Severe acute respiratory syndrome coronavirus 2 pathology and cell tropism in tongue tissues of COVID-19 autopsies.

Since 2019, Coronavirus Disease 2019(COVID-19) has affected millions of people worldwide. Except for acute respiratory distress syndrome, dysgeusis is also a common symptom of COVID-19 that burdens patients for weeks or permanently. However, the mechanisms underlying taste dysfunctions remain unclear. Here, we performed complete autopsies of five patients who died of COVID-19. Integrated tongue samples, including numerous taste buds, salivary glands, vessels, and nerves were collected to map the pathology, distribution, cell tropism, and receptor distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the tongue. Our results revealed that all patients had moderate lymphocyte infiltration around the salivary glands and in the lamina propria adjacent to the mucosa, and pyknosis in the epithelia of taste buds and salivary glands. This may be because the serous acini, salivary gland ducts, and taste buds are the primary sites of SARS-CoV-2 infection. Multicolor immunofluorescence showed that SARS-CoV-2 readily infects Keratin (KRT)7+ taste receptor cells in taste buds, secretory cells in serous acini, and inner epithelial cells in the ducts. The major receptors, angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2), were both abundantly expressed in these cells. Viral antigens and receptor were both rarely detected in vessels and nerves. This indicates that SARS-CoV-2 infection triggers pathological injury in the tongue, and that dysgeusis may be directly related to viral infection and cellular damage.

Impaired metal perception and regulation of associated human foliate papillae tongue transcriptome in long-COVID-19.

Chemosensory impairment is an outstanding symptom of SARS-CoV-2 infections. We hypothesized that measured sensory impairments are accompanied by transcriptomic changes in the foliate papillae area of the tongue. Hospital personnel with known SARS-CoV-2 immunoglobulin G (IgG) status completed questionnaires on sensory perception (n = 158). A subcohort of n = 141 participated in forced choice taste tests, and n = 43 participants consented to donate tongue swabs of the foliate papillae area for whole transcriptome analysis. The study included four groups of participants differing in IgG levels (≥ 10 AU/mL = IgG+; < 10 AU/mL = IgG-) and self-reported sensory impairment (SSI±). IgG+ subjects not detecting metallic taste had higher IgG+ levels than IgG+ participants detecting iron gluconate (p = 0.03). Smell perception was the most impaired biological process in the transcriptome data from IgG+/SSI+ participants subjected to gene ontology enrichment. IgG+/SSI+ subjects demonstrated lower expression levels of 166 olfactory receptors (OR) and 9 taste associated receptors (TAS) of which OR1A2, OR2J2, OR1A1, OR5K1 and OR1G1, as well as TAS2R7 are linked to metallic perception. The question raised by this study is whether odorant receptors on the tongue (i) might play a role in metal sensation, and (ii) are potential targets for virus-initiated sensory impairments, which needs to be investigated in future functional studies.

Short beak and dwarfism syndrome among Pekin ducks: First detection, full genome sequencing, and immunohistochemical signals of novel goose parvovirus in tongue tissue.

Novel goose parvovirus (NGPV) is continuously threatening the global duck industry, as it causes short beak and dwarfism syndrome among different duck breeds. In this study, we investigated the viral pathogenesis in the tongue of affected ducks, as a new approach for deeper understanding of the syndrome. Seventy-three, 14- to 60-day-old commercial Pekin ducks were clinically examined. Thirty tissue pools of intestine and tongue (15 per tissue) were submitted for molecular identification. Clinical signs in the examined ducks were suggestive of parvovirus infection. All examined ducks had short beaks. Necrotic, swollen, and congested protruding tongues were recorded in adult ducks (37/73, 51%). Tongue protrusion without any marked congestion or swelling was observed in 20-day-old ducklings (13/73, 18%), and no tongue protrusion was observed in 15-day-old ducklings (23/73, 32%). Microscopically, the protruding tongues of adult ducks showed necrosis of the superficial epithelial layer with vacuolar degeneration. Glossitis was present in the nonprotruding tongues of young ducks, which was characterized by multifocal lymphoplasmacytic aggregates and edema in the propria submucosa. Immunohistochemical examination displayed parvovirus immunolabeling, mainly in the tongue propria submucosa. Based on polymerase chain reaction, goose parvovirus was detected in 9 out of 15 tongue sample pools (60%). Next-generation sequencing confirmed the presence of a variant goose parvovirus that is globally named NGPV and closely related to Chinese NGPV isolates. Novel insights are being gained from the study of NGPV pathogenesis in the tongue based on molecular and immunohistochemical identification.

Morphological and Immunopathological Aspects of Lingual Tissues in COVID-19.

COVID-19, a recently emerged disease caused by SARS-CoV-2 infection, can present with different degrees of severity and a large variety of signs and symptoms. The oral manifestations of COVID-19 often involve the tongue, with loss of taste being one of the most common symptoms of the disease. This study aimed to detect SARS-CoV-2 RNA and assess possible morphological and immunopathological alterations in the lingual tissue of patients who died with a history of SARS-CoV-2 infection. Sixteen cadavers from 8 SARS-CoV-2 positive (COVID-19+) and 8 negative (COVID-19-) subjects provided 16 tongues, that were biopsied. Samples underwent molecular analysis through Real-Time RT-PCR for the detection of SARS-CoV-2 RNA. Lingual papillae were harvested and processed for histological analysis and for immunohistochemical evaluation for ACE2, IFN-γ and factor VIII. Real-Time RT-PCR revealed the presence of SARS-CoV-2 RNA in filiform, foliate, and circumvallate papillae in 6 out of 8 COVID-19+ subjects while all COVID-19- samples resulted negative. Histology showed a severe inflammation of COVID-19+ papillae with destruction of the taste buds. ACE2 and IFN-γ resulted downregulated in COVID-19+ and no differences were evidenced for factor VIII between the two groups. The virus was detectable in most COVID-19+ tongues. An inflammatory damage to the lingual papillae, putatively mediated by ACE2 and IFN-γ in tongues from COVID-19+ cadavers, was observed. Further investigations are needed to confirm these findings and deepen the association between taste disorders and inflammation in SARS-CoV-2 infection.

Mixed HPV-related Neuroendocrine Carcinoma and HPV-related Squamous Cell Carcinoma of the Base of Tongue in a Patient With Incidental Identification of Synchronous Metastatic Papillary Thyroid Carcinoma.

BACKGROUND: While it is not uncommon in patients with head and neck cancer to present with multiple metachronous primary neoplasms, rarely do these present as a singular mass composed of intertwined, histologically distinct malignant tumors. Sometimes referred to as collision tumors, these entities are poorly understood and only appear in a handful of case studies in the literature. CASE REPORT: Here we present a 58-year-old male diagnosed with a human papillomavirus-related collision tumor consisting of oropharyngeal squamous cell carcinoma and small-cell neuroendocrine carcinoma, as well as an incidentally discovered metastatic thyroid papillary carcinoma, despite an unremarkable thyroid gland. The patient underwent transoral robotic base-of-tongue resection and partial pharyngectomy with selective neck dissection followed by chemoradiotherapy. At the 18-month follow-up the patient was doing well. His thyroid was normal and no recurrent or metastatic carcinoma was identified on the computed tomography and positron-emission tomography/computed tomography imaging findings. CONCLUSION: To the best of our knowledge, this is the first such case in English literature. This case demonstrates the importance of tumor morphology and immunohistochemical testing in HPV-related oropharyngeal carcinomas, despite the overall good prognosis of such tumors, due to the possibility of synchronous or colliding primary neoplasms.

Detection of an emerging novel sublineage Ind2001BD1 and lineage PanAsia of foot-and-mouth disease virus serotype O in cattle in Manikgonj district of Bangladesh, 2018.

Background: Foot-and-mouth disease (FMD) is an endemic disease of cloven-hoofed animals in Bangladesh and multiple outbreaks occur every year because of the FMD virus (FMDV). Aim: The aim of the present investigation was to determine the molecular characterization of the VP1 coding region of FMDV serotype O outbreak in cattle. Methods: A total of four tongue epithelial specimens were collected from clinically FMD-positive cattle during June 2018 in Manikgonj district of Bangladesh. Results: All four isolates were recorded positive for FMDV serotype O. The phylogenetic analysis showed that two isolates were clustered within an emerging novel sublineage Ind2001BD1 under lineage Ind2001 of FMDV serotype O, which was identified during 2012-2016 in Bangladesh. One isolate was clustered within the lineage PanAsia of FMDV serotype O and was closely related to an isolate identified in Nepal in 2009. The phylogenetic reconstruction revealed that all the four isolates belong to the Middle East-South Asia topotype. Conclusion: Therefore, multiple lineages of the FMDV serotype O are circulating among the cattle in the outbreak area, which make it more complex for the FMD control program in Bangladesh. A comprehensive study on the genetic characteristics of FMDV across the country is required for effective FMD prevention and control strategy.

Survival of patients with oropharyngeal squamous cell carcinomas (OPSCC) in relation to TNM 8 - Risk of incorrect downstaging of HPV-mediated non-tonsillar, non-base of tongue carcinomas.

BACKGROUND: TNM-8 staging separates oropharyngeal squamous cell carcinomas (OPSCC) into human papillomavirus (HPV)-mediated and -unrelated OPSCC based on p16INK4a overexpression (p16+), as surrogate marker for HPV. However, OPSCC is histologically and clinically heterogenous including tonsillar and base of tongue squamous cell carcinomas (TSCC and BOTSCC respectively), and carcinomas of soft palate and walls (otherOPSCC). The significance of HPV is established in TSCC/BOTSCC, while its role in otherOPSCC is unclear, which is not considered in TNM-8. Here, p16+ was therefore evaluated in relation to overall survival (OS) and tumor stage per OPSCC subsite. PATIENTS AND METHODS: All 932 patients, treated with curative intent in Stockholm 2000-2016 with OPSCC, previously analyzed for p16 expression, were included. Clinical data, including stage and OS, was collected retrospectively. RESULTS: Patients with p16+ otherOPSCC had significantly poorer OS compared to patients with p16+ TSCC/BOTSCC (p = 0.005) and their survival was similar to that of patients with p16-otherOPSCC/TSCC/BOTSCC. Moreover, patients with TNM-8 stage I-II and p16+ otherOPSCC had a significant poorer OS compared to patients with p16+ TSCC/BOTSCC and similar stage (p = 0.02). Lastly, patients with otherOPSCC and low TNM-7 stage had a significant better OS, as compared to those with a high stage (p = 0.019) while no hazard discrimination was observed with TNM-7 in TSCC/BOTSCC. CONCLUSION: Our results indicate a risk of misclassification of patients with otherOPSCC and low TNM-8 stage. We suggest that p16 should only be evaluated in TSCC/BOTSCC and that patients with otherOPSCC should all be staged as patients with HPV-unrelated (p16-) OPSCC.

An Infection-Based Murine Model for Papillomavirus-Associated Head and Neck Cancer.

Human papillomavirus (HPV) is the most common sexually transmitted pathogen, and high-risk HPVs contribute to 5% of human cancers, including 25% of head and neck squamous cell carcinomas (HNSCCs). Despite the significant role played by HPVs in HNSCC, there is currently no available in vivo system to model the process from papillomavirus infection to virus-induced HNSCC. In this paper, we describe an infection-based HNSCC model, utilizing a mouse papillomavirus (MmuPV1), which naturally infects laboratory mice. Infections of the tongue epithelium of two immunodeficient strains with MmuPV1 caused high-grade squamous dysplasia with early signs of invasive carcinoma over the course of 4 months. When combined with the oral carcinogen 4-nitroquinoline-1-oxide (4NQO), MmuPV1 caused invasive squamous cell carcinoma (SCC) on the tongue of both immunodeficient and immunocompetent mice. These tumors expressed markers of papillomavirus infection and HPV-associated carcinogenesis. This novel preclinical model provides a valuable new means to study how natural papillomavirus infections contribute to HNSCC.IMPORTANCE The species specificity of papillomavirus has limited the development of an infection-based animal model to study HPV-associated head and neck carcinogenesis. Our study presents a novel in vivo model using the mouse papillomavirus MmuPV1 to study papillomavirus-associated head and neck cancer. In our model, MmuPV1 infects and causes lesions in both immunodeficient and genetically immunocompetent strains of mice. These virally induced lesions carry features associated with both HPV infections and HPV-associated carcinogenesis. Combined with previously identified cancer cofactors, MmuPV1 causes invasive squamous cell carcinomas in mice. This model provides opportunities for basic and translational studies of papillomavirus infection-based head and neck disease.

Respiratory sampling for severe acute respiratory syndrome coronavirus 2: An Overview.

The novel coronavirus disease 2019 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was declared a pandemic in March 2020. A plethora of respiratory sampling methods for SARS-CoV-2 viral detection has been used and in the current evolving situation, there is no international consensus on the recommended method of respiratory sampling for diagnosis. Otolaryngologists deal intimately with the upper respiratory tract and a clear understanding of the respiratory sampling methods is of paramount importance. This article aims to provide an overview of the various methods and their evidence till date.

Molecular characterisation in tongue squamous cell carcinoma reveals key variants potentially linked to clinical outcomes.

BACKGROUND: Oral tongue squamous cell carcinoma (OTSCC) is a highly aggressive malignancy characterized by frequent recurrence, poor survival with relatively few therapeutic options due to the late diagnosis in many cases. OBJECTIVES: Understanding the molecular pathways underlying OTSCC tumourigenesis and the discovery of diagnostic and/or prognostic biomarkers. METHODS: We performed high-throughput mutational analysis of 44 OTSCC formalin-fixed paraffin-embedded (FFPE) cases using the Cancer Hotspots Panel (CHP) v2 on the Ion Torrent™platform. We determined the frequency of human papilloma virus (HPV) using PCR and Epstein bar virus (EBV) positivity using immunohistochemistry. As a control for EBV infection we screened matched non-tumourous tissues. RESULTS: Sequencing analysis identified missense, nonsense and frameshift mutations in TP53 (66%), PIK3CA (27%), CDKN2A (25%), EGFR (18%), and PTEN (14%). Interestingly, no significant associations were found between damaging mutations and clinicopathological data. A total of 10/44 of the OTSCC samples (23%) tested was positive for HPV18 DNA. OTSCC patients with positive HPV infection had worse overall survival compared to HPV-negative cases as determined by Kaplan-Meier survival (p= 0.023). Furthermore, EBNA1 expression showed a strong tumour-enriched expression pattern in 20 out of 21 samples (95%) in the epithelial compartments of the tissues analysed. CONCLUSIONS: Taken together, this study highlights that the two most common events in OTSCC are TP53 mutations and EBV positivity. Helping to understand the contribution of TP53 mutations and EBV infection events could serve as useful biomarkers for OTSCC.

High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa.

It has been reported that ACE2 is the main host cell receptor of 2019-nCoV and plays a crucial role in the entry of virus into the cell to cause the final infection. To investigate the potential route of 2019-nCov infection on the mucosa of oral cavity, bulk RNA-seq profiles from two public databases including The Cancer Genome Atlas (TCGA) and Functional Annotation of The Mammalian Genome Cap Analysis of Gene Expression (FANTOM5 CAGE) dataset were collected. RNA-seq profiling data of 13 organ types with para-carcinoma normal tissues from TCGA and 14 organ types with normal tissues from FANTOM5 CAGE were analyzed in order to explore and validate the expression of ACE2 on the mucosa of oral cavity. Further, single-cell transcriptomes from an independent data generated in-house were used to identify and confirm the ACE2-expressing cell composition and proportion in oral cavity. The results demonstrated that the ACE2 expressed on the mucosa of oral cavity. Interestingly, this receptor was highly enriched in epithelial cells of tongue. Preliminarily, those findings have explained the basic mechanism that the oral cavity is a potentially high risk for 2019-nCoV infectious susceptibility and provided a piece of evidence for the future prevention strategy in dental clinical practice as well as daily life.

Natural Canine Distemper Virus Infection in Linnaeus's 2-Toed Sloths (Choloepus didactylus).

An outbreak of canine distemper virus in a private zoo in eastern Tennessee in July 2016 led to fatal clinical disease in 5 adult, wild-caught Linnaeus's 2-toed sloths (Choloepus didactylus). Clinical signs included hyporexia, lethargy, mucopurulent nasal discharge, and oral and facial ulcers. At necropsy, affected animals had crusts and ulcers on the lips, nose, tongue, and oral cavity. Microscopically, all sloths had widespread, random, hepatic necrosis; lymphoid depletion; and bronchointerstitial pneumonia. The central nervous system did not contain gross or histopathologic lesions in any of the 5 sloths, although immunoreactivity for viral antigen was present within vessel walls. Epithelial cells and histiocytes within numerous organs contained intranuclear and intracytoplasmic inclusions and occasional syncytial cells. Canine distemper virus was confirmed with immunohistochemistry and virus isolation. Viral sequencing identified the novel American-4 strain prevalent in eastern Tennessee wildlife. This is the first pathologic characterization of canine distemper virus infection in sloths (family Choloepodidae, order Pilosa) and emphasizes the significant morbidity and mortality in this species.

Inactivation of foot-and-mouth disease virus in epithelium samples for safe transport and processing in low-containment laboratories.

During a foot-and-mouth disease (FMD) outbreak, transport and testing of potentially infectious samples, including epithelium from suspect lesions, presents a biosafety risk, particularly in FMD-free countries. Therefore, treatment to inactivate virus prior to transport is important. Tongue epithelium from cattle infected with FMD virus (FMDV) serotype O (O ALG/3/2014 - Lineage O/ME-SA/Ind-2001d) or A (A IRN/22/2015 - Lineage A/ASIA/G-VII) was incubated in RNAlater, RNA Shield or phosphate-buffered saline (pH 7.4) at room temperature for 2, 6, 24 or 48 h. After incubation, tissues were homogenised and tested by virus titration. Viral RNA in the homogenate was quantified by RT-qPCR, used for sequencing, and transfected into LFBKαVß6 cells to recover infectious virus. RNAlater reduced A IRN/22/2015 titres by 4 log10 after 24 h, and completely after 48 h incubation. While O ALG/3/2014 was detected by VI after 2, 6 and 24 h, titration yielded no infectious virus, likely as a result of freeze-thawing. RNA Shield was cytotoxic at high concentrations but was effective at inactivating both strains after 24 h. Regardless of reagent or inactivation period, RT-qPCR, VP1 sequencing, and transfection of RNA to recover infectious virus were possible. RNA Shield appears a better choice for FMDV inactivation in tissues, however 24 h incubation is recommended.

Coinfection of a lingual lesion with bovine papular stomatitis virus and bovine papillomavirus.

To date, there have been no reports of coinfection with bovine papular stomatitis virus (BPSV) and bovine papillomavirus (BPV) in the same lesion. In the present study, one lingual papilloma-like sample was collected at an abattoir from the tongue of a 31-month-old Japanese black cow. Coinfection with BPSV and BPV was confirmed by histopathology, immunohistochemistry, PCR and RT-PCR. The evidence for coinfection with BPSV and BPV in the same lesion and an association of BPV with lingual papillomatosis will contribute to future epidemiological studies of these two viruses.

Replacement of foot-and-mouth disease virus cattle tongue titration by in vitro titration

Titration of foot-and-mouth disease cattle challenge virus in cattle tongue has been the standard for many years in many countries, although titration in animals has been replaced by in vitro methods for all other applications. The objective of the analysis was the replacement of in vivo titration of cattle challenge virus by in vitro titration. Using data from 32 in vivo titration experiments together with the in vitro titration results of the same samples obtained by plaque count on primary lamb or pig kidney cells, as well as data from the virus isolation control chart used in the laboratory, we show that the reproducibility of the in vitro titration is much higher than that of the in vivo titration. The titer on primary kidney cells was on average 1.4 log10 higher than the titer determined by titration in cattle tongue (PFU/ml compared to bovine ID50/ml), but the difference varied among different strains. The study also shows that the probability of infection in cattle tongue is high even when a lower challenge dose is used, which makes the variability between strains less important. Based on these results, we propose to change the standard dose for cattle challenge from 104 bovine ID50 to 105.4 PFU, and to replace the in vivo cattle tongue titration method with the in vitro titration method.