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Background Coronavirus Disease 2019 (COVID-19) is a viral pandemic disease that may induce severe pneumonia in humans. In this paper, we investigated the putative implication of 12 vaccines, including BCG, OPV and MMR in the protection against COVID-19. Sequences of the main antigenic proteins in the investigated vaccines and SARS-CoV-2 proteins were compared to identify similar patterns. The immunogenic effect of identified segments was, then, assessed using a combination of structural and antigenicity prediction tools. Results A total of 14 highly similar segments were identified in the investigated vaccines. Structural and antigenicity prediction analysis showed that, among the identified patterns, three segments in Hepatitis B, Tetanus, and Measles proteins presented antigenic properties that can induce putative protective effect against COVID-19. Conclusions Our results suggest a possible protective effect of HBV, Tetanus and Measles vaccines against COVID-19, which may explain the variation of the disease severity among regions.

MyD88 is a key downstream adapter for most Toll-like receptors (TLRs) and interleukin-1 receptors (IL-1Rs). MyD88 deficiency in mice leads to susceptibility to a broad range of pathogens in experimental settings of infection. We describe a distinct situation in a natural setting of human infection. Nine children with autosomal recessive MyD88 deficiency suffered from life-threatening, often recurrent pyogenic bacterial infections, including invasive pneumococcal disease. However, these patients were otherwise healthy, with normal resistance to other microbes. Their clinical status improved with age, but not due to any cellular leakiness in MyD88 deficiency. The MyD88-dependent TLRs and IL-1Rs are therefore essential for protective immunity to a small number of pyogenic bacteria, but redundant for host defense to most natural infections.

Wiskott-Aldrich syndrome (WAS) is an inborn error of immunity caused by loss-of-function mutations in the WAS gene, which encodes WASp, a key regulator of cytoskeletal remodeling. In addition to microthrombocytopenia, affected individuals often present with recurrent infections, eczema, eosinophilia and elevated IgE levels, suggesting a potential pathophysiological overlap with STAT3 hyper-IgE syndrome (HIES). Given these shared features, we investigated the immunogenetic characteristics of three WAS patients and explored the IL-6/STAT3 pathway as a potential underlying mechanism. Flow cytometry revealed absent WASp expression in P1 and P3, while P2 showed reduced level. Genetic analysis identified three hemizygous mutations: A56V substitution within the WH1 domain in P1, and two splice site mutations, c.360 + 1G>T and c.734 + 1G>C, in P2 and P3, respectively. Interestingly, all WAS patients showed impaired STAT3 phosphorylation in T cells following IL-6 stimulation and SOCS3 induction was markedly decreased. These results further suggest a potential link between WASp and STAT3. Considering the interaction of WASp with DOCK8-WIP in lymphocytes and the critical role of DOCK8 in regulating STAT3 phosphorylation following IL-6 stimulation, we analyzed DOCK8 expression in lymphoblastoid cell lines. We demonstrated normal DOCK8 levels suggesting that STAT3 signaling defect is due to the absence of WASp rather than DOCK8 loss. Our results demonstrate the impairment of T cell IL-6/STAT3 pathway in WAS patients which could underlie, in part, the overlapping phenotype with HIES patients.

Background The intra-host diversity of SARS-CoV-2 in pediatric populations remains insufficiently studied. To address this significant knowledge gap, the present study investigates the intra-host variability of SARS-CoV-2 in both immunocompetent and immunodeficient children, including those with severe cases. The research encompasses both short-term and long-term infections, aiming to provide a comprehensive understanding of viral dynamics in these vulnerable groups. Materials and methods This study analyzed 47 pediatric COVID-19 patients: 37 with short-term infections and 10 with long-term infections including 3 immunodeficient cases. Viral RNA was extracted and detected using RT-qPCR, followed by whole-genome sequencing (WGS) using the Illumina COVIDSeq assay. Bioinformatics analysis was performed with the nextflow/viralrecon pipeline. The number of single nucleotide polymorphisms (SNPs) and the frequency of Major (M-SNPs) and minor (m-SNPs) missense SNPs were analyzed using the ggplot2 R package and GraphPad Prism software, respectively. Results A total of 96 SARS-CoV-2 sequences from 45 patients (35 short-term and 10 long-term shedders), were classified into four variants: Alpha, B.1.160, Delta, and Omicron. SNPs were common across SARS-CoV-2 variants (88.21%-100%), with frequent cytosine-to-thymidine (C > T) substitutions (44.05%-52.85%). Missense mutations were also prominent (57.52% to 80.32%). Variability in SNPs numbers was observed over time in Delta and Omicron variants, particularly in severe and immunodeficient cases. Missense m-SNPs exhibited variation in long-term shedders, especially among severe immunocompetent and immunodeficient patients. Conclusion Our findings revealed significant intra-host variability in SARS-CoV-2 among severe and immunodeficient pediatric patients. These results underscore the critical importance of continuous surveillance of viral variants within pediatric populations to enhance our understanding of their impact on disease progression and clinical outcomes.

The transcription factors signal transducer and activator of transcription 1 and 3 (STAT1 and STAT3) play essential roles in immune and non-immune cell function. The clinical characterization of patients carrying germline gain or loss-of-function (GOF or LOF) mutations in these genes has significantly improved our understanding of their physiological and pathological roles. Although patients with LOF, GOF, and GOF mutations are classified into distinct inborn errors of immunity (IEI) categories, namely Hyper-IgE Syndrome, Regulatory T cell defects, and predisposition to Mucocutaneous Candidiasis, respectively, there is notable clinical overlap among these disorders. We describe a 17-year-old girl with recurrent lung infection leading to bronchiectasis, chronic onychomycosis, recurrent vulvovaginal candidiasis, and oral thrush. Additional findings included short stature, delayed puberty, and retained primary teeth. Laboratory results revealed eosinophilia and elevated IgE serum levels, with a NIH HIES score of 53. A rare heterozygous deletion within the 3'UTR of the gene (c.*351_*353del) was identified through a candidate gene approach. Although the variant is in a non-coding region, increased phosphorylation and elevated suppressor of cytokine signaling 3 (SOCS3) expressions suggested a potential GOF effect. analysis further predicted that the deletion disrupts microRNA (miRNA) binding sites and RNA binding proteins (RBP), potentially impairing post-transcriptional regulation and contributing to overexpression. Given the complexity of the phenotype and the atypical location of the variation, whole-exome sequencing (WES) was performed, revealing a heterozygous missense mutation in the DNA-binding domain ( , ), previously reported in autosomal dominant chronic mucocutaneous candidiasis (AD-CMC). Functional assays on lymphocytes confirmed an increased phosphorylation compared to both LOF patient and healthy controls. This case highlights the diagnostic complexity of overlapping IEI phenotypes and the value of combining targeted and WES strategies. This dual molecular diagnosis, comprising a regulatory variant in and a pathogenic coding mutation in , emphasizes the need to include non-coding regions in genetic analyses. It also underscores the value of using techniques that offer a broader genomic view and capture all coding exons, enabling a more comprehensive correlation with the clinical and immunological phenotype.

During the last decades, the study of primary immunodeficiencies (PIDs) has contributed tremendously to unravel novel pathways involved in a variety of immune responses. Many of these PIDs have an autosomal recessive (AR) mode of inheritance. Thus, the investigation of the molecular basis of PIDs is particularly relevant in consanguineous populations from Middle East and North Africa (MENA). Although significant efforts have been made in recent years to develop genetic testing across the MENA region, few comprehensive studies reporting molecular basis of PIDs in these settings are available. Herein, we review genetic characteristics of PIDs identified in 168 patients from an inbred Tunisian population. A spectrum of 25 genes involved was analyzed. We show that AR forms compared to X-linked or autosomal dominant forms are clearly the most frequent. Furthermore, the study of informative consanguineous families did allow the identification of a novel hyper-IgE syndrome linked to phosphoglucomutase 3 mutations. We did also report a novel form of autoimmune lymphoproliferative syndrome caused by homozygous FAS mutations with normal or residual protein expression as well as a novel AR transcription factor 3 deficiency. Finally, we identified several founder effects for specific AR mutations. This did facilitate the implementation of preventive approaches through genetic counseling in affected consanguineous families. All together, these findings highlight the specific nature of highly consanguineous populations and confirm the importance of unraveling the molecular basis of genetic diseases in this context. Besides providing a better fundamental knowledge of novel pathways, their study is improving diagnosis strategies and appropriate care.

Hyper IgE syndromes (HIES) is a heterogeneous group of Inborn Errors of Immunity characterized by eczema, recurrent skin and lung infections associated with eosinophilia and elevated IgE levels. Autosomal dominant HIES caused by loss of function mutations in Signal transducer and activator of transcription 3 ( STAT3 ) gene is the prototype of these disorders. Over the past two decades, advent in genetic testing allowed the identification of ten other etiologies of HIES. Although Dedicator of Cytokinesis 8 (DOCK8) deficiency is no more classified among HIES etiologies but as a combined immunodeficiency, this disease, characterized by severe viral infections, food allergies, autoimmunity, and increased risk of malignancies, shares some clinical features with STAT3 deficiency. The present study highlights the diagnostic challenge in eleven patients with the clinical phenotype of HIES in a resource-limited region. Candidate gene strategy supported by clinical features, laboratory findings and functional investigations allowed the identification of two heterozygous STAT3 mutations in five patients, and a bi-allelic DOCK8 mutation in one patient. Whole Exome Sequencing allowed to unmask atypical presentations of DOCK8 deficiency in two patients presenting with clinical features reminiscent of STAT3 deficiency. Our study underlies the importance of the differential diagnosis between STAT3 and DOCK8 deficiencies in order to improve diagnostic criteria and to propose appropriate therapeutic approaches. In addition, our findings emphasize the role of NGS in detecting mutations that induce overlapping phenotypes.

Purpose Primary immunodeficiencies (PIDs) are a large group of diseases characterized by susceptibility to not only recurrent infections but also autoimmune diseases and malignancies. The aim of this study was to describe and analyze the distribution, clinical features and eventual outcome of PID among Tunisian patients. Methods We reviewed the record of 710 patients diagnosed with Primary Immunodeficiency Diseases (PIDs) from the registry of the Tunisian Referral Centre for PIDs over a 25-year period. Results The male-to-female ratio was 1.4. The median age at the onset of symptoms was 6 months and at the time of diagnosis 2 years. The estimated prevalence was 4.3 per 100,000 populations. The consanguinity rate was found in 58.2 % of families. According to the International Union of Immunological Societies classification, spectrums of PIDs were as follows: combined T-cell and B-cell immunodeficiency disorders account for the most common category (28.6 %), followed by congenital defects of phagocyte (25.4 %), other well-defined immunodeficiency syndromes (22.7 %), predominant antibody deficiency diseases (17.7 %), diseases of immune dysregulation (4.8 %), defect of innate immunity (0.4 %) and complement deficiencies (0.4 %). Recurrent infections, particularly lower airway infections (62.3 %), presented the most common manifestation of PID patients. The overall mortality rate was 34.5 %, mainly observed with combined immunodeficiencies. Conclusion The distribution of PIDs was different from that reported in Western countries, with a particularly high proportion of Combined Immunodeficiencies and phagocyte defects in number and/or function. More is needed to improve PID diagnosis and treatment in our country.

Background Primary Immunodeficiency disorders (PID) can increase the risk of severe COVID-19 and prolonged infection. This study investigates the duration of SARS-CoV-2 excretion and the genetic evolution of the virus in pediatric PID patients as compared to immunocompetent (IC) patients. Materials and methods A total of 40 nasopharyngeal and 24 stool samples were obtained from five PID and ten IC children. RNA detection was performed using RT-qPCR, and whole-genome sequencing was conducted with the NexSeq 1000 platform. Data analysis used the nextflow/viralrecon pipeline. Hotspot amino acid frequencies were investigated using GraphPad Prism v10. Phylodynamic analysis was conducted with BEAST software. Results In IC children, the viral excretion period lasted up to 14 days in nasopharyngeal swabs, with an average duration of 7 days, and ranged from 7 to 14 days in stool samples. In PID patients, the viral RNA was detected in nasopharyngeal for periods between 7 and 28 days, with an average duration of 15 days, and up to 28 days in stool samples. Two SARS-CoV-2 variants were detected in PID patients: Delta (AY.122) and Omicron (BA.1.1). Patients with antibody and combined deficiencies, exhibited the most prolonged shedding periods in both nasopharyngeal and stool samples and one patient presented complications and fatal outcome. Specific Hotspot amino acid changes were detected in PID: A2821V and R550H (ORF1ab). Conclusion Our findings underscore the prolonged excretion of SARS-CoV-2 RNA in patients with antibody and combined deficiencies. Thus, specialized care is essential for effectively managing PID patients.

ALPS and IPEX are two well-characterized inborn errors of immunity with immune dysregulation, considered as two master models of monogenic auto-immune diseases. Thus, with autoimmunity as their primary clinical manifestation, these two entities may show clinical overlap. Traditionally, immunological biomarkers are used to establish an accurate differential diagnosis. Herein, we describe a patient who presented with clinical features and biomarkers fulfilling the diagnostic criteria of ALPS. Severe apoptotic defect was also shown in the patient’s cell lines and PHA-activated peripheral blood lymphocytes. Sanger sequencing of the FAS gene did not reveal any causal mutation. NGS screening revealed a novel deleterious variant located in the N terminal repressor domain of FOXP3 but no mutations in the FAS pathway-related genes. TEMRA cells (terminally differentiated effector memory cells re-expressing CD45RA) and PD1 expression were increased arguing in favor of T-cell exhaustion, which could be induced by unrestrained activation of T effector cells because of Treg deficiency. Moreover, defective FOXP3 observed in the patient could intrinsically induce increased proliferation and resistance to apoptosis in T effector cells. This observation expands the spectrum of FOXP3 deficiency and underscores the role of NGS in detecting mutations that induce overlapping phenotypes among inborn errors of immunity with immune dysregulation. In addition, these findings suggest a potential link between FOXP3 and FAS pathways.