A human monoclonal antibody potently pan-neutralizes SARS-CoV-2 VOCs by targeting RBD invariant sites

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel corona virus disease (COVID-19). The neutralizing monoclonal antibodies (mAbs) targeting the receptor binding domain (RBD) of SARS-CoV-2 are among the most promising strategies to prevent and treat COVID-19. However, SARS-CoV-2 variants of concern (VOCs) profoundly reduced the efficacies of most of mAbs and vaccines approved for clinical use. Herein, we demonstrated mAb 35B5 efficiently neutralizes both wild-type (WT) SARS-CoV-2 and VOCs, including B.1.617.2 (delta) variant, in vitro and in vivo. Cryo-electron microscopy (cryo-EM) revealed that 35B5 neutralizes SARS-CoV-2 by targeting a unique epitope that avoids the prevailing mutation sites on RBD identified in circulating VOCs, providing the molecular basis for its pan-neutralizing efficacy. The 35B5-binding epitope could also be exploited for the rational design of a universal SARS-CoV-2 vaccine.

Transcriptome analysis of PBMCs reveals distinct immune response in the asymptomatic and re-detectable positive COVID-19 patients

The existence of asymptomatic and re-detectable positive COVID-19 patients presents the disease control challenges of COVID-19. Most studies on immune response of COVID-19 have focused on the moderately or severely symptomatic patients, however little is known about the immune response in asymptomatic and re-detectable positive patients. Here we performed a comprehensive analysis of the transcriptomic profiles of PBMCs from 48 COVID-19 patients which include 8 asymptomatic, 13 symptomatic, 15 recovering and 12 RP patients. Our analysis revealed a down-regulation of IFN response and complement activation in the asymptomatic patients compared with the symptomatic, indicating a weaker immune response of the PBMCs in the asymptomatic patients. In addition, we observed a lower expression of the cytokines and chemokines in the PBMC of asymptomatic and symptomatic patients. In contrast, the cytokines and chemokines level in the RP patients are higher than the recovering. GSEA analysis showed the enrichment of TNFa/NF-{kappa}B and influenza infection in the RP patients compared with the recovering patients, indicating a flu-like, hyper-inflammatory immune response in the PBMC of RP patients. Thus our findings could extend our understanding of host immune response during the progression COVID-19 disease and help the clinical management and the immunotherapy development for COVID-19.

Study on the expression levels of antibodies against SARS-CoV-2 at different period of disease and its related factors in 192 cases of COVID-19 patients

BackgroundIn 2020, the current outbreak of Coronavirus Disease 2019(COVID-19) has constituted a global pandemic. But the question about the immune mechanism of patients with COVID-19 is unclear and cause particular concern to the world. Here, we launched a follow-up analysis of antibodies against SARS-CoV-2 of 192 COVID-19 patients, aiming to depict a kinetics profile of antibodies against SARS-CoV-2 and explore the related factors of antibodies expression against SARS-CoV-2 in COVID-19 patient. MethodsA total of 192 COVID-19 patients enrolled in the designated hospital of Guangzhou, Guangzhou Eighth Peoples Hospital, from January to February 2020 were selected as the study cohort. A cohort of 130 COVID-19 suspects who had been excluded from SARS-CoV-2 infected by negative RT-PCR result and 209 healthy people were enrolled in this study. Detection of IgM and IgG against SARS-CoV-2 were performed by Chemiluminescence immunoassay in different groups. ResultsIt has been found that the seroconversion time of IgM against SARS-CoV-2 in most patients was 5-10 days after the symptoms onset, and then rose rapidly, reaching a peak around 2 to 3 weeks, and the median peak concentration was 2.705 AU / mL. The peak of IgM maintained within one week, and then enters the descending channel. IgG seroconverted later than or synchronously with IgM, reaching peaks around 3 to 4 weeks.The median peak concentration was 33.998AU / ml,which was higher than that of IgM. IgM titers begins to gradually decrease after reaching the peak in the 4th week, after the 8th week, a majority of IgM in patients serum started to turn negative. On the contrary, titers of IgG began to decline slightly after the fifth week, and more than 90% of results of patients were positive after 8 weeks. Additionally, the concentration of antibodies positively correlated with the severity of the disease and the duration of virus exist in host. ConclusionWe depict a kinetics profile of antibodies against SARS-CoV-2 in COVID-19 patients and found out that the levels of antibodies were related to the disease severity, age, gender and virus clearance or continuous proliferation of COVID-19 patients.

A Tool to Early Predict Severe 2019-Novel Coronavirus Pneumonia (COVID-19) : A Multicenter Study using the Risk Nomogram in Wuhan and Guangdong, China

BackgroundDue to no reliable risk stratification tool for severe corona virus disease 2019 (COVID-19) patients at admission, we aimed to construct an effective model for early identifying cases at high risk of progression to severe COVID-19. MethodsIn this retrospective three-centers study, 372 non-severe COVID-19 patients during hospitalization were followed for more than 15 days after admission. Patients who deteriorated to severe or critical COVID-19 and patients who kept non-severe state were assigned to the severe and non-severe group, respectively. Based on baseline data of the two groups, we constructed a risk prediction nomogram for severe COVID-19 and evaluate its performance. ResultsThe train cohort consisted of 189 patients, while the two independent validation cohorts consisted of 165 and 18 patients. Among all cases, 72 (19.35%) patients developed severe COVID-19. We found that old age, and higher serum lactate dehydrogenase, C-reactive protein, the coefficient of variation of red blood cell distribution width, blood urea nitrogen, direct bilirubin, lower albumin, are associated with severe COVID-19. We generated the nomogram for early identifying severe COVID-19 in the train cohort (AUC 0.912 [95% CI 0.846-0.978], sensitivity 85.71%, specificity 87.58%); in validation cohort (0.853 [0.790-0.916], 77.5%, 78.4%). The calibration curve for probability of severe COVID-19 showed optimal agreement between prediction by nomogram and actual observation. Decision curve and clinical impact curve analysis indicated that nomogram conferred high clinical net benefit. ConclusionOur nomogram could help clinicians to early identify patients who will exacerbate to severe COVID-19, which will enable better centralized management and early treatment of severe patients. SummaryOlder age; higher LDH, CRP, RDW, DBIL, BUN; lower ALB on admission correlated with higher odds of severe COVID-19. An effective prognostic nomogram composed of 7 features could allow early identification of patients at risk of exacerbation to severe COVID-19.

Immunopathological characteristics of coronavirus disease 2019 cases in Guangzhou, China

Coronavirus disease 2019 (COVID-19) is a respiratory disorder caused by the highly contagious SARS-CoV-2. The immunopathological characteristics of COVID-19 patients, either systemic or local, have not been thoroughly studied. In the present study, we analyzed both the changes in the cellularity of various immune cell types as well as cytokines important for immune reactions and inflammation. Our data indicate that patients with severe COVID-19 exhibited an overall decline of lymphocytes including CD4+ and CD8+ T cells, B cells, and NK cells. The number of immunosuppressive regulatory T cells was moderately increased in patients with mild COVID-19. IL-2, IL-6, and IL-10 were remarkably up-regulated in patients with severe COVID-19. The levels of IL-2 and IL-6 relative to the length of hospital stay underwent a similar "rise-decline"pattern, probably reflecting the therapeutic effect. In conclusion, our study shows that the comprehensive decrease of lymphocytes, and the elevation of IL-2 and IL-6 are reliable indicators of severe COVID-19.

Expressions of multiple inflammation markers in the patients with 2019 novel coronavirus pneumonia and their clinical values / 中华检验医学杂志

Objective@#To explore the Expressions of multiple inflammation markers in the patients with 2019 novel coronavirus pneumonia (COVID-19) and their clinical values, and to provide theoretical basis for clinical diagnosis and treatment.@*Methods@#A total of 164 patients, diagnosed with COVID-19 and admitted to Guangzhou Eighth People's Hospital from January to February 2020, were selected as the research group and divided into three groups (ordinary, severe, and critically severe pneumonia) according to the disease severity. Meandwhile 66 non-infected patients during the same period were selected as negative control group. The expressions of WBC, LYM, CRP, SAA, and PCT were retrospective studied and compared between groups. The diagnostic values of WBC, CRP, SAA and the combination of these three markers in all patients with COVID-19 and in different severity groups were analyzed by ROC curve.@*Results@#Compared with control group (WBC count :8.13(6.51,9.42)×109/L, LYM count:2.00(1.28,2.43)×109/L), WBC count [4.94(4.05, 6.67) ×109/L] and LYM count [1.33(0.94, 1.96) ×109/L] of COVID-19 patients were significantly reduced (Z=-7.435, P<0.01; Z=-4.906, P<0.01) . Compared with the control group [CRP: 1.36 (0.57~5.67) mg/ml; SAA:[4.98 (4.80~15.75) mg/mL], CRP [7.93 (2.45~23.98) mg/ml] and SAA [34.13 (4.83~198.40) mg/ml] were increased in research group (Z=-5.72, P<0.01; Z=-4.166, P<0.01) . PCT in the control group and the research group were 0.100 0(0.030 6~0.100 0)ng/ml and 0.044 5(0.031 6~0.077 0)ng/ml, respectively. There was no statistical difference between two groups (Z=-1.451, P=0.147) . The areas under the ROC curve (AUC) of WBC, CRP and SAA in patients with COVID-19 were 0.814, 0.742, 0.673, respectively (P<0.01), while the AUC of the combination of three indexes for COVID-19 diagnosis was 0.882, with 83.33%(55/66) specificity and 84.76% (139/164) sensitivity, P<0.01.The AUCs of WBC, CRP, and SAA for predicting severe and critically severe COVID-19 were 0.799, 0.779, and 0.886 , respectively (P<0.01), and the AUC of the combination of three indexes for the diagnosis of severe and critically severe COVID-19 was 0.924, with 78.67% (118/150) specificity and 14/14 sensitivity (P<0.01).@*Conclusion@#Combining detection of WBC, CRP and SAA can improve the specificity and sensitivity of COVID-19 diagnosis, with a high diagnostic value for severe and critically severe COVID-19.

The clinical application of serum amyloid A in the diagnosis and treatment of COVID-19 / 中华检验医学杂志

Serum amyloid A(SAA) is a novel marker widely used in the acute infection disease, especially viral infection. SAA has shown a cerntain value in assisting the clinical diagnosis, discrimination of severity and monitoring of progress and outcome of COVID-19. This paper introduces the application of SAA structural, function andits dynamic detection in the diagnosis of COVID-19, and the significance of combined detection with COVID-19 antibodies, nucleic acid and other diagnostic indicators.

Expressions of multiple inflammation markers in the patients with COVID-19 and their clinical values / 中华检验医学杂志

Objective:To explore the expressions of multiple inflammation markers in the patients with COVID-19 and their clinical values, and to provide theoretical basis for clinical diagnosis and treatment.Methods:A total of 164 patients, diagnosed with COVID-19 and admitted to Guangzhou Eighth People′s Hospital from January to February 2020, were selected as the research group and divided into three groups (ordinary, severe, and critically severe pneumonia) according to the disease severity. Meanwhile 66 non-infected patients during the same period were selected as negative control group. The expressions of white blood cell (WBC), lymphocyte (LYM), C-reactive protein (CRP), serum amyloid A protein (SAA), and procalcitonin (PCT) were retrospective studied and compared between groups. The diagnostic values of WBC, CRP, SAA and the combination of these three markers in all patients with COVID-19 and in different severity groups were analyzed by receiver operator characteristic (ROC) curve.Results:Compared with control group [WBC count:8.13(6.51,9.42)×10 9/L, LYM count:2.00(1.28,2.43)×10 9/L], WBC count [4.94(4.05, 6.67) ×10 9/L] and LYM count [1.33(0.94, 1.96) ×10 9/L] of COVID-19 patients were significantly reduced ( Z=-7.435, P<0.01; Z=-4.906, P<0.01) . Compared with the control group [CRP: 1.36 (0.57~5.67) mg/ml; SAA:4.98 (4.80-15.75) mg/ml], CRP [7.93 (2.45-23.98) mg/ml] and SAA [34.13 (4.83-198.40) mg/ml] were increased in research group ( Z=-5.72, P<0.01; Z=-4.166, P<0.01) . PCT in the control group and the research group were 0.100 0(0.030 6-0.100 0)ng/ml and 0.044 5(0.031 6-0.077 0)ng/ml, respectively. There was no statistical difference between two groups ( Z=-1.451, P=0.147) . The areas under the receiver operator characteristic curve (AUC) of WBC, CRP and SAA in patients with COVID-19 were 0.814, 0.742, 0.673, respectively ( P<0.01), while the AUC of the combination of three indexes for COVID-19 diagnosis was 0.882, with 83.33%(55/66) specificity and 84.76% (139/164) sensitivity, P<0.01.The AUCs of WBC, CRP, and SAA for predicting severe and critically severe COVID-19 were 0.799, 0.779, and 0.886, respectively ( P<0.01).The AUC of the combination of three indexes for the diagnosis of severe and critically severe COVID-19 was 0.924, with 78.67% (118/150) specificity and 14/14 sensitivity ( P<0.01). Conclusion:Combining detection of WBC, CRP and SAA can improve the specificity and sensitivity of COVID-19 diagnosis, with a high diagnostic value for severe and critically severe COVID-19.

Performance evaluation and clinical application of three antibody test kits for novel coronavirus / 中华微生物学和免疫学杂志

Objective:To evaluate the performance of three antibody kits for novel coronavirus (SARS-CoV-2) and to investigate the feasibility and advantages of them in clinical application.Methods:A total of 104 patients who were admitted to Guangzhou Eighth People′s Hospital with COVID-19 from January to February 2020 were selected as research group. Fifty-one healthy subjects were selected during the same period as negative control group. Serum antibodies (IgM/IgG) against SARS-CoV-2 were detected using two kinds of colloidal gold kits (A and B kits) and one chemiluminescence kit (C kit). The positive rates of SARS-CoV-2 nucleic acid in different samples from patients with COVID-19 were retrospectively analyzed.Results:The clinical sensitivity of A kit to detect SARS-CoV-2-specific IgM and IgG was 77.88% (81/104) and 65.38% (68/104), respectively, and the clinical specificity was 70.59% (36/51) and 100.00% (51/51). However, the false positive rate in IgM detection was as high as 29.41% (15/51). The sensitivity of B kit to test total antibodies to SARS-CoV-2 was 63.46% (66/104), and the clinical specificity was 94.12% (48/51). The clinical sensitivity of C kit to detect SARS-CoV-2-specific IgM and IgG were respectively 31.73% (33/104) and 64.42% (67/104), and the clinical specificity were both 98.04% (50/51). There was a moderate correlation between the detection results of two colloidal gold kits and the chemiluminescence kit with the Kappa values of 0.462 and 0.587 ( Z=6.157, P<0.01; Z=7.345, P<0.01). C kit had the highest positive detection rate for IgG, and would be more reliable to be used for IgG detection in COVID-19 patients 14 d after onset. The total positive detection rate of nucleic acid in all types of samples was 63.46% (66/104). The highest positive detection rate was in throat swabs or sputum samples, followed by those in blood samples and anal swabs. No viral nucleic acid was detected in urine samples for the time being. Conclusions:SARS-CoV-2-specific antibodies could be detected in the early or late stage of COVID-19. The method of antibody detection has the advantages of shorter detection time, simple operation and high biological safety, indicating that it could be used as a supplementary or auxiliary detection for the diagnosis of suspected COVID-19 cases with negative nucleic acid test results. The chemiluminescence kit has good sensitivity and specificity, and is well recommended for clinical laboratories.

Functional outcome and recurrence 1 year after first-ever ischemic stroke in non-diabetic patients / 国际脑血管病杂志

Objective:To investigate the risk factors for poor outcome and recurrence at 1 year after first-ever ischemic stroke in non-diabetic patients.Methods:Using Xi'an Stroke Registry Research Database, the clinical data of patients with non-diabetic first-ever ischemic stroke diagnosed in 4 tertiary A hospitals in Xi'an from January to December 2015 were collected. The National Institute of Health Stroke Scale (NIHSS) was used to evaluate the severity of stroke. Prognosis (functional outcome and recurrence) was followed up at 1 year after diagnosis. Functional outcome was assessed using the modified Rankin scale. 0-2 was defined as good outcome and >2 as poor outcome. Recurrence was defined as new focal neurological dysfunction caused by cerebral infarction or cerebral hemorrhage events during follow-up and confirmed by cranial CT or MRI. Multivariable logistic regression analysis was used to identify the independent influencing factors of clinical outcomes at 1 year. Multivariable Cox proportional hazard model was used to identify the independent influencing factors of recurrence within 1 year. Results:A total of 1 214 non-diabetic patients with first-ever ischemic stroke were included. One year follow-up showed that 210 patients (17.3%) had a poor outcome, 88 (7.2%) of them died, and 47 (3.9%) had recurrence. Multivariate logistic regression analysis showed that age (odds ratio [ OR] 1.065, 95% confidence interval [ CI] 1.042-1.090; P<0.001), atrial fibrillation ( OR 3.170, 95% CI 1.588-6.327; P=0.001), white blood cell count ( OR 1.106, 95% CI 1.006-1.216; P=0 037), baseline NIHSS score ( OR 1.210, 95% CI 1.147-1.277; P<0.001), and stroke associated-pneumonia (SAP; OR 3.677, 95% CI 1.451-9.316; P=0.006) were independently associated with poor outcomes. Multivariate Cox proportional hazards regression analysis showed that baseline NIHSS score (hazard ratio [ HR] 1.055, 95% CI 1.003-1.109; P=0.036) and SAP ( HR 7.067, 95% CI 3.154-15.836; P<0.001) were independently associated with recurrence. Kaplan-Meier survival curve analysis showed that the 1-year recurrence rate of patients with severe stroke was significantly higher than that of patients with mild to moderate stroke (log-rank test, P<0.001), and the 1-year recurrence rate of patients with SAP was significantly higher than that of patients without SAP (log-rank test, P<0.001). Conclusion:Age, atrial fibrillation, white blood cell count, baseline NIHSS score and SAP are the independent predictors of poor outcomes at 1 year after first-ever ischemic stroke in non-diabetic patients. Baseline NIHSS score and SAP are the independent predictors of recurrence within 1 year after first-ever ischemic stroke in non-diabetic patients.

Study on flow cytometry for detecting T lymphocytes in patients with dengue fever / 国际检验医学杂志

Objective To investigarte the immune status in the patients with dengue fever .Methods The flow cytometry was used to detect the T lymphocytes in the patients with dengue fever for analyzing their immune status .Results Compared with the reference range in the healthy individuals ,it was found that the T lymphocyte proportion in the patients with dengue fever was sig‐nificantly reduced compared with the healthy individuals .The percentages of CD3+CD4+ and CD3+CD8+ lymphocytes were (36 .54 ± 9 .78)% and (17 .7 ± 10 .01)% respectively ,which had statistical difference compared with the control group(P<0 .05) ,CD3+CD4+ lymphocyte count was (49 .98 ± 240 .2)cells/μL ,the difference was statistically significant (P<0 .05) ,CD3+ CD8+ lympho‐cytes count was (380 .9 ± 364 .6)cells/μL ,the difference was statistically significant(P<0 .05) .Conclusion The immune status in the patients with dengue fever is abnormal ,T lymphocyte percentage is significantly reduced compared with the healthy individuals .

Curative effect of interferon in the treatment of chronic hepatitis / 中国基层医药

Objective To investigate the effect of recombinant interferon in the treatment of chronic hepatitis and the influence of neutralizing antibody (NA) on its clinical efficacy.Methods 80 cases with chronic hepatitis were randomly divided into the treatment group(n=40) and control group(n=40).The content of HBV DNA was determined by fluorescence quantitative polymerase chain reaction ( PCR) assay.The neutralizing antibodies against interferon were measured by antiviral-neutralizing assay(AVA).Results After the treatment,the content of HBV DNA in the observation group was significantly lower than before treatment (F=12.55,P0.05).The contents of HBV DNA in NA positive group had no significant difference before and after treatment (F=0.88,P>0.05);The contents of HBV DNA in NA negative group had significant difference before and after the treatment ( F=11.55,P<0.05).In 80 cases,degree of cell lesions in 0 grade(10 cases),1 grade(25 cases),2 grade (25 cases),3 grade (12 cases) and 4 grade(8 cases).Conclusion The recombinant interferon in the treatment of chronic hepatitis has certain effect,but NA can affect its treatment effect .