IL-1β blockade in periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome: case-based review

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis recurrence temporally associated with allergen-specific immunotherapy in a female adolescent: a case report

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is the most common periodic fever syndrome in pediatric patients. It is clinically characterized by fever flares lasting 3-7 days, reappearing every 2-8 weeks with a distinctive clockwork regularity. PFAPA generally begins before 5 years of age and usually ceases 3-5 years after onset. Recurrences may be observed in adolescence and adulthood in up to 20% of cases. The authors aim to describe a case of PFAPA recurrence in adolescence temporally associated with allergen-specific immunotherapy (ASIT). A 16-year-old female patient was referred to the rheumatology unit due to recurrent episodes of fever one month after initiating ASIT for allergic rhinitis. These episodes occurred every 4 weeks and lasted 3 days. During these episodes, she also presented with a sore throat, tonsillar exudates, and cervical lymphadenopathy. Abortive treatment with oral prednisolone was attempted in these episodes, with complete resolution of fever after a single dose. After reviewing her medical background, she had previously experienced febrile episodes accompanied by aphthous ulcers and tonsillar exudates occurring every 7-8 weeks from age 2-7. The etiopathogenesis of PFAPA remains uncertain. Environmental triggers, particularly those with immunomodulator effects, may interfere with the immune responses responsible for PFAPA occurrence, but the mechanisms are still unclear. The authors describe the first report of the reappearance of PFAPA flares, possibly due to ASIT. Further studies are needed to fully clarify if ASIT constitutes a true environmental trigger of PFAPA.

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.

PFAPA syndrome in children

ABSTRACT

Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome is, as the name implies, characterized by an extremely regular cycle of fevers that is accompanied by one or more other symptoms such as oral ulcers, pharyngitis, adenitis, tonsillitis, sore throat, cervical adenopathy, and headache. Originally known as Marshall syndrome, PFAPA is most commonly identified in children younger than age 5 years; however, adults may also present with the disease, though they may report additional symptoms. PFAPA is now understood to be a diagnosis of exclusion. Laboratory studies are typically unremarkable except for increases in acute phase reactants such as C-reactive protein. Treatment is primarily supportive and most frequently uses systemic steroids to suppress the inflammatory response. Acute flares are self-limited, and the syndrome typically resolves on its own as the child reaches age 7 or 8 years.

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.

Efficacy of canakinumab in a patient with adult-onset glucocorticoid-resistant periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome, a polygenic or multifactorial condition, is the most frequent autoinflammatory disease in children. There is increasing evidence that some patients may have a disease onset during adulthood. With regard to PFAPA syndrome treatment, single medium-to-high doses of glucocorticoids during flares constitute the therapy of choice in children and adults, colchicine may be useful in some patients, and tonsillectomy has been reported of utility mainly in paediatric patients. Interleukin-1 (IL-1) blockers have been sporadically used with good response in glucocorticoid-resistant cases. We report a patient with an adult onset of glucocorticoid-resistant PFAPA syndrome and inconsistent response to colchicine and anakinra, who later achieved a complete and sustained response to canakinumab. Although canakinumab seems to be a good therapeutic option in paediatric and adult patients with refractory PFAPA syndrome, the best anti-IL-1 agent and the sequence of administration have to be still determined in well-designed clinical trials.

Off-label use of canakinumab in pediatric rheumatology and rare diseases

Since the first success of interleukin-1 blockade in cryopyrin-associated periodic syndrome, the use of interleukin-1 inhibitors has expanded to other disorders, including off-label indications. In particular, canakinumab has been employed in an off-label fashion in several diseases such as rare monogenic autoinflammatory diseases and multifactorial autoinflammatory diseases, disclosing an excellent efficacy and good safety profile in pediatric patients unresponsive to standards of care. In addition, hyperferritinemic syndromes and complex disorders, as well as Kawasaki disease, uveitis, and other pediatric rare disorders, represent additional areas where canakinumab efficacy is worth exploring. Altogether, the results summarized below are of paramount importance in pediatric patients where a considerable proportion of treatments are prescribed off-label. This review focuses on the off-label use of canakinumab in pediatric patients affected by systemic immune-mediated diseases.

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.

Therapeutic potential of targeting IL-1 family cytokines in chronic inflammatory skin diseases

The interleukin-1 (IL-1) family of cytokines is a central regulator of a myriad of immunological responses. It comprises several cytokines, including those belonging to the IL-1, IL-36 and IL-18 subfamilies, as well as IL-33. The IL-1 family primarily plays a role in orchestrating innate immune responses but also in adaptive immunity. Increased interest in the IL-1 family occurred following the discovery that dysregulation of IL-1 signalling underlies the pathogenesis of several monogenic auto-inflammatory diseases, characterized by sterile inflammation involving the skin and other organs. This also provided increased understanding of the role of innate immunity and the IL-1 family in polygenic auto-inflammatory skin conditions, such as neutrophilic dermatoses, as well as in some of the most common chronic inflammatory skin diseases, such as psoriasis or hidradenitis suppurativa. Several therapeutic agents have been developed to inhibit the IL-1 family members and their signalling pathways. These have shown therapeutic efficacy in several chronic inflammatory skin disorders. The aim of this review is to thoroughly describe the consequences of pathological dysregulation of IL-1, IL-33, IL-36, IL-18 pathways in dermatological conditions and to provide a forward-looking update on therapeutic strategies targeting signalling by IL-1 family cytokines.

Evaluation of Novel Topical Camel Whey Protein Gel for the Treatment of Recurrent Aphthous Stomatitis: Randomized Clinical Study

Aim:

The aim of this article is to evaluate the topical effect of camel whey protein (CWP) on the healing of recurrent aphthous stomatitis (RAS) and the serum levels of interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-α.

Materials and Methods:

Forty patients with minor RAS were randomly assigned into control and study groups. The control group applied placebo methylcellulose gel topically over the aphthous ulcer, whereas the study group used CWP dissolved in methylcellulose gel topically over the aphthous ulcer. Healing period, pain scale, and serum inflammatory biomarkers were evaluated before and after gel application. Collected data were analyzed statistically using the paired t-test or independent sample t-test.

Results:

Ulcer healing period, pain scale, and immunological biomarkers were statistically improved in both groups with significant shortening of the ulcer duration and significant regulation of immunological values related to the study group.

Conclusion:

Topical CWP gel is potentially effective in the treatment of RAS.

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.

Off-label use of anti-IL-1 drugs in rheumatic diseases

Interleukin-1 (IL-1) plays a key role in the pathogenesis of different rheumatic diseases. There are now several agents available on the market capable of blocking IL-1. The proven effectiveness and excellent safety of these drugs makes them a possible therapeutic option in the treatment of IL-1 driven diseases, when previous therapies are contraindicated or ineffective. This article discusses the European wide off-label use of these drugs for the treatment of rheumatic diseases.

Should we stimulate or suppress immune responses in COVID-19? Cytokine and anti-cytokine interventions

The coronavirus disease-19 pandemic (COVID-19), which appeared in China in December 2019 and rapidly spread throughout the world, has forced clinicians and scientists to take up extraordinary challenges. This unprecedented situation led to the inception of numerous fundamental research protocols and many clinical trials. It quickly became apparent that although COVID-19, in the vast majority of cases, was a benign disease, it could also develop a severe form with sometimes fatal outcomes. Cytokines are central to the pathophysiology of COVID-19; while some of them are beneficial (type-I interferon, interleukin-7), others appear detrimental (interleukin-1β, -6, and TNF-α) particularly in the context of the so-called cytokine storm. Yet another characteristic of the disease has emerged: concomitant immunodeficiency, notably involving impaired type-I interferon response, and lymphopenia. This review provides an overview of current knowledge on COVID-19 immunopathology. We discuss the defective type-I IFN response, the theoretical role of IL-7 to restore lymphocyte repertoire, as well as we mention the two patterns observed in severe COVID-19 (i.e. interleukin-1β-driven macrophage activation syndrome vs. interleukin-6-driven immune dysregulation). Next, reviewing current evidence drawn from clinical trials, we examine a number of cytokine and anti-cytokine therapies, including interleukin-1, -6, and TNF inhibitors, as well as less targeted therapies, such as corticosteroids, chloroquine, or JAK inhibitors.

Current Therapeutic Options for the Main Monogenic Autoinflammatory Diseases and PFAPA Syndrome: Evidence-Based Approach and Proposal of a Practical Guide

Monogenic autoinflammatory diseases are rare conditions caused by genetic abnormalities affecting the innate immunity. Previous therapeutic strategies had been mainly based on results from retrospective studies and physicians' experience. However, during the last years, the significant improvement in their genetic and pathogenic knowledge has been accompanied by a remarkable progress in their management. The relatively recent identification of the inflammasome as the crucial pathogenic mechanism causing an aberrant production of interleukin 1β (IL-1β) in the most frequent monogenic autoinflammatory diseases led to the introduction of anti-IL-1 agents and other biologic drugs as part of the previously limited therapeutic armamentarium available. Advances in the treatment of autoinflammatory diseases have been favored by the use of new biologic agents and the performance of a notable number of randomized clinical trials exploring the efficacy and safety of these agents. Clinical trials have contributed to increase the level of evidence and provided more robust therapeutic recommendations. This review analyzes the treatment of the most frequent monogenic autoinflammatory diseases, namely, familial Mediterranean fever, tumor necrosis factor receptor-associated periodic fever syndrome, hyperimmunoglobulin D syndrome/mevalonate kinase deficiency, and cryopyrin-associated periodic syndromes, together with periodic fever with aphthous stomatitis, pharyngitis, and cervical adenitis syndrome, which is the most common polygenic autoinflammatory disease in children, also occurring in adult patients. Finally, based on the available expert consensus recommendations and the highest level of evidence of the published studies, a practical evidence-based guideline for the treatment of these autoinflammatory diseases is proposed.

Should we stimulate or suppress immune responses in COVID-19? Cytokine and anti-cytokine interventions

The coronavirus disease-19 pandemic (COVID-19), which appeared in China in December 2019 and rapidly spread throughout the world, has forced clinicians and scientists to take up extraordinary challenges. This unprecedented situation led to the inception of numerous fundamental research protocols and many clinical trials. It quickly became apparent that although COVID-19, in the vast majority of cases, was a benign disease, it could also develop a severe form with sometimes fatal outcomes. Cytokines are central to the pathophysiology of COVID-19; while some of them are beneficial (type-I interferon, interleukin-7), others appear detrimental (interleukin-1β, -6, and TNF-α) particularly in the context of the so-called cytokine storm. Yet another characteristic of the disease has emerged: concomitant immunodeficiency, notably involving impaired type-I interferon response, and lymphopenia. This review provides an overview of current knowledge on COVID-19 immunopathology. We discuss the defective type-I IFN response, the theoretical role of IL-7 to restore lymphocyte repertoire, as well as we mention the two patterns observed in severe COVID-19 (i.e. interleukin-1β-driven macrophage activation syndrome vs. interleukin-6-driven immune dysregulation). Next, reviewing current evidence drawn from clinical trials, we examine a number of cytokine and anti-cytokine therapies, including interleukin-1, -6, and TNF inhibitors, as well as less targeted therapies, such as corticosteroids, chloroquine, or JAK inhibitors.