MEFV M694V mutation has a role in susceptibility to ankylosing spondylitis: A meta-analysis

Familial mediterranean fever in a patient with ankylosing spondylitis: could familial mediterranean fever explain a typical eight-year ankylosing spondylitis?

Patients with familial mediterranean fever (FMF) often present with musculoskeletal involvement typical of spondyloarthropathy (SpA) or ankylosing spondylitis (AS), posing a diagnostic challenge for medical practitioners and leading to the description of the FMF-related SpA/AS clinical spectrum. Currently, the available data focuses on SpA diagnosis in patients with known FMF, while the contrary is rarely reported in the medical literature. We describe an unusual case of concomitant FMF diagnosis in a patient with an eight-year long history of typical, human leukocyte antigen-B27 positive AS on adalimumab treatment, who presented with recurrent febrile attacks and abdominal pain. The laboratory work-up revealed high titres of serum amyloid A while genetic testing was positive for the pathogenic M694V heterozygous variant in the MEFV gene. The patient was promptly treated with colchicine, showing complete remission of clinical symptoms and normalisation of inflammatory markers to date. We also performed a review of the available literature elaborating on the interrelationship of AS and FMF in terms of pathogenesis and clinical characteristics. Our case highlights the need for reporting of similar cases and further explores the association of AS and FMF as distinct clinical entities or as constituents of the same disease continuum model.

Spondyloarthritis in familial Mediterranean fever: a cohort study

Familial Mediterranean fever (FMF) and spondyloarthritis (SpA) may show several common signs. This study aimed to evaluate the frequency of SpA and its manifestations in FMF, the impact of SpA on FMF, and the associations of non-episodic findings (heel enthesitis, protracted arthritis, and sacroiliitis) with the FMF features. Demographic, clinical, imaging, and genetic data were retrieved from medical records of the patients with adult FMF. To identify patients who met the classification criteria for SpA, data including rheumatologic inquiry were recorded. Patients with SpA and those who did not meet the criteria were compared in terms of FMF features. Regression analyses were performed to determine the factors that were most associated with sacroiliitis, enthesitis, and protracted arthritis. Of the 283 patients with FMF, 74 (26.1%) met the SpA criteria (64 axial, 10 peripheral); and 65 (22.9%) patients had sacroiliitis, 27 (9.5%) protracted arthritis, and 61 (21.6%) heel enthesitis. Patients with SpA were older and had more FMF severity, and heel pain rate than those without; however, genetic features, CRP, resistance to colchicine, and heel enthesitis did not differ. A meaningful number of patients without SpA had also displayed heel enthesitis, protracted arthritis, inflammatory back pain, heel pain, family history of SpA, and elevated CRP. Age was found to be the main predictor of heel enthesitis and protracted arthritis was linked with FMF severity. A significant number of patients with FMF meet the peripheral SpA classification criteria as well as axial SpA. SpA and its shared manifestations with FMF may have an impact on FMF.

Clinical Phenotypes of Adult-Onset Still's Disease: New Insights from Pathophysiology and Literature Findings

Adult-onset Still's disease (AOSD) is a non-familial, polygenic systemic autoinflammatory disorder. It is traditionally characterized by four cardinal manifestations-spiking fever, an evanescent salmon-pink maculopapular rash, arthralgia or arthritis and a white-blood-cell count (WBC) ≥ 10,000/mm³, mainly neutrophilic polymorphonuclear cells (PMNs)-but many other manifestations and complications can be associated, making clinical expression very heterogeneous and diagnosis sometimes difficult. The AOSD course can be diverse and is currently impossible to predict. Several clinical phenotypes have been described, either on the basis of the evolution of symptoms over time (monocyclic, polycyclic and chronic evolution) or according to dominant clinical evolution (systemic and arthritis subtypes). However, these patterns are mainly based on case series and not on robust epidemiological studies. Furthermore, they have mainly been established a long time ago, before the era of the biological treatments. Thus, based on our personal experience and on recent advances in the understanding of disease pathogenesis, it appears interesting to reshuffle AOSD phenotypes, emphasizing the continuum between AOSD profiles and other systemic autoinflammatory disorders, eventually proposing a research agenda.

Ankylosing spondylitis: an autoimmune or autoinflammatory disease?

Ankylosing spondylitis (AS) is a chronic inflammatory disorder of unknown aetiology. Unlike other systemic autoimmune diseases, in AS, the innate immune system has a dominant role characterized by aberrant activity of innate and innate-like immune cells, including γδ T cells, group 3 innate lymphoid cells, neutrophils, mucosal-associated invariant T cells and mast cells, at sites predisposed to the disease. The intestine is involved in disease manifestations, as it is at the forefront of the interaction between the mucosal-associated immune cells and the intestinal microbiota. Similarly, biomechanical factors, such as entheseal micro-trauma, might also be involved in the pathogenesis of the articular manifestation of AS, and sentinel immune cells located in the entheses could provide links between local damage, genetic predisposition and the development of chronic inflammation. Although these elements might support the autoinflammatory nature of AS, studies demonstrating the presence of autoantibodies (such as anti-CD74, anti-sclerostin and anti-noggin antibodies) and evidence of activation and clonal expansion of T cell populations support an autoimmune component to the disease. This Review presents the evidence for autoinflammation and the evidence for autoimmunity in AS and, by discussing the pathophysiological factors associated with each, aims to reconcile the two hypotheses.

The musculoskeletal system manifestations in children with familial Mediterranean fever

OBJECTIVE

Familial Mediterranean fever (FMF) is a monogenic inherited periodic fever syndrome presenting with episodes of self-limiting fever and inflammation of serosal membranes. Besides the findings in the diagnostic criteria, musculoskeletal findings can also be seen in FMF patients attacks. In this study, we aim to reveal the frequency and genotype association of musculoskeletal manifestations in children with FMF.

METHODS

The patients diagnosed with FMF between January 1, 2017 and June 1, 2019, and followed for at least six months in our pediatric rheumatology clinic were included in this study. Musculoskeletal manifestations of patients were enrolled. The patients were grouped according to the "Mediterranean Fever" (MEFV) gene variants. Musculoskeletal manifestations of the patients were compared between the groups.

RESULTS

The study group included 634 children with FMF (336 female and 298 male, F/M: 1.13/1). The clinical manifestations of patients in the attack period were as follows: 99% of the patients had a fever, 87.3% had abdominal pain, 20.7% had chest pain, 11.3% had vomiting, 10.7% had erysipelas like erythema, and 9.3% had a headache. The musculoskeletal symptoms were accompanied by 58.6% (n=372) of the patients during the attack period. The most common musculoskeletal manifestation was found as arthralgia (32.6%, n=206). Also, the other musculoskeletal manifestations were as follows during attacks: arthritis in 23.7% (n=150), myalgia in 20.5% (n=130), exertional leg pain in 6.5% (n=41), and protracted febrile myalgia in 1% (n=7) of the patients. It was observed that the musculoskeletal manifestations were significantly higher in patients with homozygous M694V variants in exon-10 (p=0.017). The musculoskeletal manifestations were more common in the attack periods of patients carrying the M694V variant in at least one allele (p=0.019).

CONCLUSION

We found that the musculoskeletal manifestations were accompanied in more than half of patients with FMF. M694V variant was found as a risk factor for emerging musculoskeletal manifestations.

Recurrent synovitis of hip and MEFV gene related arthritis in children

BACKGROUND

Recurrent and relapsing arthritis has been proposed to describe a group of arthritis with recurring and periodic nature, in which the joints are intermittently involved. This study reports three non-FMF patients with heterozygous MEFV gene mutations and an extraordinary arthritis as a recurrent synovitis of hip (RSH).

METHODS

During 16-years from 2003 to 2019 at pediatric rheumatologic clinic among 195 recorded files with chronic oligoarthritis, 3 patients with diagnosis of recurrent synovitis of hip (RSH) were reviewed thoroughly. Peripheral blood was collected from patients and the samples were screened for the 12 common MEFV gene pathogenic variants.

RESULTS

This study included three patients, two female and one male with relapsing idiopathic arthritis that has been located on hip joints as a sole manifestation and pathologic findings of MEFV mutations as follow: A744S, V726A, and R761H.

CONCLUSION

On the basis of possible role of MEFV gene in different rheumatic disease, MEFV gene related arthritis may be considered as a background of RSH particularly in Mediterranean area.

How autoinflammation may turn into autoimmune inflammation: Insights from monogenetic and complex IL-1 mediated auto-inflammatory diseases

IL-1 mediated auto-inflammatory diseases are characterised by episodes of unexplained fever, generalized and localized inflammation. The characteristic symptoms predominantly result from exaggerated activation of innate immune pathways. However, in some patients with typical IL-1 mediated diseases, chronic disease manifestations develop in the absence of acute inflammation, suggesting the involvement of adaptive immune pathways. We discuss clinical observations as well as novel insights in how chronic activation of innate immune pathways can lead to auto-immune disease features in patients with auto-inflammatory diseases and how we need to better understand these sequelae in order to improve treatment strategies.

The association of MEFV gene mutations with the disease risk and severity of systemic juvenile idiopathic arthritis

BACKGROUND

Systemic juvenile idiopathic arthritis (sJIA) has many clinical features overlapping with familial Mediterranean fever (FMF), which is caused by mutations in MEFV gene. And FMF patients were easily misdiagnosed as sJIA in China. So we speculate that MEFV is critical genetic background for sJIA and influences patients' severity. In this study, we aim to figure out whether MEFV mutations are risk factor for the occurrence of sJIA and to study the association of MEFV mutations with disease severity of sJIA patients.

METHODS

The present study includes 57 sJIA children and 2573 healthy controls. Odd ratio with 95% confidence interval based on allelic frequency of MEFV mutations or variants was used to evaluate their contribution to sJIA susceptibility. Meta-analysis was then performed to reach comprehensive conclusion. All included sJIA patients were grouped by presence and number of MEFV mutations. Clinical data and indicators of disease severity were compared among different groups. Multiple linear regression method was used to find out whether the number of MEFV variants is associated with the severity of sJIA. Kaplan-Meier curves and log rank test were used to estimate the probability of the first relapse.

RESULTS

The MEFV mutations of our subjects predominantly existed in exons 2 and 3. No significant difference was found in allelic frequency between sJIA children and healthy controls. Meta-analysis demonstrated that p.M694V/I was a risk factor for sJIA (pooled OR: 7.13, 95% CI: 3.01-16.89). The relative period of activity was significantly lower in the one mutation group than those with more than one mutation (p = 0.0194). However, no relevance was found in multiple linear regression models.

CONCLUSIONS

The mutation p.M694V/I in MEFV might be a risk factor for sJIA. SJIA patients carrying more than one heterozygous mutation in MEFV tend to be more severe than those containing only one, but studies in other cohort of patients need to be performed to validate it.

The effect of genotype on musculoskeletal complaints in patients with familial Mediterranean fever

Objectives: Familial Mediterranean fever (FMF) is an autosomal recessive disease, characterized by recurrent, self limited attacks of fever with serositis. The aim of this study was to describe the frequency of musculoskeletal complaints in children with FMF and to investigate the effect of genotype on these findings.Methods: Files of patients who had been seen in our department (during routine follow-up visits) were retrospectively evaluated. Comparisons regarding musculoskeletal findings were performed between patients with homozygous/compound heterozygous and heterozygous mutations. Thereafter, patients with two mutations were divided into three groups; M694V/M694V, M694V/other mutation, and patients carrying two mutations other than M694V. Patients with single mutation were divided into two groups; M694V and non M694V carriers.Results: The study group comprised 317 FMF patients (170 females) with a mean age of 12.2 ± 5.7 years. Arthralgia (42.6%), leg pain (42.9%), and heel pain (35.6%) were the most common musculoskeletal complaints in children with FMF. Frequency of musculoskeletal findings of the patients who had two mutations did not differ from the patients with single mutations (p > 0.05). Leg and heel pain were more frequently detected in patients with homozygous M694V mutation (p = 0.001). Among patients with heterozygous mutations; children with M694V mutation had more frequently arthralgia, leg, and heel pain (p < 0.05).Conclusions: Musculoskeletal problems were commonly encountered in patients with FMF. Genotype seems to affect the frequency of these problems and M694V mutation is a predisposing factor for musculoskeletal complaints.

Sacroiliitis in Children With Familial Mediterranean Fever

BACKGROUND/OBJECTIVE

Familial Mediterranean fever (FMF) is an autosomal recessive disease, characterized by recurrent, self-limited attacks of fever with serositis. Various diseases were reported to be associated with FMF. The aim of this study was to investigate the frequency and characteristics of sacroiliitis in children with FMF.

METHODS

Files of FMF patients who had been seen in 2 reference hospitals in Ankara were retrospectively evaluated. Patients with FMF and concomitant sacroiliitis were included to the study. All patients had magnetic resonance imaging evidence of sacroiliitis.

RESULTS

Among 650 FMF patients, 17 (11 females, 6 males; mean age, 13.32 ± 4.24 years) (2.6%) of them were found to have sacroiliitis. Familial Mediterranean fever diagnosis was done prior to sacroiliitis diagnosis in 11 patients (65%) and concurrently or afterward in 6 patients (35%). Ten patients had isolated sacroiliitis, and 7 had associated diseases (5 enthesitis-related arthritis, 1 psoriatic arthritis, and 1 ulcerative colitis). Arthritis (59%), arthralgia (77%), leg pain (71%), heel pain (41%), and enthesitis (29%) were common complaints. Sacroiliac tenderness was detected in 77%, and M694V mutation in almost 90% of the patients. All patients received colchicine therapy. Additionally, 14 of them were treated with nonsteroidal anti-inflammatory drugs, 10 were on sulfasalazine treatment, and 7 of them were on biological agents.

CONCLUSIONS

Sacroiliitis can be seen in patients with FMF during childhood, and M694V mutation seems to be a susceptibility factor for its development. Inflammatory low-back pain and leg and heel pain could suggest sacroiliitis.

FMF Is Associated With a Wide Spectrum of MHC Class I- and Allied SpA Disorders but Not With Classical MHC Class II-Associated Autoimmune Disease: Insights From a Large Cohort Study

Objectives: To test the hypothesis that familial Mediterranean fever (FMF)-associated autoinflammation may exaggerate the tendency toward adaptive immunopathology or spondyloarthritis (SpA)-associated disorders including major histocompatibility complex (MHC) class I associated disorders but not classical MHC class II-associated disorders that exhibit transplacental autoimmunity including myasthenia gravis and pemphigus.

Methods: Seven thousand seven hundred forty-seven FMF patients and 10,080 age- and sex-matched controls in the Clalit Health Services medical database were identified and compared in terms of prevalence of SpA-associated disorders. We also evaluated four classical and strong MHC class II-associated disorders, namely, pemphigus vulgaris, myasthenia gravis, sarcoidosis, and pernicious anemia, to ascertain whether such associations with SpA-spectrum disease were specific or merely reflected the non-specific consequences of innate immune system activation on driving divergent types of immunity. The diagnosis of FMF was based on the medical records and not genetically proven.

Results: FMF showed a strong association with MHC class I-related diseases: odds ratio (OR) of 28.58 [95% confidence interval (95% CI), 6.93–117.87; p < 0.0001] for Behçet's disease, OR of 10.33 (95% CI, 4.09–26.09; p < 0.0001) for ankylosing spondylitis, and OR of 1.67 (95% CI, 1.19–2.33; p = 0.0029) for psoriasis. For weakly MHC class I-linked diseases, an OR of 3.76 (95% CI, 2.48–5.69; p < 0.0001) for Crohn's disease and OR of 2.64 (95% CI, 1.52–4.56; p = 0.0005) for ulcerative colitis were found. No association was found between FMF and the four MHC class II-associated autoimmune disorders.

Conclusion: FMF patients are associated with increased risk of SpA-related disease diagnosis including MHC-I-opathies but not MHC-II-associated autoimmune diseases, suggesting that tissue-specific dysregulation of innate immunity share between FMF and SpA spectrum disorders may drive adaptive immune MHC class I-associated conditions.

Inflammasome biology, molecular pathology and therapeutic implications

Inflammasomes are intracellular multiprotein signaling complexes, mainly present in myeloid cells. They commonly assemble around a cytoplasmic receptor of the nucleotide-binding leucine-rich repeat containing receptor (NLR) family, although other cytoplasmic receptors like pyrin have been shown to form inflammasomes. The nucleation of the multiprotein scaffolding platform occurs upon detection of a microbial, a danger or a homeostasis pattern by the receptor that will, most commonly, associate with the adaptor protein ASC (apoptosis-associated speck-like protein containing a CARD) through homotypic domain interactions resulting in recruitment of procaspase-1. This will lead to the autoproteolytic activation of caspase-1, which regulates the secretion of proinflammatory IL1β and IL18 cytokines and pyroptosis, a caspase-1-mediated form of cell death. Pyroptosis occurs through cleavage of Gasdermin D, a membrane pore forming protein. Recently, non-canonical inflammasomes have been described, which directly sense intracellular pathogens through caspase-4 and -5 in humans, leading to pyroptosis. Inflammasomes are important in host defense; however, a deregulated activity is associated with a number of inflammatory, immune and metabolic disorders. Furthermore, mutations in inflammasome receptor coding genes are causal for an increasing number of rare autoinflammatory diseases. Biotherapies targeting the products of inflammasome activation as well as molecules that directly or indirectly inhibit inflammasome nucleation and activation are promising therapeutic areas. This review discusses recent advances in inflammasome biology, the molecular pathology of several inflammasomes, and current therapeutic approaches in autoinflammatory diseases and in selected common multifactorial inflammasome-mediated disorders.