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.

Covid-19 and oral diseases: Crosstalk, synergy or association?

The coronavirus disease 2019 (Covid-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that clinically affects multiple organs of the human body. Cells in the oral cavity express viral entry receptor angiotensin-converting enzyme 2 that allows viral replication and may cause tissue inflammation and destruction. Recent studies have reported that Covid-19 patients present oral manifestations with multiple clinical aspects. In this review, we aim to summarise main signs and symptoms of Covid-19 in the oral cavity, its possible association with oral diseases, and the plausible underlying mechanisms of hyperinflammation reflecting crosstalk between Covid-19 and oral diseases. Ulcers, blisters, necrotising gingivitis, opportunistic coinfections, salivary gland alterations, white and erythematous plaques and gustatory dysfunction were the most reported clinical oral manifestations in patients with Covid-19. In general, the lesions appear concomitant with the loss of smell and taste. Multiple reports show evidences of necrotic/ulcerative gingiva, oral blisters and hypergrowth of opportunistic oral pathogens. SARS-CoV-2 exhibits tropism for endothelial cells and Covid-19-mediated endotheliitis can not only promote inflammation in oral tissues but can also facilitate virus spread. In addition, elevated levels of proinflammatory mediators in patients with Covid-19 and oral infectious disease can impair tissue homeostasis and cause delayed disease resolution. This suggests potential crosstalk of immune-mediated pathways underlying pathogenesis. Interestingly, few reports suggest recurrent herpetic lesions and higher bacterial growth in Covid-19 subjects, indicating SARS-CoV-2 and oral virus/bacteria interaction. Larger cohort studies comparing SARS-CoV-2 negative and positive subjects will reveal oral manifestation of the virus on oral health and its role in exacerbating oral infection.

Immune Dysregulation in the Tonsillar Microenvironment of Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis (PFAPA) Syndrome.

Periodic Fever, Aphthous stomatitis, Pharyngitis and Adenitis (PFAPA) syndrome is an inflammatory disorder of childhood classically characterized by recurrent fevers, pharyngitis, stomatitis, cervical adenitis, and leukocytosis. While the mechanism is unclear, previous studies have shown that tonsillectomy can be a therapeutic option with improvement in quality of life in many patients with PFAPA, but the mechanisms behind surgical success remain unknown. In addition, long-term clinical follow-up is lacking. In our tertiary care center cohort, 62 patients with PFAPA syndrome had complete resolution of symptoms after surgery (95.3%). Flow cytometric evaluation demonstrates an inflammatory cell population, distinct from patients with infectious pharyngitis, with increased numbers of CD8+ T cells (5.9% vs. 3.8%, p < 0.01), CD19+ B cells (51% vs. 35%, p < 0.05), and CD19+CD20+CD27+CD38-memory B cells (14% vs. 7.7%, p < 0.01). Cells are primed at baseline with increased percentage of IL-1ß positive cells compared to control tonsil-derived cells, which require exogenous LPS stimulation. Gene expression analysis demonstrates a fivefold upregulation in IL1RN and TNF expression in whole tonsil compared to control tonsils, with persistent activation of the NF-κB signaling pathway, and differential microbial signatures, even in the afebrile period. Our data indicates that PFAPA patient tonsils have localized, persistent inflammation, in the absence of clinical symptoms, which may explain the success of tonsillectomy as an effective surgical treatment option. The differential expression of several genes and microbial signatures suggests the potential for a diagnostic biomarker for PFAPA syndrome.

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome: main features and an algorithm for clinical practice.

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is a recurrent fever syndrome of early childhood with increasing number of adult-onset cases. Although it is a self-limited disease, it may negatively affect the quality of life. The aim of this review is to present a detailed analysis of PFAPA syndrome and an algorithm for diagnosis, therapeutic options, and evaluation of outcome. A comprehensive literature search was conducted through the Cochrane Library, Scopus, and MEDLINE/PubMed databases. The main topics covered are the epidemiology, clinical manifestations, diagnosis, differential diagnosis, etiopathogenesis, genetics, management, disease course and prognosis, disease in adults, unsolved issues, and unmet needs in PFAPA. The diagnosis of PFAPA is mainly based on clinical classification criteria. The most relevant hypothesis for pathogenesis is that dysregulated immune system in a genetically predisposed individual responds to a yet unidentified trigger in an exaggerated way. The pedigree analyses suggest a genetic background for the disease with an autosomal dominant pattern of inheritance. For management, single-dose corticosteroids during attacks and tonsillectomy remain the most effective therapies, while colchicine is a promising option to decrease attack frequency. There remain unsolved issues in PFAPA such as the exact etiopathogenesis and genetic background, the reason why the inflammation is restricted to the oropharyngeal lymphoid tissue, reasons for clock-work regularity of attacks, and self-limited disease course. There is need for a valid diagnostic criteria set with a high performance for both children and adults and consensus on management of PFAPA.

Interleukin-4 and Interleukin-4 Receptor Alpha Gene Polymorphisms in Recurrent Aphthous Stomatitis.

BACKGROUND: Recurrent aphthous stomatitis (RAS) is a common oral condition with a major impact on the quality of life. The condition is thought to be due to the overexpression of T helper-1(Th1)-related cytokines. Since interleukin-4 (IL-4) and its receptor (IL-4Rα) are antagonistic to Th-1 pathways, polymorphisms in their genes may also be involved in the pathogenesis of aphthous stomatitis. METHODS: Sixty-four patients diagnosed with minor RAS and 141 (age- and sex-matched) healthy controls were assessed for 3 single-nucleotide polymorphisms (SNPs) within the promoter region of the IL-4 gene (-1098G/T, -590C/T, and -33C/T), and 1 SNP in IL-4Rα gene (+1902 A/G). RESULTS: No significant differences were detected between the patient and the control group regarding IL-4 allele frequencies. However, the patient group demonstrated a higher frequency of IL-4 -590 CC genotype and a lower rate of IL-4 -590 TC genotype. The TCT, GTT, GCT, and GTC haplotypes of the IL-4 gene (-1098, -590, -33) were significantly more frequent in the patients and the GCC, and TTT haplotypes were more common in healthy controls. No significant differences were found in IL-4Rα gene polymorphism between the 2 groups. CONCLUSIONS: Certain polymorphisms of IL4 gene could predispose individuals to RAS.

Recurrent aphthous stomatitis and gene variability in selected interleukins: a case-control study.

Genetic factors, especially those related to immune system functioning, have been intensively studied to determine their role in the development of recurrent aphthous stomatitis (RAS). The aim of the present study was to analyze gene variability in interleukin (IL)2, IL4 (and its receptor α, IL4Rα), IL10, and IL13, which were selected based on literature review and/or their functional relevance, in Czech patients with RAS and in healthy controls. In total, 252 subjects (178 controls and 74 patients with RAS) were enrolled in this case-control study, and their detailed anamnestic, clinical, and laboratory data were obtained. Nine polymorphisms in the genes encoding interleukins were determined using PCR techniques. There were no significant differences in allele or genotype frequencies of the IL2, IL4, IL4Rα, IL10, and IL13 polymorphisms rs2069762/rs2069763, rs2243250/rs79071878, rs1801275, rs1800896, and rs1800925, respectively, between controls and patients with RAS. The minority alleles rs1800871 and rs1800872, which encode variants of IL10, were associated with a statistically significantly higher risk of RAS, as confirmed by the results of genotype and haplotype analyses. We suggest that variability in the IL10 gene may play an important role in the development of RAS in the Czech population.

Establishment of Role of IL-2, IL-10 and IL-12 in Patients with Recurrent Aphthous Stomatitis-A Clinical Study.

BACKGROUND: Recurrent aphthous stomatitis is a vesiculobul-lous disease characterized by painful ulcers in the oral cavity. The role of interleukins such as IL-2, IL-10 and IL-12 in initiating disease demands careful assessment. The present study was conducted to determine the level of IL-2, IL-10 and IL-12 in patients with recurrent aphthous stomatitis. MATERIALS AND METHODS: The present study was conducted on 40 patients diagnosed with recurrent aphthous stomatitis. An equal number of age and gender-matched subjects (40) was included as a control. They were divided into 2 age groups from 20 to 40 years and 40 to 60 years. All were made to sit comfortably on a dental chair, and 1 ml of unstimulated saliva was collected in a sterile tube to assess the level of IL-2, IL-10 and IL-12 using ELISA. The level of IL-2, IL-10 and IL-12 was measured in pg/mL. RESULTS: Each group had 10 males and 10 females. The difference was non-significant (P-1). Age group 20-40 years comprised of 14 patients in group I (eight males and six females) and 12 in group II (five males and seven females). Age group 40-60 years had six patients in group I (two males and four females) and 8 patients in group II (five males and three females). The difference was significant (p < 0.05). The most common form was minor (82%) followed by herpetiform (13%) and major (5%). In group I, the mean value of IL-2 level was 32.24 pg/mL, IL-10 was 1.24 ± 0.6 and IL-12 was 28.34 ± 4.04 and in group II, mean value of IL-2 level was 12.10 pg/mL, IL-10 was 2.56 ± 1.12 and IL-12 was 23.16 ± 4.16. The difference was significant (p < 0.05). CONCLUSION: Age group 20 to 40 years showed higher prevalence. The level of IL-2 and IL-12 is highly increased while IL-10 is decreased in patients. CLINICAL SIGNIFICANCE: Role of interleukins as a precipitating factor along with stress is well established. With the thorough knowledge of the disease process, the newer treatment modality specific against interleukins may be proven useful in controlling the disease.

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.

Immune response of patients with recurrent aphthous stomatitis challenged with a symbiotic.

BACKGROUND: There are indications that Th1 polarization of immune response plays an important role in the pathogenesis of recurrent aphthous stomatitis (RAS), and that the use of probiotics can stimulate immune regulatory activity, influencing the course of the disease. The aim of this study was to characterize the initial immune profile of RAS patients and evaluate clinical and serological response following a challenge with symbiotic treatment containing fructooligosaccharide, Lactobacillus, and Bifidobacterium. METHODS: The immune responses of the 45 patients with RAS, submitted to symbiotic or placebo for 120 days, in relation to 30 RAS-free controls, were evaluated over a period of 6 months. Peripheral blood was collected from all patients at 0 (T0), 120 (T4), and 180 days (T6) after the start of treatment and Th1 (IL12-p70, IFN-γ), Th2 (IL-4), Treg (IL-10), Th17 (IL-17A), inflammatory (TNF-α, IL-6)-associated cytokines, and clinical parameters were quantified. RESULTS: At T0, significant differences were found in the serological levels of the IFN-γ, IL-4, and IL-6 cytokines of the RAS patients in comparison with the controls. It was observed that the cytokine profile of the RAS group was comprised of 2 distinct clusters: a pure Th2 and a Mixed (Th1/Th2) subtype and that symbiotic treatment induced an improvement in pain and an increase in IFN-γ levels, producing a reduction in Th2 response. CONCLUSIONS: In RAS, symbiotic treatment based on a fructooligosaccharide, Lactobacillus, and Bifidobacterium composition produced an alteration in the Th2 serological immune profile in the direction of Th1 and improved pain symptomatology.

Oral manifestations of inflammatory bowel disease.

Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, have important extraintestinal manifestations, notably in the oral cavity. These oral manifestations can constitute important clinical clues in the diagnosis and management of IBD, and include changes at the immune and bacterial levels. Aphthous ulcers, pyostomatitis vegetans, cobblestoning and gingivitis are important oral findings frequently observed in IBD patients. Their presentations vary considerably and might be well diagnosed and distinguished from other oral lesions. Infections, drug side effects, deficiencies in some nutrients and many other diseases involved with oral manifestations should also be taken into account. This article discusses the most recent findings on the oral manifestations of IBD with a focus on bacterial modulations and immune changes. It also includes an overview on options for management of the oral lesions of IBD.

Anemia and hematinic deficiencies in anti-gastric parietal cell antibody-positive and -negative recurrent aphthous stomatitis patients with anti-thyroid antibody positivity.

BACKGROUND/PURPOSE: Serum anti-gastric parietal cell (GPCA), anti-thyroglobulin (TGA), and anti-thyroid microsomal antibodies (TMA) can be found in some recurrent aphthous stomatitis (RAS) patients. This study mainly assessed whether serum GPCA, TGA, TMA and RAS itself played significant roles in causing anemia and hematinic deficiencies in TGA/TMA-positive RAS patients with GPCA positivity (GPCA+/TGA/TMA/RAS patients) or negativity (GPCA-/TGA/TMA/RAS patients). METHODS: The mean corpuscular volume (MCV) and mean blood hemoglobin (Hb), iron, vitamin B12, and folic acid levels were measured and compared between any two of the four groups of 15 GPCA+/TGA/TMA/RAS patients, 69 GPCA-/TGA/TMA/RAS patients, 240 all autoantibodies-negative RAS patients (Abs-/RAS patients), and 342 healthy control subjects. RESULTS: GPCA+/TGA/TMA/RAS patients had significantly lower mean Hb (for men only) and vitamin B12 levels as well as significantly greater frequencies of Hb, iron, and vitamin B12 deficiencies than healthy control subjects. GPCA+/TGA/TMA/RAS patients had lower serum vitamin B12 level and higher MCV as well as a significantly greater frequency of vitamin B12 deficiency than GPCA-/TGA/TMA/RAS patients. Furthermore, both GPCA-/TGA/TMA/RAS and Abs-/RAS patients did have significantly lower mean Hb, MCV, and iron levels as well as significantly greater frequencies of Hb, iron and vitamin B12 deficiencies than healthy control subjects. There were no significant differences in blood data between GPCA-/TGA/TMA/RAS and Abs-/RAS patients CONCLUSION: Both serum GPCA positivity and RAS itself are the contributing factors causing anemia and hematinic deficiencies in GPCA+/TGA/TMA/RAS patients. RAS itself but not TGA/TMA positivity plays a significant role in causing anemia and hematinic deficiencies in GPCA-/TGA/TMA/RAS patients.

Reduced Number of CD8+ Cells in Tonsillar Germinal Centres in Children with the Periodic Fever, Aphthous Stomatitis, Pharyngitis and Cervical Adenitis Syndrome.

The syndrome of periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) is an autoinflammatory disorder of unknown aetiology. Tonsillectomy may cause a prompt resolution of the syndrome. The aim was to study the histologic and immunological aspects of the palatine tonsils in PFAPA, to help understand the pathophysiology of the syndrome. Tonsils from children with PFAPA (n = 11) and children with tonsillar hypertrophy (n = 16) were evaluated histologically after haematoxylin and eosin staining. The number of different cell types was identified immunohistochemically by cluster of differentiation (CD) markers: CD3 (T cells), CD4 (T helper cells), CD8 (cytotoxic T cells), CD15 (neutrophils), CD20 (B cells), CD45 (all leucocytes), CD57 (NK cells) and CD163 (monocytes and macrophages). Tonsils from children with PFAPA showed reactive lymphoid hyperplasia dominated by well-developed germinal centres with many tingible body macrophages. The histologic findings were unspecific, and a similar morphologic appearance was also found in the tonsils from controls. The number of CD8+ cells in germinal centres differed between children with PFAPA [median 9 cells (quartiles: 5, 15)] and controls [18 cells (12, 33) (P = 0.001)] and between children with PFAPA with (median 14 cells; 9, 16) and without (4 cells; 3, 8) aphthous stomatitis (P = 0.015). For the other cell types, no differences in germinal centres were found between children with PFAPA and controls. In conclusion, a lower number of CD8+ cells were found in germinal centres of tonsils in children with PFAPA compared to controls, which may be a feature linked to the aetiology of the syndrome.

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.

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-) 1ß secretion during flares, the overexpression of inflammasome-associated genes during attacks, and, last but not least, the therapeutic efficacy of IL-1ß 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.

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.

Differential expression of suppressor of cytokine signalling proteins in Behçet's disease.

Behçet's disease (BD) is a chronic, multisystemic, recurrent vasculitis disease of unknown aetiology. Proinflammatory cytokines are a key feature of the disease, but the triggers for their induction are not well understood and/or controversial. Suppressor of cytokine signalling (SOCS) proteins which negatively regulate the JAK-STAT signalling pathway of cytokine induction may be dysregulated in BD. The expression of SOCS1 and 3 mRNA and protein was studied in peripheral blood mononuclear cells (PBMCs) and neutrophils of patients with BD and compared with healthy controls (HCs) and patients with recurrent aphthous stomatitis (RAS) using RT-PCR, Western blot and immunohistochemistry. SOCS1 and 3 mRNA was also measured in buccal mucosal cells (BMC) of patients with BD and HCs. SOCS1 and 3 mRNA was significantly upregulated in PBMCs of patients with BD compared with HCs (P = 0.0149; P = 0.0007). In addition, there were subtle differences between expression in active and symptom-free BD (quiescent BD). SOCS1 and SOCS 3 were also significantly upregulated in BMC from oral ulcers of BD compared with HCs (both at P = 0.0001). A differential expression of both SOCS1 and 3 was observed between PBMCs and neutrophils in patients with BD. Immunohistochemical analysis revealed differential expression of SOCS proteins in the buccal mucosa with an increased expression at the ulcer surface of ulcers than in the non-ulcerated tissue. These observations suggest a dysregulation of the expression of these important regulators not only between patients with BD and healthy controls but also between mucosal and systemic tissues, which may reflect the nature of the aetiopathology of the disease.

Increased intracellular oxygen radical production in neutrophils during febrile episodes of periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome.

OBJECTIVE: Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is an autoinflammatory disease of unknown etiology that primarily affects preschool-aged children. PFAPA syndrome is characterized by recurrent attacks of fever and symptoms of inflammation consistent with the disease acronym. Since autoinflammatory diseases are, by definition, mediated by cells of the innate immune system, the aim of this study was to evaluate the functional features of neutrophils, the most abundant innate immune cell in the circulation, in children with PFAPA syndrome. METHODS: Blood polymorphonuclear leukocytes (PMNs), obtained from patients with PFAPA syndrome during both febrile and asymptomatic, afebrile phases of the disease, as well as from healthy children (afebrile controls) and children with fever and abdominal pain (febrile controls), were analyzed for 3 key neutrophil characteristics: 1) apoptosis (measured by annexin V/7-aminoactinomycin D staining), 2) production of reactive oxygen species (ROS) (measured by luminol/isoluminol-amplified chemiluminescence), and 3) priming status (measured as responsiveness to galectin-3 and up-regulation of CD11b). RESULTS: Compared to PMNs obtained from patients with PFAPA syndrome during an afebrile interval and those from febrile controls, PMNs obtained from patients during a PFAPA syndrome flare produced elevated levels of intracellular NADPH oxidase-derived ROS, had significantly diminished rates of spontaneous apoptosis, and displayed signatures of priming. In contrast, PMNs from afebrile patients with PFAPA syndrome had a significantly elevated rate of spontaneous apoptosis compared to PMNs from afebrile controls. CONCLUSION: These findings demonstrate that 3 key aspects of neutrophil innate immune function, namely, apoptosis, priming, and generation of an intracellular oxidative burst, are altered, most prominently during febrile attacks, in children with PFAPA syndrome.

Serum Th1, Th2 and Th17 cytokine profiles and alpha-enolase levels in recurrent aphthous stomatitis.

BACKGROUND: All aspects of aetiopathogenesis of recurrent aphthous stomatitis (RAS) have not been elucidated. RAS and Behçet's disease (BD) have clinical and immunological characteristics in common. Although T17 cytokines and alpha-enolase have been shown to play effective roles in BD and many other autoinflammatory diseases recently, their roles in RAS have not been studied extensively. In the present study, we investigated levels of several Th1, Th2 and Th17 pathways related cytokines and alpha-enolase to elucidate pathogenesis of RAS and to obtain data about possible treatment alternatives for the condition. METHODS: Serum interleukin-1, interleukin-13, interleukin-17, interleukin-18, interferon gamma and alpha-enolase levels in 24 patients with RAS, 30 patients with BD and 20 healthy controls were measured. RESULTS: Serum interleukin-1, interleukin-13, interleukin-17, interleukin-18, interferon gamma and alpha-enolase levels were higher in patients with RAS and patients with BD than in healthy controls (P < 0.005). CONCLUSION: Like Th1 and Th2 cells, Th17 cells were found to be effective in pathogenesis of RAS. In addition, alpha-enolase, the levels of which were high, may play an important role in etio-pathogenesis of RAS. Further studies to be designed in the light of these findings are required to shed light on pathogenesis and treatment of the condition.

IL-17C and its receptor IL-17RA/IL-17RE identify human oral epithelial cell as an inflammatory cell in recurrent aphthous ulcer.

BACKGROUND: Recurrent aphthous ulcer (RAU) is an ulcerative disease of non-keratinized oral mucosa. Colon and bronchial epithelial cells produce interleukin-17C (IL-17C) upon stimulation of Toll-like receptor 2 (TLR2), TLR3 and TLR5, which are highly expressed in epithelial cells in RAU lesions. We therefore investigated the eventual presence and function of IL-17C in cultured human oral keratinocytes (HOK) and control biopsies compared to RAU lesions. METHODS: Expression of IL-17A, IL-17C, IL-17RA and IL-17RE was analysed in cultured HOK cells using quantitative real-time polymerase chain reaction (qRT-PCR). HOK cells were stimulated with IL-17C and analysed for IL-8 and tumour necrosis factor-α (TNF-α) using qRT-PCR. Control mucosa (n = 5) was immunostained for IL-17A, IL-17C, IL-8, TNF-α and mast cell tryptase and compared with RAU lesions (n = 5) using the mean grey scale value. RESULTS: IL-17C, but no IL-17A, mRNA was found in cultured HOK cells. Components of the heterodimeric IL-17RA/IL-17RE receptor for IL-17C were also highly expressed. Stimulation of HOK with IL-17C increased TNF-α mRNA (P = 0.03; IL-8 increase was not statistically significant). HOK in RAU lesions stained intensively for IL-17C compared to controls (P = 0.006). This was associated with increased epithelial immunostaining of TNF-α (P = 0.04) and IL-8 (P = 0.02). Most of the inflammatory cells which stained for IL-17A in control mucosa and RAU lesions were also mast cell tryptase positive. CONCLUSION: IL-17C is highly expressed in epithelial cells in RAU lesions, where it seems to stimulate oral keratinocytes via IL-17RA/IL-17RE to produce pro-inflammatory cytokines. Human oral epithelial cells are probably important inflammatory cells in RAU.

IL-18 gene polymorphisms in aphthous stomatitis vs. Behçet's disease in a cohort of Egyptian patients.

OBJECTIVE: A clinical investigation of the potential correlation of two single-nucleotide polymorphisms at -137 (G/C) and -607 (C/A) in the promoter region of the IL-18 gene, with the susceptibility to aphthous stomatitis and Behçet's disease. PATIENT AND METHODS: This study included 80 aphthous stomatitis patients and 80 patients with Behçet's disease. Eighty healthy subjects were enrolled as a control group. IL-18 single-nucleotide polymorphisms at -607 and -137 regions were analyzed using polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: The genotype and allele distributions of the two regions did not differ significantly between patients with aphthous stomatitis and controls. The genotype and allele distributions at -607 were significantly different between patients with Behçet's disease [CC (P = 0.044), C allele (P = 0.043), A allele (P = 0.043)], and controls. The frequency of the GG genotype at position -137 in patients with Behçet's disease was associated only with a higher rate of ocular manifestations (OR= 1.4, CI= 0.76-2.7, P = 0.031). CONCLUSION: IL-18 gene polymorphisms were not associated with any susceptibility to aphthous stomatitis, while a positive association was found with patients with Behçet's disease regarding -607 promoter site. Moreover, patients with Behçet's disease carrying the GG genotype at position -137 had a higher risk of developing ocular manifestations.