Advances of mRNA vaccine in tumor: a maze of opportunities and challenges.

High-frequency mutations in tumor genomes could be exploited as an asset for developing tumor vaccines. In recent years, with the tremendous breakthrough in genomics, intelligence algorithm, and in-depth insight of tumor immunology, it has become possible to rapidly target genomic alterations in tumor cell and rationally select vaccine targets. Among a variety of candidate vaccine platforms, the early application of mRNA was limited by instability low efficiency and excessive immunogenicity until the successful development of mRNA vaccines against SARS-COV-2 broken of technical bottleneck in vaccine preparation, allowing tumor mRNA vaccines to be prepared rapidly in an economical way with good performance of stability and efficiency. In this review, we systematically summarized the classification and characteristics of tumor antigens, the general process and methods for screening neoantigens, the strategies of vaccine preparations and advances in clinical trials, as well as presented the main challenges in the current mRNA tumor vaccine development.

Contribution of CD4+ T cell-mediated inflammation to diarrhea in patients with COVID-19.

OBJECTIVES: This study aimed to explore the role of CD4+ T cells in the mechanisms of COVID-19 related diarrhea. METHODS: We analyzed lymphocyte subsets in patients with COVID-19 and the expression of angiotensin-converting enzyme 2 (ACE2), the transmembrane protease serine 2, and CD4+ T cell-related indicators in the colon were compared between patients with and without diarrhea. Correlation analyses were performed for ACE2 and other indicators to identify the relationship between SARS-CoV-2 infection and CD4+ mediated inflammation. The expression and distribution of CD4+ T cell-associated chemokines and their receptors were detected to determine the possibility of migration of CD4+ T cells to inflammation sites. RESULTS: The CD4+ T cell counts and percentages and CD4/CD8 ratio showed the most significant differences between the 2 groups. The diarrhea group expressed higher levels of ACE2, T-box expressed in T cells (Tbet), and tumor necrosis factor-alpha (TNFα) at both the mRNA and protein levels, with no difference from the nondiarrhea group for the percentage of ACE2+TNFα+ cells, indicating an indirect association between ACE2 and TNFα. The mRNA expression of CXCL10, CXCL11, and CXCR3 and the number of CD4+CXCR3+T cells were increased in the diarrhea group. CONCLUSIONS: CD4+ T cell-mediated inflammation may contribute to COVID-19 related diarrhea. CXCR3+ mediated migration of CD4+ T cells into the gut may perpetuate inflammation.

Single-Cell Landscape of Lungs Reveals Key Role of Neutrophil-Mediated Immunopathology during Lethal SARS-CoV-2 Infection.

Due to the limitation of human studies with respect to individual difference or the accessibility of fresh tissue samples, how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in pathological complications in lung, the main site of infection, is still incompletely understood. Therefore, physiologically relevant animal models under realistic SARS-CoV-2 infection conditions would be helpful to our understanding of dysregulated inflammation response in lung in the context of targeted therapeutics. Here, we characterized the single-cell landscape in lung and spleen upon SARS-CoV-2 infection in an acute severe disease mouse model that replicates human symptoms, including severe lung pathology and lymphopenia. We showed a reduction of lymphocyte populations and an increase of neutrophils in lung and then demonstrated the key role of neutrophil-mediated lung immunopathology in both mice and humans. Under severe conditions, neutrophils recruited by a chemokine-driven positive feedback produced elevated "fatal signature" proinflammatory genes and pathways related to neutrophil activation or releasing of granular content. In addition, we identified a new Cd177high cluster that is undergoing respiratory burst and Stfahigh cluster cells that may dampen antigen presentation upon infection. We also revealed the devastating effect of overactivated neutrophil by showing the highly enriched neutrophil extracellular traps in lung and a dampened B-cell function in either lung or spleen that may be attributed to arginine consumption by neutrophil. The current study helped our understanding of SARS-CoV-2-induced pneumonia and warranted the concept of neutrophil-targeting therapeutics in COVID-19 treatment. IMPORTANCE We demonstrated the single-cell landscape in lung and spleen upon SARS-CoV-2 infection in an acute severe disease mouse model that replicated human symptoms, including severe lung pathology and lymphopenia. Our comprehensive study revealed the key role of neutrophil-mediated lung immunopathology in SARS-CoV-2-induced severe pneumonia, which not only helped our understanding of COVID-19 but also warranted the concept of neutrophil targeting therapeutics in COVID-19 treatment.

Updated approaches against SARS-CoV-2

Novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lies behind the ongoing outbreak of coronavirus disease 2019 (COVID-19). There is a growing understanding of SARS-CoV-2 in virology, epidemiology, and clinical management strategies. However, no anti-SARS-CoV-2 drug or vaccine has been officially approved due to the absence of adequate evidence. Scientists are racing to develop a treatment for COVID-19. Recent studies have revealed many attractive therapeutic options, even if some of them remain to be further confirmed in rigorous preclinical models and clinical trials. In this minireview, we aim to summarize the updated potential approaches against SARS-CoV-2. We emphasize that further efforts are warranted to develop the safest and most effective approach.

Clinical Characteristics of Refractory Coronavirus Disease 2019 in Wuhan, China.

BACKGROUND: Since December 2019, coronavirus disease 2019 (COVID-19), caused by severe adult respiratory syndrome coronavirus 2, occurred in Wuhan, and rapidly spread throughout China. This study aimed to clarify the characteristics of patients with refractory COVID-19. METHODS: In this retrospective single-center study, we included 155 consecutive patients with confirmed COVID-19 in Zhongnan Hospital of Wuhan University from 1 January to 5 February. The cases were divided into general and refractory COVID-19 groups according to the clinical efficacy of treatment after hospitalization, and the differences between groups were compared. RESULTS: Compared with patients with general COVID-19 (45.2%), those with refractory disease were older, were more likely to be male, and had more underlying comorbid conditions, a lower incidence of fever, higher maximum temperatures among patients with fever, higher incidences of shortness of breath and anorexia, more severe disease assessment at admission, higher neutrophil, aspartate aminotransferase, lactate dehydrogenase, and C-reactive protein levels, lower platelet counts and albumin levels, and higher incidences of bilateral pneumonia and pleural effusion (P < .05). Patients with refractory COVID-19 were more likely to receive oxygen, mechanical ventilation, expectorant, and adjunctive treatment, including corticosteroids, antiviral drugs, and immune enhancers (P < .05). Considering the factors of disease severity at admission, mechanical ventilation, and intensive care unit transfer, patients with refractory COVID-19 were also more likely to be male, have manifestations of anorexia on admission, and receive oxygen, expectorant, and adjunctive agents (P < .05). CONCLUSION: In nearly 50% of patients with COVID-19 obvious clinical and radiological remission was not achieved within 10 days after hospitalization. Male, anorexia, and no fever at admission was predictive of poor treatment efficacy.

COVID-19 and its effects on the digestive system.

Coronavirus disease 2019 (COVID-19) is caused by infection of the coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with typical respiratory symptoms. SARS-CoV-2 invades not only the respiratory system, but also other organs expressing the cell surface receptor angiotensin converting enzyme 2. In particular, the digestive system is a susceptible target of SARS-CoV-2. Gastrointestinal symptoms of COVID-19 include anorexia, nausea, vomiting, diarrhea, abdominal pain, and liver damage. Patients with digestive damage have a greater chance of progressing to severe or critical illness, a poorer prognosis, and a higher risk of death. This paper aims to summarize the digestive system symptoms of COVID-19 and discuss fecal-oral contagion of SARS-CoV-2. It also describes the characteristics of inflammatory bowel disease patients with SARS-CoV-2 infection and discusses precautions for preventing SARS-CoV-2 infection during gastrointestinal endoscopy procedures. Improved attention to digestive system abnormalities and gastrointestinal symptoms of COVID-19 patients may aid health care providers in the process of clinical diagnosis, treatment, and epidemic prevention and control.

Clinical characteristics, laboratory outcome characteristics, comorbidities, and complications of related COVID-19 deceased: a systematic review and meta-analysis.

BACKGROUND: At present, novel coronavirus disease 2019 (COVID-19) has become a serious global public health problem. The current meta-analysis aimed to find risk factors for the COVID-19-related death, helping to enhance the efficacy and reduce the mortality of COVID-19. METHODS: We searched PubMed, Embase, medRxiv, and Cochrane Library for articles published between January 1, 2020, and April 13, 2020. We statistically analyzed the risk factors of the COVID-19 deceased with meta-analysis. RESULTS: A total of 2401 patients in 15 articles were included in this study. Meta-analysis showed that 66.6% of COVID-19 deceased were male, with a median age of 69.9 years. Common symptoms of deceased included fever (70.6-100%), dyspnea (38.89-85.7%), cough (22.4-78%), and fatigue (22-61.9%). The incidence of hypertension, chronic cardiovascular disease, diabetes, and chronic cerebrovascular disease among the COVID-19 deceased were 38.56% (95% confidence interval (CI) 25.84 ~ 52.12%), 17.54% (95% CI 13.38 ~ 21.69%), 22.2% (95% CI 19.30 ~ 25.10%), and 15.58% (95% CI 10.05 ~ 21.12%), respectively. Compared with the surviving COVID-19 patients, the deceased had lower platelet levels (mean difference (MD) = - 39.35, 95% CI - 55.78 ~ - 22.93) and higher C-reactive protein (CRP) (MD = 80.85, 95% CI 62.53 ~ 99.18) and lactate dehydrogenase (LDH) (MD = 246.65, 95% CI 157.43 ~ 335.88) at admission. The most common complications of the deceased were acute respiratory distress syndrome (ARDS) (OR = 100.36, 95% CI 64.44 ~ 156.32) and shock (OR = 96.60, 95% CI 23.80 ~ 392.14). CONCLUSION: Most of the COVID-19 deceased were elderly males. Fever, dyspnea, dry cough, fatigue, hypertension, chronic cardiovascular and cerebrovascular disease, diabetes, and laboratory examinations showed low levels of platelet content, increased CRP and LDH were associated with the risk of dying. ARDS and shock were risk factors for death in COVID-19 patients.

Characteristics of Peripheral Lymphocyte Subset Alteration in COVID-19 Pneumonia.

BACKGROUND: In December 2019, novel coronavirus (SARS-CoV-2) pneumonia (COVID-19) was reported in Wuhan and has since rapidly spread throughout China. We aimed to clarify the characteristics and clinical significance of peripheral lymphocyte subset alteration in COVID-19. METHODS: The levels of peripheral lymphocyte subsets were measured by flow cytometry in 60 hospitalized COVID-19 patients before and after treatment, and their association with clinical characteristics and treatment efficacy was analyzed. RESULTS: Total lymphocytes, CD4+ T cells, CD8+ T cells, B cells, and natural killer (NK) cells decreased in COVID-19 patients, and severe cases had a lower level than mild cases. The subsets showed a significant association with inflammatory status in COVID-19, especially CD8+ T cells and CD4+/CD8+ ratio. After treatment, 37 patients (67%) showed clinical response, with an increase in CD8+ T cells and B cells. No significant change in any subset was detected in nonresponsive cases. In multivariate analysis, posttreatment decrease in CD8+ T cells and B cells and increase in CD4+/CD8+ ratio were indicated as independent predictors of poor efficacy. CONCLUSIONS: Peripheral lymphocyte subset alteration was associated with clinical characteristics and treatment efficacy of COVID-19. CD8+ T cells tended to be an independent predictor for COVID-19 severity and treatment efficacy.

Neutrophil to CD4+ lymphocyte ratio as a potential biomarker in predicting virus negative conversion time in COVID-19.

BACKGROUND: Since December 2019, novel coronavirus (SARS-CoV-2)-infected pneumonia (COVID-19) occurred in Wuhan, and rapidly spread throughout China. Our study aimed to evaluate the robustness of neutrophil to CD4+ lymphocyte ratio (NCD4LR) in predicting the negative conversion time (NCT) of SARS-CoV-2 in COVID-19 patients. METHODS: Univariate and multivariate analysis were conducted to evaluate the independency of NCD4LR in predicting NCT. Receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) were used to assess the diagnostic accuracy. RESULTS: Compared with low NCD4LR patients, patients with high NCD4LR had an older age; higher incidence of fever, fatigue, chest distress/breath shortness, severer disease assessment on admission; higher levels of inflammatory indicators; low levels of lymphocyte subsets, and a longer NCT. Multivariate analysis also identified NCD4LR as an independent risk factor for delayed NCT. ROC analysis showed that NCD4LR had a better performance than neutrophil to lymphocyte ratio in predicting the virus negative conversion within 2 weeks (AUC = 0.772), 3 weeks (AUC = 0.710), 4 weeks (AUC = 0.728), or 5 weeks (AUC = 0.815). CONCLUSION: This study suggests that NCD4LR is a potential and useful biomarker for predicting the virus negative conversion time in COVID-19 patients. Furthermore, due to the NCDLR value is easily calculated, it can be widely used as a clinical biomarker for disease progression and clinical outcomes in COVID-19 patients.

Liver impairment in COVID-19 patients: A retrospective analysis of 115 cases from a single centre in Wuhan city, China.

BACKGROUND: The SARS-CoV-2 pandemic is an ongoing global health emergency. The aim of our study was to investigate the changes of liver function and its clinical significance in COVID-19 patients. METHOD: This retrospective, single-centre study was conducted on 115 confirmed cases of COVID-19 in Zhongnan hospital of Wuhan University from 18 January 2020 to 22 February 2020. Liver function and related indexes were analysed to evaluate its relationship with disease progression in COVID-19 patients. RESULTS: Part of the COVID-19 patients presented with varying degrees of abnormality in liver function indexes. However, the levels of ALT, AST, TBIL, GGT and LDH in COVID-19 patients were not significantly different when compared with hospitalised community-acquired pneumonia patients, and the levels of albumin is even significantly higher. The levels of ALT, AST, TBIL, LDH and INR showed statistically significant elevation in severe COVID-19 cases compared with that in mild cases. However, the clinical significance of the elevation is unremarkable. Majority of severe COVID-19 patients showed significantly decreasing in albumin level and continuously decreasing in the progress of illness. Most of the liver function indexes in COVID-19 patients were correlated with CRP and NLR, the markers of inflammation. Logistic regression analysis further identified NLR as the independent risk factor for severe COVID-19, as well as age. CONCLUSIONS: Although abnormalities of liver function indexes are common in COVID-19 patients, the impairment of liver function is not a prominent feature of COVID-19, and also may not have serious clinical consequences.

The effect of corticosteroid treatment on patients with coronavirus infection: a systematic review and meta-analysis.

OBJECTIVES: An outbreak of novel coronavirus in 2019 threatens the health of people, and there is no proven pharmacological treatment. Although corticosteroids were widely used during outbreaks of severe acute respiratory syndrome and Middle East respiratory syndrome, their efficacy remainedhighly controversial. We aimed to further evaluate the influence of corticosteroids on patients with coronavirus infection. METHODS: We conducted a comprehensive search of literature published in PubMed, Embase, Cochrane library, and China National Knowledge Infrastructure (CNKI) from January 1, 2002 to March 15, 2020. All statistical analyses in this study were performed on stata14.0. RESULTS: A total of 5270 patients from 15 studies were included in this meta-analysis. The result indicated that critical patients were more likely to require corticosteroids therapy (risk ratio [RR] = 1.56, 95% confidence interval [CI] = 1.28-1.90, P<0.001). However, corticosteroid treatment was associated with higher mortality (RR = 2.11, 95%CI = 1.13-3.94, P = 0.019), longer length of stay (weighted mean difference [WMD] = 6.31, 95%CI = 5.26-7.37, P<0.001), a higher rate of bacterial infection (RR = 2.08, 95%CI = 1.54-2.81, P<0.001), and hypokalemia (RR = 2.21, 95%CI = 1.07-4.55, P = 0.032) but not hyperglycemia (RR = 1.37, 95%CI=0.68-2.76, P = 0.376) or hypocalcemia (RR = 1.35, 95%CI = 0.77-2.37, P = 0.302). CONCLUSIONS: Patients with severe conditions are more likely to require corticosteroids. Corticosteroid use is associated with increased mortality in patients with coronavirus pneumonia.