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

Age-Dependent Signature of Serum Inflammatory Cytokines in Healthy Children and Young Adults

The study of sensitive and specific biomarkers, such as blood inflammatory cytokines, could provide an answer to the challenges faced in the differential diagnosis of patients with systemic inflammation. Limited data exist on the impact of age on serum levels of inflammatory cytokines. We collected serum samples of 42 healthy children and young adults (1 month to 21 years). Serum levels of interleukin 1 receptor antagonist (IL-1Ra), IL-1β, IL-6, IL-18, tumor necrosis factor-alpha (TNF-α), CXCL9, and CXCL10 were measured. Data were analyzed for three different age groups (<6, 6-17, and 18-21 years). IL-18, TNF-α, and CXCL9 values varied significantly according to age group. Median values of IL-18 and TNF-α decline with age, whereas CXCL9 and CXCL10 are lowest at 6-17 years. IL-1Ra is stable among age groups. In the majority of cases, IL-1β and IL-6 are not measurable above the lower limit of quantification. A scoping literature review revealed highly variable data on IL-1Ra, IL-18, TNF-α, and CXCL10. For CXCL9, pediatric reference data are scarce. In conclusion, we report an age-dependent signature of multiple inflammatory cytokines measured in the serum of healthy children and young adults, suggesting the need to use age-specific reference values in future pediatric studies.

Unravelling the clinical heterogeneity of undefined recurrent fever over time in the European registries on Autoinflammation

BACKGROUND

Systemic autoinflammatory disorders (SAIDs) represent a growing spectrum of diseases characterized by dysregulation of the innate immune system. The most common pediatric autoinflammatory fever syndrome, Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis (PFAPA), has well defined clinical diagnostic criteria, but there is a subset of patients who do not meet these criteria and are classified as undefined autoinflammatory diseases (uAID). This project, endorsed by PRES, supported by the EMERGE fellowship program, aimed to analyze the evolution of symptoms in recurrent fevers without molecular diagnosis in the context of undifferentiated AIDs, focusing on PFAPA and syndrome of undifferentiated recurrent fever (SURF), using data from European AID registries.

METHODS

Data of patients with PFAPA, SURF and uSAID were collected from 3 registries including detailed epidemiological, demographic and clinical data, results of the genetic testing and additional laboratory investigations with retrospective application of the modified Marshall and PRINTO/Eurofever classification criteria on the cohort of PFAPA patients and preliminary SURF criteria on uSAID/SURF patients.

RESULTS

Clinical presentation of PFAPA is variable and some patients did not fit the conventional PFAPA criteria and exhibit different symptoms. Some patients did not meet the criteria for either PFAPA or SURF, highlighting the heterogeneity within these groups. The study also explored potential overlaps between PFAPA and SURF/uAID, revealing that some patients exhibited symptoms characteristic of both conditions, emphasizing the need for more precise classification criteria.

CONCLUSIONS

Patients with recurrent fevers without molecular diagnoses represent a clinically heterogeneous group. Improved classification criteria are needed for both PFAPA and SURF/uAID to accurately identify and manage these patients, ultimately improving clinical outcomes.

Clinical updates in inborn errors of immunity: a focus on the noninfectious clinical manifestations

PURPOSE OF REVIEW

In the last 5 years, several new inborn errors of immunity (IEI) have been described, especially in the areas of immune dysregulation and autoinflammation. As a result, the clinical presentation of IEIs has broadened. We review the heterogeneous presentation of IEIs and detail several of the recently described IEIs with a focus on the noninfectious manifestations commonly seen.

RECENT FINDINGS

IEIs may present with early onset and/or multiple autoimmune manifestations, increased risk for malignancy, lymphoproliferation, severe atopy, autoinflammation and/or hyperinflammation. Because of this, patients can present to a wide array of providers ranging from primary care to various pediatric subspecialists. The International Union of Immunological Societies (IUIS) expert committee has created a phenotypic classification of IEIs in order to help clinicians narrow their evaluation based on the laboratory and clinical findings.

SUMMARY

Both primary care pediatricians and pediatric subspecialists need to be aware of the common clinical features associated with IEI and recognize when to refer to allergy-immunology for further evaluation. Early diagnosis can lead to earlier treatment initiation and improve clinical outcomes for our patients.

The expanding clinical spectrum of autoinflammatory diseases with NOD2 variants: a case series and literature review

Objective

To assess the impact conferred by NOD2 variants on the clinical spectrum of patients with systemic autoinflammatory diseases (SAIDs) in Greece.

Methods

Consecutive patients (n=167) with confirmed SAIDs who underwent screening by next generation sequencing (NGS) targeting 26 SAID-associated genes, and carried at least one NOD2 gene variant, were retrospectively studied. The demographic, clinical and laboratory parameters were recorded.

Results

In total, 24 rare NOD2 variants in 23/167 patients (14%) were detected. Notably, 18 patients had at least one co-existing variant in 13 genes other than NOD2. Nine patients had juvenile- and 14 adult-onset disease. All patients presented with symptoms potentially induced by the NOD2 variants. In particular, the candidate clinical diagnosis was Yao syndrome (YAOS) in 12 patients (7% of the whole SAID cohort). The clinical spectrum of patients with YAOS (mean episode duration 8 days) was fever (n=12/12), articular symptoms (n=8), gastrointestinal symptoms (n=7; abdominal pain/bloating in 7; diarrhea in 4; oral ulcers in 3), serositis (n=7), and rash (n=5), while the inflammatory markers were elevated in all but one patient. Most of these patients showed a poor response to nonsteroidal anti-inflammatory drugs (n=7/9), colchicine (n=6/8) and/or anti-TNF treatment (n=3/4), while a complete response was observed in 6/10 patients receiving steroids and 3/5 on anti-IL1 treatment. Another 8 patients were diagnosed with either FMF (n=6) or PFAPA syndrome (n=2) presenting with prominent diarrhea (n=7), oral ulcers (n=2), periorbital swelling and sicca-like symptoms (n=1), or maculopapular rash (n=1). One patient had a clinically undefined SAID, albeit characterized by oral ulcers and diarrhea. Finally, one patient presented with chronic relapsing urticaria with periorbital edema and inflammatory markers, and another one had a Crohn-like syndrome with good response to anti-IL-1 but refractory to anti-TNF treatment.

Conclusion

NOD2 variants were detected in 1 out of 7 SAID patients and seem to have an impact on disease phenotype and treatment response. Further studies should validate combined molecular and clinical data to better understand these distinct nosological entities.

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.

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.

Periodic Fever in Children: Etiology and Diagnostic Challenges

Periodic fever in children is an autoinflammatory illness with an unknown cause. Symptoms include frequent episodes of fever that are followed by an increase in inflammatory markers. A genetic background for periodic fever of unknown origin has been hypothesized, based on its family clustering and parallels to other autoinflammatory illnesses such as familial Mediterranean fever. Genome analysis has been used in studies to look for related gene variations in periodic fever of unknown origin in the pediatric population. 

Children with periodic fevers might be a diagnostic challenge. After ruling out the most prevalent causes, a wide variety of other possibilities are investigated. Infectious and noninfectious causes of periodic fever in children are discussed in this article.

Inflammasomes (intracellular proteins that activate interleukin (IL)-1b and IL-18) and genetic/hereditary variations are thought to be implicated in the pathogenesis of periodic fever. Evaluation and ruling out possible infective or noninfective causes is vital in the diagnosis of periodic fever in children. Investigations demonstrate that there isn't a single gene linked to it, suggesting that it may have a multifactorial or polygenic origin, with an environmental trigger causing inflammasome activation and fever flares. Treatment is usually symptomatic, with drugs such as colchicine and cimetidine having shown promising results in trials.

We explored the literature on periodic fever in children for its epidemiology, pathophysiology, the role of various genes and how they influence the disease and associated complications, and its various treatment modalities.

Network Pharmacology and Molecular Docking Study of Yupingfeng Powder in the Treatment of Allergic Diseases

Objective

To explore the potential mechanisms of Yupingfeng Powder (YPFP) in the treatment of allergic diseases by using network pharmacology and molecular docking technology.

Methods

The active components and targets of YPFP were screened by the TCMSP database. The targets associated with atopic dermatitis, asthma, allergic rhinitis, and food allergy were obtained from GeneCards and OMIM databases, respectively. The intersection of the above disease-related targets was identified as allergy-related targets. Then, allergy-related targets and YPFP-related targets were crossed to obtain the potential targets of YPFP for allergy treatment. A protein-protein-interaction (PPI) network and a drug-target-disease topology network were constructed to screen hub targets and key ingredients. Next, GO and KEGG pathway enrichment analyses were performed separately on the potential targets and hub targets to identify the biological processes and signaling pathways involved. Finally, molecular docking was conducted to verify the binding affinity between key ingredients and hub targets.

Results

In this study, 45 active ingredients were identified from YPFP, and 48 allergy-related targets were predicted by network pharmacology. IL6, TNF, IL1B, PTGS2, CXCL8, JUN, CCL2, IL10, IFNG, and IL4 were screened as hub targets by the PPI network. However, quercetin, kaempferol, wogonin, formononetin, and 7-O-methylisomucronulatol were identified as key ingredients by the drug-target-disease topological network. GO and KEGG pathway enrichment analysis indicated that the therapeutic effect of YPFP on allergy involved multiple biological processes and signaling pathways, including positive regulation of fever generation, positive regulation of neuroinflammatory response, vascular endothelial growth factor production, negative regulation of cytokine production involved in immune response, positive regulation of mononuclear cell migration, type 2 immune response, and negative regulation of lipid storage. Molecular docking verified that all the key ingredients had good binding affinity with hub targets.

Conclusion

This study revealed the key ingredients, hub targets, and potential mechanisms of YPFP antiallergy, and these data can provide some theoretical basis for subsequent allergy treatment and drug development.

Clinical characterization, long-term follow-up, and response to treatment of patients with syndrome of undifferentiated recurrent fever (SURF)

OBJECTIVES

To describe a homogeneous group of patients with undifferentiated recurrent fevers followed-up in a tertiary referral center for systemic autoinflammatory diseases (SAIDs).

METHODS

Patients with undifferentiated recurrent fevers seen at our Center from 2008 to 2021 and followed-up for at least one year were included in a retrospective study. Monogenic recurrent fevers, patients carrying variants of unknown origin and PFAPA (Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis) syndrome were excluded.

RESULTS

Fifty patients (34 male, 16 female) were included in the study. The median age at onset was 3 years, and the median follow-up was 3.3 years. At baseline, arthralgia (70%) and abdominal pain (65%) were the most frequent manifestations. NSAIDs or steroids on demand had a variable and transient effect. Tonsillectomy was ineffective in the 10 patients (20%) that underwent surgery. Forty-eight patients (96%) were treated with colchicine. A complete response (absence of fever) was achieved in 31 patients (64.6%). Nine patients (18%) showed a partial response, with a median reduction of fever episodes per year of 72%. Nine patients (16.7%) were considered resistant to colchicine. The presence of generalized lymphadenopathy and, to a lesser extent, exudative tonsillitis was associated with a lack of response to colchicine.

CONCLUSIONS

We describe the largest series of patients with syndrome of undifferentiated recurrent fever (SURF) reported in the literature so far. SURF should be considered as a distinct clinical entity in the context of multifactorial autoinflammatory diseases.

Risk, Mechanisms and Implications of Asthma-Associated Infectious and Inflammatory Multimorbidities (AIMs) among Individuals With Asthma: a Systematic Review and a Case Study

Our prior work and the work of others have demonstrated that asthma increases the risk of a broad range of both respiratory (e.g., pneumonia and pertussis) and non-respiratory (e.g., zoster and appendicitis) infectious diseases as well as inflammatory diseases (e.g., celiac disease and myocardial infarction [MI]), suggesting the systemic disease nature of asthma and its impact beyond the airways. We call these conditions asthma-associated infectious and inflammatory multimorbidities (AIMs). At present, little is known about why some people with asthma are at high-risk of AIMs, and others are not, to the extent to which controlling asthma reduces the risk of AIMs and which specific therapies mitigate the risk of AIMs. These questions represent a significant knowledge gap in asthma research and unmet needs in asthma care, because there are no guidelines addressing the identification and management of AIMs. This is a systematic review on the association of asthma with the risk of AIMs and a case study to highlight that 1) AIMs are relatively under-recognized conditions, but pose major health threats to people with asthma; 2) AIMs provide insights into immunological and clinical features of asthma as a systemic inflammatory disease beyond a solely chronic airway disease; and 3) it is time to recognize AIMs as a distinctive asthma phenotype in order to advance asthma research and improve asthma care. An improved understanding of AIMs and their underlying mechanisms will bring valuable and new perspectives improving the practice, research, and public health related to asthma.

Syndrome of Undifferentiated Recurrent Fever (SURF): An Emerging Group of Autoinflammatory Recurrent Fevers

Syndrome of undifferentiated recurrent fever (SURF) is a heterogeneous group of autoinflammatory diseases (AID) characterized by self-limiting episodes of systemic inflammation without a confirmed molecular diagnosis, not fulfilling the criteria for periodic fever, aphthous stomatitis, pharyngitis and adenopathy (PFAPA) syndrome. In this review, we focused on the studies enrolling patients suspected of AID and genotyped them with next generation sequencing technologies in order to describe the clinical manifestations and treatment response of published cohorts of patients with SURF. We also propose a preliminary set of indications for the clinical suspicion of SURF that could help in everyday clinical practice.