Abnormal global alternative RNA splicing in COVID-19 patients.

Viral infections can alter host transcriptomes by manipulating host splicing machinery. Despite intensive transcriptomic studies on SARS-CoV-2, a systematic analysis of alternative splicing (AS) in severe COVID-19 patients remains largely elusive. Here we integrated proteomic and transcriptomic sequencing data to study AS changes in COVID-19 patients. We discovered that RNA splicing is among the major down-regulated proteomic signatures in COVID-19 patients. The transcriptome analysis showed that SARS-CoV-2 infection induces widespread dysregulation of transcript usage and expression, affecting blood coagulation, neutrophil activation, and cytokine production. Notably, CD74 and LRRFIP1 had increased skipping of an exon in COVID-19 patients that disrupts a functional domain, which correlated with reduced antiviral immunity. Furthermore, the dysregulation of transcripts was strongly correlated with clinical severity of COVID-19, and splice-variants may contribute to unexpected therapeutic activity. In summary, our data highlight that a better understanding of the AS landscape may aid in COVID-19 diagnosis and therapy.

Transcriptional and proteomic insights into the host response in fatal COVID-19 cases.

Coronavirus disease 2019 (COVID-19), the global pandemic caused by SARS-CoV-2, has resulted thus far in greater than 933,000 deaths worldwide; yet disease pathogenesis remains unclear. Clinical and immunological features of patients with COVID-19 have highlighted a potential role for changes in immune activity in regulating disease severity. However, little is known about the responses in human lung tissue, the primary site of infection. Here we show that pathways related to neutrophil activation and pulmonary fibrosis are among the major up-regulated transcriptional signatures in lung tissue obtained from patients who died of COVID-19 in Wuhan, China. Strikingly, the viral burden was low in all samples, which suggests that the patient deaths may be related to the host response rather than an active fulminant infection. Examination of the colonic transcriptome of these patients suggested that SARS-CoV-2 impacted host responses even at a site with no obvious pathogenesis. Further proteomics analysis validated our transcriptome findings and identified several key proteins, such as the SARS-CoV-2 entry-associated protease cathepsins B and L and the inflammatory response modulator S100A8/A9, that are highly expressed in fatal cases, revealing potential drug targets for COVID-19.

Deficiency of Tfh Cells and Germinal Center in Deceased COVID-19 Patients.

The COVID-19 pandemic caused by SARS-CoV2 is characterized by a remarkable variation in clinical severity ranging from a mild illness to a fatal multi-organ disease. Understanding the dysregulated human immune responses in the fatal subjects is critical for management of COVID-19 patients and the pandemic. In this study, we examined the immune cell compositions in the lung tissues and hilar lymph nodes using immunohistochemistry on 6 deceased COVID-19 patients and 4 focal organizing pneumonia (FOP) patients who underwent lung surgery and served as controls. We found a dominant presence of macrophages and a general deficiency of T cells and B cells in the lung tissues from deceased COVID-19 patients. In contrast to the FOP patients, Tfh cells and germinal center formation were largely absent in the draining hilar lymph nodes in the deceased COVID-19 patients. This was correlated with reduced IgM and IgG levels compared to convalescent COVID-19 patients. In summary, our data highlight a defect of germinal center structure in deceased COVID-19 patients leading to an impaired humoral immunity. Understanding the mechanisms of this deficiency will be one of the key points for the management of this epidemic.

Coronavirus Disease 2019 in the Perioperative Period of Lung Resection: A Brief Report From a Single Thoracic Surgery Department in Wuhan, People's Republic of China.

Coronavirus disease 2019 (COVID-19) is an emerging infectious disease that was first reported in Wuhan, People's Republic of China, and has subsequently spread worldwide. Clinical information on patients who contracted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the perioperative period is limited. Here, we report seven cases with confirmed SARS-CoV-2 infection in the perioperative period of lung resection. Retrospective analysis suggested that one patient had been infected with the SARS-CoV-2 infection before the surgery and the other six patients contracted the infection after the lung resection. Fever, lymphopenia, and ground-glass opacities revealed on computed tomography are the most common clinical manifestations of the patients who contracted COVID-19 after the lung resection. Pathologic studies of the specimens of these seven patients were performed. Pathologic examination of patient 1, who was infected with the SARS-CoV-2 infection before the surgery, revealed that apart from the tumor, there was a wide range of interstitial inflammation with plasma cell and macrophage infiltration. High density of macrophages and foam cells in the alveolar cavities, but no obvious proliferation of pneumocyte, was found. Three of seven patients died from COVID-19 pneumonia, suggesting lung resection surgery might be a risk factor for death in patients with COVID-19 in the perioperative period.