Polyarteritis nodosa (PAN) is a vasculitic disease characterized primarily by necrotizing vasculitis - inflammatory lesions in blood vessels that lead to vessel wall necrosis. Our understanding of ...PAN and necrotizing vasculitis has evolved over time. In addition to PAN, necrotizing vasculitis is now a recognized feature of a broad range of diseases with different aetiopathogenesis. For example, necrotizing vasculitis associated with hepatitis B virus infection has a different aetiopathogeneis to PAN and is now classified as a separate disease. Additionally, although 'classic' PAN is not an inherited disease, mutations in specific genes, such as ADA2 (also known as CECR1), can result in a necrotizing vasculopathy similar to PAN. The literature also suggests that the course of PAN differs in childhood-onset disease and in cases confined to the skin (so-called cutaneous PAN). Dissecting PAN and other autoinflammatory diseases with PAN-like features has enabled more-specific therapies and might also help us better understand the pathogenesis of these devastating conditions.
Autoinflammatory diseases (AIDs) are diseases of the innate immune system, with clinical and laboratory evidence of attacks of inflammation. The more common AIDs are those associated with periodic ...fevers: Familial Mediterranean fever (FMF); Mevalonate Kinase Deficiency (MKD)/Hyperimmunoglobulin D Syndrome (HIDS); Cryopyrin-associated Autoinflammatory Syndrome (CAPS); and Tumor Necrosis Factor Receptor-Associated Periodic Syndrome (TRAPS). Classification criteria have been developed for all these types. FMF is the most common AID worldwide with a particularly high prevalence in the Eastern Mediterranean region. Environmental factors are thought to affect the course of the disease. Outcome measures are being developed for AIDs.
Autoinflammatory diseases are associated with abnormal activation of the innate immune system, leading to clinical inflammation and high levels of acute-phase reactants. The first group to be ...identified was the periodic fever diseases, of which familial Mediterranean fever (FMF) is the most common. In FMF, genetic results are not always straightforward; thus, flowcharts to guide the physician in requesting mutation analyses and interpreting the findings are presented in this Review. The other periodic fever diseases, which include cryopyrin-associated periodic syndromes (CAPS), TNF receptor-associated periodic syndrome (TRAPS) and mevalonate kinase deficiency/hyperimmunoglobulin D syndrome (MKD/HIDS), have distinguishing features that should be sought for carefully during diagnosis. Among this group of diseases, increasing evidence exists for the efficacy of anti-IL-1 treatment, suggesting a major role of IL-1 in their pathogenesis. In the past decade, we have started to learn about the other rare autoinflammatory diseases in which fever is less pronounced. Among them are diseases manifesting with pyogenic lesions of the skin and bone; diseases associated with granulomatous lesions; diseases associated with psoriasis; and diseases associated with defects in the immunoproteasome. A better understanding of the pathogenesis of these autoinflammatory diseases has enabled us to provide targeted biologic treatment at least for some of these conditions.
Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease (AID) affecting mainly the ethnic groups originating from Mediterranean basin. The disease is characterized by ...self-limited inflammatory attacks of fever and polyserositis along with elevated acute phase reactants. FMF is inherited autosomal recessively; however, a significant proportion of heterozygotes also express the phenotype. FMF is caused by mutations in the
gene coding for pyrin, which is a component of inflammasome functioning in inflammatory response and production of interleukin-1β (IL-1β). Recent studies have shown that pyrin recognizes bacterial modifications in Rho GTPases, which results in inflammasome activation and increase in IL-1β. Pyrin does not directly recognize Rho modification but probably affected by Rho effector kinase, which is a downstream event in the actin cytoskeleton pathway. Recently, an international group of experts has published the recommendations for the management of FMF. Colchicine is the mainstay of FMF treatment, and its regular use prevents attacks and controls subclinical inflammation in the majority of patients. Furthermore, it decreases the long-term risk of amyloidosis. However, a minority of FMF patients fail to response or tolerate colchicine treatment. Anti-interleukin-1 drugs could be considered in these patients. One should keep in mind the possibility of non-compliance in colchicine-non-responders. Although FMF is a relatively well-described AID and almost 20 years has passed since the discovery of the
gene, there are still a number of unsolved problems about it such as the exact mechanism of the disease, symptomatic heterozygotes and their treatment, and the optimal management of colchicine resistance.
Abstract Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory syndrome characterized by recurrent serositis or arthritis attacks and, in some patients, chronic subclinical inflammation ...that predisposes to secondary amyloidosis. Colchicine is the gold standard of treatment, which reduces attack frequency and amyloidosis risk. However, up to 5% of patients are considered resistant or inadequately respond to colchicine, and some others cannot tolerate the side effects of effective doses of colchicine (colchicine intolerant). The definition of “colchicine resistance” has evolved over the last decade, although a consensus definition has not been reached. Key factors in assessing colchicine resistance include attack frequency and severity, levels of acute phase reactants, colchicine dosage and composition, and treatment compliance. Promising clinical results have been obtained with biologics targeting interleukin-1 in colchicine-resistant or -intolerant patients with FMF. These results underscore the need to identify patients who are not optimally managed with colchicine and who might therefore benefit from additional biologic therapies.
Abstract
Vasculitis is a challenging disease for paediatricians. Certain vasculitides are quite common in children whereas others are much rarer compared with adults. The most common vasculitides in ...childhood are IgA-associated vasculitis (Henoch–Schönlein purpura) and Kawasaki disease, which are usually self-limiting vasculitides although children do develop complications as a result. We now have much better knowledge of how to manage these patients and prevent the deleterious complications. This review provides an up-to-date discussion on childhood vasculitides, including diagnosis, treatment and follow-up strategies, together with a comparison with vasculitides in adults. It also discusses the newly defined monogenic vasculitides that often present during early childhood.
Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease, but many rheumatologists are not well acquainted with its management. The objective of this report is to ...produce evidence-based recommendations to guide rheumatologists and other health professionals in the treatment and follow-up of patients with FMF. A multidisciplinary panel, including rheumatologists, internists, paediatricians, a nurse, a methodologist and a patient representative, was assembled. Panellists came from the Eastern Mediterranean area, Europe and North America. A preliminary systematic literature search on the pharmacological treatment of FMF was performed following which the expert group convened to define aims, scope and users of the guidelines and established the need for additional reviews on controversial topics. In a second meeting, recommendations were discussed and refined in light of available evidence. Finally, agreement with the recommendations was obtained from a larger group of experts through a Delphi survey. The level of evidence (LoE) and grade of recommendation (GR) were then incorporated. The final document comprises 18 recommendations, each presented with its degree of agreement (0-10), LoE, GR and rationale. The degree of agreement was greater than 7/10 in all instances. The more controversial statements were those related to follow-up and dose change, for which supporting evidence is limited. A set of widely accepted recommendations for the treatment and monitoring of FMF is presented, supported by the best available evidence and expert opinion. It is believed that these recommendations will be useful in guiding physicians in the care of patients with FMF.
Our aim was to report our experiences of pediatric macrophage activation syndrome (MAS) patients treated with anakinra and to review previous studies reporting anakinra treatment in pediatric MAS ...patients associated with systemic juvenile idiopathic arthritis (sJIA) or autoinflammatory diseases (AIDs). The study group consisted of pediatric MAS patients due to sJIA or AIDs, followed up in the Pediatric Rheumatology Unit of Hacettepe University between January 2015 and January 2017 and treated with anakinra (anti-IL1). We conducted a systematic review of the published literature involving pediatric MAS patients associated with sJIA or AIDs, treated with anakinra. Thirteen sJIA patients and two AIDs patients were included the study. Nineteen MAS episodes were observed in 15 patients. Anakinra (2 mg/kg/day) was started in with a median 1 day after admission. Clinical symptoms resolved, and laboratory findings normalized within median (minimum–maximum) 2 (1–4) and 6 (4–9) days, respectively after the introduction of anakinra. Steroid treatment was stopped in a median of 10 (4–13) weeks after the initiation of anakinra treatment. Patients were followed up for a median of 13 (6–24) months. Two patients developed recurrent MAS episodes when the anakinra dose was reduced, while the other patients achieved remission. In the literature review, we identified nine articles, describing 35 pediatric MAS patients associated with sJIA or AIDs and treated with anakinra. Except for two, all the patients reached remission. Our study and systematic literature review may help to improve the knowledge on the role of anakinra treatment in the management of MAS.
Protein coding genes constitute only approximately 1% of the human genome but harbor 85% of the mutations with large effects on disease-related traits. Therefore, efficient strategies for selectively ...sequencing complete coding regions (i.e., "whole exome") have the potential to contribute to the understanding of rare and common human diseases. Here we report a method for whole-exome sequencing coupling Roche/NimbleGen whole exome arrays to the Illumina DNA sequencing platform. We demonstrate the ability to capture approximately 95% of the targeted coding sequences with high sensitivity and specificity for detection of homozygous and heterozygous variants. We illustrate the utility of this approach by making an unanticipated genetic diagnosis of congenital chloride diarrhea in a patient referred with a suspected diagnosis of Bartter syndrome, a renal salt-wasting disease. The molecular diagnosis was based on the finding of a homozygous missense D652N mutation at a position in SLC26A3 (the known congenital chloride diarrhea locus) that is virtually completely conserved in orthologues and paralogues from invertebrates to humans, and clinical follow-up confirmed the diagnosis. To our knowledge, whole-exome (or genome) sequencing has not previously been used to make a genetic diagnosis. Five additional patients suspected to have Bartter syndrome but who did not have mutations in known genes for this disease had homozygous deleterious mutations in SLC26A3. These results demonstrate the clinical utility of whole-exome sequencing and have implications for disease gene discovery and clinical diagnosis.
Familial Mediterranean fever (FMF) is an autoinflammatory disease caused by homozygous or compound heterozygous gain-of-function mutations in MEFV, which encodes pyrin, an inflammasome protein. ...Heterozygous carrier frequencies for multiple MEFV mutations are high in several Mediterranean populations, suggesting that they confer selective advantage. Among 2,313 Turkish people, we found extended haplotype homozygosity flanking FMF-associated mutations, indicating evolutionarily recent positive selection of FMF-associated mutations. Two pathogenic pyrin variants independently arose >1,800 years ago. Mutant pyrin interacts less avidly with Yersinia pestis virulence factor YopM than with wild-type human pyrin, thereby attenuating YopM-induced interleukin (IL)-1β suppression. Relative to healthy controls, leukocytes from patients with FMF harboring homozygous or compound heterozygous mutations and from asymptomatic heterozygous carriers released heightened IL-1β specifically in response to Y. pestis. Y. pestis-infected Mefv
FMF knock-in mice exhibited IL-1-dependent increased survival relative to wild-type knock-in mice. Thus, FMF mutations that were positively selected in Mediterranean populations confer heightened resistance to Y. pestis.
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