PFAPA syndrome and Behçet's disease: a comparison of two medical entities based on the clinical interviews performed by three different specialists

Clinical heterogeneity and five phenotypes identified in pediatric Behçet's syndrome: a cohort study from Shanghai Behçet's syndrome database

OBJECTIVES

Behçet's syndrome (BS) is a rare disease of unknown etiology, with limited reports especially in pediatric BS. The clinical characteristics and phenotypes of pediatric BS as a highly heterogeneous variable vessel vasculitis were investigated in this study.

METHODS

A cross-sectional study was conducted to compare clinical variables and descriptive characteristics of BS by age of onset and gender. Cluster analysis was then performed to identify the phenotypes of pediatric BS.

RESULTS

A total of 2082 BS patients were included in this study, 1834 adults and 248 children. Compared with adult-onset BS, pediatric BS had a higher incidence of folliculitis [relative risks (RR) and 95% confidence interval (CI) 1.3 (1.0-1.5)], uveitis of the left eye [RR and 95% CI 2.3 (1.0-5.0)], intestinal ulcer complications [RR and 95% CI 2.1 (1.1-4.2)], pericarditis [RR and 95% CI 2.5 (1.0-6.2)], and psychiatric disorders [RR and 95% CI 2.8(1.0-7.9)], while the incidence of thrombocytopenia was lower [RR 0.2 (0.1-1.0)]. Among pediatric BS, females had more genital ulcers, while males were more likely to have skin lesions, panuveitis, vascular involvement, venous lesions, cardiac involvement, and aortic aneurysms. Cluster analysis classified pediatric BS into five clusters (C1-C5): C1 (n = 61, 24.6%) showed gastrointestinal (GI) involvement; C2 (n = 44, 17.7%) was the central nervous system (CNS) type where 23 cases overlapped joint involvement; in C3 (n = 35, 14.1%), all patients presented with arthritis or arthralgia; all patients in C4 (n = 29, 11.7%) manifested ocular involvement, with a few patients overlapping with GI involvement or joint damage; C5 (n = 79, 31.9%) was the mucocutaneous type, presenting both oral ulcers, genital ulcers, and skin lesions.

CONCLUSIONS

The clinical features of pediatric and adult BS differ significantly. Male and female pediatric BS also have a distinct demography. Five phenotypes including GI, CNS, joint, ocular, and mucocutaneous types were identified for pediatric BS.

What is PFAPA syndrome? Genetic clues about the pathogenesis

PURPOSE OF REVIEW

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is the most common periodic fever syndrome in childhood. Recent studies report genetic susceptibility variants for PFAPA syndrome and the efficacy of tonsillectomy in a broader cohort of patients with recurrent stereotypical fever. In this review, we highlight the findings of these studies and what they may reveal about the pathogenesis of PFAPA.

RECENT FINDINGS

Newly identified genetic susceptibility loci for PFAPA suggest that it is a complex genetic disorder linked to Behçet's disease and recurrent aphthous ulcers. Patients who have PFAPA with some features of Behçet's disease have been reported. Moreover, the efficacy of tonsillectomy has now been described in patients who do not meet the full diagnostic criteria for PFAPA, although the immunologic profile in the tonsils is different from those with PFAPA. Factors that predict response to tonsillectomy are also reported.

SUMMARY

These findings highlight the heterogeneous phenotypes that may be related to PFAPA due to common genetic susceptibility or response to therapy. These relationships raise questions about how to define PFAPA and highlight the importance of understanding of the genetic architecture of PFAPA and related diseases.

Paediatric Behçet’s Disease: A Comprehensive Review with an Emphasis on Monogenic Mimics

Behçet’s disease (BD) is a polygenic condition with a complex immunopathogenetic background and challenging diagnostic and therapeutic concepts. Advances in genomic medicine have provided intriguing insights into disease pathogenesis over the last decade, especially into monogenic mimics of BD. Although a rare condition, paediatric BD should be considered an important differential diagnosis, especially in cases with similar phenotypes. Emerging reports of monogenic mimics have indicated the importance of genetic testing, particularly for those with early-onset, atypical features and familial aggregation. Treatment options ought to be evaluated in a multidisciplinary setting, given the complexity and diverse organ involvement. Owing to the rarity of the condition, there is a paucity of paediatric trials; thus, international collaboration is warranted to provide consensus recommendations for the management of children and young people. Herein, we summarise the current knowledge of the clinical presentation, immunopathogenetic associations and disease mechanisms in patients with paediatric BD and BD-related phenotypes, with particular emphasis on recently identified monogenic mimics.

Development and implementation of the AIDA International Registry for patients with Periodic Fever, Aphthous stomatitis, Pharyngitis, and cervical Adenitis syndrome

OBJECTIVE

Aim of this paper is to illustrate the methodology, design, and development of the AutoInflammatory Disease Alliance (AIDA) International Registry dedicated to patients with the Periodic Fever, Aphthous stomatitis, Pharyngitis, and cervical Adenitis (PFAPA) syndrome.

METHODS

This is a physician-driven, non-population- and electronic-based registry proposed to gather real-world demographics, clinical, laboratory, instrumental and socioeconomic data from PFAPA patients. Data recruitment is realized through the on-line Research Electronic Data Capture (REDCap) tool. This registry is thought to collect standardized information for clinical research leading to solid real-life evidence. The international scope and the flexibility of the registry will facilitate the realization of cutting-edge study projects through the constant updating of variables and the possible merging and transfer of data between current and future PFAPA registries.

RESULTS

A total of 112 centers have already been involved from 23 countries and 4 continents starting from August 24th, 2021, to April 6th, 2022. In total 56/112 have already obtained the formal approval from their local Ethics Committees. The platform counts 321 users (113 principal investigators, 203 site investigators, two lead investigators, and three data managers). The registry collects retrospective and prospective data using 3,856 fields organized into 25 instruments, including PFAPA patient's demographics, medical histories, symptoms, triggers/risk factors, therapies, and impact on the healthcare systems.

CONCLUSIONS

The development of the AIDA International Registry for PFAPA patients will enable the on-line collection of standardized data prompting real-life studies through the connection of worldwide groups of physicians and researchers. This project can be found on https://clinicaltrials.gov NCT05200715.

PFAPA (periodic fever, aphthous stomatitis, pharyngitis, and adenitis) syndrome: an overview of genetic background

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is an autoinflammatory disorder with an uncertain origin. PFAPA manifestations occur in the form of regular attacks accompanied by a rise in inflammatory markers. Regarding the family clustering of PFAPA and its similarities with other autoinflammatory disorders such as familial Mediterranean fever, a genetic basis is suggested for the disease. Studies have conducted genome analysis in order to find possible gene variants in PFAPA. Associations with variations in several genes such as MEFV, NLRP, TNFRSF1A, CARD15/NOD2, and MVK have been suggested and analyzed. Inflammasomes, intracellular proteins that are members of innate immunity and activate interleukin-1b (IL-1b) and IL-18, are proposed to be involved in PFAPA pathogenesis. The investigations show that a single gene cannot be found in association with PFAPA, and that it might have a multifactorial or polygenic basis, in which an environmental trigger can provoke inflammasome activation and activate PFAPA flares.

Genetic and immunologic findings in children with recurrent aphthous stomatitis with systemic inflammation

BACKGROUND

Recurrent aphthous stomatitis with systemic signs of inflammation can be encountered in inflammatory bowel disease, Behçet's disease (BD), Systemic Lupus Erythematosus (SLE). In addition, it has been proposed that cases with very early onset in childhood can be underpinned by rare monogenic defects of immunity, which may require targeted treatments. Thus, subjects with early onset recurrent aphthous stomatitis receiving a clinical diagnosis of BD-like or SLE-like disease may deserve a further diagnostic workout, including immunologic and genetic investigations.

OBJECTIVE

To investigate how an immunologic, genetic and transcriptomics assessment of interferon inflammation may improve diagnosis and care in children with recurrent aphthous stomatitis with systemic inflammation.

METHODS

Subjects referred to the pediatric rheumatologist for recurrent aphthous stomatitis associated with signs of systemic inflammation from January 2015 to January 2020 were enrolled in the study and underwent analysis of peripheral lymphocyte subsets, sequencing of a 17-genes panel and measure of interferon score.

RESULTS

We enrolled 15 subjects (12 females, median age at disease onset 4 years). The clinical diagnosis was BD in 8, incomplete BD in 5, BD/SLE overlap in 1, SLE in 1. Pathogenic genetic variants were detected in 3 patients, respectively 2 STAT1 gain of function variants in two patients classified as BD/SLE overlap and SLE, and 1 TNFAIP3 mutation (A20 haploinsufficiency) in patients with BD. Moreover 2 likely pathogenic variants were identified in DNASE1L3 and PTPN22, both in patients with incomplete BD. Interferon score was high in the two patients with STAT1 GOF mutations, in the patient with TNFAIP3 mutation, and in 3 genetic-negative subjects. In two patients, the treatment was modified based on genetic results.

CONCLUSIONS

Although recurrent aphthous stomatitis associated with systemic inflammation may lead to a clinical diagnosis of BD or SLE, subjects with early disease onset in childhood deserve genetic investigation for rare monogenic disorders. A wider genetic panel may help disclosing the genetic background in the subset of children with increased interferon score, who tested negative in this study.

French recommendations for the management of Behçet's disease

Behçet's disease (BD) is a systemic variable vessel vasculitis that involves the skin, mucosa, joints, eyes, arteries, veins, nervous system and gastrointestinal system, presenting with remissions and exacerbations. It is a multifactorial disease, and several triggering factors including oral cavity infections and viruses may induce inflammatory attacks in genetically susceptible individuals. BD vasculitis involves different vessel types and sizes of the vascular tree with mixed-cellular perivascular infiltrates and is often complicated by recurrent thrombosis, particularly in the venous compartment. Several new therapeutic modalities with different mechanisms of action have been studied in patients with BD. A substantial amount of new data have been published on the management of BD, especially with biologics, over the last years. These important therapeutic advances in BD have led us to propose French recommendations for the management of Behçet's disease [Protocole National de Diagnostic et de Soins de la maladie de Behçet (PNDS)]. These recommendations are divided into two parts: (1) the diagnostic process and initial assessment; (2) the therapeutic management. Thirty key points summarize the essence of the recommendations. We highlighted the main differential diagnosis of BD according to the type of clinical involvement; the role of genetics is also discussed, and we indicate the clinical presentations that must lead to the search for a genetic cause.

Pediatric Behçet's Disease

Behçet's Disease (BD) is a systemic vasculitis firstly described as a disorder causing aphthous lesion in oral and genital mucosae and uveitis. The disease has an extremely unique distribution characterized by the highest incidence in communities living along the historical Silk road. Although our understanding of the etiopathogenesis of BD has expanded over time, there are still lots of unidentified points in the underlying mechanisms of the disease. The accepted opinion in the light of the current knowledge is that various identified and/or unidentified infectious and/or environmental triggers can take a role as a trigger in individuals with genetic susceptibility. Although the disease usually develops in young adulthood, it is reported that about 15-20% of all Behçet's patients develop in childhood. Pediatric BD differs from adult BD not only with the age of onset but also in the frequency and distribution of clinical findings, disease severity and outcome. While gastrointestinal system involvement, neurological findings, arthralgia and positive family history are more common in children, genital lesions and vascular lesions are more common in adult patients. In addition, a better disease outcome with lower severity score and activity index has been reported in children. The diagnosis of the disease is made according to clinical findings. It can be challenging to diagnose the disease due to the absence of a specific diagnostic test, and the long time interval from the first finding of the disease to the full-blown disease phenotype in pediatric cases. Therefore, many classification criteria have been proposed so far. The widely accepted ones are proposed by the International Study Group. The new sets of classification criteria which is the only one for pediatric BD were also developed for pediatric cases by the PEDBD group. The primary goal for the treatment is preventing the organ damages by suppressing the ongoing inflammation and forestalling the disease flares. The treatment of the BD can be onerous due to its multisystemic nature and a multidisciplinary approach is essential for the management of the patients. In this review article, the definition, clinical findings, epidemiology, etiopathogenesis, and treatment will be discussed.

Evaluation of different classification criteria in children with Behcet disease: results from a single referral center

OBJECTIVES

Behcet Disease (BD) is a systemic vasculitis, first described with a triad of oral aphthous ulcers, genital ulcers, and uveitis. The authors aimed to share the clinical properties and utilities of three distinct classification criteria for BD in this study.

METHODS

This case-control study was conducted in pediatric BD patients, diagnosed between January 2012 and July 2019. The control group included 53 children with other rheumatic disorders. Sensitivity and specificity for International Study Group (ISG), International Criteria for BD (ICBD), and pediatric criteria for BD (PEDBD) criteria were tested.

RESULTS

The mean age at symptom onset and diagnosis of the 16 BD patients (6 females, 10 males) were 11.2 ± 3.6 and 13 ± 3.1 years, respectively. The sensitivity and specificity of ISG criteria were 87.5% and 100%. Furthermore, ICBD criteria had a sensitivity and specificity of 93.7% and 98.1%, whereas the authors found sensitivity and specificity as 93.7% and 96.2% for PEDBD.

CONCLUSION

ICBD and PEDBD reached higher sensitivity for pediatric BD diagnosis and ICBD had the highest specificity. The authors speculate that the utilization of ICBD may provide early diagnosis of BD in childhood, prevent related morbidities and misdiagnosis.

Common genetic susceptibility loci link PFAPA syndrome, Behçet's disease, and recurrent aphthous stomatitis

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is the most common periodic fever syndrome in children. The disease appears to cluster in families, but the pathogenesis is unknown. We queried two European-American cohorts and one Turkish cohort (total n = 231) of individuals with PFAPA for common variants previously associated with two other oropharyngeal ulcerative disorders, Behçet's disease and recurrent aphthous stomatitis. In a metaanalysis, we found that a variant upstream of IL12A (rs17753641) is strongly associated with PFAPA (OR 2.13, P = 6 × 10-9). We demonstrated that monocytes from individuals who are heterozygous or homozygous for this risk allele produce significantly higher levels of IL-12p70 upon IFN-γ and LPS stimulation than those from individuals without the risk allele. We also found that variants near STAT4, IL10, and CCR1-CCR3 were significant susceptibility loci for PFAPA, suggesting that the pathogenesis of PFAPA involves abnormal antigen-presenting cell function and T cell activity and polarization, thereby implicating both innate and adaptive immune responses at the oropharyngeal mucosa. Our results illustrate genetic similarities among recurrent aphthous stomatitis, PFAPA, and Behçet's disease, placing these disorders on a common spectrum, with recurrent aphthous stomatitis on the mild end, Behçet's disease on the severe end, and PFAPA intermediate. We propose naming these disorders Behçet's spectrum disorders to highlight their relationship. HLA alleles may be factors that influence phenotypes along this spectrum as we found new class I and II HLA associations for PFAPA distinct from Behçet's disease and recurrent aphthous stomatitis.

Behçet's Disease in Children: Diagnostic and Management Challenges

Behçet’s Disease (BD) is an inflammatory disease of unknown etiology with multisystemic involvement, being the main clinical manifestations represented by recurrent oral and genital ulcerations and uveitis. The disease has typically a chronic-relapsing course and may cause significant morbidity and mortality due to eye, vascular and neurological involvement. Although BD is more frequently diagnosed in adulthood, the disease onset can also be in pediatric age. Pediatric-onset BD is commonly featured by an incomplete clinical picture, and therefore the diagnosis represents a considerable clinical challenge for the physicians. The first classification criteria for pediatric BD, based on a scoring system, have been proposed few years ago. This work focuses on the main difficulties concerning both the diagnostic approach and the treatment of BD in pediatric age. The recommendation for the treatment of pediatric BD has been recently updated and allowed a considerable improvement of the therapeutic strategies. In particular, the use of anti-TNFα drugs as a second-line option for refractory BD, and as a first-line treatment in severe ocular and neurological involvement, has demonstrated to be effective in improving the outcome of BD patients. The knowledge about the molecular pathogenesis is progressively increasing, showing that BD shares common features with autoimmune and autoinflammatory disorders, and thus leading to the use of new biologic agents targeting the main mediators involved in the determination of BD. Anti-IL-17, anti-IL-23, anti-IL-1 and anti-IL-6 agents have shown promising results for the treatment of refractory BD in clinical trials and will represent an important alternative for the therapeutic approach to the disease.

Juvenile-onset Behçet's syndrome and mimics

Behçet's syndrome (BS) presents in childhood in up to 20% of reported cases. Diagnosis is clinical and multiple classification criteria have been developed. Presentation is heterogenous with recurrent oral ulceration often being the presenting feature. Mucocutaneous disease including genital ulceration and skin involvement is a common phenotype. Vascular and neurological manifestations are rarer, particularly in childhood. Musculoskeletal and gastro-intestinal involvement which do not form part of commonly used classification criteria, appear more frequent in children. Treatment approaches are extrapolated from studies of adult onset disease. The pathogenesis of BS is not well defined although dysregulation in both innate and adaptive immune systems, together with abnormal antigen presentation have been described. The recent discovery of monogenic mimics of BS requires further genetic studies to understand the burden of monogenic autoinflammatory conditions affecting those with a BS phenotype.

Hints for Genetic and Clinical Differentiation of Adult-Onset Monogenic Autoinflammatory Diseases

Monogenic autoinflammatory diseases (mAIDs) are inherited errors of innate immunity characterized by systemic inflammation recurring with variable frequency and involving the skin, serosal membranes, synovial membranes, joints, the gastrointestinal tube, and/or the central nervous system, with reactive amyloidosis as a potential severe long-term consequence. Although individually uncommon, all mAIDs set up an emerging chapter of internal medicine: recent findings have modified our knowledge regarding mAID pathophysiology and clarified that protean inflammatory symptoms can be variably associated with periodic fevers, depicting multiple specific conditions which usually start in childhood, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome, cryopyrin-associated periodic syndrome, and mevalonate kinase deficiency. There are no evidence-based studies to establish which potential genotype analysis is the most appropriate in adult patients with clinical phenotypes suggestive of mAIDs. This review discusses genetic and clinical hints for an ideal diagnostic approach to mAIDs in adult patients, as their early identification is essential to prompt effective treatment and improve quality of life, and also highlights the most recent developments in the diagnostic work-up for the most frequent hereditary periodic febrile syndromes worldwide.

The Broad-Ranging Panorama of Systemic Autoinflammatory Disorders with Specific Focus on Acute Painful Symptoms and Hematologic Manifestations in Children

Systemic autoinflammatory disorders (SAIDs) are inherited defects of innate immunity characterized by recurrent sterile inflammatory attacks involving skin, joints, serosal membranes, gastrointestinal tube, and other tissues, which recur with variable rhythmicity and display reactive amyloidosis as a potential long-term complication. Dysregulated inflammasome activity leading to overproduction of many proinflammatory cytokines, such as interleukin-1 (IL-1), and delayed shutdown of inflammation are considered crucial pathogenic keys in the vast majority of SAIDs. Progress of cellular biology has partially clarified the mechanisms behind monogenic SAIDs, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome, cryopyrin-associated periodic syndrome, mevalonate kinase deficiency, hereditary pyogenic diseases, idiopathic granulomatous diseases and defects of the ubiquitin-proteasome pathway. Whereas, little is clarified for the polygenic SAIDs, such as periodic fever, aphthous stomatitis, pharyngitis, and cervical adenopathy (PFAPA) syndrome. The puzzle of symptomatic febrile attacks recurring over time in children requires evaluating the mixture of clinical data, inflammatory parameters in different disease phases, the therapeutic efficacy of specific drugs such as colchicine, corticosteroids or IL-1 antagonists, and genotype analysis in selected cases. The long-term history of periodic fevers should also need to rule out chronic infections and malignancies. This review is conceived as a practical template for proper classification of children with recurring fevers and includes tips useful for the diagnostic approach to SAIDs, focusing on the specific acute painful symptoms and hematologic manifestations encountered in childhood.

Neither hereditary periodic fever nor periodic fever, aphthae, pharingitis, adenitis: Undifferentiated periodic fever in a tertiary pediatric center

AIM

To describe the frequency and clinical characteristics of patients with undifferentiated periodic fever (UPF) and to investigate whether a clinical classification of UPF based on the PRINTO-Eurofever score can help predicting the response to treatment and the outcome at follow-up.

METHODS

Clinical and therapeutic information of patients with recurrent fever who presented at a single pediatric rheumatology center from January 2006 through April 2016 were retrospectively collected. Patients with a clinical suspicion of hereditary periodic fever (HPF) syndrome and patients with clinical picture of periodic fever, aphthae, pharingitis, adenitis (PFAPA) who were refractory to tonsillectomy underwent molecular analysis of five HPF-related genes: MEFV (NM_000243.2), MVK (NM_000431.3), TNFRSF1A (NM_001065.3), NLRP3 (NM_001079821.2), NLRP12 (NM_001277126.1). All patients who had a negative genetic result were defined as UPF and further investigated. PRINTO-Eurofever score for clinical diagnosis of HPF was calculated in all cases.

RESULTS

Of the 221 patients evaluated for periodic fever, twelve subjects with a clinical picture of PFAPA who were refractory to tonsillectomy and 22 subjects with a clinical suspicion of HPF underwent genetic analysis. Twenty-three patients (10.4%) resulted negative and were classified as UPF. The median age at presentation of patients with UPF was 9.5 mo (IQR 4-24). Patients with UPF had a higher frequency of aphthae (52.2% vs 0%, P = 0.0026) and musculoskeletal pain (65.2% vs 18.2%, P = 0.0255) than patients with genetic confirmed HPF. Also, patients with UPF had a higher frequency of aphthous stomatitis (52.2% vs 10.7%, P < 0.0001), musculoskeletal pain (65.2% vs 8,0%, P < 0.0001), and abdominal pain (52.2% vs 4.8%, P < 0.0001) and a lower frequency of pharyngitis (56.6% vs 81.3%, P = 0.0127) compared with typical PFAPA in the same cohort. Twenty-one of 23 patients with UPF (91.3%) received steroids, being effective in 16; 13 (56.2%) were given colchicine, which was effective in 6. Symptoms resolution occurred in 2 patients with UPF at last follow-up. Classification according to the PRINTO-Eurofever score did not correlate with treatment response and prognosis.

CONCLUSION

UPF is not a rare diagnosis among patients with periodic fever. Clinical presentation place UPF half way on a clinical spectrum between PFAPA and HPF. The PRINTO-Eurofever score is not useful to predict clinical outcome and treatment response in these patients.

Diagnostic Criteria for Adult-Onset Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis (PFAPA) Syndrome

Objective

To identify a set of variables that could discriminate patients with adult-onset periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome from subjects with fever of unknown origin (FUO).

Methods

We enrolled 74 adults diagnosed with PFAPA syndrome according to the currently used pediatric diagnostic criteria and 62 additional patients with FUO. After having collected clinical and laboratory data from both groups, univariate and multivariate analyses were performed to identify the variables associated with PFAPA diagnosis. Odds ratio (OR) values, their statistical significance, and corresponding 95% confidence interval (CI) were evaluated for each diagnostic factor both at the univariate and multivariate analyses. Diagnostic accuracy was evaluated by the area under receiver operating characteristic (ROC) curve, while the leave-one-out cross-validation procedure was used to ensure that the model maintains the same diagnostic power when applied to new data.

Results

According to the multivariate analysis, the clinical variables that discriminated PFAPA patients were: fever episodes associated with cervical lymphadenitis (OR = 92; p < 0.0001), fever attacks associated with erythematous pharyngitis (OR = 231; p < 0.0001), increased inflammatory markers during fever attacks (OR = 588; p = 0.001), and the lack of clinical and laboratory signs of inflammation between flares (OR = 1202; p < 0.0001). These variables were considered for a diagnostic model which accounted for their OR values. The diagnostic accuracy of the proposed set of criteria corresponded to an area under ROC curve of 0.978 (95% CI 0.958–0.998), with a model sensitivity and specificity equal to 93.4% (95% CI 87.5–96.5%) and 91.7% (95% CI 82.8–96.7%), respectively.

Conclusion

we have provided herein a set of clinical diagnostic criteria for adult-onset PFAPA syndrome. Our criteria represent an easy-to-use diagnostic tool aimed at identifying PFAPA patients among subjects with FUO with a high-predictive potential, as shown by its very high sensitivity and specificity.

Periodic Fever with Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis Syndrome Is Associated with a CARD8 Variant Unable To Bind the NLRP3 Inflammasome

Periodic fever with aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) is a relatively common autoinflammatory condition that primarily affects children. Although tendencies were reported for this syndrome, genetic variations influencing risk and disease progression are poorly understood. In this study, we performed next-generation sequencing for 82 unrelated PFAPA patients and identified a frameshift variant in the CARD8 gene (CARD8-FS). Subsequently, we compared the frequency of CARD8-FS carriers in our PFAPA cohort (13.9%) with a healthy local population group (3.2%) and found a significant association between the CARD8-FS polymorphism and risk for PFAPA syndrome (p = 0.012; odds ratio: 4.96 [95% confidence interval, 1.33-18.47]). Moreover, CARD8-FS carriers display a distinct PFAPA phenotype that is characterized by a higher prevalence of symptoms out of flares and oral aphthosis (both p = 0.02 compared with PFAPA patients without the frameshift variant). CARD8 encodes a protein component of the NLRP3 inflammasome, which plays an important role in inflammation and contributes to the pathology of various autoinflammatory diseases. We found that the CARD8-FS variant led to a truncated CARD8 protein lacking the FIIND and CARD domains. As a result, the mutant CARD8 protein lost the ability to interact with the NOD domain of NLRP3. In summary, these results identify a new CARD8 variant associated with PFAPA and further suggest that disruption of the interaction between CARD8 and NLRP3 can regulate autoinflammation in patients.

Behçet's disease in children, an overview

BD is a systemic inflammatory disease with a variable vasculitis. Paediatric onset is very rare and carries a strong genetic component. Oral ulcers and fever of unknown origin are frequent at onset and difficult to distinguish from other inflammatory disorders; therefore, expert opinion is still mandatory to recognize the disease early. An international expert consensus has recently proposed new classification criteria for children with BD. The clinical spectrum of BD is heterogeneous and influenced by gender, ethnicity and country of residence. Young males have the worst prognosis with significantly more frequent neurological, ocular and vascular involvement. BD treatment is aimed at alleviating inflammation. Among all drugs, TNFα inhibitors have become a standard to control severe ocular, neurological and digestive system involvement.

Basic Characteristics of Adults with Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Adenopathy Syndrome in Comparison with the Typical Pediatric Expression of Disease

Autoinflammatory diseases are caused by inflammasome dysregulation leading to overproduction of proinflammatory cytokines and a pathological delay in the inflammation switching off. The progress of cellular biology has partially clarified pathogenic mechanisms behind monogenic autoinflammatory diseases, whereas little is known about the polygenic ones. Although the genetic susceptibility of periodic fever, aphthous stomatitis, pharyngitis, and adenopathy (PFAPA) syndrome is still obscure, the presence of overlapping symptoms with monogenic periodic fevers, the recurrence in family members, the important role played by dysregulated interleukin- (IL-) 1β secretion during flares, the overexpression of inflammasome-associated genes during attacks, and, last but not least, the therapeutic efficacy of IL-1β blockade strongly indicate a potential genetic involvement in its pathogenesis, probably linked with environmental factors. PFAPA syndrome has a typical inception in the pediatric age, but a delayed onset during adulthood has been described as well. Treatments required as well as effectiveness of tonsillectomy remain controversial, even if the disease seems to have a self-limited course mostly in children. The purpose of this review is to provide an overview of this complex polygenic/multifactorial autoinflammatory disorder in which the innate immune system undoubtedly plays a basic role.