Cryopyrin-associated Periodic Syndromes Research Articles

Equally potent: Nlrp3 mutation in macrophages or neutrophils is sufficient to drive autoinflammation.

Gain-of-function mutation in NLRP3 is associated with a spectrum of autoinflammatory disorders including familial cold autoinflammatory syndrome, Muckle-Wells syndrome, and neonatal onset multisystem inflammatory disease, collectively known as cryopyrin-associated periodic syndrome (CAPS). However, the cell types mediating the pathogenesis of CAPS are not completely understood. Two studies in EMBO Reports now demonstrate that gain-of-function Nlrp3 mutation in either macrophages or neutrophils alone is sufficient to trigger systemic autoinflammation and lethality in mice.

Real-world safety and effectiveness of canakinumab in patients with cryopyrin-associated periodic fever syndrome: a long-term observational study in Japan.

A post-marketing all-patient surveillance program was conducted to evaluate the safety and effectiveness of canakinumab, a monoclonal anti-interleukin-1β antibody, in patients in Japan with cryopyrin-associated periodic fever syndrome (CAPS), including familial cold auto-inflammatory syndrome, Muckle-Wells syndrome, and neonatal onset multisystem inflammatory disease. All patients with CAPS who received canakinumab treatment after drug approval in Japan were registered in this non-interventional, observational study. The observation period per patient was two years. Patients newly treated with canakinumab (New patients; NP) and those continuously treated with canakinumab following clinical trials (Roll-over patients; RP) were included. Data collection of clinical symptoms affecting physical function and prognosis was not mandated but assessed where available. Here, the interim results are reported. Of 87 patients in the safety set, the proportion of patients with any adverse drug reactions (ADRs) and any serious ADRs was 31.03% and 3.45%, respectively. The most common ADRs reported under system organ class were infections and infestations (20.69%). Of 84 patients in the effectiveness set, 75.76% and 83.33% of NP and RP, respectively, were responders at Week 24, achieving complete response without relapse. Responder rates were maintained up to Week 104. Clinical symptoms affecting physical function and prognosis remained unchanged in over half of those patients. Interim results provided the safety profile of canakinumab in a real-world setting, and identified no new safety concerns. Treatment with canakinumab has suggested sustained remission in the majority of patients in the real-world setting.

Reactogenicity and immunogenicity of the second COVID-19 vaccination in patients with inborn errors of immunity or mannan-binding lectin deficiency.

BackgroundPatients with inborn errors of immunity (IEI) are at increased risk for severe courses of SARS-CoV-2 infection. COVID-19 vaccination provides effective protection in healthy individuals. However, it remains unclear whether vaccination is efficient and safe in patients with constitutional dysfunctions of the immune system. Thus, we analyzed the humoral response, adverse reactions and assessed the disease activity of the underlying disease after COVID-19 vaccination in a cohort of patients suffering from IEIs or mannan-binding lectin deficiency (MBLdef).MethodsVaccination response was assessed after basic immunization using the Elecsys anti-SARS-CoV-2 S immunoassay and via Vero E6 cell based assay to detect neutralization capabilities. Phenotyping of lymphocytes was performed by flow cytometry. Patient charts were reviewed for disease activity, autoimmune phenomena as well as immunization status and reactogenicity of the vaccination. Activity of the underlying disease was assessed using a patient global numeric rating scale (NRS).ResultsOur cohort included 11 individuals with common variable immunodeficiency (CVID), one patient with warts hypogammaglobulinemia immunodeficiency myelokathexis (WHIM) syndrome, two patients with X-linked agammaglobulinemia (XLA), one patient with Muckle Wells syndrome, two patients with cryopyrin-associated periodic syndrome, one patient with Interferon-gamma (IFN-gamma) receptor defect, one patient with selective deficiency in pneumococcal antibody response combined with a low MBL level and seven patients with severe MBL deficiency. COVID-19 vaccination was generally well tolerated with little to no triggering of autoimmune phenomena. 20 out of 26 patients developed an adequate humoral vaccine response. 9 out of 11 patients developed a T cell response comparable to healthy control subjects. Tested immunoglobulin replacement therapy (IgRT) preparations contained Anti-SARS-CoV-2 S antibodies implicating additional protection through IgRT.SummaryIn summary the data support the efficacy and safety of a COVID-19 vaccination in patients with IEIs/MBLdef. We recommend evaluation of the humoral immune response and testing for virus neutralization after vaccination in this cohort.

FAAH served a key membrane-anchoring and stabilizing role for NLRP3 protein independently of the endocannabinoid system.

NLRP3, the sensor protein of the NLRP3 inflammasome, plays central roles in innate immunity. Over-activation of NLRP3 inflammasome contributes to the pathogenesis of a variety of inflammatory diseases, while gain-of-function mutations of NLRP3 cause cryopyrin-associated periodic syndromes (CAPS). NLRP3 inhibitors, particularly those that inhibit inflammasome assembly and activation, are being intensively pursued, but alternative approaches for targeting NLRP3 would be highly desirable. During priming NLRP3 protein is synthesized on demand and becomes attached to the membranes of ER and mitochondria. Here, we show that fatty acid amide hydrolase (FAAH), the key integral membrane enzyme in the endocannabinoid system, unexpectedly served the critical membrane-anchoring and stabilizing role for NLRP3. The specific interaction between NLRP3 and FAAH, mediated by the NACHT and LRR domains of NLRP3 and the amidase signature sequence of FAAH, was essential for preventing CHIP- and NBR1-mediated selective autophagy of NLRP3. Heterozygous knockout of FAAH, resulting in ~50% reduction in both FAAH and NLRP3 expression, was sufficient to substantially inhibit the auto-inflammatory phenotypes of the NLRP3-R258W knock-in mice, while homozygous FAAH loss almost completely abrogates these phenotypes. Interestingly, select FAAH inhibitors, in particular URB597 and PF-04457845, disrupted NLRP3-FAAH interaction and induced autophagic NLRP3 degradation, leading to diminished inflammasome activation in mouse macrophage cells as well as in peripheral blood mononuclear cells isolated from CAPS patients. Our results unraveled a novel NLRP3-stabilizing mechanism and pinpointed NLRP3-FAAH interaction as a potential drug target for CAPS and other NLRP3-driven diseases.

NLRP3 leucine-rich repeats control induced and spontaneous inflammasome activation in cryopyrin-associated periodic syndrome

The cryopyrin-associated periodic syndromes (CAPS) comprise a group of rare autoinflammatory diseases caused by gain-of-function mutations in the NLRP3 gene. NLRP3 contains a leucine-rich repeats (LRR) domain with a highly conserved exonic organization that is subjected to extensive alternative splicing. Aberrant NLRP3 inflammasome assembly in CAPS causes chronic inflammation; however, the mechanisms regulating inflammasome function remain unclear. We aimed to elucidate the mechanisms regulating NLRP3-mediated autoinflammation in human disease, characterizing the role of LRR in inflammasome activation. We analyzed sequence read archive data to characterize the pattern of NLRP3 splicing in human monocytes and investigated the role of each LRR-coding exon in inflammasome regulation in genetically modified U937 cells representing CAPS and healthy conditions. We detected a range of NLRP3 splice variants in human primary cells and monocytic cell lines, including 2 yet-undescribed splice variants. We observe that lipopolysaccharides affect the abundance of certain splice variants, suggesting that they may regulate NLRP3 activation by affecting alternative splicing. We showed that exons 4, 5, 7, and 9 are essential for inflammasome function, both in the context of wild-type NLRP3 activation by the agonist molecule nigericin and in a model of CAPS-mediated NLRP3 inflammasome assembly. Moreover, the SGT1-NLRP3 interaction is decreased in nonfunctional variants, suggesting that alternative splicing may regulate the recruitment of proteins that facilitate inflammasome assembly. These findings demonstrate the contribution of the LRR domain in inflammasome function and suggest that navigating LRR exon usage within NLRP3 is sufficient to dampen inflammasome assembly in CAPS.

Cutaneous manifestations of monogenic auto-inflammatory diseases: An international cohort study from the Juvenile Inflammatory Rheumatism cohort

To the Editor: Dermatological manifestations of monogenic auto-inflammatory diseases (AIDs) are frequent.1 The Juvenile Inflammatory Rheumatism (JIR) cohort is an international repository of patients with AIDs. The objective of this observational study was to describe the cutaneous manifestations in the 4 main monogenic AIDs from the JIR cohort: familial Mediterranean fever (FMF), tumor necrosis factor-receptor-associated periodic syndrome (TRAPS), cryopyrin-associated periodic syndrome (CAPS), and mevalonate kinase deficiency (MKD).

Interleukin-6 inhibition in the treatment of autoinflammatory diseases.

Autoinflammatory diseases are characterized by abnormalities that prevent innate immune cells from producing autoantibodies. While interleukin (IL)-6 is not directly associated with inflammasomes, like IL-1β or IL-18, it plays an important role in the pathogenesis of autoinflammatory diseases. Studies of autoinflammatory diseases, such as familial Mediterranean fever, cryopyrin-associated periodic syndrome, and tumor necrosis factor receptor-associated periodic syndrome, have shown IL-6 to be a promising therapeutic target. It has also been suggested that inhibition of IL-6 may have a therapeutic effect on amyloidosis, which is frequently associated with these chronic inflammatory diseases. In this study, we discuss the most recent research on the role of IL-6 in autoinflammatory diseases and its potential as a therapeutic target in their treatment.

Efficacy of anakinra treatment in pediatric rheumatic diseases: Our single-center experience.

This study aims to present our experience on anakinra, a recombinant interleukin-1 (IL-1) receptor antagonist, and efficacy results in pediatric rheumatic diseases in our clinic. Between July 1st, 2016 and July 1st, 2020, a total of 33 pediatric patients (18 males, 15 females; mean age: 6±3.4 years; range 4 to 13 years) with pediatric rheumatic diseases who were treated with anakinra were retrospectively analyzed. The patients with over one-month treatment period and followed for at least one year were included. Demographic and clinical findings, outcomes, adverse events, prior and/or additional treatments were collected at baseline, at 3 and 12 months of therapy. There were 33 patients with different pediatric rheumatic diseases (11 with systemic juvenile idiopathic arthritis [sJIA] complicated by macrophage activation syndrome [MAS], six with hyperimmunoglobulin-D syndrome, five with cryopyrin-associated periodic syndrome, five with familial Mediterranean fever, four with idiopathic recurrent pericarditis, one with NLRP12-associated periodic fever syndrome and one with unclassified systemic autoinflammatory disease), in the study group. The complete response was observed 69.7% of patients, partial response in 24.2%, and no response in 6.1% at three months of treatment. Inactive disease status was achieved in 45.5% of the patients with remission-on medication and 18.2% of the patients with remission-off medication at the end of a year. Anakinra was switched to other biological treatments in 51.5% of patients (n=17). Biological switch to canakinumab and tocilizumab were observed in 70.6% and 29.4% of these patients. Except for local reactions (n=2), no adverse events were observed in any of the patients. Anakinra appears to be a promising treatment alternative owing to its rapid effect as a result of its short half-life in autoinflammatory conditions. While short-term therapy seems to be sufficient for the sJIA complicated by MAS, the patients with systemic autoinflammatory diseases maintenance a more anakinra-dependent course.

Rare mutations in NLRP3 and NLRP12 associated with familial cold autoinflammatory syndrome: two Chinese pedigrees.

Familial cold autoinflammatory syndrome (FCAS) is the mildest subtype of cryopyrin-associated periodic syndrome (CAPS) and is a rare inherited systemic autoinflammatory disease (SAID). CAPS is the consequence of a rare group of genetic disorders that are mostly reported in European and American populations, but scarcely reported in Chinese populations. NLRP3, NLRP12, PLCG2, and NLRC4 are known pathogenic genes associated with FCAS, and the aim of this study was to identify pathogenic mutations in two intact pedigrees of Chinese FCAS. We performed Sanger sequencing of genomic DNA samples from 25 affected and 32 unaffected members of the two intact pedigrees and analyzed the pathogenic mutations for their conservativeness using multiple sequence alignment tools. In addition, we reviewed previously reported pathogenic genes of FCAS and their pathogenicity classification and summarized the characteristics of different genotypes and phenotypes of FCAS. This study reported two intact FCAS pedigrees with different genotypes and phenotypes, the heterozygous mutation (p.V72M) in NLRP3 in pedigree 1 and the heterozygous mutation (p.R754H) in NLRP12 in pedigree 2. There are no reports targeting p.V72M in NLRP3 in FCAS1, and there are relatively few relevant phenotypic data on the clinical manifestations identified in previous pedigrees. Multiple sequence comparisons of NLRP3 indicate that the p.V72M mutation is highly conserved during evolution. Our study has enriched the understanding of the pathogenesis of FCAS, a rare disease especially in Asian populations. KEY POINTS: •The NLRP3 (p.V72M) variant was first discovered in the Chinese pedigree of FCAS1 •NLRP12 (p.R754H) variants are not conserved in multiple sequence alignments, but they are still co-segregated and expressed in the big Chinese diseased pedigree.

The Clinical Chameleon of Autoinflammatory Diseases in Children.

The very first line of defense in humans is innate immunity, serving as a critical strongpoint in the regulation of inflammation. Abnormalities of the innate immunity machinery make up a motley group of rare diseases, named ‘autoinflammatory’, which are caused by mutations in genes involved in different immune pathways. Self-limited inflammatory bouts involving skin, serosal membranes, joints, gut and other districts of the human body burst and recur with variable periodicity in most autoinflammatory diseases (ADs), often leading to secondary amyloidosis as a long-term complication. Dysregulated inflammasome activity, overproduction of interleukin (IL)-1 or other IL-1-related cytokines and delayed shutdown of inflammation are pivotal keys in the majority of ADs. The recent progress of cellular biology has clarified many molecular mechanisms behind monogenic ADs, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome (or ‘autosomal dominant familial periodic fever’), cryopyrin-associated periodic syndrome, mevalonate kinase deficiency, hereditary pyogenic diseases, idiopathic granulomatous diseases and defects of the ubiquitin-proteasome pathway. A long-lasting history of recurrent fevers should require the ruling out of chronic infections and malignancies before considering ADs in children. Little is known about the potential origin of polygenic ADs, in which sterile cytokine-mediated inflammation results from the activation of the innate immunity network, without familial recurrency, such as periodic fever/aphthous stomatitis/pharyngitis/cervical adenopathy (PFAPA) syndrome. The puzzle of febrile attacks recurring over time with chameleonic multi-inflammatory symptoms in children demands the inspection of the mixture of clinical data, inflammation parameters in the different disease phases, assessment of therapeutic efficacy of a handful of drugs such as corticosteroids, colchicine or IL-1 antagonists, and genotype analysis to exclude or confirm a monogenic origin.

When All Is Not as It Seems: Recurrent Fever and New-onset Joint Pain in a 17-Month-old Girl.

When All Is Not as It Seems: Recurrent Fever and New-onset Joint Pain in a 17-Month-old Girl.

The 2021 EULAR/American College of Rheumatology Points to Consider for Diagnosis, Management and Monitoring of the Interleukin-1 Mediated Autoinflammatory Diseases: Cryopyrin-Associated Periodic Syndromes, Tumour Necrosis Factor Receptor-Associated Periodic Syndrome, Mevalonate Kinase Deficiency, and Deficiency of the Interleukin-1 Receptor Antagonist.

The interleukin-1 (IL-1) mediated systemic autoinflammatory diseases, including the cryopyrin- associated periodic syndromes (CAPS), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD) and deficiency of the IL-1 receptor antagonist (DIRA), belong to a group of rare immunodysregulatory diseases that primarily present in early childhood with variable multiorgan involvement. When untreated, patients with severe clinical phenotypes have a poor prognosis, and diagnosis and management of these patients can be challenging. However, approved treatments targeting the proinflammatory cytokine IL-1 have been life changing and have significantly improved patient outcomes. To establish evidence-based recommendations for diagnosis, treatment and monitoring of patients with IL-1 mediated autoinflammatory diseases to standardise their management. A multinational, multidisciplinary task force consisting of physician experts, including rheumatologists, patients or caregivers and allied healthcare professionals, was established. Evidence synthesis, including systematic literature review and expert consensus (Delphi) via surveys, was conducted. Consensus methodology was used to formulate and vote on statements to guide optimal patient care. The task force devised five overarching principles, 14 statements related to diagnosis, 10 on therapy, and nine focused on long-term monitoring that were evidence and/or consensus-based for patients with IL-1 mediated diseases. An outline was developed for disease-specific monitoring of inflammation-induced organ damage progression and reported treatments of CAPS, TRAPS, MKD and DIRA. The 2021 EULAR/American College of Rheumatology points to consider represent state-of-the-art knowledge based on published data and expert opinion to guide diagnostic evaluation, treatment and monitoring of patients with CAPS, TRAPS, MKD and DIRA, and to standardise and improve care, quality of life and disease outcomes.

NLRP3 licenses NLRP11 for inflammasome activation in human macrophages

Intracellular sensing of stress and danger signals initiates inflammatory innate immune responses by triggering inflammasome assembly, caspase-1 activation and pyroptotic cell death as well as the release of interleukin 1β (IL-1β), IL-18 and danger signals. NLRP3 broadly senses infectious patterns and sterile danger signals, resulting in the tightly coordinated and regulated assembly of the NLRP3 inflammasome, but the precise mechanisms are incompletely understood. Here, we identified NLRP11 as an essential component of the NLRP3 inflammasome in human macrophages. NLRP11 interacted with NLRP3 and ASC, and deletion of NLRP11 specifically prevented NLRP3 inflammasome activation by preventing inflammasome assembly, NLRP3 and ASC polymerization, caspase-1 activation, pyroptosis and cytokine release but did not affect other inflammasomes. Restored expression of NLRP11, but not NLRP11 lacking the PYRIN domain (PYD), restored inflammasome activation. NLRP11 was also necessary for inflammasome responses driven by NLRP3 mutations that cause cryopyrin-associated periodic syndrome (CAPS). Because NLRP11 is not expressed in mice, our observations emphasize the specific complexity of inflammasome regulation in humans.

Cryo-sensitive aggregation triggers NLRP3 inflammasome assembly in cryopyrin-associated periodic syndrome.

Cryopyrin-associated periodic syndrome (CAPS) is an autoinflammatory syndrome caused by mutations of NLRP3 gene encoding cryopyrin. Familial cold autoinflammatory syndrome, the mildest form of CAPS, is characterized by cold-induced inflammation induced by the overproduction of IL-1β. However, the molecular mechanism of how mutated NLRP3 causes inflammasome activation in CAPS remains unclear. Here, we found that CAPS-associated NLRP3 mutants form cryo-sensitive aggregates that function as a scaffold for inflammasome activation. Cold exposure promoted inflammasome assembly and subsequent IL-1β release triggered by mutated NLRP3. While K+ efflux was dispensable, Ca2+ was necessary for mutated NLRP3-mediated inflammasome assembly. Notably, Ca2+ influx was induced during mutated NLRP3-mediated inflammasome assembly. Furthermore, caspase-1 inhibition prevented Ca2+ influx and inflammasome assembly induced by the mutated NLRP3, suggesting a feed-forward Ca2+ influx loop triggered by mutated NLRP3. Thus, the mutated NLRP3 forms cryo-sensitive aggregates to promote inflammasome assembly distinct from canonical NLRP3 inflammasome activation.

Effective ex vivo inhibition of cryopyrin-associated periodic syndrome (CAPS)-associated mutant NLRP3 inflammasome by MCC950/CRID3.

Effective ex vivo inhibition of cryopyrin-associated periodic syndrome (CAPS)-associated mutant NLRP3 inflammasome by MCC950/CRID3.

Nlrp3 inflammasome activation in macrophages suffices for inducing autoinflammation in mice.

Cryopyrin-associated periodic syndromes (CAPS) are a spectrum of autoinflammatory disorders caused by gain-of-function NLRP3 mutant proteins that form hyperactive inflammasomes leading to overproduction of the pro-inflammatory cytokines IL-1β and IL-18. Expressing the murine gain-of-function Nlrp3A350V mutant selectively in neutrophils recapitulates several autoinflammatory features of human CAPS, but the potential contribution of macrophage inflammasome hyperactivation to CAPS development is poorly defined. Here, we show that expressing Nlrp3A350V in macrophages is sufficient for driving severe multi-organ autoinflammation leading to perinatal lethality in mice. In addition, we show that macrophages contribute to autoinflammation also in adult mice, as depleting macrophages in mice ubiquitously expressing Nlrp3A350V significantly diminishes splenic and hepatic IL-1β production. Interestingly, inflammation induced by macrophage-selective Nlrp3A350V expression does not provoke an influx of mature neutrophils, while neutrophil influx is still occurring in macrophage-depleted mice with body-wide Nlrp3A350V expression. These observations identify macrophages as important cellular drivers of CAPS in mice and support a cooperative cellular model of CAPS development in which macrophages and neutrophils act independently of each other in propagating severe autoinflammation.

NLRC3 Localizes to the Endoplasmic Reticulum via Interactions with a Novel ER-Resident Protein

Abstract Nucleotide binding domain, leucine rich repeat CARD containing protein 3 (NLRC3) is a member of the NLR gene family. Members of this family have been associated with human inflammatory diseases such as Crohn’s disease and cryopyrin-associated periodic syndrome. Although NLRC3 (and others) are not associated with human diseases, it is expressed preferentially in the immune system and functions in pathogen recognition. NLRC3 is an intracellular protein involved in the sensing of lipopolysaccharide and cytosolic nucleic acids. NLRC3 is hypothesized to act as a negative regulator in response to bacterial and viral infection, suggesting that the vertebrate immune system has evolved specific inhibitors to limit the inflammatory response. We performed an unbiased yeast two-hybrid screen using an amino terminal fragment of NLRC3 to identify putative interacting proteins that might help elucidate the mechanism by which NLRC3 might inhibit inflammatory responses. To this end, we identified several interacting proteins. One protein in particular localizes to the endoplasmic reticulum (ER) and might serve as a localization-dependent anchor for NLRC3, thus facilitating its interaction with STING and TBK1. Here we show NLRC3 is distributed to the ER where it can interact with several important signaling molecules involved in type I interferon production. Supported by a grant from the NIH (R15 GM134430)

Next-Generation Sequencing Analysis of MVK, NLRP3, TNFRSF1A, and PSTPIP1 Genes in Patients without MEFV Gene Variation and Genotype-Phenotype Correlation.

Objective: In this study, we aimed to evaluate other interleukin-1b-mediated monogenic autoinflam- matory diseases (AIDs) (tumor necrosis factor receptor-1-associated periodic syndrome, hyperimmuno- globulin D syndrome, cryopyrin-associated periodic syndrome (CAPS), pyogenic arthritis, pyoderma gangrenosum, and acne syndrome) by the next-generation sequencing method (NGS) in cases with clinical Familial Mediterranean Fever symptoms, and no variant detected in the MEFV gene. Methods: The cases included in this study and their parents were interviewed and filled in a survey form. The targeted genetic panel for interleukin-1b-mediated AIDs covering four genes (MVK, NLRP3,TNFRSF1A, and PSTPIP1) was studied for cases with a negative result from the MEFV gene analysis. The genetic analysis was conducted using the targeted NGS method. Results: Variants were found in 16 out of the 40 patients in the study sample. These variants were pri- orly reported in variant databases, and three of them were identified as definitely pathogenic (V377I of the MVK gene, C52Y of the TNFRSF1A gene, and I313V of the NLRP3 gene), four as a variant of uncer- tain significance (VUS) (R92Q of the TNFRSF1A, A372V of the PSTPIP1, and V198M and Q703K of the NLRP3), and one as benign polymorphism (S52N of the MVK gene). The median age of onset among variant-positive cases was 10.5 (3.5-18) years. The most common clinical findings in the variant-positive group were arthralgia, fever, and abdominal pain. While three out of 40 patients met the classification criteria before genetic analysis, only one patient was diagnosed with CAPS as a result of genetic analy- sis, and other patients were considered as nonspecific phenotype. Conclusion: The use of NGS gene panels seems beneficial in diseases with heterogeneous clinical manifestations such as systemic AIDs. Although the number of variants detected is high, clinical diag- nosis rates remain low. The genotype–phenotype relationship in these diseases is still unclear.

Auditory and Vestibular Characteristics of NLRP3 Inflammasome Related Autoinflammatory Disorders: Monogenic Hearing Loss Can Be Improved by Anti-interleukin-1 Therapy.

Inflammasomes are large multimeric protein complexes which regulate the activation of the proinflammatory cytokines interleukins-1β and−18 and inflammatory cell death called pyroptosis. NLRP1, NLRP3, NLRC4, AIM2, and pyrin can induce the formation of inflammasomes. Of these, the NLRP3 inflammasome is the most well-characterized. Recent studies revealed that variants of the NLRP3 gene cause genetic diseases, including systemic inflammatory syndrome called cryopyrin-associated periodic syndrome (CAPS) and non-syndromic sensorineural hearing loss DFNA34. NLRP3 variants cause CAPS and DFNA34 by constitutively activating the NLRP3 inflammasome and increasing IL-1β release. Patients with CAPS show systemic inflammatory symptoms, and hearing loss is a characteristic feature. Patients with CAPS and DFNA34 show progressive bilateral sensorineural hearing loss. Hearing loss has unique characteristics that can be improved or stabilized by anti-interluekin-1 therapy, although it is usually difficult to alleviate genetic hearing loss by drugs. However, it should be noted that there is a window of opportunity to respond to treatment, and younger patients are most likely to respond. It is important to know the characteristics of CAPS and DFNA34 for early diagnosis, and mutation analysis of NLRP3 will lead to a definite diagnosis. In this review, we summarize the current understanding of the mechanisms of the NLRP3 inflammasome and characteristics of patients with CAPS and DFNA34, especially focused on auditory and vestibular findings.

Cryopyrin-associated periodic syndrome assess the efficacy and safety of anakinra therapy: a single center experience

The aim of this study was to analyze the clinical, laboratory and molecular genetic data of 20 patients (9 boys, 11 girls) diagnosed with cryopyrin-associated periodic syndrome (CAPS) with an assessment of the efficacy and safety of therapy in 6 patients with an inhibitor of the interleukin-1 receptor – anakinra. The study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI. The patients' parents gave their consent to the use of their child's data, including photographs, for research purposes and in publications. The age of CAPS manifestation ranged from 0 to 27.0 months (median – 2 months). The clinical manifestations were dominated by fever, rash, lesions of the central nervous system, musculoskeletal system. During the attack, all 20 patients had an increase acute phase proteins of blood. All patients had heterozygous mutation in the NLRP3 gene, with the highest frequency of localization in exon 3 (17/20). 6/20 patients were initiated on anakinra therapy. All 6 patients who have been treated of anakinra enough to assess the effect of the treatment, drastic improvement of the condition was noted, but only in 5/6 patients achieved full remission.