Impact of the Omicron Strain on Febrile Convulsions Requiring Hospitalization in Children: A Single-Center Observational Study.

BACKGROUND: The emergence of the Omicron strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the end of December 2021 has drastically increased the number of infected children in Japan, along with the number of children with febrile convulsions, but its clinical impact is unclear. MATERIALS AND METHODS: We compared the frequency of SARS-CoV-2 infection in children hospitalized with febrile convulsions with the frequency of SARS-CoV-2 infection in children with fever and respiratory symptoms without convulsions. RESULTS: In 2021 and 2022, 49 and 58 children required emergency hospitalization for febrile convulsions (FC group) with status epilepticus or cluster spasms, in which 24 and 38 children underwent a Filmarray® respiratory panel test (FA test), respectively, and others received a quantitative antigen test for SARS-CoV-2. In 2022, only six patients tested positive for SARS-CoV-2 (10.3%, 6/58). As a reference group, 655 children aged <10 years who underwent the FA test for fever and respiratory symptoms during the same period were investigated, and 4 (1.8%, 4/223) and 42 (9.7%, 42/432) tested positive for SARS-CoV-2 in 2021 and 2022, respectively. Rhinovirus/enterovirus (RV/EV) was the most frequently detected virus (40.3%, 264/655), followed by respiratory syncytial virus (RSV) (18.9%, 124/655) and parainfluenza virus 3 (PIV3) (7.8%, 51/655). There was no significant difference in the trend of detected viruses between the two groups. CONCLUSIONS: The frequency and severity of febrile convulsions requiring hospitalization associated with SARS-CoV-2 infection of the Omicron strain may be similar to that of other respiratory viruses in children.

Pseudomonas paralcaligenes sp. nov., isolated from a hospitalized patient.

A Gram-stain-negative, aerobic, rod-shaped, non-endospore-forming bacterium, designated as strain MRCP1333T, was isolated from a faecal sample from a hospital patient in Japan. MRCP1333T grew at temperatures of 15-40 °C (optimum 25-35 °C), with 1.0-3.0 % (w/v, 171-513 mM) NaCl [optimum 1-2 % (w/v), 171-342 mM], and at pH 6.0-9.5 (optimum pH 7.0-8.0). The results of phylogenetic analysis based on the sequences of the 16S rRNA gene and the 53 genes encoding the bacterial ribosome protein subunits indicated that MRCP1333T represented a member of the Pseudomonas aeruginosa group, most closely related to Pseudomonas alcaligenes. Whole-genome comparisons, using average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity, confirmed that MRCP1333T represented a distinct species in the P. aeruginosa group. Phenotypic characterization tests demonstrated utilization by this strain of citrate, glycerol, and d-malic acid, the ability to reduce nitrite to nitrogen and the ability of this strain to grow in the presence of minocycline and tetrazolium blue, distinguishing this strain from P. alcaligenes and other closely related species of the P. aeruginosa group. The major fatty acids of MRCP1333T were summed feature 8 (C18 : 1ω7c/C18 : 1ω6c; 38.4 %), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 21.1 %) and C16 : 0 (20.6 %). The DNA G+C content of MRCP1333T was 66.5 mol%. Genetic and phenotypic evidence indicated that MRCP1333T should be classified as representing a novel species, for which the name Pseudomonas paralcaligenes sp. nov. is proposed. The type strain is MRCP1333T (=LMG 32254T,=JCM 34250T).

Membranous nephropathy in a female patient with X-linked thrombocytopenia.

BACKGROUND: Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency characterized by thrombocytopenia and eczema and is caused by a mutation in the WAS gene. WAS has heterogeneous clinical manifestations, and its clinically milder form is called X-linked thrombocytopenia (XLT). Patients with WAS/XLT sometimes have kidney complications, the most common of which is immunoglobulin (Ig)A nephropathy associated with aberrant glycosylation of IgA. CASE DIAGNOSIS/TREATMENT: The patient was a 6-year-old girl who was diagnosed with female XLT at the age of 4 years; she presented with microscopic hematuria and proteinuria at a school urinalysis. Her father had thrombocytopenia and IgA nephropathy while in his 20 s. The patient and her father had the same WAS gene mutations. A kidney biopsy was performed, and no abnormal findings were observed by light microscopy. Immunofluorescence analysis revealed a granular pattern of IgG staining along the capillary wall. Electron microscopy revealed small electron-dense deposits in subepithelial lesions. Consequently, we diagnosed her with membranous nephropathy (MN). Tissue PLA2R and THSD7A were negative, and she was judged unlikely to have secondary MN on the basis of blood test findings and IgG staining. We started the administration of angiotensin-converting enzyme inhibitors, and her proteinuria gradually decreased. CONCLUSION: To our knowledge, this is the first report of MN in a female WAS/XLT patient. WAS protein expression defects affect all immune system cells; however, the mechanisms underlying the occurrence of autoimmunity are not completely understood. In WAS/XLT patients, MN may develop as a result of increased autoantibody production, similar to other types of immunodeficiency.

An adolescent girl diagnosed with IgA nephropathy following the first dose of the COVID-19 vaccine.

There has been growing interest in reported cases of IgA nephropathy (IgAN) flare-up following administration of the coronavirus disease 2019 (COVID-19) vaccine. Our patient is a previously healthy 17-year-old girl who presented with a 10-year history of microscopic hematuria. Because there were no abnormal findings in blood examination or ultrasonography, we followed her up twice per year as asymptomatic hematuria. Although she never developed gross hematuria when she had upper respiratory infections or received an influenza vaccine, she presented with gross hematuria and proteinuria within a few days after receiving the first dose of the Pfizer vaccine. We performed renal biopsy 2 weeks after the first vaccination. It revealed minor glomerular abnormalities with diffuse mesangial IgA deposits, and we diagnosed her with mild IgAN. Gross hematuria was detected after both the first and second doses, although it changed to microscopic hematuria within 1 week. Additionally, her proteinuria resolved spontaneously approximately 10 days after the second dose of the vaccine. Therefore, we opted to observe her without administering medication. The causation between COVID-19 vaccination and IgAN flare-up remains unclear. Several reports showed IgAN patients presenting gross hematuria following the second dose of the Pfizer or Moderna vaccines. However, our patient developed gross hematuria and proteinuria even after the first dose and without known severe acute respiratory syndrome coronavirus 2 exposure. Nephrologists should inform both patients with IgAN and those with asymptomatic hematuria that this side effect can occur even after the first vaccination.

Obesity and febrile urinary tract infection in young children.

BACKGROUND: Obesity is a risk factor for infectious diseases. However, the relationship between obesity and febrile urinary tract infection (fUTI) is controversial. This study aimed to determine the relationship between obesity and fUTI in young children. METHODS: We analyzed the medical records of children aged <2 years who were admitted to our hospital because of fever between April 2013 to March 2018. The children were categorized into three groups of non-obese, overweight, and obese according to the World Health Organization weight-for-length curves for children aged <2 years. RESULTS: A total of 600 patients were enrolled in this study, of whom 118 were diagnosed with first fUTI. Patients in the fUTI group were younger than those in the control group (patients who were diagnosed with other febrile diseases) (5 ± 5.11 vs 11 ± 6.53 months; P < 0.001). There were no significant differences in the populations of overweight and obese children between the fUTI and control groups. In the fUTI group, the duration of fever, types of pathogen, recurrent rate, the grades of vesicoureteral reflux, and renal scarring were not associated with obesity. The white blood cell count and C-reactive protein levels were not significantly different among the three weight-for-length categories. The same results were obtained when the fUTI group was compared with an age-matched control group (n = 192, 4 ± 2.55 months old; P = 0.261). CONCLUSIONS: Obesity is not a significant risk factor for fUTI in febrile hospitalized young children. Our study suggests that conducting urinalysis for febrile young children without obvious sources, irrespective of obesity, should be considered.

Central diabetes insipidus developing in a 6-year-old patient 4 years after the remission of unifocal bone Langerhans cell histiocytosis.

A six-year-old boy was referred with a one-and-a-half months history of polyuria and polydipsia. At the age of two, he had a single lytic bone lesion in his femoral head, diagnosed as Langerhans cell histiocytosis (LCH) by biopsy at another hospital. As no other affected organs were detected and the affected bone lesion was self-limited, he was not followed up afterward and was doing well. He was diagnosed with diabetes insipidus (DI) by confirming hypernatremia (Na: 148 mEq/l) with hyperosmolar serum (s-Osm 298 mOSM/kg) and inappropriately diluted urine (u-Osm 205 mOSM/kg). His polyuria and polydipsia improved dramatically using the perioral diuretic hormone, and other pituitary functions were not impaired. Magnetic resonance imaging revealed an enlarged pituitary stalk. Sensitive and specific biomarkers of germ cell tumors, including alpha-fetoprotein, placental alkaline phosphatase, and ß-hCG in the cerebrospinal fluid, were not detected, indicating relapse of LCH. Genetic analysis revealed a BRAF V600E mutation in the primary bone lesion. We recommend systematic follow-up of patients with a history of LCH, even non-CNS single-system single-site disease, especially with BRAF V600E mutation.

An eight-year-old girl with autoimmune polyglandular syndrome type3A that developed during the course of primary Epstein-Barr virus (EBV) infection: clinical implication of EBV in autoimmune thyroid disease.

An eight-year-old girl was admitted for prolonged fever and general fatigue. Bilateral reddened and swollen tonsils covered with white fur and increased numbers of atypical lymphocytes in blood led to a diagnosis of infectious mononucleosis (IM) due to primary Epstein-Barr virus (EBV) infection, which was confirmed by a positive anti-EBV viral capsid antigen IgM antibody reaction. She had a swollen thyroid gland and glycosuria at admission, which persisted after IM resolved. Undetectable thyroid-stimulating hormone (TSH), increased thyroid hormone and elevated HbA1c levels led to a diagnosis of autoimmune polyglandular syndrome type3A, based on the presence of antibodies for TSH receptor and glutamic acid decarboxylase. The clinical significance of EBV infection in the development of autoimmune endocrine disorders has been discussed.

TARC and MDC are produced by CD40 activated human B cells and are elevated in the sera of infantile atopic dermatitis patients.

We report here that human B cells produce thymus and activation-regulated chemokine (TARC/CCL17) and macrophage derived chemokine (MDC/CCL22) if stimulated with anti-CD40 and IL-4. The production was determined by both protein and mRNA level using specific ELISA and semi-quantitative RT-PCR methods. Since the ligand of the TARC and MDC is CCR4, which is specifically expressed on Th2 type T cells, the production of these CC chemokines is likely to play important roles in the T cell and B cell interaction. Consistent with this, ovalbumin (OVA) specific IgE levels, which reflect the T-B cell interaction, are significantly correlated with the amounts of TARC and MDC in sera. Furthermore, we found that TARC and MDC levels are significantly increased in the sera obtained from patients with atopic dermatitis, and that the amounts are correlated with the severity of atopic dermatitis. Since CD40 ligand and IL-4 are produced by activated T helper cells, these results indicate that TARC and MDC produced by B cells play important roles in the production of antigen specific IgE by the T-B cell interaction and in the pathogenesis of allergic disease.