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

Altered serum antibody levels in children with periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis

Objectives

This study aimed to extend the literature by analyzing immunoglobulin (Ig) A, IgE, IgG, IgG2, IgG3, and IgM antibody levels in periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) patients.

Patients and methods

This study retrospectively analyzed the antibody test results of 20 pediatric patients (10 males, 10 females; mean age: 2.5±1.5 years; range, 0.5 to 5.4 years) with and without flare who were initially evaluated for a number of underlying diseases due to periodic fever/infectious symptoms but then diagnosed with PFAPA between January 2015 and December 2020. Antibody levels were determined by chemiluminescence microparticle immunoassay. The results were retrospectively compared with a group of healthy children after the PFAPA diagnosis was confirmed.

Results

The chemiluminescence microparticle immunoassay revealed 35%, 65%, 20%, 86.6%, and 55% of PFAPA cases with low serum levels of IgA, IgG, IgG2, IgG3, and IgM respectively, while 56.2% had high IgE levels. Moreover, low serum levels of at least two antibody classes or subclasses were reported in 80% of the PFAPA children. While cases with low IgG serum levels were with the highest incidence rates among the low IgG3 PFAPA patient population, both high IgE and low IgM cases were common in the rest of the patients.

Conclusion

Our results suggest an association between PFAPA and low serum antibody levels, particularly of IgG3. Future studies are needed to confirm our conclusion.

Tonsil microbiome in pediatric patients with post tonsillectomy hemorrhage for tonsillar hypertrophy

OBJECTIVE

This study aimed to compare the tonsillar microbiota between post tonsillectomy patients with bleeding and without bleeding, and to investigate the potential role of tonsillar microbiota in the development of post-tonsillectomy hemorrhage (PTH).

METHODS

Nineteen tonsillar tissues from PTH patients and 21 tissues from control patients were collected. Metagenomic sequencing was used to compare the microbiota in PTH and control groups. Alpha diversity indices were used to compare the richness and evenness of the microbiota between the two groups. PCoA and NMDS analyses were used to evaluate beta diversity. LDA analysis was conducted to identify significantly abundant genera.

RESULTS

No significant difference in alpha diversity indices was found between PTH and control patients. The dominant bacteria in the tonsillar microbiota were Haemophilus, Streptococcus, and Fusobacterium. PCoA and NMDS analyses showed significant differences in beta diversity between PTH and control patients. PTH patients had a significantly higher relative abundance of Neisseria, Capnocytophaga, and Veillonella. Capnocytophaga was also identified as a significantly abundant genus by LDA analysis.

CONCLUSION

This study demonstrates that there is a difference in the tonsillar microbiota between PTH and control patients. The results suggest that Neisseria, Capnocytophaga, and Veillonella may be associated with the development of PTH. These findings provide new insights into the potential role of the tonsillar microbiota in the development of PTH, and may help to develop new strategies for preventing and treating this potentially life-threatening complication.

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.

Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Adenitis Syndrome and Syndrome of Unexplained Recurrent Fevers in Children and Adults

Children and adults with autoinflammatory disorders, who often experience recurrent fevers, rashes, cold-induced symptoms, conjunctivitis, lymphadenopathy, recurrent infections, aphthous stomatitis, and abnormal blood cell counts, may present to the allergist/immunologist because the symptoms mimic allergies and disorders of immunity. In recent years, there has been increased recognition of non-monogenic autoinflammatory disorders, including periodic fever, aphthous stomatitis, pharyngitis, and adenitis syndrome and syndrome of undifferentiated recurrent fevers. For many clinical practitioners, the natural history, diagnostic criteria, differential diagnoses, and preferred therapies remain challenging because of the presumed rarity of patients and the evolving field of autoinflammation. Here, we aim to provide a practical framework for the clinical allergist/immunologist to evaluate and treat this patient population.

Dermatologic Manifestations of Noninflammasome-Mediated Autoinflammatory Diseases

Autoinflammatory diseases (AIDs) arise from disturbances that alter interactions of immune cells and tissues. They give rise to prominent (auto)inflammation in the absence of aberrant autoantibodies and/or autoreactive T cells. AIDs that are predominantly caused by changes in the inflammasome pathways, such as the NLRP3- or pyrin-associated inflammasome, have gained substantial attention over the last years. However, AIDs resulting primarily from other changes in the defense system of the innate immune system are less well-studied. These noninflammasome-mediated AIDs relate to, for example, disturbance in the TNF or IFN signaling pathways or aberrations in genes affecting the IL-1RA. The spectrum of clinical signs and symptoms of these conditions is vast. Thus, recognizing early cutaneous signs constitutes an important step in differential diagnoses for dermatologists and other physicians. This review provides an overview of the pathogenesis, clinical presentation, and available treatment options highlighting dermatologic aspects of noninflammasome-mediated AIDs.

Epidemiology and clinical features of PFAPA: a retrospective cohort study of 336 patients in western Sweden

BACKGROUND

Periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome is generally regarded as the most common autoinflammatory disease, but the epidemiology of the disease is largely unknown. The objectives of this study were to estimate the annual incidence and describe the clinical features of PFAPA in a large cohort from western Sweden.

METHODS

The study retrospectively included children < 18 years of age diagnosed with PFAPA between 2006 and 2017 at three hospitals: NU Hospital Group, Skaraborg Hospital and Queen Silvia Children's Hospital. Patients were identified by searching for relevant diagnostic ICD-10 codes in the comprehensive electronic medical records and data were retrieved by reviewing case records. To estimate incidence, patients with symptom onset from January 1, 2006, to December 31, 2016, were included. Population data for the study area during this period were retrieved from Statistics Sweden.

RESULTS

In this study, 336 patients with PFAPA were identified. Of these, 156 (46%) were girls and 180 (54%) were boys. Almost 90% of the children with PFAPA (291 patients) experienced their first symptoms before the age of 5 years and fewer than 3% presented at ages above 10 years. Pharyngitis was the most common symptom during febrile episodes, followed by cervical adenitis and aphthous stomatitis. Fourteen percent of the patients displayed atypical features, of which skin rash was the most common. To calculate incidence, 251 patients with symptom onset during the study period were identified. The mean annual incidence was estimated at 0.86/10,000 for children < 18 years of age and 2.6/10,000 for children < 5 years of age.

CONCLUSIONS

This study adds to the understanding of the epidemiology of PFAPA syndrome by presenting incidence rates based on a large cohort and in different age groups in a population-based setting. It also shows the distribution of age of onset of PFAPA, with a peak in 1-year-olds and waning at older ages. Signs and symptoms of PFAPA syndrome were similar in children with symptom onset before vs. after 5 years of age.

New insights on multigenic autoinflammatory diseases

Autoinflammatory diseases are disorders of the innate immune system, which can be either monogenic due to a specific genetic mutation or complex multigenic due to the involvement of multiple genes. The aim of this review is to explore and summarize the recent advances in pathogenesis, diagnosis, and management of genetically complex autoinflammatory diseases, such as Schnitzler's syndrome; adult-onset Still's disease; synovitis, acne, pustulosis, hyperostosis, osteitis syndrome/chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis; Adamantiades-Behçet's disease; Yao syndrome; and periodic fever with aphthous stomatitis, pharyngitis, and adenitis syndrome. The PubMed database was screened for relevant articles using free text words and specific search strings. The search was limited to English-language articles, reporting the results of studies in humans, published through March 2021. Evidence from literature suggest that these rare multigenic autoinflammatory diseases can present with different clinical features and the diagnosis of these diseases can be challenging due to a combination of nonspecific manifestations that can be seen in a variety of other conditions. Diagnostic delays and disease complications may occur due to low disease awareness and the lack of pathognomonic markers. The pathogeneses of these diseases are complex and in some cases precise pathogenesis is not clearly understood. Conventional treatments are commonly used for the management of these conditions, but biologics have shown promising results. Biologics targeting proinflammatory cytokines including IL-1, IL-6, TNF-α, IL-17A and IL-18 have been shown to ameliorate signs and symptoms of different multigenic autoinflammatory diseases.

The role of inflammatory mediators in the pathogenesis of periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome

INTRODUCTION

As a recurrent disease, periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is characterized by episodes of febrile attacks and is often prominent in children under five years of age. However, the etiology of this condition has not been fully understood yet.

MATERIALS AND METHODS

The search in the extensive literature of peer-reviewed articles published from the inception to December 2021 was conducted to identify the relevant studies, using the electronic databases of MEDLINE/PubMed, Embase, Scopus, the Cochrane Library, and the Web of Science.

RESULTS

The analysis of complex relationships indicates that inflammatory factors, such as various cytokines and acute-phase proteins (APPs), play leading roles in the pathogenesis of this disease. Accordingly, this article summarizes the current state of knowledge to explain the mechanisms involved in inflammatory responses among patients with PFAPA syndrome and investigate its role in the pathogenesis of this disease. Moreover, the possibilities for further implementation of new therapeutic strategies are pointed out.

CONCLUSION

It is concluded that some pathophysiological processes are associated with immune dysregulation, which itself may be secondary to environmental factors, genetic background, and underlying diseases, including latent infections that multiply inflammatory mediators. elevated inflammatory markers similarly play a significant part in the clinical outcomes of this condition, whose pyrogenic nature is the reason for the development of episodes of febrile attacks in the population of patients suffering from PFAPA syndrome.

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome (PFAPA) or recurrent urinary tract infections: a case report

BACKGROUND

Fever is the most frequent reason for medical consultation in children, and makes up 15-25% of all consultations in primary care and emergency departments. In here we report a case of a 13 year-old girl who referred with an unusual presentation of fever and was misdiagnosed with recurrent urinary tract infection for 8 years.

CASE PRESENTATION

This is a Clinical Reasoning Cycle case study. A 13 year-old girl was referred with a chief complaint of recurrent fevers from 8 years. During her first febrile episode, she had a 5-day high-grade fever associated with loss of appetite. Her physical examination at that time was unremarkable. Blood tests showed leukocytosis with a shift to the left and urine examination was in favor of pyuria. The urine culture was positive for bacterial growth. The episodes of fever were repeated every 45 days. Accordingly, the patient was diagnosed as a case of recurrent urinary tract infection. In the intervals between her febrile episodes, the patient was healthy and laboratory tests were normal. Ultrasonography, voiding cystourethrogram and dimercaptosuccinic acid scans were normal. During her last visit, the patient mentioned difficulty in swallowing and on examination cervical lymph nodes, exudative tonsillitis and painful aphthous stomatitis were detected. All antibiotics were stopped and corticosteroids were started. The patient's symptoms were relieved and the interval between her febrile episodes became longer.

CONCLUSIONS

Our study shows that a patient should never be marked, particularly when the symptom and signs aren't completely justifying a patient's condition.

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.

Altered tonsillar toll-like receptor (TLR)-1 and TLR-2 expression levels between periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA), and group A beta-hemolytic streptococcal (GAβHS) recurrent tonsillitis patients

INTRODUCTION

Tonsillar microenvironment is thought to contribute to innate immune dysregulation responsible for the periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) because of beneficial effects of tonsillectomy on treatment of the syndrome. Accordingly previous studies reported altered lymphocyte frequency, cytokine level and microbial composition in PFAPA tonsils. The aim of our study is to monitor expression levels of pro-inflammatory cell surface Toll-like receptors (TLRs) which have important role in induction of inflammation and maintaining tissue haemostasis.

MATERIALS AND METHODS

Seven patients with PFAPA syndrome, and eight patients with group A beta-hemolytic streptococcal (GAβHS) recurrent tonsillitis were included in our study. Tonsillar expression levels of TLR-1, -2, -4, -5, and -6 were monitored by immunohistochemistry (IHC). Expression levels were scored using semi-quantitative analysis method and were statistically analyzed by Two-Way Repeated Measures Analysis of Variance test.

RESULTS

IHC analysis demonstrated expression of all TLRs in tonsillar surface epithelium (SE) and lymphoid interior (LI) except for TLR-6 which was not present in the former. There has not been any statistically significant difference in TLR expression levels between PFAPA and GAβHS tonsils, except for TLR-1 and TLR-2 which were higher on LI and lower on SE of PFAPA tonsils, respectively, than that of the GAβHS samples.

CONCLUSIONS

Altered TLR expression levels may be involved in PFAPA pathogenesis. Future studies with higher patient number, uninflamed tonsils and cellular markers are required to further enlighten the role of TLRs in the development of syndrome.

Undifferentiated recurrent fevers in pediatrics are clinically distinct from PFAPA syndrome but retain an IL-1 signature

Autoinflammatory disorders of the innate immune system present with recurrent episodes of inflammation often beginning in early childhood. While there are now more than 30 genetically-defined hereditary fever disorders, many patients lack a clear diagnosis. Many pediatric patients are often grouped with patients with periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome despite failing to meet diagnostic criteria. Here, we categorize these patients as syndrome of undifferentiated recurrent fever (SURF), and identify the unique features which distinguish them from the PFAPA syndrome. SURF patients were more likely to report gastrointestinal symptoms of nausea, vomiting and abdominal pain, and experienced inconsistent responses to on-demand steroid therapy compared to PFAPA patients. For this previously undefined cohort, an optimal course of therapy remains uncertain, with medical and surgical therapies largely driven by parental preference. A subset of patients with SURF underwent tonsillectomy with complete resolution. Flow cytometric evaluation demonstrates leukocytic populations distinct from PFAPA patients, with reduced CD3+ T cell numbers. SURF patient tonsils were predominantly characterized by an IL-1 signature compared to PFAPA, even during the afebrile period. Peripheral blood signatures were similar between groups suggesting that PFAPA and SURF patient tonsils have localized, persistent inflammation, without clinical symptoms. These data suggest that SURF is a heterogenous syndrome on the autoinflammatory disease spectrum.

Colchicine Effectiveness and Safety in Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Adenitis

Introduction: Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) is the most common fever syndrome in childhood. High disease activity (DA) dramatically impacts the health-related quality of life. Thus, effective and safe treatment is crucial. Colchicine might be effective, but data are still lacking. Study aimed to assess colchicine safety and effectiveness in PFAPA. Methods: This single center study was conducted between 03/2012 and 05/2021 in PFAPA patients without variants in genetic panel testing aged ≤ 18 years fulfilling Marshall criteria and classification criteria of Gattorno et al. Exclusion criteria were elevated liver enzymes, impaired kidney function, celiac disease, lactose intolerance, previous/ongoing biologics, known colchicine-intolerance. Demographics, clinical characteristics, treatment, DA, colchicine effectiveness and safety were recorded at baseline, first and last visit. Colchicine was started at 0.5-1.0 mg/day. DA was captured by physician (PGA) and patient/parent (PPGA) global assessment on a 10 cm visual analog scale, categorized as mild (<2), moderate (2-4), and high (≥5). Adverse event (AE) monitoring included gastrointestinal symptoms, liver enzyme/creatinine elevation, leukopenia, neutropenia. Primary outcome included response (R; composite of PPGA + PGA decrease ≥2) at last follow-up. Secondary outcomes were partial response (PR; PGA decrease = 1 + PPGA decrease ≥1), no response (NR; unchanged/worsened PGA/PPGA), colchicine safety, flare characteristics. Results: Twenty-seven PFAPA patients were included, 52% were female, median age was 5.8 years (1-10.75), median follow-up time was 13 months. At baseline, median PPGA was high; median PGA moderate. All patients had febrile flares. Median flare frequency was every 4-5 weeks; median duration 5-6 days. Nine patients were pre-treated with corticosteroids, increasing flare frequency in 8/9. Primary Outcome: 17 patients (63%) were responders. Secondary outcomes: PR was achieved in 15%; NR in 22% at last follow-up. DA decreased significantly (p <0.0001). At last follow-up, 52% reported no flares, median flare duration decreased to 1-2 days. At first follow-up, 22% reported mild abdominal pain/diarrhea. Moderate abdominal pain/diarrhea occurred with ≥1 mg/day. Mild asymptomatic liver enzyme elevation or leucopenia were rare; no severe AE or colchicine discontinuation were observed. Conclusion: Colchicine seems to be safe, well-tolerated, and effective in PFAPA patients. It can be considered in children with moderate/high DA even those without corticosteroid-benefit.

Pediatric recurrent fever and autoinflammation from the perspective of an allergist/immunologist

Autoinflammatory diseases are monogenic and polygenic disorders due to dysregulation of the innate immune system. The inherited conditions have been clustered with primary immunodeficiencies in the latest practice parameters; however, these diseases have unique clinical presentations, genetics, and available therapies. Given the presentation of fevers, rashes, and mucosal symptoms observed in many of these syndromes, patients are likely to present to an allergist/immunologist. Although there has been attention in the literature to diagnosis and treatment of rare, genetically defined autoinflammatory disorders, physicians are challenged by increasing numbers of patients with intermittent or periodic fevers who face unnecessary morbidities due to a lack of a diagnosis. The broad differential of diseases presenting with fever includes autoinflammatory syndromes, infections associated with immunodeficiency and/or allergies complicated by infection, and less commonly, autoimmune disorders or malignancy. To address this challenge, we review the history of the medical approach to fever, current diagnostic paradigms, and controversies in management. We describe the spectrum of disorders referred to a recurrent fever disorders clinic established in an Allergy/Immunology division at a tertiary pediatric care center. Finally, we provide practical recommendations including historical features and initial laboratory investigations that can help clinicians appropriately manage these patients.