows in autoinflammatory syndromes from the childhood and adulthood perspective.

In a high percentage of cases, the monogenic autoinflammatory syndromes (AIS), caused by subversion in the inflammasome homeostasis leading to cytokine oversecretion and characterized by multiple inflammatory pictures, start in childhood. However, the description of tardive manifestations, veiled phenotypes, and atypical clinical signs beginning in adulthood has been more and more reported in recent times, requiring that many specialists become confident with concepts, details, and management strategies of AIS. Differences between child- and adult-onset syndromes raise the question of whether pathogenic mechanisms might differ when the timetable of AIS onset diverges, but show that carefulness is needed to establish a straightforward diagnosis.