Characteristics of SARS - CoV - 2 nucleic acids and serum antibodies in different clinical specimens and their correlation with the course of COVID -19

To investigate the characteristics of the nucleic acids of severe acute respiratory syndrome coronavirus (SARS-CoV) -2 and antibodies in different specimens obtained from coronavirus disease 2019 (COVID-19) patients;if a correlation between these parameters and the disease course was present. The throat swabs and stool samples of 39 COVID-19 patients admitted to our hospital were collected in this study. Real-time reverse transcription-quantitative polymerase chain reaction (RT-PCR) was undertaken on throat swabs and stool samples. Peripheral blood was taken and serum levels of immunoglobulin IgM and IgG measured. Results showed That, Throat swabs and stool samples tested positive for the nucleic acid of SARS-CoV-Z, but nucleic acid levels were reduced significantly 15 days after disease onset compared with that upon diagnosis. The Ct value of the nucleic acid test was increased significantly. Serum levels of IgM and IgG were significantly higher than those of healthy people. nucleic acid loads in throat swabs and stool samples as well as serum levels of IgM and IgG were highly correlated with the disease course (r = 0.7387,0.5696, -0.546 and 0.6117,respectively, P < 0.05). In this study nucleic acid loads in throat swabs and stool samples as well as serum levels of IgM and IgG are highly correlated with the course of COVID-19.

Detection method for antibodies against SARS-CoV-2 and clinical application

To determine if a method to detect antibodies against SARS-CoV-2 can be applied clinically. In this retrospective study, the sera samples of 39 patients with newly diagnosed coronavirus disease 2019 (COVID- 19) and 90 healthy people were analyzed by antibody-detection reagents within enzyme-linked immunosorbent assays. The sera samples of confirmed cases at different onset times and 40 suspected cases were also tested. Then. we combined the results of antibody tests. nucleic-acid tests, and patient data. The sensitivity and specificity for SARS-COV-2-specific total antibodies was 92.31% and 100%, respectively. The production time of total antibodies in serum samples increased with time. and the median detection time was 13 days. The result of antibody testing of one confirmed case preceded the result of the nucleic-acid test. Moreover, the antibodies 0f 40 suspected cases were all negative. Detection of the total antibodies against SARS-CoV-2 can be used as an auxiliary diagnostic indicator of infection by this virus, as well as a supplementary means to exclude suspected cases/populations in areas with a high prevalence of negative detection of the nucleic acids of SARS-CoV-2.

Serum IgM and IgG antibody response six months post-COVID-19 vaccination

Objective: To determine the serum IgM and IgG antibody levels post-COVID-19 vaccination, and provide scientific evidence for COVID-19 antibody response after vaccination.

CD8+ T cells predicted the conversion of common covid-19 to severe.

To evaluate the predictive effect of T-lymphoid subsets on the conversion of common covid-19 to severe. The laboratory data were collected retrospectively from common covid-19 patients in the First People's Hospital of Zaoyang, Hubei Province, China and the Third People's Hospital of Kunming, Yunnan Province, China, between January 20, 2020 and March 15, 2020 and divided into training set and validation set. Univariate and multivariate logistic regression was performed to investigate the risk factors for the conversion of common covid-19 to severe in the training set, the prediction model was established and verified externally in the validation set. 60 (14.71%) of 408 patients with common covid-19 became severe in 6-10 days after diagnosis. Univariate and multiple logistic regression analysis revealed that lactate (P = 0.042, OR = 1097.983, 95% CI 1.303, 924,798.262) and CD8+ T cells (P = 0.010, OR = 0.903, 95% CI 0.835, 0.975) were independent risk factors for general type patients to turn to severe type. The area under ROC curve of lactate and CD8+ T cells was 0.754 (0.581, 0.928) and 0.842 (0.713, 0.970), respectively. The actual observation value was highly consistent with the prediction model value in curve fitting. The established prediction model was verified in 78 COVID-19 patients in the verification set, the area under the ROC curve was 0.906 (0.861, 0.981), and the calibration curve was consistent. CD8+ T cells, as an independent risk factor, could predict the transition from common covid-19 to severe.

Analysis of early characteristics of patients with novel coronavirus infection in Kunming City, Yunnan Province, China

To analyze the epidemiological characteristics and early clinical characteristics of patients with new coronavirus (2019-nCoV) infection in Kunming, and to provide evidence for clinical diagnosis and treatment. The epidemiological history, clinical symptoms, and laboratory test data of 41 of 2019-nCoV confirmed patients admitted to the isolation ward of The third People's Hospital of Kunming from January 23 to February 10, 2020 were retrospectively analyzed. The vast majority of 41 2019-nCoV confirmed patients were imported cases, with incubation periods ranging from 2 to 20 days;severe and critically ill patients were Severe and critically ill patients were older, had higher BMI, similar clinical symptoms, and lymphocytes than patients with mild and general type Lower counts, earlier changes in blood gas, higher erythrocyte sedimentation, lower CA and FE, and more significant decreases in CD4 and CD8 counts. The changes of lymphocyte count, blood gas, ESR, CA and FE and T lymphocyte subsets will appear earlier in the week before the disease is aggravated, which has a certain early warning effect on the severity of the disease.

Effects of Short-Term Low-Dose Glucocorticoids for Patients with Mild COVID-19.

OBJECTIVES: To evaluate the role of short-term low-dose glucocorticoids in mild COVID-19 patients. METHODS: We conducted a retrospective, cross-sectional, single-center study in Kunming, China. A total of 33 mild COVID-19 cases were divided into two treatment groups (with and without glucocorticoids, methylprednisolone, were used in this setting), and the absolute value of peripheral blood lymphocyte count; CD3+, CD4+, and CD8+ T cell counts; and the time to achieve negative transformation of a nucleic acid pharyngeal swab were recorded. Peripheral blood lymphocyte and T cell counts were compared between the treatment group and 25 healthy individuals. At the point of time when there was a 50% accumulation conversion rate (positive to negative nucleic acid on pharyngeal swab), and the nucleic acid turned negative in half of the patients in two groups, the peripheral blood lymphocyte and T cell counts were compared between treatment groups. RESULTS: The mean cumulative time for the 50% negative conversion rate of the nucleic acid in the pharyngeal swab was 17.7 ± 5.1 days and 13.9 ± 5.4 days in the glucocorticoid group and the nonglucocorticoid group, respectively. The absolute peripheral blood lymphocyte count and the T cell subset count in the glucocorticoid group were lower than those in the nonglucocorticoid group. When the nucleic acid turned negative in half of the patients, the absolute value of peripheral blood lymphocyte count and CD4+ T cells of the glucocorticoid group and the nonglucocorticoid group was not significantly different; the CD3+ and CD8+ T cells in the glucocorticoid group were lower than those in the nonglucocorticoid group. The absolute peripheral blood lymphocyte count, CD3+ T cells, and CD4+ T cells in the glucocorticoid group were lower than those of the healthy group during the whole disease period, and CD8+ T cells returned to normal at 19-21 days of the disease period. There was no significant difference between the nonglucocorticoid group and the healthy group for absolute peripheral blood lymphocyte and CD8+ T cells; moreover, CD3+ T cells and CD4+ T cells were lower in the nonglucocorticoid group than those in the healthy group from the day of admission to the 18th day and returned to normal at the period of 19-21 days. The absolute peripheral lymphocyte count (P = 0.048, effect size d = 0.727) and T cell subset count (CD3: P = 0.042, effect size d = 0.655; CD4: P < 0.01, effect size d = 0.599; and CD8: P = 0.034, effect size d = 0.550) in the nonglucocorticoid group were higher than those in the glucocorticoid group, and the difference between the groups was statistically significant. CONCLUSIONS: This study found that the use of short-term, low-dose glucocorticoids does not negatively influence the clinical outcome, without affecting the final clearance of viral nucleic acid in mild COVID-19 patients.

Difference in Biomarkers Between COVID-19 Patients and Other Pulmonary Infection Patients.

BACKGROUND: The pandemic due to the novel coronavirus disease 2019 (COVID-19) has resulted in an increasing number of patients need to be tested. We aimed to determine if the use of integrated laboratory data can discriminate COVID-19 patients from other pulmonary infection patients. METHODS: This retrospective cohort study was conducted at Kunming Third People's Hospital in China from January 20 to February 28, 2020. Medical records and laboratory data were extracted and combined for COVID-19 and other pulmonary infection patients on admission. A partial least square discriminant analysis (PLS-DA) model was constructed and calibrated to discriminate COVID-19 from other pulmonary infection patients. RESULTS: COVID-19 patients diagnosed and treated in Kunming were balanced in terms of sex and covered all age groups. Most of them were mild cases; only five were severe cases. The first two dimensions of the PLS-DA model could classify COVID-19 and other pulmonary infection patients with an accuracy of 96.6% (95.1% in the cross-validation model). Basophil count, the proportion of basophils, prothrombin time, prothrombin time activity, and international normalized ratio were the five most discriminant biomarkers. CONCLUSION: Integration of biomarkers can discriminate COVID-19 patients from other pulmonary infections on admission to hospital and thus may be a supplement to nucleic acid tests.