Vyzhga Y, Wittkowski H, Hentgen V, Georgin-Lavialle S, Theodoropoulou A , et al.
Pediatric rheumatology online journal •
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. 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. 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. 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.
Theodoropoulou K, Wittkowski H, Busso N, Von Scheven-Gête A, Moix I , et al.
Frontiers in immunology •
The inflammasome has been recognized as one of the key components of innate immunity. Gain-of-function mutations in the exon 3 of gene have been implicated in inflammatory diseases suggesting the presence of functionally important sites in this region. Q703K (c.2107C>A, p.Gln703Lys, also known in the literature as Q705K) is a common variant of , that has been considered to be both clinically unremarkable or disease-causing with a reduced penetrance. We aimed to investigate the potential genetic impact of the variant Q703K in patients with recurrent fever presenting with two autoinflammatory diseases: PFAPA (periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis) and CAPS (cryopyrin-associated periodic syndrome), as well as with undefined autoinflammatory disease (uAID). This is an international multicentric observational retrospective study characterizing the clinical phenotype of patients presenting with recurrent fever suspected to be of auto-inflammatory origin and where the Q703K variant was found. Monocytes of parents of 6 Q703K+ PFAPA patients were studied and levels of pro-inflammatory cytokines produced by monocytes of Q703K+ and Q703K- parents have been compared by ELISA. We report 42 patients with the Q703K genetic variant: 21 were PFAPA patients, 6 had a CAPS phenotype, and 15 had an uAID. The phenotypes of PFAPA, CAPS and uAID were quite similar between Q703K positive and negative patients with the exception of increased prevalence of pharyngitis in the Q703K positive CAPS population compared to the negative one. The production of IL-1β was not significantly different between Q703K+ and Q703K- monocytes from asymptomatic parents. The evidence we report in our study shows an increased prevalence of Q703K in patients with autoinflammatory diseases, suggesting an association between the Q703K variant and the risk of PFAPA, CAPS and uAID syndromes. However, we did not show a functional effect of this mutation on the inflammasome basal activity.
Gattorno M, Hofer M, Federici S, Vanoni F, Bovis F , et al.
Annals of the rheumatic diseases •
Different diagnostic and classification criteria are available for hereditary recurrent fevers (HRF)-familial Mediterranean fever (FMF), tumour necrosis factor receptor-associated periodic fever syndrome (TRAPS), mevalonate kinase deficiency (MKD) and cryopyrin-associated periodic syndromes (CAPS)-and for the non-hereditary, periodic fever, aphthosis, pharyngitis and adenitis (PFAPA). We aimed to develop and validate new evidence-based classification criteria for HRF/PFAPA. Step 1: selection of clinical, laboratory and genetic candidate variables; step 2: classification of 360 random patients from the Eurofever Registry by a panel of 25 clinicians and 8 geneticists blinded to patients' diagnosis (consensus ≥80%); step 3: statistical analysis for the selection of the best candidate classification criteria; step 4: nominal group technique consensus conference with 33 panellists for the discussion and selection of the final classification criteria; step 5: cross-sectional validation of the novel criteria. The panellists achieved consensus to classify 281 of 360 (78%) patients (32 CAPS, 36 FMF, 56 MKD, 37 PFAPA, 39 TRAPS, 81 undefined recurrent fever). Consensus was reached for two sets of criteria for each HRF, one including genetic and clinical variables, the other with clinical variables only, plus new criteria for PFAPA. The four HRF criteria demonstrated sensitivity of 0.94-1 and specificity of 0.95-1; for PFAPA, criteria sensitivity and specificity were 0.97 and 0.93, respectively. Validation of these criteria in an independent data set of 1018 patients shows a high accuracy (from 0.81 to 0.98). Eurofever proposes a novel set of validated classification criteria for HRF and PFAPA with high sensitivity and specificity.
Sundqvist M, Wekell P, Osla V, Bylund J, Christenson K , et al.
Arthritis and rheumatism •
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. 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). 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. 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.
Kolly L, Busso N, von Scheven-Gete A, Bagnoud N, Moix I , et al.
The Journal of allergy and clinical immunology •
The exact pathogenesis of the pediatric disorder periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis (PFAPA) syndrome is unknown. We hypothesized that PFAPA might be due to dysregulated monocyte IL-1β production linked to genetic variants in proinflammatory genes. Fifteen patients with PFAPA syndrome were studied during and outside a febrile episode. Hematologic profile, inflammatory markers, and cytokine levels were measured in the blood. The capacity of LPS-stimulated PBMCs and monocytes to secrete IL-1β was assessed by using ELISA, and active IL-1β secretion was visualized by means of Western blotting. Real-time quantitative PCR was performed to assess cytokine gene expression. DNA was screened for variants of the MEFV, TNFRSF1A, MVK, and NLRP3 genes in a total of 57 patients with PFAPA syndrome. During a febrile attack, patients with PFAPA syndrome revealed significantly increased neutrophil counts, erythrocyte sedimentation rates, and C-reactive protein, serum amyloid A, myeloid-related protein 8/14, and S100A12 levels compared with those seen outside attacks. Stimulated PBMCs secreted significantly more IL-1β during an attack (during a febrile episode, 575 ± 88 pg/mL; outside a febrile episode, 235 ± 56 pg/mL; P < .001), and this was in the mature active p17 form. IL-1β secretion was inhibited by ZYVAD, a caspase inhibitor. Similar results were found for stimulated monocytes (during a febrile episode, 743 ± 183 pg/mL; outside a febrile episode, 227 ± 92 pg/mL; P < .05). Genotyping identified variants in 15 of 57 patients, with 12 NLRP3 variants, 1 TNFRSF1A variant, 4 MEFV variants, and 1 MVK variant. Our data strongly suggest that IL-1β monocyte production is dysregulated in patients with PFAPA syndrome. Approximately 20% of them were found to have NLRP3 variants, suggesting that inflammasome-related genes might be involved in this autoinflammatory syndrome.