Calculating the fraction of Kawasaki disease potentially attributable to seasonal pathogens: a time series analysis.

Background: Kawasaki disease is an acute, febrile, systemic vasculitis of children that primarily affects medium-sized blood vessels with a tropism for the coronary arteries. Although the etiological factors remain unknown, infections have been suggested as the trigger of Kawasaki disease. We sought to calculate the fraction of Kawasaki disease potentially attributable to seasonal infections. Methods: This cohort study used a population-based time series analysis from the French hospitalisation database (Programme de Médicalisation des Systèmes d'Information), which includes all inpatients admitted to any public or private hospital in France. We included all children aged 0-17 years hospitalised for Kawasaki disease in France over 13 years. The monthly incidence of Kawasaki disease per 10,000 children over time was analysed by a quasi-Poisson regression model. The model accounted for seasonality by using harmonic terms (a pair of sines and cosines with 12-month periods). The circulation of eight common seasonal pathogens (adenovirus, influenza, metapneumovirus, Mycoplasma pneumoniae, norovirus, rhinovirus, rotavirus, respiratory syncytial virus, and Streptococcus pneumonia) over the same period was included in the model to analyse the fraction of Kawasaki disease potentially attributable to each pathogen. Infections were identified on the basis of polymerase chain reaction or rapid antigen testing in hospital laboratories. Findings: Between Jan 1, 2007, and Dec 31, 2019, we included 10,337 children with Kawasaki disease and 442,762 children with the selected infectious diseases. In the Kawasaki disease cohort, the median age [IQR] was 2 [0-4] years, 6164 [59.6%] were boys. Adenovirus infection was potentially responsible for 24.4% [21.5-27.8] (p < 0.001) of Kawasaki diseases, Norovirus for 6.7% [1.3-11.2] (p = 0.002), and RSV 4.6% [1.2-7.8] (p = 0.022). Sensitivity analyses found similar results. Interpretation: This cohort study of data from a comprehensive national hospitalisation database indicated that approximately 35% of Kawasaki diseases was potentially attributable to seasonal infections. Funding: None.

Detection of enterovirus in cerebrospinal fluids without pleocytosis in febrile infants under 3 months old reduces antibiotherapy duration.

Background: Infants under 3 months old with fever often receive empirical antibiotic treatment. Enterovirus is one of the leading causes of infection and aseptic meningitis but is not systematically screened. We aimed to evaluate enterovirus positive RT-PCR proportion in cerebrospinal fluid (CSF) with no pleocytosis and its impact on antibiotic treatment duration. Methods: During the enterovirus endemic season, from 2015 to 2018, we retrospectively studied infants under 3 months old, consulting for fever without cause, with normal CSF analysis, and receiving empirical antibiotic treatment. Clinical and biological data were analyzed, notably enterovirus RT-PCR results. The primary outcome was the duration of antibiotic therapy. Results: 92 patients were recruited. When tested, 41% of infants were positive for enterovirus, median antibiotic duration was reduced in enterovirus positive in comparison to negative patients with respectively 1.9 [interquartile range (IQR), 1.7-2] vs. 4.1 [IQR, 2-6], p < 0.001. No clinical nor biological features differed according to the enterovirus status. Conclusion: In this population, enterovirus positive CSF are frequent despite the absence of pleocytosis. However, its research was not guided by clinical or biological presentations. Systematic and routine use of enterovirus RT-PCR during enterovirus season, regardless of CSF cell count, could reduce the prescription of antibiotics in febrile infants under 3 months old without clinical orientation.

Influence of FLG loss-of-function mutations in host-microbe interactions during atopic skin inflammation.

BACKGROUND: Loss-of-function mutations in the filaggrin (FLG) gene directly alter skin barrier function and critically influence atopic inflammation. While skin barrier dysfunction, Th2-associated inflammation and bacterial dysbiosis are well-known characteristics of atopic dermatitis (AD), the mechanisms interconnecting genotype, transcriptome and microbiome remain largely elusive. OBJECTIVE: In-depth analysis of FLG genotype-associated skin gene expression alterations and host-microbe interactions in AD. METHODS: Multi-omics characterization of a cohort of AD patients carrying heterozygous loss-of-function mutations in the FLG gene (ADMut) (n = 15), along with matched wild-type (ADWt) patients and healthy controls. Detailed clinical characterization, microarray gene expression and 16 S rRNA-based microbial marker gene data were generated and analyzed. RESULTS: In the context of filaggrin dysfunction, the transcriptome was characterized by dysregulation of barrier function and water homeostasis, while the lesional skin of ADWt demonstrated the specific upregulation of pro-inflammatory cytokines and T-cell proliferation. S. aureus dominated the microbiome in both patient groups, however, shifting microbial communities could be observed when comparing healthy with non-lesional ADWt or ADMut skin, offering the opportunity to identify microbe-associated transcriptomic signatures. Moreover, an AD core signature with 28 genes, including CCL13, CCL18, BTC, SCIN, RAB31 and PCLO was identified. CONCLUSIONS: Our integrative approach provides molecular insights for the concept that FLG loss-of-function mutations are a genetic shortcut to atopic inflammation and unravels the complex interplay between genotype, transcriptome and microbiome in the human holobiont.

Characterization and functional interrogation of the SARS-CoV-2 RNA interactome.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the COVID-19 pandemic, which has led to a devastating global health crisis. The emergence of variants that escape neutralizing responses emphasizes the urgent need to deepen our understanding of SARS-CoV-2 biology. Using a comprehensive identification of RNA-binding proteins (RBPs) by mass spectrometry (ChIRP-MS) approach, we identify 107 high-confidence cellular factors that interact with the SARS-CoV-2 genome during infection. By systematically knocking down their expression in human lung epithelial cells, we find that the majority of the identified RBPs are SARS-CoV-2 proviral factors. In particular, we show that HNRNPA2B1, ILF3, QKI, and SFPQ interact with the SARS-CoV-2 genome and promote viral RNA amplification. Our study provides valuable resources for future investigations into the mechanisms of SARS-CoV-2 replication and the identification of host-centered antiviral therapies.

Transcriptome-based identification of novel endotypes in adult atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a frequent and heterogeneous inflammatory skin disease, for which personalized medicine remains a challenge. High-throughput approaches have improved understanding of the complex pathophysiology of AD. However, a purely data-driven AD classification is still lacking. METHODS: To address this question, we applied an original unsupervised approach on the largest available transcriptome dataset of AD lesional (n = 82) and healthy (n = 213) skin biopsies. RESULTS: Taking into account pathological and physiological state, a variance-based filtering revealed 222 AD-specific hyper-variable genes that efficiently classified the AD samples into 4 clusters that turned out to be clinically and biologically distinct. Comparison of gene expressions between clusters identified 3 sets of upregulated genes used to derive metagenes (MGs): MG-I (19 genes) was associated with IL-1 family signaling (including IL-36A and 36G) and skin remodeling, MG-II (23 genes) with negative immune regulation (including IL-34 and 37) and skin architecture, and MG-III (17 genes) with B lymphocyte immunity. Sample clusters differed in terms of disease severity (p = .02) and S. aureus (SA) colonization (p = .02). Cluster 1 contained the most severe AD, highest SA colonization, and overexpressed MG-I. Cluster 2 was characterized by less severe AD, low SA colonization, and high MG-II expression. Cluster 3 included mild AD, mild SA colonization, and mild expression of all MGs. Cluster 4 had the same clinical features as cluster 3 but had hyper-expression of MG-III. Last, we successfully validated our method and results in an independent cohort. CONCLUSION: Our study revealed unrecognized AD endotypes with specific underlying biological pathways, highlighting novel pathophysiological mechanisms. These data could provide new insights into personalized treatment strategies.

A comparison of individual and ecological indicators of social deprivation and their association with hospital efficiency in the context of infectious diseases in two French general paediatric departments.

BACKGROUND: To identify deprivation indicators usable in everyday practice and included in medico-administrative databases, particularly with infectious diseases, which represent the greatest proportion of hospitalizations. Our objective was to compare ecological indicators to individual questionnaires and apply both types to the study of the impact of deprivation on hospital efficiency. METHODS: We conducted an epidemiological observational prospective multicentre study in two French public hospitals between 20 October 2016 and 20 March 2017. Children hospitalized for one of the four most common infectious diseases were included and their parents were asked to answer the Evaluation of Precarity and Inequalities in Health Examination Centers (EPICES) questionnaire. The ecological indicator French DEPrivation index (FDep) was derived from patients' address, both at the zip code and at a smaller geographical area (IRIS [ilôts de regroupement pour l'information statistique]) level. Correlation and concordance between the three indicators were assessed. The endpoint used to assess the impact on hospital efficiency was the ratio between patients' length of stay (LOS) and the national LOS of their disease-related group. RESULTS: Data were available for 540 patients with a mean age of 9 mo. A total of 56.1% of patients were considered deprived with EPICES, 50.4% with zip code FDep and 45.7% with IRIS FDep. Concordance between EPICES and either type of FDep was <0.1. There was no increase in LOS compared with national LOS with any of the indicators. CONCLUSIONS: Individual and ecological indicators do not measure the same aspects of deprivation. The decision to use one or the other must be carefully weighed when studying the impact of deprivation on the healthcare system.

Five Functional Aspects of the Epidermal Barrier.

The epidermis is a living, multilayered barrier with five functional levels, including a physical, a chemical, a microbial, a neuronal, and an immune level. Altogether, this complex organ contributes to protect the host from external aggression and to preserve its integrity. In this review, we focused on the different functional aspects.

Machine Learning Approaches in Study of Multiple Sclerosis Disease Through Magnetic Resonance Images.

Multiple sclerosis (MS) is one of the most common autoimmune diseases which is commonly diagnosed and monitored using magnetic resonance imaging (MRI) with a combination of clinical manifestations. The purpose of this review is to highlight the main applications of Machine Learning (ML) models and their performance in the MS field using MRI. We reviewed the articles of the last decade and grouped them based on the applications of ML in MS using MRI data into four categories: 1) Automated diagnosis of MS, 2) Prediction of MS disease progression, 3) Differentiation of MS stages, 4) Differentiation of MS from similar disorders.

Coronavirus Disease 2019 Pandemic: Impact Caused by School Closure and National Lockdown on Pediatric Visits and Admissions for Viral and Nonviral Infections-a Time Series Analysis.

A time series analysis of 871 543 pediatric emergency visits revealed that the coronavirus disease 2019 (COVID-19) lockdown and school closures were associated with a significant decrease in infectious diseases disseminated through airborne or fecal-oral transmission: common cold, gastroenteritis, bronchiolitis, and acute otitis. No change was found for urinary tract infections.

Different Clinical Presentations and Outcomes of Disseminated Varicella in Children With Primary and Acquired Immunodeficiencies.

Primary infection with varicella-zoster virus (VZV) causes chickenpox, a benign and self-limited disease in healthy children. In patients with primary or acquired immunodeficiencies, primary infection can be life-threatening, due to rapid dissemination of the virus to various organs [lung, gastrointestinal tract, liver, eye, central nervous system (CNS)]. We retrospectively described and compared the clinical presentations and outcomes of disseminated varicella infection (DV) in patients with acquired (AID) (n= 7) and primary (PID) (n= 12) immunodeficiencies. Patients with AID were on immunosuppression (mostly steroids) for nephrotic syndrome, solid organ transplantation or the treatment of hemopathies, whereas those with PID had combined immunodeficiency (CID) or severe CID (SCID). The course of the disease was severe and fulminant in patients with AID, with multiple organ failure, no rash or a delayed rash, whereas patients with CID and SICD presented typical signs of chickenpox, including a rash, with dissemination to other organs, including the lungs and CNS. In the PID group, antiviral treatment was prolonged until immune reconstitution after bone marrow transplantation, which was performed in 10/12 patients. Four patients died, and three experienced neurological sequelae. SCID patients had the worst outcome. Our findings highlight substantial differences in the clinical presentation and course of DV between children with AID and PID, suggesting differences in pathophysiology. Prevention, early diagnosis and treatment are required to improve outcome.

A deep intronic splice mutation of STAT3 underlies hyper IgE syndrome by negative dominance.

Heterozygous in-frame mutations in coding regions of human STAT3 underlie the only known autosomal dominant form of hyper IgE syndrome (AD HIES). About 5% of familial cases remain unexplained. The mutant proteins are loss-of-function and dominant-negative when tested following overproduction in recipient cells. However, the production of mutant proteins has not been detected and quantified in the cells of heterozygous patients. We report a deep intronic heterozygous STAT3 mutation, c.1282-89C>T, in 7 relatives with AD HIES. This mutation creates a new exon in the STAT3 complementary DNA, which, when overexpressed, generates a mutant STAT3 protein (D427ins17) that is loss-of-function and dominant-negative in terms of tyrosine phosphorylation, DNA binding, and transcriptional activity. In immortalized B cells from these patients, the D427ins17 protein was 2 kDa larger and 4-fold less abundant than wild-type STAT3, on mass spectrometry. The patients' primary B and T lymphocytes responded poorly to STAT3-dependent cytokines. These findings are reminiscent of the impaired responses of leukocytes from other patients with AD HIES due to typical STAT3 coding mutations, providing further evidence for the dominance of the mutant intronic allele. These findings highlight the importance of sequencing STAT3 introns in patients with HIES without candidate variants in coding regions and essential splice sites. They also show that AD HIES-causing STAT3 mutant alleles can be dominant-negative even if the encoded protein is produced in significantly smaller amounts than wild-type STAT3.

Inherited IFNAR1 deficiency in otherwise healthy patients with adverse reaction to measles and yellow fever live vaccines.

Vaccination against measles, mumps, and rubella (MMR) and yellow fever (YF) with live attenuated viruses can rarely cause life-threatening disease. Severe illness by MMR vaccines can be caused by inborn errors of type I and/or III interferon (IFN) immunity (mutations in IFNAR2, STAT1, or STAT2). Adverse reactions to the YF vaccine have remained unexplained. We report two otherwise healthy patients, a 9-yr-old boy in Iran with severe measles vaccine disease at 1 yr and a 14-yr-old girl in Brazil with viscerotropic disease caused by the YF vaccine at 12 yr. The Iranian patient is homozygous and the Brazilian patient compound heterozygous for loss-of-function IFNAR1 variations. Patient-derived fibroblasts are susceptible to viruses, including the YF and measles virus vaccine strains, in the absence or presence of exogenous type I IFN. The patients' fibroblast phenotypes are rescued with WT IFNAR1 Autosomal recessive, complete IFNAR1 deficiency can result in life-threatening complications of vaccination with live attenuated measles and YF viruses in previously healthy individuals.

Incomplete penetrance for isolated congenital asplenia in humans with mutations in translated and untranslated RPSA exons.

Isolated congenital asplenia (ICA) is the only known human developmental defect exclusively affecting a lymphoid organ. In 2013, we showed that private deleterious mutations in the protein-coding region of RPSA, encoding ribosomal protein SA, caused ICA by haploinsufficiency with complete penetrance. We reported seven heterozygous protein-coding mutations in 8 of the 23 kindreds studied, including 6 of the 8 multiplex kindreds. We have since enrolled 33 new kindreds, 5 of which are multiplex. We describe here 11 new heterozygous ICA-causing RPSA protein-coding mutations, and the first two mutations in the 5'-UTR of this gene, which disrupt mRNA splicing. Overall, 40 of the 73 ICA patients (55%) and 23 of the 56 kindreds (41%) carry mutations located in translated or untranslated exons of RPSA. Eleven of the 43 kindreds affected by sporadic disease (26%) carry RPSA mutations, whereas 12 of the 13 multiplex kindreds (92%) carry RPSA mutations. We also report that 6 of 18 (33%) protein-coding mutations and the two (100%) 5'-UTR mutations display incomplete penetrance. Three mutations were identified in two independent kindreds, due to a hotspot or a founder effect. Finally, RPSA ICA-causing mutations were demonstrated to be de novo in 7 of the 23 probands. Mutations in RPSA exons can affect the translated or untranslated regions and can underlie ICA with complete or incomplete penetrance.

Kaposi sarcoma, oral malformations, mitral dysplasia, and scoliosis associated with 7q34-q36.3 heterozygous terminal deletion.

Chromosome 7 germline macrodeletions have been implicated in human congenital malformations and developmental delays. We herein report a novel heterozygous macrodeletion of 7q34-q36.3 in a 16-year-old girl originally from West Indies. Similar to previously reported cases of germline chromosome 7q terminal deletions, our patient has dental malposition, and developmental (growth and intellectual) delay. Novel phenotypic features include endemic Kaposi sarcoma (KS), furrowed tongue, thoracolumbar scoliosis, and mild mitral valve dysplasia. The occurrence of human herpes virus 8-driven KS, in a child otherwise normally resistant to other infectious agents and without any other tumoral lesion, points to a very selective immunodeficiency. While defects in organogenesis have been described with such macrodeletions, this is the first report of immunodeficiency and cancer predisposition.

Circulating cell-free BRAFV600E as a biomarker in children with Langerhans cell histiocytosis.

The BRAFV600E mutation is reported in half of patients with Langerhans cell histiocytosis (LCH). This study investigated the detection of the BRAFV600E allele in circulating cell-free (ccf) DNA in a paediatric LCH cohort. Children with BRAFV600E -mutated LCH were investigated to detect ccf BRAFV600E at diagnosis (n = 48) and during follow-up (n = 17) using a picolitre-droplet digital PCR assay. At diagnosis, ccf BRAFV600E was positive in 15/15 (100%) patients with risk-organ positive multisystem (RO+ MS) LCH, 5/12 (42%) of patients with RO- MS LCH and 3/21 (14%) patients with single-system (SS) LCH (P < 0·001, Fisher's exact test). The positive BRAFV600E load was higher for RO+ patients (mean, 2·90%; range, 0·04-11·4%) than for RO- patients (mean, 0·16%; range, 0·01-0·39) (P = 0·003, Mann-Whitney U test). After first-line vinblastine-steroid induction therapy, 7/7 (100%) of the non-responders remained positive for ccf BRAFV600E compared to 2/4 (50%) of the partial-responders and 0/4 of the complete responders (P = 0·002, Fisher's exact test). Six children treated with vemurafenib showed a clinical response that was associated with a decrease in the ccf BRAFV600E load at day 15. Thus, ccf BRAFV600E is a promising biomarker for monitoring the response to therapy for children with RO+ MS LCH or RO- LCH resistant to first-line chemotherapy.

Mammalian target of rapamycin inhibition counterbalances the inflammatory status of immune cells in patients with chronic granulomatous disease.

BACKGROUND: Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defective production of reactive oxygen species in phagocytic cells that results in life-threatening infections and severe inflammatory manifestations. The treatment of inflammatory manifestations remains challenging because it can be associated with an increased risk of infections. Previous studies have shown that phagocytes from patients with CGD display a defect in autophagy and a reactive oxygen species-independent activation of the inflammasome. OBJECTIVE: Because the intersections between autophagy and the inflammasome have been observed in patients with various diseases and microbial infections, we investigated the possible benefit of restoring the autophagy defect through rapamycin, a potent autophagy inducer, in the setting of CGD. METHODS: We studied 15 patients given a diagnosis of CGD and followed in our institution. All patients were free of any active infection at the time of the study. RESULTS: We show that patients with CGD present a consistent inflammatory phenotype defined by (1) increased nonclassical and intermediate monocytes, (2) a proinflammatory state of mononuclear phagocytes with increased IL-1ß and TNF-α content, (3) a TH17 bias of CD4+ T cells, (4) and an increase in IL-17A-secreting neutrophil numbers. We document the reversion of CGD inflammatory status by the mammalian target of rapamycin inhibitor rapamycin on the different immune cell subsets. We also provide evidence for the enhancement of rapamycin's inhibitory effect on IL-1ß secretion by the IL-1 receptor antagonist anakinra in phagocytes of patients with CGD. CONCLUSION: Altogether, these data open new therapeutic approaches for CGD-related inflammatory manifestations.

Coronary artery abnormalities in children with systemic-onset juvenile idiopathic arthritis.

Still's disease (Systemic-onset Juvenile Idiopathic Arthritis: SoJIA) is characterised by high-spiking daily fevers, arthritis and evanescent rashes. Diagnosis of Still's disease is often challenging. Infectious diseases and other inflammatory conditions, especially in young children, Kawasaki disease may look similar. Clinicians often rely on echocardiographic evidence of coronary artery abnormalities to differentiate between Kawasaki disease and Still's disease. Coronary artery dilation would typically favour the diagnosis of Kawasaki disease. We present four children with Still's disease and coronary artery abnormalities who were initially misdiagnosed as Kawasaki disease. The first patient had pericarditis and an irregular wall of the left coronary artery, without dilation on echocardiography. The second patient had a left coronary artery dilatation and a pericarditis. The third patient had thickened left coronary artery walls, and the fourth patient had a hyperechogenicity of the left and right coronary arteries. They received IVIG without success. The diagnosis of Still's disease was made secondary with evidence of persistent arthritis. All but one patient finally needed biologic treatments. Coronary abnormalities may be observed during various febrile conditions and do not exclude the diagnosis of Still's disease.