SARS-CoV-2-Reactive Mucosal B Cells in the Upper Respiratory Tract of Uninfected Individuals.

SARS-CoV-2 is a respiratory pathogen that can cause severe disease in at-risk populations but results in asymptomatic infections or a mild course of disease in the majority of cases. We report the identification of SARS-CoV-2-reactive B cells in human tonsillar tissue obtained from children who were negative for coronavirus disease 2019 prior to the pandemic and the generation of mAbs recognizing the SARS-CoV-2 Spike protein from these B cells. These Abs showed reduced binding to Spike proteins of SARS-CoV-2 variants and did not recognize Spike proteins of endemic coronaviruses, but subsets reacted with commensal microbiota and exhibited SARS-CoV-2-neutralizing potential. Our study demonstrates pre-existing SARS-CoV-2-reactive Abs in various B cell populations in the upper respiratory tract lymphoid tissue that may lead to the rapid engagement of the pathogen and contribute to prevent manifestations of symptomatic or severe disease.

Identification of resident memory CD8+ T cells with functional specificity for SARS-CoV-2 in unexposed oropharyngeal lymphoid tissue.

Cross-reactive CD4+ T cells that recognize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are more commonly detected in the peripheral blood of unexposed individuals compared with SARS-CoV-2­reactive CD8+ T cells. However, large numbers of memory CD8+ T cells reside in tissues, feasibly harboring localized SARS-CoV-2­specific immune responses. To test this idea, we performed a comprehensive functional and phenotypic analysis of virus-specific T cells in tonsils, a major lymphoid tissue site in the upper respiratory tract, and matched peripheral blood samples obtained from children and adults before the emergence of COVID-19 (coronavirus disease 2019). We found that SARS-CoV-2­specific memory CD4+ T cells could be found at similar frequencies in the tonsils and peripheral blood in unexposed individuals, whereas functional SARS-CoV-2­specific memory CD8+ T cells were almost only detectable in the tonsils. Tonsillar SARS-CoV-2­specific memory CD8+ T cells displayed a follicular homing and tissue-resident memory phenotype, similar to tonsillar Epstein-Barr virus­specific memory CD8+ T cells, but were functionally less potent than other virus-specific memory CD8+ T cell responses. The presence of preexisting tissue-resident memory CD8+ T cells in unexposed individuals could potentially enable rapid sentinel immune responses against SARS-CoV-2.

Detecting epidemiological relevance of adenoid hypertrophy, rhinosinusitis, and allergic rhinitis through an Internet search.

PURPOSE: This study aimed to detect the epidemiological relevance between adenoid hypertrophy (AH) and rhinosinusitis, and AH and allergic rhinitis (AR) through an Internet search. METHODS: Internet search query data from January 2011 to December 2019 in China were retrieved from the Baidu Index (BI). Spearman's correlation coefficients were used to detect the correlation among the search volumes of AH, rhinosinusitis, and AR. We also collected search data from the first 5 months of 2020, when quarantine was implemented in China due to the coronavirus disease 2019 epidemic. Then, we compared the search data to those obtained during the same period in 2019 to assess the effects of isolation on AH and AR. RESULTS: Statistically significant relevance was found between the search variations of AH and rhinosinusitis during 2011-2019 (R = 0.643, P < 0.05). However, the relationship between AH and AR was weak (R = - 0.239, P < 0.05) and that between rhinosinusitis and AR (R = - 0.022, P > 0.05) was not relevant. The average monthly search volume of AH and rhinosinusitis had a strong correlation (R = 0.846, P < 0.01), but AH and AR and rhinosinusitis and AR were not correlated (R = - 0.350, P > 0.05; R = - 0.042, P > 0.05, respectively). AH and rhinosinusitis search volumes decreased consistently during the first 5 months of 2020 (isolation), whereas that for AR increased during January-February. CONCLUSION: AH had an epidemiological relationship with rhinosinusitis, which was not consistent with AR. The decrease in public gathering effectively reduced the morbidities of AH and rhinosinusitis but not those of AR.

ENT manifestation in COVID-19 patients.

OBJECTIVE: to detect, analyze and discuss the different ear nose throat (ENT) manifestations those were reported in COVID19 positive patients in the reviewed and published literatures. METHODS: We performed a search in the PubMed databases, Web of Science, LILACS, MEDLINE, SciELO, and Cochrane Library using the keywords; COVID-19, Novel coronavirus, corona, 2019-nCoV, SARS-CoV-2, ENT, ear, nose, throat, otorhinolaryngology, ORL, pharynx, ORL, smell, larynx, different ENT related symptoms. We reviewed published and peer reviewed studies that reported the ENT manifestations in COVID-19 laboratory-confirmed positive patients. RESULTS: within the included 1773 COVID-19 laboratory-confirmed positive patients, the most common ENT manifestations of COVID-19 were sore throat (11.3%) and headache (10.7%). While the other reported ENT manifestations were pharyngeal erythema (5.3%), nasal congestion (4.1%), runny nose or rhinorrhea (2.1%), upper respiratory tract infection (URTI) (1.9%), and tonsil enlargement (1.3%). CONCLUSION: ENT manifestations for COVID-19 are not common as fever and cough. But, a universal questionnaire using well-defined COVID-19 manifestations is needed to make the COVID-19 data precisely defined, complete and homogenous.