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.

Pediatric Inflammatory Multisystem Syndrome (PIMS) - Potential role for cytokines such Is IL-6.

COVID-19 is a transmissible respiratory disease caused by coronavirus SARS-CoV-2, which is similar to SARS or MERS. Its increased severity was noted in aged patients usually over 65 years of age. Children and young people have an asymptomatic or mild course of the disease.Unfortunately, the number of children with problems after mild or asymptomatic COVID-19 recovery is increasing and their troubles resemble Kawasaki disease, although the laboratory findings seem to be different. This condition is called pediatric inflammatory multisystem syndrome (PIMS), and it is a new disease seen in children directly influenced by previous SARS-CoV-2 infection. The literature reports that PIMS typically follows 2-4 weeks after SARS-CoV-2 infection. The clinical symptoms of the affected children are extremely complex, ranging from gastrointestinal to cardiovascular problems with frequent skin and mucosal manifestations, and without intensive treatment they can be fatal. The exact causes of PIMS are recently unknown, however, it is explained as hyperactivation of immunity.In this minireview, we summarize data on the prominent role of the IL-6-IL-6R-STAT3 axis in PIMS aetiopathogenesis. Therapeutic manipulation of IL-6 or IL-6 receptor could be an approach to the treatment of children with severe PIMS.

Methotrexate efficacy, but not its intolerance, is associated with the dose and route of administration.

BACKGROUND: There is a lack of published evidence on the importance of methotrexate (MTX) dose and route of administration on both its efficacy and adverse events in children with Juvenile Idiopathic Arthritis (JIA). We aimed to document our clinical practice based on the treat-to-target approach in order to support the concept that better therapeutic effect achieved with an optimal dose of parenteral MTX is associated with clinically acceptable adverse effects comparable to those reported for oral treatment. METHODS: Study inclusion criteria were indication of new MTX therapy for active arthritis in confirmed JIA patients younger than 18 years. Eligible patients were evaluated prospectively every 3 months for 1 year using standardized instruments for treatment response (American College of Rheumatology Pediatric (ACRPedi) response, Juvenile Arthritis Disease Activity Score (JADAS) 71, Clinically Inactive Disease (CID)) and adverse events (laboratory monitoring, Methotrexate Intolerance Severity Score (MISS)). MTX responders had to achieve at least ACRPedi 70 response. MTX intolerance was defined by MISS ≥ 6. RESULTS: In 45/55 patients (81.8 %) MTX was started as subcutaneous injection. The initial median weekly dose was 14.4 mg/m(2) in parenteral and 11.7 mg/m(2) in oral administration. MTX therapy was effective in the level of ACRpedi70 and CID in 50.9 % and 30.9 % of patients at month 6 and in 70.9 % and 56.4 % after 12 months of the treatment, respectively. MTX intolerance at 6 and 12 months was noted in 25.5 % and 30.6 %, respectively. Management of intolerance included change in the dose and/or route of administration, education and councelling. Adverse events led to MTX withdrawal in 5 patients (9 %) due to toxicity (n = 3) and intolerance (n = 2). We did not find any significant predictive factors for either MTX therapeutic response or intolerance. CONCLUSION: Subcutaneous MTX weekly dose around 15 mg/m(2) is associated not only with a high response rate within the first 12 months of treatment, but also with a relatively low rate of significant adverse effects that would lead to the treatment termination. It allows early recognition of MTX non-responders and addition of biologic therapy. Sustainability of therapeutic effect and longer-term evolution of adverse events will be addressed by an ongoing extension of the study.