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Microbiology Spectrum Sep 2023In the present study, we show that SARS-CoV-2 can infect palatine tonsils, adenoids, and secretions in children without symptoms of COVID-19, with no history of recent...
In the present study, we show that SARS-CoV-2 can infect palatine tonsils, adenoids, and secretions in children without symptoms of COVID-19, with no history of recent upper airway infection. We studied 48 children undergoing tonsillectomy due to snoring/OSA or recurrent tonsillitis between October 2020 and September 2021. Nasal cytobrushes, nasal washes, and tonsillar tissue fragments obtained at surgery were tested by RT-qPCR, immunohistochemistry (IHC), flow cytometry, and neutralization assay. We detected the presence of SARS-CoV-2 in at least one specimen tested in 27% of patients. IHC revealed the presence of the viral nucleoprotein in epithelial surface and in lymphoid cells in both extrafollicular and follicular regions, in adenoids and palatine tonsils. Also, IHC for the SARS-CoV-2 non-structural protein NSP-16 indicated the presence of viral replication in 53.8% of the SARS-CoV-2-infected tissues. Flow cytometry showed that CD20 B lymphocytes were the most infected phenotypes, followed by CD4+ lymphocytes and CD123 dendritic cells, CD8+ T lymphocytes, and CD14+ macrophages. Additionally, IF indicated that infected tonsillar tissues had increased expression of ACE2 and TMPRSS2. NGS sequencing demonstrated the presence of different SARS-CoV-2 variants in tonsils from different tissues. SARS-CoV-2 antigen detection was not restricted to tonsils but was also detected in nasal cells from the olfactory region. Palatine tonsils and adenoids are sites of prolonged RNA presence by SARS-CoV-2 in children, even without COVID-19 symptoms. IMPORTANCE This study shows that SRS-CoV-2 of different lineages can infect tonsils and adenoids in one quarter of children undergoing tonsillectomy. These findings bring advancement to the area of SARS-CoV-2 pathogenesis, by showing that tonsils may be sites of prolonged infection, even without evidence of recent COVID-19 symptoms. SARS-CoV-2 infection of B and T lymphocytes, macrophages, and dendritic cells may interfere with the mounting of immune responses in these secondary lymphoid organs. Moreover, the shedding of SARS-CoV-2 RNA in respiratory secretions from silently infected children raises concern about possible diagnostic confusion in the presence of symptoms of acute respiratory infections caused by other etiologies.
PubMed: 37737615
DOI: 10.1128/spectrum.01347-23 -
Nature Immunology Jan 2023Most studies of adaptive immunity to SARS-CoV-2 infection focus on peripheral blood, which may not fully reflect immune responses at the site of infection. Using samples...
Most studies of adaptive immunity to SARS-CoV-2 infection focus on peripheral blood, which may not fully reflect immune responses at the site of infection. Using samples from 110 children undergoing tonsillectomy and adenoidectomy during the COVID-19 pandemic, we identified 24 samples with evidence of previous SARS-CoV-2 infection, including neutralizing antibodies in serum and SARS-CoV-2-specific germinal center and memory B cells in the tonsils and adenoids. Single-cell B cell receptor (BCR) sequencing indicated virus-specific BCRs were class-switched and somatically hypermutated, with overlapping clones in the two tissues. Expanded T cell clonotypes were found in tonsils, adenoids and blood post-COVID-19, some with CDR3 sequences identical to previously reported SARS-CoV-2-reactive T cell receptors (TCRs). Pharyngeal tissues from COVID-19-convalescent children showed persistent expansion of germinal center and antiviral lymphocyte populations associated with interferon (IFN)-γ-type responses, particularly in the adenoids, and viral RNA in both tissues. Our results provide evidence for persistent tissue-specific immunity to SARS-CoV-2 in the upper respiratory tract of children after infection.
Topics: Humans; Child; SARS-CoV-2; COVID-19; Pandemics; Adaptive Immunity; Palatine Tonsil; Antibodies, Viral
PubMed: 36536106
DOI: 10.1038/s41590-022-01367-z -
The Journal of Experimental Medicine Jul 2023Macrophages play a central role in tissue homeostasis and host defense. However, the properties of human macrophages in non-diseased tissues remain poorly understood....
Macrophages play a central role in tissue homeostasis and host defense. However, the properties of human macrophages in non-diseased tissues remain poorly understood. Here, we characterized human tonsil macrophages and identified three subsets with distinct phenotype, transcriptome, life cycle, and function. CD36hi macrophages were related to monocytes, while CD36lo macrophages showed features of embryonic origin and CD36int macrophages had a mixed profile. scRNA-seq on non-human primate tonsils showed that monocyte recruitment did not pre-exist an immune challenge. Functionally, CD36hi macrophages were specialized for stimulating T follicular helper cells, by producing Activin A. Combining reconstruction of ligand-receptor interactions and functional assays, we identified stromal cell-derived TNF-α as an inducer of Activin A secretion. However, only CD36hi macrophages were primed for Activin A expression, via the activity of IRF1. Our results provide insight into the heterogeneity of human lymphoid organ macrophages and show that tonsil CD36hi macrophage specialization is the result of both intrinsic features and interaction with stromal cells.
Topics: Animals; Humans; Palatine Tonsil; Macrophages; Monocytes; Phenotype; Transcriptome
PubMed: 37036425
DOI: 10.1084/jem.20230002 -
Diagnostics (Basel, Switzerland) Feb 2023This case-control study aimed to assess the size and echogenicity of inflamed tonsils using ultrasonography. It was carried out at different hospitals, nurseries, and...
This case-control study aimed to assess the size and echogenicity of inflamed tonsils using ultrasonography. It was carried out at different hospitals, nurseries, and primary schools in Khartoum state. About 131 Sudanese volunteers between 1 and 24 years old were recruited. The sample included 79 volunteers with normal tonsils and 52 with tonsillitis according to hematological investigations. The sample was divided into groups according to age-1-5 years old, 6-10 years old, and more than ten years. Measurements in centimeters of height (AP) and width (transverse) of both tonsils (right and left) were taken. Echogenicity was assessed according to normal and abnormal appearances. A data collection sheet containing all the study variables was used. The independent samples test (-test) showed an insignificant height difference between normal controls and cases with tonsillitis. The transverse diameter increased significantly with inflammation (-value < 0.05) for both tonsils in all groups. Echogenicity can differentiate between normal and abnormal tonsils (-value < 0.05 using the chi-square test) for samples from 1-5 years and 6-10 years. The study concluded that measurements and appearance are reliable indicators of tonsillitis, which can be confirmed with the use of ultrasonography, helping physicians to make the correct diagnosis and decisions.
PubMed: 36832230
DOI: 10.3390/diagnostics13040742 -
Journal of Clinical Medicine Nov 2023In recent years, the prevalence of laryngopharyngeal reflux has risen, especially among pediatric patients. The diagnosis of laryngopharyngeal reflux relies on patient...
In recent years, the prevalence of laryngopharyngeal reflux has risen, especially among pediatric patients. The diagnosis of laryngopharyngeal reflux relies on patient history and clinical assessment using the Reflux Finding Score and Reflux Symptom Index as crucial diagnostic tools. Some studies have proposed a link between pepsin and laryngopharyngeal reflux, potentially triggering palatine tonsil hypertrophy. Our study aimed to investigate the correlation between laryngeal and pharyngeal manifestations of laryngopharyngeal reflux through two questionnaires and the presence of pepsin in saliva and palatine tonsils in a pediatric population. Pepsin in saliva was detected using a Western blot method, while immunohistochemistry assessed its presence in palatine tonsils. Although no statistically significant differences in Reflux Finding Score and Reflux Symptom Index were found between the immunohistochemistry-positive (IHC-positive) and immunohistochemistry-negative (IHC-negative) groups, median reflux symptom index and Reflux Finding Score values consistently trended higher in the IHC-positive group. This suggests a potential connection between elevated index values and pepsin presence in tonsillar tissue. Further investigations are essential to fully comprehend the clinical implications of these findings.
PubMed: 38068477
DOI: 10.3390/jcm12237425 -
Journal of Clinical Medicine Oct 2023(1) Background: This narrative review aims to explore the predictors of success for pharyngeal surgery in the treatment of obstructive sleep apnea (OSA). An extensive... (Review)
Review
(1) Background: This narrative review aims to explore the predictors of success for pharyngeal surgery in the treatment of obstructive sleep apnea (OSA). An extensive literature search was conducted, identifying relevant studies published up to June 2023, utilizing various databases and key search terms related to OSA, surgical interventions, and predictors of success. The review encompasses both retrospective and prospective studies, case series, and cohort studies to provide a broad understanding of the topic; (2) Methods: Review of English scientific literature on phenotypes of OSA related to predictors of success of pharyngeal surgery; (3) Results: Of 75 articles, 21 were included, in these the following were determined to be factors for surgical success: body mass index (BMI) (8 articles), apnea/hypopnea index (AHI) (8 articles), cephalometry (8 articles), palatine tonsil size (7 articles), Modified Mallampati score (2 articles), genioglossus electromyography (2 articles), Friedman score or upper airway anatomy (3 articles), nasopharyngolaryngoscopy (2 articles), drug-induced sleep endoscopy (DISE) (1 article), oral cavity anatomy (1 article) and oxygen desaturation index (ODI) (1 article); (4) Conclusions: The lack of standardized protocols for the indication of pharyngeal surgery is a reality, however identifying known predictors of surgical success may facilitate homogenizing indications.
PubMed: 37959237
DOI: 10.3390/jcm12216773 -
British Journal of Hospital Medicine... Dec 2022
Topics: Humans; Palatine Tonsil; Polyps
PubMed: 36594774
DOI: 10.12968/hmed.2022.0289 -
Frontiers in Immunology 2021Tonsil hyperplasia is the most common cause of pediatric obstructive sleep apnea (OSA). Despite the growing knowledge in tissue immunology of tonsils, the...
Tonsil hyperplasia is the most common cause of pediatric obstructive sleep apnea (OSA). Despite the growing knowledge in tissue immunology of tonsils, the immunopathology driving tonsil hyperplasia and OSA remains unknown. Here we used multi-parametric flow cytometry to analyze the composition and phenotype of tonsillar innate lymphoid cells (ILCs), T cells, and B cells from pediatric patients with OSA, who had previous polysomnography. Unbiased clustering analysis was used to delineate and compare lymphocyte heterogeneity between two patient groups: children with small tonsils and moderate OSA (n = 6) or large tonsils and very severe OSA (n = 13). We detected disturbed ILC and B cell proportions in patients with large tonsils, characterized by an increase in the frequency of naïve CD27CD21 B cells and a relative reduction of ILCs. The enrichment of naïve B cells was not commensurate with elevated Ki67 expression, suggesting defective differentiation and/or migration rather than cellular proliferation to be the causative mechanism. Finally, yet importantly, we provide the flow cytometry data to be used as a resource for additional translational studies aimed at investigating the immunological mechanisms of pediatric tonsil hyperplasia and OSA.
Topics: Child, Preschool; Female; Flow Cytometry; Humans; Hyperplasia; Immunity, Innate; Lymphocytes; Male; Memory B Cells; Palatine Tonsil; Receptors, CXCR5; Sleep Apnea, Obstructive; Tumor Necrosis Factor Receptor Superfamily, Member 7
PubMed: 34745084
DOI: 10.3389/fimmu.2021.674080 -
Science (New York, N.Y.) Feb 2022Deciphering immune responses to viruses and vaccines using human tonsil organoids.
Deciphering immune responses to viruses and vaccines using human tonsil organoids.
Topics: Adaptive Immunity; Humans; Immunogenicity, Vaccine; Organoids; Palatine Tonsil; Vaccines; Virus Diseases
PubMed: 35201866
DOI: 10.1126/science.abn9652 -
Nature Immunology Jun 2021Maturation of B cells within germinal centers (GCs) generates diversified B cell pools and high-affinity B cell antigen receptors (BCRs) for pathogen clearance....
Maturation of B cells within germinal centers (GCs) generates diversified B cell pools and high-affinity B cell antigen receptors (BCRs) for pathogen clearance. Increased receptor affinity is achieved by iterative cycles of T cell-dependent, affinity-based B cell positive selection and clonal expansion by mechanisms hitherto incompletely understood. Here we found that, as part of a physiologic program, GC B cells repressed expression of decay-accelerating factor (DAF/CD55) and other complement C3 convertase regulators via BCL6, but increased the expression of C5b-9 inhibitor CD59. These changes permitted C3 cleavage on GC B cell surfaces without the formation of membrane attack complex and activated C3a- and C5a-receptor signals required for positive selection. Genetic disruption of this pathway in antigen-activated B cells by conditional transgenic DAF overexpression or deletion of C3a and C5a receptors limited the activation of mechanistic target of rapamycin (mTOR) in response to BCR-CD40 signaling, causing premature GC collapse and impaired affinity maturation. These results reveal that coordinated shifts in complement regulation within the GC provide crucial signals underlying GC B cell positive selection.
Topics: Animals; Animals, Genetically Modified; B-Lymphocytes; CD55 Antigens; CD59 Antigens; Cell Line, Tumor; Clonal Hematopoiesis; Complement Activation; Complement C3a; Complement C5a; Germinal Center; Humans; Lymphocyte Activation; Mice; Palatine Tonsil; Proto-Oncogene Proteins c-bcl-6; Receptor, Anaphylatoxin C5a; Receptors, Antigen, B-Cell; Receptors, Complement; Signal Transduction; TOR Serine-Threonine Kinases
PubMed: 34031614
DOI: 10.1038/s41590-021-00926-0