Effect of Colchicine Treatment on Clinical Course in Children with PFAPA Syndrome.

INTRODUCTION: Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome (PFAPA) is the most common periodic fever condition in children. There is no consensus on treatment to prevent attacks and reduce their frequency. In this study, we aimed to evaluate the effectiveness of colchicine treatment in PFAPA syndrome. In addition, we described the demographic and clinical features of PFAPA patients. MATERIALS AND METHODS: We retrospectively analyzed 58 PFAPA patients who were started on colchicine treatment between January 2017 and January 2022. Demographic data, clinical features, laboratory tests, genetic analysis of MEditerranean FeVer (MEFV) mutations, and autoinflammatory disease activity index (AIDAI) scores of all patients were evaluated. In addition, patients were divided into two groups according to MEFV variants and compared. RESULTS: Attack frequency, duration, and AIDAI scores decreased in all patients after colchicine treatment. Duration of follow-up was 13.53±6.65 months. The median±IQR age at diagnosis was 3.2 (2-5) years. Thirty three (56.9%) patients had heterozygous mutations of MEFV. The most common MEFV variants were M694V (63.6%). There was no significant difference between the two groups in terms of colchicine responses. CONCLUSION: Colchicine treatment is effective and safe in patients with PFAPA who have frequent attacks. No association was established between the presence of heterozygous mutations of MEFV and colchicine response.

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.

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.

A Potential Partnership between Genetics and the Oral Microbiome in Children Displaying Periodic Fever/Aphthosis/Pharyngitis/Adenitis Syndrome.

Periodic fever/aphthosis/pharyngitis/adenitis (PFAPA) syndrome was initially described in a small cohort of American children [...].

The rs13075270 and rs13092160 polymorphisms of CCR1 and CCR3 genes on oral aphthous-like lesions in PFAPA syndrome.

Fever is a common symptom of infection in children. Periodic fever syndromes are less common but more complex. One of these Periodic fever syndromes is PFAPA (periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis) syndrome which is known as the most benign syndromes. The cause of this disease is unknown. Various factors, including environmental and genetic factors, are involved in the development of this disease. In this study, the association of rs13075270 and rs13092160 polymorphisms were investigated in CCR1 and CCR3 genes with susceptibility to this syndrome in the Chinese population. In this regard, 38 patients with PFAPA syndrome and 100 healthy individuals were selected. After DNA sampling and extraction, polymorphisms of CCR1 and CCR3 receptor genes were examined by the PCR-RFLP method. Findings were analyzed using SPSS software version 22 with a significant level of P <0.05. The frequency of T/T genotype rs13092160 polymorphism in the patient and control groups was 78.95% and 83%, respectively, C/T genotype was 21.05% and 17% (P = 0.421). The frequency of the C/C genotype was 0 in both groups. Regarding rs13075270 polymorphism, the frequency of T/T genotype in patient and control groups was 15.79% and 81%, C/T genotype was 78.95% and 18% and C/C genotype was 5.26% and 1%, respectively (P<0.05). Thus, in rs13075270 polymorphism, the C/T genotype was associated with the risk of PFAPA syndrome (P<0.05), but rs13092160 polymorphism did not show a significant difference between individuals with PFAPA syndrome and controls.

Making a diagnosis of periodic fever syndrome: Experience from a single tertiary centre.

AIM: This study aims to evaluate the utility of genetic testing of patients diagnosed with periodic fever syndromes and to assess the validity of existing scoring criteria. METHODS: This study retrospectively reviewed the clinical history of patients diagnosed with periodic fever syndromes at Queensland Children's Hospital between November 2014 and June 2018. RESULTS: Forty-three patients were diagnosed with periodic fever syndromes. Diagnoses in the cohort included periodic fever, adenitis, pharyngitis and aphthous stomatitis (10), tumour necrosis factor receptor-associated periodic syndrome (9), cryopyrin-associated periodic syndrome (6), mevalonate kinase deficiency (4) while 14 remained unspecified. No presenting symptoms were uniquely associated with any particular diagnosis. Genetic testing of between 1 and 26 genes was performed in 26 (60%) patients. Two (7.7%) patients had pathogenic variants identified. Variants of uncertain significance which were insufficient to confirm a monogenic disorder were identified in a further 7 (27%) patients. The Eurofever classification criteria correlated with clinical diagnosis for patients diagnosed with cryopyrin-associated periodic syndrome (P = 0.046) and tumour necrosis factor receptor-associated periodic syndrome (P = 0.025) but not for patients diagnosed with mevalonate kinase deficiency (P = 0.47); however, the Eurofever classification criteria were often positive for more than one diagnosis in these patients. CONCLUSION: The European classification criteria can form a potentially useful tool to guide diagnosis; however, clinical judgement remains essential, because the score is often positive for multiple diagnoses. The diagnostic yield of genetic testing in this cohort was low and genetic testing may be more useful to confirm a strong clinical suspicion than to clarify a diagnosis for patients with less clear symptoms.

The role of Mediterranean fever gene variants in patients with periodic fever, aphthous stomatitis, pharyngitis, and adenitis syndrome.

This study was conducted to investigate the relationship between clinic features and Mediterranean fever gene (MEFV) variants in patients with periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome. In total, 167 patients with PFAPA syndrome were included in the study. Female:male ratio of the patients was 0.75 (72 females, 95 males). In total 59.9% of patients with PFAPA had at least one MEFV variant and the most common heterozygous variants were M694V in 29.3% of the patients (40/167), E148Q in 8.3% (14/167), and V726A in 7.1% (12/167). The median age at the disease onset was significantly higher and the median duration of the episodes was significantly lower in patient with variants in exon 10 comparing to the others (both p = 0.01). Similarly, the median age at the disease onset was significantly higher (p = 0.01) and the median duration of the episodes was significantly lower (p = 0.04) in patient with MEFV variants than in the remaining patients. There were no significant differences according to the genotypes of the patients in terms of both treatment response and the frequency of clinical findings.Conclusion: In PFAPA syndrome, MEFV variants may be a modifier for disease onset and attack duration. What is Known: • Due to periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome having clinical findings resembling familial Mediterranean fever (FMF), it can be difficult to distinguish PFAPA syndrome and FMF especially in endemic regions for FMF. • Underlying MEFV mutations could affect the periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome's clinical presentation and response to treatment. What is New: • Having one of the underlying MEFV variants is related to later disease onset and shorter episode duration in patients with PFAPA syndrome.

Molecular and Phenotypic Characterization of Nine Patients with STAT1 GOF Mutations in China.

PURPOSE: Signal transducer and activator of transcription 1 (STAT1) is a transcription factor that mediates cellular responses to interferons (IFNs) and other cytokines and growth factors in diverse cell types. STAT1 gain-of-function (GOF) mutations result in an unexpectedly wide range of clinical features. It remains unclear why STAT1 GOF mutations result in such a broad spectrum of phenotypes. METHODS: We analyzed the clinical, molecular, and phenotypic characteristics of nine Chinese patients with STAT1 GOF mutations. RESULTS: This study enrolled nine patients with STAT1 GOF mutations including five novel mutations. We discuss the molecular and phenotypic characterization such as unique Penicillium marneffei lymphadenitis. Patients with STAT1 GOF mutations had defects in both innate and adaptive immunity, including impaired T cell receptor (TCR) diversity; reduced numbers of naïve and effector memory CD4+ T cells, memory B cells, and NK cells; and defects in the production of IL-17A and IFN-γ. In addition, experiments with primary immune cells revealed that enhanced STAT1 phosphorylation resulted from not only lower rates of STAT1 dephosphorylation but also increased total STAT1 expression. CONCLUSIONS: Our report provides the first comprehensive overview of the molecular genetics, clinical heterogeneity, and underlying immunological abnormalities of patients with STAT1 GOF mutations in China. In further study, to find the relationship between different STAT1 GOF mutations and clinical phenotype as well as the mechanism of increased total STAT1 expression will be needed.

Validation of the new classification criteria for hereditary recurrent fever in an independent cohort: experience from the JIR Cohort Database.

OBJECTIVE: The new classification criteria for the hereditary recurrent fever (HRF) syndrome [cryopyrin-associated periodic syndrome (CAPS), TNF-α receptor-associated periodic syndrome (TRAPS), FMF and mevalonate kinase deficiency] have been published recently. These criteria define two core sets of criteria for each HRF: mixed criteria, including genetic and clinical variables, and clinical criteria, relying on clinical variables only. Our aim was to validate the criteria for HRF in an independent cohort, the JIR Cohort database, an international repository of systemic inflammatory diseases. METHODS: We enrolled patients with HRF, periodic fever, adenitis, pharyngitis and aphthous stomatitis syndrome (PFAPA) and syndrome of undefined recurrent fever (SURF). A score ranging from zero to two was attributed to their respective genotypes: zero (no mutation), one (non-confirmatory genotype) or two (confirmatory genotype). The criteria were applied to all patients based on genotype scoring. The treating physician's diagnosis served as the gold standard for the determination of specificity. RESULTS: We included 455 patients. The classification criteria showed excellent specificity for CAPS and TRAPS (98% specificity each), fair specificity for FMF (88%), but poor specificity for mevalonate kinase deficiency (58%). Sub-analysis showed excellent accuracy of the mixed criteria for all four HRFs. Misclassification was mainly attributable to clinical criteria sets, with false-positive patients in all four HRF clinical criteria sets. CONCLUSION: This study represents the final validation step of the HRF classification criteria as recommended by the ACR. Genetic data appear to be necessary to classify patients with HRF correctly.

Haploinsufficiency of A20 and other paediatric inflammatory disorders with mucosal involvement.

PURPOSE OF REVIEW: This review aims at summarizing the current knowledge of A20 haploinsufficiency and other paediatric inflammatory disorders with mucosal involvement. RECENT FINDINGS: A20 haploinsufficiency is a newly described autoinflammatory disease caused by loss-of-function mutations in TNFAIP3 that result in the activation of the nuclear factor (NF)-kB pathway. Patients may present with dominantly inherited, early-onset systemic inflammation and a Behçet-like disease, or a variety of autoinflammatory and autoimmune features. In Behçet disease, recent literature provides insights into genetic susceptibility and emerging treatment options; in addition, the first paediatric classification criteria were published. Recent advances in periodic fever, aphthous stomatitis, pharyngitis and adenitis syndrome (PFAPA) suggest that the disease has a complex underlying genetic mechanism and in some cases is inherited in an autosomal dominant pattern with reduced penetrance phenotype in many family members. Activation of the pyrin inflammasome through the RoA signalling pathway uncovers an interesting molecular connection between hyperimmunoglobulinemia D syndrome and familial Mediterranean fever. The description of new monogenic types of inflammatory bowel disease (IBD) may provide novel insights into disease pathogenesis. Finally, recent studies highlighted the role of gut microorganisms and dysbiosis in IBD. SUMMARY: Monogenic diseases such as A20 haploinsufficiency may help to advance our understanding of disease pathogenesis and to develop targeted therapies for more common, multifactorial disorders with mucosal inflammation.

Unraveling the pathogenesis of periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis through genetic, immunologic, and microbiologic discoveries: an update.

PURPOSE OF REVIEW: Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is considered the most common periodic fever syndrome of childhood. Although it was first described three decades ago, the pathogenesis has been poorly understood. Recent studies on the heritability and immunology of the disorder have begun to shed light into the mechanisms of this autoinflammatory disorder. This review will focus on the pathogenesis of PFAPA, especially as it pertains to the genetic susceptibility, tonsillar immunology, and the role of the microbiome. RECENT FINDINGS: Recent literature provides insights into the heritability, potential genetic modifiers, and the immunologic and microbiological profile of the tonsils in this syndrome. SUMMARY: Evidence is mounting that PFAPA is inherited as a complex genetic disease. Furthermore, tonsillectomy is curative in the majority of patients, including those who do not meet the complete clinical criteria for PFAPA. The tonsils in PFAPA patients may exhibit unique immunologic and microbiological features. The goal of this review is to outline these new developments.

Is colchicine more effective to prevent periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis episodes in Mediterranean fever gene variants?

BACKGROUND: Periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome is the most frequent repetitive fever syndrome in childhood. It is characterized by fever episodes lasting for approximately 3-6 days, once every 3-8 weeks. METHODS: Clinical and laboratory data for PFAPA syndrome patients between January 2010 and December 2014 followed up at a tertiary pediatric care hospital were reviewed. RESULTS: Four hundred children (256 male, 144 female; mean age at diagnosis, 4.2 ± 2.2 years), were enrolled in the study. During the episodes, mean leukocyte number was high (12 725/mm3 ) with predominant neutrophils. The mean number of monocytes was 1256/mm3 , and 90.2% had monocytosis. Serum amyloid A and C-reactive protein were high in 84.6% and in 77.8% of the patients, respectively. Mediterranean fever (MEFV) gene heterozygous mutation was identified in 57 of the 231 patients (24.7%) in whom genetic analysis had been performed. The most frequent mutation was heterozygous M694V (10%, n = 23). Extension of between-episode interval following prophylaxis was noted in 85% of those on regular colchicine treatment (n = 303). In the colchicine group, between-episode interval was prolonged from 18.8 ± 7.9 days (before colchicine treatment) to 49.5 ± 17.6 days on prophylactic colchicine therapy; also, prophylactic treatment was more effective in reducing episode frequency in patients with MEFV gene variant (n = 54, 96%) than in those without (n = 122, 80%; P = 0.003). CONCLUSIONS: This study has involved the largest number of PFAPA syndrome patients in the literature. It is particularly important to assess and to demonstrate the high rate of response to colchicine prophylaxis in PFAPA syndrome patients, especially those with MEFV variant. On blood screening, neutrophilia associated with monocytosis and low procalcitonin could contribute to diagnosis.

De novo PIK3R1 gain-of-function with recurrent sinopulmonary infections, long-lasting chronic CMV-lymphadenitis and microcephaly.

PIK3R1 (phosphoinositide-3-kinase, regulatory subunit 1) gain-of-function has recently been described in patients with recurrent sinopulmonary infections, chronic CMV-/EBV-infections, lymphoproliferation, and hypogammaglobulinemia. Here we report a 15-year-old boy with treatment refractory CMV lymphadenitis, severe combined immunodeficiency, microcephaly and a severe developmental defect of Th17 cells. To avoid poor outcome, hematopoietic stem cell transplantation (HSCT) was performed. Subsequently, whole exome sequencing revealed a de novo heterozygous G-to-C mutation (chr5: 5:67,589,663: G>C) at the splice donor site of the PIK3R1 gene. Our data suggest that PIK3R1 gain-of-function leads to developmental defects in helper and regulatory T-cell subsets, the latter expanding the immunological features of PIK3R1 gain-of-function. T-cell subsets play a critical role in the regulation of immune response against infectious agents and of autoimmunity and thus may be particularly accountable for the clinical phenotype of affected patients.

Could familial Mediterranean fever gene mutations be related to PFAPA syndrome?

BACKGROUND: The cause and pathophysiology of PFAPA syndrome is unknown. The aim of this study was to determine all MEFV gene variants relevant to familial Mediterranean fever in children with PFAPA syndrome. METHODS: All MEFV gene variants were analyzed in patients with PFAPA syndrome. All patients were evaluated using the Gaslini scoring system. Serum immunoglobulin levels were also determined upon admission. RESULTS: We evaluated 64 patients with PFAPA syndrome. The median age at diagnosis was 37.5 (min-max: 6-96) months, and the percentage of male patients was 55.0%. The Gaslini diagnostic score for periodic fever was high in 81.0% of the patients. An MEFV gene mutation was found in 42 (66.0%) children. Mostly, heterozygous or compound heterozygous variants of the MEFV gene were found. Two patients were homozygous for R202Q. MEFV gene mutations were not detected in 22 (34.0%) patients. No significant differences in clinical or laboratory findings were observed between the two groups (p > 0.05), and there were no significant differences in period and duration of the fever episodes (p > 0.05). The fever of all 47 patients (100.0%) who received prednisolone during the episodes decreased within hours and did not recur. Eighteen of the patients using prednisolone underwent prophylaxis with colchicine, and the fever episodes of 9/18 (50.0%) patients using colchicine decreased within months. CONCLUSIONS: Most patients presenting with PFAPA syndrome have heterozygous MEFV gene mutations. Whether carrying a heterozygous MEFV gene is the primary cause of this syndrome requires further investigation.

The first case of adult-onset PFAPA syndrome in Japan.

A 26-year-old woman presented with fever and pharyngitis. She previously experienced four periodic febrile episodes at 30- to 40-day intervals. We suspected periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome, and prescribed predisolone, thereby her fever rapidly subsided. Her febrile episodes improved after daily cimetidine treatment. Genetic testing results of genomic DNA for periodic fever syndromes were negative, although she was heterozygous for p.Glu148Gln variation in MEFV, supporting the diagnosis of PFAPA syndrome.

Clinical features and genetic background of the periodic Fever syndrome with aphthous stomatitis, pharyngitis, and adenitis: a single center longitudinal study of 81 patients.

PFAPA syndrome is the most common autoinflammatory disorder in childhood with unknown etiology. The aim of our study was clinical evaluation of PFAPA patients from a single tertiary care center and to determine whether variations of AIM2, MEFV, NLRP3, and MVK genes are involved in PFAPA pathogenesis. Clinical and laboratory data of consecutive patients with PFAPA syndrome followed up at the University Children's Hospital, Ljubljana, were collected from 2008 to 2014. All four genes were PCR amplified and directly sequenced. Eighty-one patients fulfilled criteria for PFAPA syndrome, 50 (63%) boys and 31 (37%) girls, with mean age at disease onset of 2.1 ± 1.5 years. Adenitis, pharyngitis, and aphthae were present in 94%, 98%, and 56%, respectively. Family history of recurrent fevers in childhood was positive in 78%. Nineteen variants were found in 17/62 (27%) patients, 4 different variants in NLRP3 gene in 13 patients, and 6 different variants in MEFV gene in 5 patients, and 2 patients had 2 different variants. No variants of clinical significance were found in MVK and AIM2 genes. Our data suggest that PFAPA could be the result of multiple low-penetrant variants in different genes in combination with epigenetic and environmental factors leading to uniform clinical picture.

The Pathogenesis of Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis Syndrome: A Review of Current Research.

BACKGROUND: PFAPA syndrome is a chronic disease that is characterized by recurrent episodes of high fever, aphthous stomatitis, pharyngitis, and cervical adenitis. Knowledge regarding the etiology of PFAPA is limited. OBJECTIVES: To provide up-to-date information considering etiology of PFAPA syndrome, by summarizing what has been explored and established in this area so far. MATERIALS AND METHODS: PubMed, Web of Science, and Scopus databases were searched for pertinent reports. Eventually 19 articles were selected. The results were classified into categories regarding three areas of interest: familial occurrence, genetic basis, and immunological mechanisms of PFAPA. RESULTS: Recent findings suggest that there is a familial tendency to PFAPA but the level of evidence does not warrant definite conclusions. The absence of a clear monogenic trait indicates a heterogenous, polygenic, or complex inheritance of PFAPA syndrome. As two mutations with a possible functional effect on the inflammasomes (MEFV E148Q and NLRP3 Q703K) have been found in several PFAPA cohorts, the role of inflammasome-related genes in PFAPA pathogenesis cannot be excluded. Immunological mechanisms of PFAPA involve an abnormal, IL-1ß dependent innate immune response to an environmental trigger, which leads to Th1-driven inflammation expressed by recruitment of T-cells to the periphery.

Clinical and genetic characterization of Japanese sporadic cases of periodic Fever, aphthous stomatitis, pharyngitis and adenitis syndrome from a single medical center in Japan.

PURPOSE: To investigate clinical presentation, genetic background and cytokine profile of Japanese sporadic cases of periodic fever, aphthous stomatitis, pharyngitis and adenitis (PFAPA) syndrome. METHODS: Nine PFAPA syndrome patients were recruited. DNA sequence analysis of auto inflammatory disorder susceptibility genes, MEFV, MVK, NLRP3, and TNFRSF1A, were performed. Serum cytokine levels and monocyte IL-1ß levels were measured by ELISA. RESULTS: The study population consisted of six males and three females (mean age of onset 26.8 months). Febrile episodes lasted 3-6 days with symptom-free intervals ranging from 2 to 12 weeks. Fever was accompanied by pharyngitis (n = 8), aphthous stomatitis (n = 4), and cervical adenitis (n = 5). White blood cells and C-reactive protein were increased during the attack phase. Mean IgD serum levels were 7.32 ± 9.51 mg/dl during the attack phase, and were mildly elevated in two patients. Heterozygous MEFV, NLRP3 and TNFRSF1A variants were detected in four, one and three cases, respectively. Serum TNF-α and IL-18 levels were elevated during the attack-free and attack periods compared with controls. Other cytokines, IL-1ß, IL-1ra, IL-6, and sTNFR1, were only increased during the attack phase. Oral prednisolone was administered to eight patients and immediately reduced fever. Tonsillectomy performed in five patients induced cessation of fever in four patients. One case with repeated fever attacks after tonsillectomy showed increased monocyte IL-1ß production, similar to the other active case with genetic variants of auto inflammatory disorder-associated genes. CONCLUSIONS: Japanese PFAPA syndrome patients may have cytokine regulation dysfunction as a result of genetic variants of auto inflammatory disorder-associated genes.

Periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis syndrome is linked to dysregulated monocyte IL-1ß production.

BACKGROUND: The exact pathogenesis of the pediatric disorder periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis (PFAPA) syndrome is unknown. OBJECTIVES: We hypothesized that PFAPA might be due to dysregulated monocyte IL-1ß production linked to genetic variants in proinflammatory genes. METHODS: Fifteen patients with PFAPA syndrome were studied during and outside a febrile episode. Hematologic profile, inflammatory markers, and cytokine levels were measured in the blood. The capacity of LPS-stimulated PBMCs and monocytes to secrete IL-1ß was assessed by using ELISA, and active IL-1ß secretion was visualized by means of Western blotting. Real-time quantitative PCR was performed to assess cytokine gene expression. DNA was screened for variants of the MEFV, TNFRSF1A, MVK, and NLRP3 genes in a total of 57 patients with PFAPA syndrome. RESULTS: During a febrile attack, patients with PFAPA syndrome revealed significantly increased neutrophil counts, erythrocyte sedimentation rates, and C-reactive protein, serum amyloid A, myeloid-related protein 8/14, and S100A12 levels compared with those seen outside attacks. Stimulated PBMCs secreted significantly more IL-1ß during an attack (during a febrile episode, 575 ± 88 pg/mL; outside a febrile episode, 235 ± 56 pg/mL; P < .001), and this was in the mature active p17 form. IL-1ß secretion was inhibited by ZYVAD, a caspase inhibitor. Similar results were found for stimulated monocytes (during a febrile episode, 743 ± 183 pg/mL; outside a febrile episode, 227 ± 92 pg/mL; P < .05). Genotyping identified variants in 15 of 57 patients, with 12 NLRP3 variants, 1 TNFRSF1A variant, 4 MEFV variants, and 1 MVK variant. CONCLUSION: Our data strongly suggest that IL-1ß monocyte production is dysregulated in patients with PFAPA syndrome. Approximately 20% of them were found to have NLRP3 variants, suggesting that inflammasome-related genes might be involved in this autoinflammatory syndrome.