Impaired local intrinsic immunity to SARS-CoV-2 infection in severe COVID-19.

SARS-CoV-2 infection can cause severe respiratory COVID-19. However, many individuals present with isolated upper respiratory symptoms, suggesting potential to constrain viral pathology to the nasopharynx. Which cells SARS-CoV-2 primarily targets and how infection influences the respiratory epithelium remains incompletely understood. We performed scRNA-seq on nasopharyngeal swabs from 58 healthy and COVID-19 participants. During COVID-19, we observe expansion of secretory, loss of ciliated, and epithelial cell repopulation via deuterosomal cell expansion. In mild and moderate COVID-19, epithelial cells express anti-viral/interferon-responsive genes, while cells in severe COVID-19 have muted anti-viral responses despite equivalent viral loads. SARS-CoV-2 RNA+ host-target cells are highly heterogenous, including developing ciliated, interferon-responsive ciliated, AZGP1high goblet, and KRT13+ "hillock"-like cells, and we identify genes associated with susceptibility, resistance, or infection response. Our study defines protective and detrimental responses to SARS-CoV-2, the direct viral targets of infection, and suggests that failed nasal epithelial anti-viral immunity may underlie and precede severe COVID-19.

Pleomorphic Leiomyosarcoma Presenting as a Upper Back Epidermal Inclusion Cyst.

ABSTRACT: Leiomyosarcoma is a common sarcoma of both organs and soft tissues; however, large intradermal tumors are extremely rare. Presented is a pleomorphic leiomyosarcoma in a 64-year-old man, initially considered to be a ruptured epidermal inclusion cyst. The patient had a mildly tender, enlarging soft-tissue mass with a central pore on his right upper back. Incomplete extirpation showed a 5 × 5 cm heterogeneous, predominantly pleomorphic sarcoma with areas of fascicular and storiform spindled cells infiltrating the subcutaneous soft tissue to the underlying fascia and extending upward into the middle and upper dermis with prominent extension into pilosebaceous units. There were small foci with myxoid stroma and large areas of necrosis. CD31 demonstrated thin-walled curvilinear vessels throughout the tumor. The first desmin immunohistochemical stain near areas with myxoid stroma was negative but smooth muscle actin positive. However, desmin positivity was strong and diffuse in the spindled and more pleomorphic areas on 2 additional tissue sections. No rhabdomyoblasts or striated muscle fibers were seen. A diagnosis of pleomorphic leiomyosarcoma was rendered. This case highlights a unique clinical and histological presentation of a leiomyosarcoma initially mistaken to be a ruptured epidermal inclusion cyst, and the need to sometimes apply ancillary immunohistochemical studies to sections from more than one tissue block to accurately differentiate heterogeneous sarcomas with similar histologic features.

The gut microbiome of COVID-19 recovered patients returns to uninfected status in a minority-dominated United States cohort.

To investigate the relationship between intestinal microbiota and SARS-CoV-2-mediated pathogenicity in a United States, majority African American cohort. We prospectively collected fecal samples from 50 SARS-CoV-2 infected patients, 9 SARS-CoV-2 recovered patients, and 34 uninfected subjects seen by the hospital with unrelated respiratory medical conditions (controls). 16S rRNA sequencing and qPCR analysis was performed on fecal DNA/RNA. The fecal microbial composition was found to be significantly different between SARS-CoV-2 patients and controls (PERMANOVA FDR-P = .004), independent of antibiotic exposure. Peptoniphilus, Corynebacterium and Campylobacter were identified as the three most significantly enriched genera in COVID-19 patients compared to controls. Actively infected patients were also found to have a different gut microbiota than recovered patients (PERMANOVA FDR-P = .003), and the most enriched genus in infected patients was Campylobacter, with Agathobacter and Faecalibacterium being enriched in the recovered patients. No difference in microbial community structure between recovered patients and uninfected controls was observed, nor a difference in alpha diversity between the three groups. 24 of the 50 COVID-19 patients (48%) tested positive via RT-qPCR for fecal SARS-CoV-2 RNA. A significant difference in gut microbial composition between SARS-CoV-2 positive and negative samples was observed, with Klebsiella and Agathobacter being enriched in the positive cohort. No significant associations between microbiome composition and disease severity was found. The intestinal microbiota is sensitive to the presence of SARS-CoV-2, with increased relative abundance of genera (Campylobacter, Klebsiella) associated with gastrointestinal (GI) disease. Further studies are needed to investigate the functional impact of SARS-CoV-2 on GI health.

Impaired local intrinsic immunity to SARS-CoV-2 infection in severe COVID-19.

Infection with SARS-CoV-2, the virus that causes COVID-19, can lead to severe lower respiratory illness including pneumonia and acute respiratory distress syndrome, which can result in profound morbidity and mortality. However, many infected individuals are either asymptomatic or have isolated upper respiratory symptoms, which suggests that the upper airways represent the initial site of viral infection, and that some individuals are able to largely constrain viral pathology to the nasal and oropharyngeal tissues. Which cell types in the human nasopharynx are the primary targets of SARS-CoV-2 infection, and how infection influences the cellular organization of the respiratory epithelium remains incompletely understood. Here, we present nasopharyngeal samples from a cohort of 35 individuals with COVID-19, representing a wide spectrum of disease states from ambulatory to critically ill, as well as 23 healthy and intubated patients without COVID-19. Using standard nasopharyngeal swabs, we collected viable cells and performed single-cell RNA-sequencing (scRNA-seq), simultaneously profiling both host and viral RNA. We find that following infection with SARS-CoV-2, the upper respiratory epithelium undergoes massive reorganization: secretory cells diversify and expand, and mature epithelial cells are preferentially lost. Further, we observe evidence for deuterosomal cell and immature ciliated cell expansion, potentially representing active repopulation of lost ciliated cells through coupled secretory cell differentiation. Epithelial cells from participants with mild/moderate COVID-19 show extensive induction of genes associated with anti-viral and type I interferon responses. In contrast, cells from participants with severe lower respiratory symptoms appear globally muted in their anti-viral capacity, despite substantially higher local inflammatory myeloid populations and equivalent nasal viral loads. This suggests an essential role for intrinsic, local epithelial immunity in curbing and constraining viral-induced pathology. Using a custom computational pipeline, we characterized cell-associated SARS-CoV-2 RNA and identified rare cells with RNA intermediates strongly suggestive of active replication. Both within and across individuals, we find remarkable diversity and heterogeneity among SARS-CoV-2 RNA+ host cells, including developing/immature and interferon-responsive ciliated cells, KRT13+ "hillock"-like cells, and unique subsets of secretory, goblet, and squamous cells. Finally, SARS-CoV-2 RNA+ cells, as compared to uninfected bystanders, are enriched for genes involved in susceptibility (e.g., CTSL, TMPRSS2) or response (e.g., MX1, IFITM3, EIF2AK2) to infection. Together, this work defines both protective and detrimental host responses to SARS-CoV-2, determines the direct viral targets of infection, and suggests that failed anti-viral epithelial immunity in the nasal mucosa may underlie the progression to severe COVID-19.

Proximal Humerus Fractures in the Geriatric Population Present an Opportunity to Improve Recognition and Treatment of Osteoporosis.

INTRODUCTION: Osteoporosis remains an undertreated disease entity causing substantial morbidity and mortality. Proximal humerus fractures are a common sentinel fracture, providing an opportunity to intervene with antiresorptive therapy before more subsequent fractures occur. Despite the success of programs aimed to improve postfracture osteoporosis recognition and management, less than 30% of patients presenting with a fragility fracture are diagnosed or treated for osteoporosis nationally. Further elucidation of diagnosis and management of osteoporosis following humerus fracture is warranted. METHODS: This study is a retrospective cohort review intended to demonstrate the current state and clinical import of osteoporosis diagnosis and management following a humerus fracture at a large academic tertiary care center without an established secondary fracture prevention program. All patients 50 years of age or older who presented with a new humerus fracture between 2008 and 2014 were included. Outcome measures included: The initiation of antiresorptive therapy or screening before fracture, within the year following fracture, or not at all. RESULTS: One thousand seven hundred unique geriatric patients were seen for humerus fractures. Nineteen percent of these patients (n = 324) were already on an antiresorptive medication. Three percent of previously untreated patients were started on antiresorptive therapy during the year after their fracture, with 31 or 2% of untreated patients starting at any subsequent point. Seventy-six percent of patients (n = 1301) were never prescribed antiresorptive therapy. DISCUSSION AND CONCLUSION: In the absence of a dedicated program to improve secondary fracture prevention following minimal trauma spinal fractures, recognition and treatment of osteoporosis in patients remained inadequate over time despite numerous calls to action on the topic in the orthopedic literature and public health initiatives. Undertreatment of osteoporosis puts patients at increased risk for additional fractures. This study underscores an opportunity to improve bone health by aggressively screening for and treating osteoporosis in geriatric humerus fracture patients.