COVID-19-associated morbidity and mortality have been attributed to a pathologic host response. Two divergent hypotheses have been proposed: a hyper-inflammatory ‘cytokine-storm’-mediated injury versus failure of host protective immunity resulting in unrestrained viral dissemination and organ injury. A key explanation for the inability to address this controversy has been the lack of diagnostic tools to evaluate immune function in COVID-19 infections. ELISpot, a highly sensitive, functional immunoassay was employed in 27 COVID-19, 51 septic, 18 critically-ill non-septic (CINS), and 27 healthy controls to evaluate adaptive and innate immune status by quantitating T cell IFN-ɣ and monocyte TFN-α production. Circulating T cell subsets were profoundly reduced in COVID-19 patients. Additionally, stimulated blood mononuclear cells produced less than 40% to 50% of the IFN-ɣ and TNF-α observed in septic and CINS patients, consistent with markedly impaired immune effector cell function. Approximately 25% of COVID-19 patients had increased IL-6 levels greater than 1,000 pg/mL that were not associated with elevations in other canonical pro-inflammatory cytokines. Collectively, these findings support the hypothesis that COVID-19 suppresses host functional adaptive and innate immunity. Importantly, Interleukin-7 administered ex vivo restored T cell IFN-ɣ production in COVID-19 patients. Thus, ELISpot may functionally characterize host immunity in COVID-19 and inform prospective therapies.
Kenneth E. Remy, Monty Mazer, David A. Striker, Ali H. Ellebedy, Andrew H. Walton, Jacqueline Unsinger, Teresa M. Blood, Philip A. Mudd, Daehan J. Yi, Daniel A. Mannion, Dale F. Osborne, R. Scott Martin, Nitin J. Anand, James P. Bosanquet, Jane Blood, Anne M. Drewry, Charles C. Caldwell, Isaiah R. Turnbull, Scott C. Brakenridge, Lyle L. Moldawer, Richard S. Hotchkiss
Reprogramming of host metabolism supports viral pathogenesis by fueling viral proliferation, by providing, for example, free amino acids and fatty acids as building blocks. To investigate metabolic effects of SARS-COV-2 infection, we evaluated serum metabolites of COVID-19 patients (n = 33; diagnosed by nucleic acid testing), as compared to COVID-19-negative controls (n = 16). Targeted and untargeted metabolomics analyses identified altered tryptophan metabolism into the kynurenine pathway, which regulates inflammation and immunity. Indeed, these changes in tryptophan metabolism correlated with interleukin-6 (IL-6) levels. Widespread dysregulation of nitrogen metabolism was also seen in infected patients, with altered levels of most amino acids, along with increased markers of oxidant stress (e.g., methionine sulfoxide, cystine), proteolysis, and renal dysfunction (e.g., creatine, creatinine, polyamines). Increased circulating levels of glucose and free fatty acids were also observed, consistent with altered carbon homeostasis. Interestingly, metabolite levels in these pathways correlated with clinical laboratory markers of inflammation (i.e., IL-6 and C-reactive protein) and renal function (i.e., blood urea nitrogen). In conclusion, this initial observational study identified amino acid and fatty acid metabolism as correlates of COVID-19, providing mechanistic insights, potential markers of clinical severity, and potential therapeutic targets.
Tiffany Thomas, Davide Stefanoni, Julie A. Reisz, Travis Nemkov, Lorenzo Bertolone, Richard O. Francis, Krystalyn E. Hudson, James C. Zimring, Kirk C. Hansen, Eldad A. Hod, Steven L. Spitalnik, Angelo D’Alessandro
Background Identifying immune correlates of COVID-19 disease severity is an urgent need for clinical management, vaccine evaluation and drug development. Here we present a temporal analysis of key immune mediators, cytokine and chemokines in blood of hospitalised COVID-19 patients from serial sampling and follow up over four weeks. Methods A total of 71 patients with laboratory-confirmed COVID-19 admitted to Beijing You’an hospital in China with either mild (53 patients) or severe disease (18 patients) were enrolled with 18 healthy volunteers. We measured 34 immune mediators, cytokines and chemokines in peripheral blood every 4-7 days over one month per patient using a bio-plex multiplex immunoassay. Results We found that the chemokine RANTES(CCL5) was significantly elevated, from an early stage of the infection, in patients with mild but not severe disease. We also found that early production of inhibitory mediators including IL-10 and IL-1RA were significantly associated with disease severity, and a combination of CCL5, IL-1Ra and IL-10 at week 1 may predict patient outcomes. The majority of cytokines that are known to be associated with the cytokine storm in virus infections such as IL-6 and IFN-gamma were only significantly elevated in the late stage of severe COVID-19 illness. TNF- alpha and GM-CSF showed no significant differences between severe and mild cases. Conclusion Together our data suggest early intervention to increase expression of CCL5 may prevent patients from developing severe illness. Our data also suggest that measurement of levels of CCL5, as well as IL-1Ra, IL-10 in blood individually and in combination might be useful prognostic bio-markers to guide treatment strategies.
Yan Zhao, Ling Qin, Ping Zhang, Kang Li, Lianchun Liang, Jianping Sun, Bin Xu, Yanchao Dai, Xuemei Li, Chi Zhang, Yanchun Peng, Yingmei Feng, Ang Li, Zhongjie Hu, Haiping Xiang, Graham Ogg, Ling-Pei Ho, Andrew J. McMichael, Ronghua Jin, Julian C. Knight, Tao Dong, Yonghong Zhang
BACKGROUND. Severe acute respiratory coronavirus 2 (SARS-CoV-2) caused coronavirus disease 2019 (COVID-19) has become a pandemic. This study addressed the clinical and immunopathological characteristics of severe COVID-19. METHODS. Sixty-nine COVID-19 patients were classified into as severe and non-severe groups to analyze their clinical and laboratory characteristics. A panel of blood cytokines was quantified over time. Biopsy specimens from two deceased cases were obtained for immunopathological, ultrastructural, and in situ hybridization examinations. RESULTS. Circulating cytokines, including IL8, IL6, TNFα, IP10, MCP1, and RANTES, were significantly elevated in severe COVID-19 patients. Dynamic IL6 and IL8 were associated with disease progression. SARS-CoV-2 was demonstrated to infect type II, type I pneumocytes and endothelial cells, leading to severe lung damage through cell pyroptosis and apoptosis. In severe cases, lymphopenia, neutrophilia, depletion of CD4+ and CD8+ T lymphocytes, and massive macrophage and neutrophil infiltrates were observed in both blood and lung tissues. CONCLUSIONS. A panel of circulating cytokines could be used to predict disease deterioration and inform clinical interventions. Severe pulmonary damage was predominantly attributed to both SARS-CoV-2 caused cytopathy and immunopathologic damage. Strategies that encourage pulmonary recruitment and overactivation of inflammatory cells by suppressing cytokine storm might improve the outcomes of severe COVID-19 patients.
Shaohua Li, Lina Jiang, Xi Li, Fang Lin, Yijin Wang, Boan Li, Tianjun Jiang, Weimin An, Shuhong Liu, Hongyang Liu, Pengfei Xu, Lihua Zhao, Lixin Zhang, Jinsong Mu, Hongwei Wang, Jiarui Kang, Yan Li, Lei Huang, Caizhong Zhu, Shousong Zhao, Jiangyang Lu, Junsheng Ji, Jingmin Zhao
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of human coronavirus disease 2019 (COVID-19), emerged in Wuhan, China in December 2019. The virus rapidly spread globally, resulting in a public-health crisis including more than 3.1 million cases and 224,000 deaths as of May 1, 2020. Here, we describe the identification and evaluation of commercially available reagents and assays for the molecular detection of SARS-CoV-2 in infected formalin fixed paraffin embedded (FFPE) cell pellets. We identified a suitable rabbit polyclonal anti-SARS-CoV spike protein antibody and a mouse monoclonal anti-SARS-CoV nucleocapsid protein (NP) antibody for cross detection of the respective SARS-CoV-2 proteins by immunohistochemistry (IHC) and immunofluorescence assay (IFA). Next, we established RNAscope in situ hybridization (ISH) to detect SARS-CoV-2 RNA. Furthermore, we established a multiplex fluorescence ISH (mFISH) to detect positive-sense SARS-CoV-2 RNA and negative-sense SARS-CoV-2 RNA (a replicative intermediate indicating viral replication). Finally, we developed a dual staining assay using IHC and ISH to detect SARS-CoV-2 antigen and RNA in the same FFPE section. These reagents and assays will accelerate COVID-19 pathogenesis studies in humans and in COVID-19 animal models.
Jun Liu, April M. Babka, Brian J. Kearney, Sheli R. Radoshitzky, Jens H. Kuhn, Xiankun Zeng
BACKGROUND. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a novel viral pneumonia (COVID-19), which is rapidly spreading in the world. The positive result of nucleic acid test is a golden criterion to confirm SARS-CoV-2 infection, but the detection features remain unclear. METHODS. We performed a retrospective analysis in 5,630 high-risk individuals receiving SARS-CoV-2 nucleic acid tests in Wuhan, China, and investigated their characteristics and diagnosis rates. RESULTS. The overall diagnosis rate was 34.7% (1,952/5,630). Male (P = 0.025) and older age (P = 2.525 × 10–39) were two significant risk factors of SARS-CoV-2 infection. People were generally susceptible, and most cases concentrated in people of 30- to 69-years-old. Besides, we investigated the association between diagnosis rate and the number of testing in 501 subjects. Results revealed a 1.27-fold improvement (35.5%/27.9%) of diagnosis rate from testing once to twice (P = 5.847 × 10–9), and a 1.43-fold improvement (39.9%/27.9%) from testing once to three times (P = 7.797 × 10–14). More than three testing times was not helpful for further improvement. However, this improvement was not observed in subjects with pneumonia (P = 0.097). CONCLUSION. All populations are susceptible to SARS-Cov-2 infection, and male and older age are two significant risk factors. Increasing the number of testing could significantly improve diagnosis rates, except for subjects with pneumonia. It is recommended to test twice in those high-risk individuals whose results are negative for the first time, and to perform three testing times is better if available.
Na Shen, Yaowu Zhu, Xiong Wang, Jing Peng, Weiyong Liu, Feng Wang, Yanjun Lu, Liming Cheng, Ziyong Sun
In severe cases of coronavirus disease 2019 (COVID-19), viral pneumonia progresses to respiratory failure. Neutrophil extracellular traps (NETs) are extracellular webs of chromatin, microbicidal proteins, and oxidant enzymes that are released by neutrophils to contain infections. However, when not properly regulated, NETs have potential to propagate inflammation and microvascular thrombosis — including in the lungs of patients with acute respiratory distress syndrome. While elevated levels of blood neutrophils predict worse outcomes in COVID-19, the role of NETs has not been investigated. We now report that sera from patients with COVID-19 (n = 50 patients, n = 84 samples) have elevated levels of cell-free DNA, myeloperoxidase(MPO)-DNA, and citrullinated histone H3 (Cit-H3); the latter two are highly specific markers of NETs. Highlighting the potential clinical relevance of these findings, cell-free DNA strongly correlated with acute phase reactants including C-reactive protein, D-dimer, and lactate dehydrogenase, as well as absolute neutrophil count. MPO-DNA associated with both cell-free DNA and absolute neutrophil count, while Cit-H3 correlated with platelet levels. Importantly, both cell-free DNA and MPO-DNA were higher in hospitalized patients receiving mechanical ventilation as compared with hospitalized patients breathing room air. Finally, sera from individuals with COVID-19 triggered NET release from control neutrophils in vitro. In summary, these data reveal high levels of NETs in many patients with COVID-19, where they may contribute to cytokine release and respiratory failure. Future studies should investigate the predictive power of circulating NETs in longitudinal cohorts, and determine the extent to which NETs may be novel therapeutic targets in severe COVID-19.
Yu Zuo, Srilakshmi Yalavarthi, Hui Shi, Kelsey Gockman, Melanie Zuo, Jacqueline A. Madison, Christopher N. Blair, Andrew Weber, Betsy J. Barnes, Mikala Egeblad, Robert J. Woods, Yogendra Kanthi, Jason S. Knight
Background: The Coronavirus Disease-2019 (COVID-19), infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a severe outbreak in China. The host immunity of COVID-19 patients is unknown. Methods: The routine laboratory tests and host immunity in COVID-19 patients with different severity of illness were compared after patient admission. Results: A total of 65 SARS-CoV-2-positive patients were classified as mild (n=30), severe (n=20), and extremely severe (n=15) illness. Many routine laboratory tests such as ferritin, lactate dehydrogenase and D-dimer were increased in severe and extremely severe patients. The absolute numbers of CD4+ T cells, CD8+ T cells and B cells were all gradually decreased with increased severity of illness. The activation markers such as HLA-DR and CD45RO expressed on CD4+ and CD8+ T cells were increased in severe and extremely severe patients compared with mild patients. The co-stimulatory molecule CD28 had opposite results. The percentage of natural regulatory T cells was decreased in extremely severe patients. The percentage of IFN-γ producing CD8+ T cells was increased in both severe and extremely severe patients compared with mild patients. The percentage of IFN-γ producing CD4+ T cells was increased in extremely severe patients. The IL-2R, IL-6, and IL-10 were all increased in extremely severe patients. The activation of DC and B cells was decreased in extremely severe patients. Conclusions: The number and function of T cells are inconsistent in COVID-19 patients. The hyperfunction of CD4+ and CD8+ T cells is associated with the pathogenesis of extremely severe SARS-CoV-2 infection.
Feng Wang, Hongyan Hou, Ying Luo, Guoxing Tang, Shiji Wu, Min Huang, Weiyong Liu, Yaowu Zhu, Qun Lin, Liyan Mao, Minghao Fang, Huilan Zhang, Ziyong Sun
Complications of COVID-19 have been particularly severe among older adults, who are the focus of this article. Public policy goals should prioritize pandemic preparedness in nursing homes, as well as civic and local government-based support programs for community-dwelling older adults, to ensure that risk of infection is mitigated while promoting wellness during a period of stress and uncertainty.
John P. Mills, Keith S. Kaye, Lona Mody
Lessons from history underline the importance of having direct lines of communication to and from public health officials, who must remain free from policital bias in times of crisis.
Kathleen L. Collins, Howard Markel, Andrew P. Lieberman
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