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Background: Lower respiratory tract infections due to respiratory syncytial virus are associated with morbidity and mortality in infants and children. Thus precise elucidation of respiratory syncytial virus lower respiratory tract infection pathophysiology is important., Methods: Medical records of hospitalized patients were reviewed. Patients were divided into three groups. Group I: patients who improved without oxygen supply. Group II: patients who received oxygen supply, but not nasal high-flow cannula therapy. Group III: patients who received nasal high-flow cannula. Patients were also divided by age group into the <6 months and ≥6 months groups. Parameters for differentiating the severity among groups were then evaluated. Further, serum concentration of high-mobility group box-1 and several cytokines (Inerleukin-6, soluble tumor necrosis factor receptor-1/2, Interleukin-18, Interferon-gamma responsive protein-100) were evaluated., Results: One hundred eighty-nine were enrolled. An analysis of variance for those <6 months showed overall differences including younger age, lower pH, and increased partial pressure of carbon dioxide (pCO2), bicarbonate (HCO3-), and base excess at the time of admission. On the other hand, analysis of variance for ≥6 months revealed that, in addition to a lower pH and increased pCO2, patients showed differences including decreased serum total protein and albumin, and increased aspartate aminotransferase (AST), alanin aminotransferase (ALT), lactate dehydrogenase (LDH), Ferritin and C-reactive protein (CRP) levels. Further, evaluation of serum cytokines showed that IL-6, s tumor necrotizing factor receptor-1/2, and high-mobility group box-1 were higher in Group II/III among the ≥6 months age group, but not for those in the <6 months group., Conclusions: The pathophysiology of severe respiratory syncytial virus lower respiratory tract infection varies according to the age at onset. In late infancy and childhood, a certain proportion of patients show a hyperinflammatory status., (© 2021 Japan Pediatric Society.)

Background: A heterozygous mutation of STAT3 causes autosomal dominant hyper immunoglobulin E (IgE) syndrome; however, there are still many unclear points regarding the clinical spectrum of this syndrome., Methods: In addition to a clinical description of patients in terms of pedigree, a genetic analysis, quantitation of peripheral blood Th17 and ex vivo IL-17 production were carried out., Results: The proband, a 2-year-old boy (Patient 1) with early onset atopic dermatitis-like eczema and recurrent bacterial infections, was suspected of autosomal dominant hyper immunoglobulin E syndrome on the basis of his symptoms and family history. His mother (Patient 2) also had skin eczema and recurrent bacterial infections, and his sister (Patient 3) had skin eczema. A novel STAT3 mutation (p.S476F) was detected in all three patients, but not in the father, who had no such symptoms. A significant decrease in peripheral blood Th17 subsets and IL-17 production was found in all the patients. Curiously, all three patients carrying the p.S476F mutation in STAT3 lacked connective tissue signs such as distinctive facial features, retention of primary teeth, and joint hyperextensibility., Conclusions: Autosomal dominant hyper IgE syndrome should, perhaps, be considered even if patients lack connective tissue signs, as long as hypersensitivity to infection and skin manifestations with hyper IgE are present., (© 2020 Japan Pediatric Society.)

Background: The appropriate antimicrobial treatment period for febrile urinary tract infection (UTI) can be changed, depending on whether the patient has acute focal bacterial nephritis (AFBN). The aim of this study was to clarify the characteristics of AFBN compared with those of acute pyelonephritis (APN) and establish a strategy to detect AFBN., Methods: A total of 77 patients diagnosed with febrile UTI were enrolled. They were divided into APN (n = 64) and AFBN groups (n = 13). The clinical data and other laboratory biomarkers were retrospectively analyzed., Results: The time required for fever resolution after antimicrobial treatment was significantly longer in the AFBN group than in the APN group (2.77 days vs 1.11 days, respectively, P < 0.001). Also, the time to disappearance of pyuria after antimicrobial treatment was longer in the AFBN group than in the APN group (6.22 days vs 2.32 days, respectively, P = 0.001). Fever lasting >1.75 days after antimicrobial treatment had a sensitivity of 92% and specificity of 79% for the detection of AFBN, while pyuria disappearance after 4 days had a sensitivity of 88% and specificity of 85%. When patients fulfilled both cut-offs, the sensitivity and specificity were 89% and 97%., Conclusion: Acute focal bacterial nephritis was associated with fever of significantly longer duration after antimicrobial treatment, and it took a longer time for pyuria to disappear. Children with febrile UTI should be evaluated for AFBN if the fever persists ≥48 h after the initiation of antimicrobial treatment and if pyuria lasts for 4 days., (© 2019 Japan Pediatric Society.)