ABSTRACT
BackgroundViral clearance is one important indicator for the recovery of SARS-CoV-2 infected patients. Previous studies have pointed out that suboptimal T and B cell responses can delay viral clearance in MERS-CoV and SARS-CoV infected patients. The role of leukomonocytes in viral clearance of COVID-19 patients is not yet well defined. MethodsFrom January 26 to February 28, 2020, an observational study was launched at the Department of Infectious Diseases, Zhongnan Hospital of Wuhan University, Wuhan, China. We enrolled 25 laboratory-confirmed COVID-19 patients, whose throat-swab specimens were tested positive for SARS-CoV-2 infection by qRT-PCR. To investigate the factors that contribute to the viral clearance, we comprehensively analyzed clinical records, counts of lymphocyte subsets including CD3+, CD4+, CD8+ T cells, B cells and NK cells in the patients who successfully cleared SARS-CoV-2, and compared to those that failed to, after a standardized treatment of 8-14 days. FindingsIn 25 enrolled COVID-19 patients, lymphopenia was a common feature. After the treatment, 14 out of the 25 enrolled patients were tested negative for SARS-CoV-2. The patients that cleared the infection had restored the numbers of CD3+, CD4+, CD8+ T cells and B cells as compared to the still viral RNA positive patients, while the recovered patients had a higher count of leukomonocytes. ConclusionsBy comparison of leukomonocytes counts in COVID-19 patients at different stages of the disease, we found that CD3+, CD4+, CD8+ T cells and B cells appear to play important roles in viral clearance. The restoration of leukomonocytes counts from peripheral blood can be used as prognosis for the recovery of an COVID-19 infection. We propose that restoration of leukomonocytes counts can be added to the COVID-19 diagnostic guidance as a criterion for releasing and discharging patients.
ABSTRACT
Real time fluorescent quantitative PCR (RT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. However, due to the low viral load in patient throats and the limitations of RT-PCR, significant numbers of false negative reports are inevitable, which results in failure to timely diagnose, early treat, cut off transmission, and assess discharge criteria. To improve this situation, an optimized droplet digital PCR (ddPCR) was used for detection of SARS-CoV-2, which showed that the limit of detection of ddPCR is significantly lower than that of RT-PCR. We further explored the feasibility of ddPCR to detect SARS-CoV-2 nucleic acid from 77 clinical throat swab samples, including 63 suspected outpatients with fever and 14 supposed convalescents who were about to discharge after treatment, and compared with RT-PCR in terms of the diagnostic accuracy. In this double-blind study, we tested, surveyed subsequently and statistically analyzed 77 clinical samples. According to our study, 26 samples from COVID-19 patients with RT-PCR negative were detected as positive by ddPCR. No FPRs of RT-PCR and ddPCR were observed. The sensitivity, specificity, PPV, NPV, NLR and accuracy were improved from 40% (95% CI: 27-55%), 100% (95% CI: 54-100%), 100%, 16% (95% CI: 13-19%), 0.6 (95% CI: 0.48-0.75) and 47% (95% CI: 33-60%) for RT-PCR to 94% (95% CI: 83-99%), 100% (95% CI: 48-100%), 100%, 63% (95% CI: 36-83%), 0.06 (95% CI: 0.02-0.18) and 95% (95% CI: 84-99%) for ddPCR, respectively. Moreover, 14 (42.9 %) convalescents still carry detectable SARS-CoV-2 after discharge. Overall, ddPCR shows superiority for clinical diagnosis of SARS-CoV-2 to reduce the false negative reports, which could be a powerful complement to the current standard RT-PCR. It also suggests that the current clinical practice that the convalescent after discharge continues to be quarantined for at least 2 weeks is completely necessary which can prevent potential viral transmission.
ABSTRACT
Objective:To analyze the clinical data of 203 discharged patients with corona virus disease 2019(COVID-19), and to investigate the predictors for the severe cases.Methods:Confirmed COVID-19 cases hospitalized at Zhongnan Hospital of Wuhan University from January 1 to February 1, 2020 were consecutively enrolled, who were divided into severe group and non-severe group.The clinical data of enrolled patients were collected and the clinical manifestations, laboratory results, imaging, treatments and prognosis of patients in the two groups were analyzed. Mann-Whitney U rank sum test and chi-square test were used for statistical analysis. Results:A total of 203 discharged patients with COVID-19 were enrolled. The common clinical manifestations included fever (89.2%, 181/203), dry cough (60.1%, 122/203), chest distress (35.5%, 72/203), shortness of breath(29.1%, 59/203)and myalgia or arthralgia (26.6%, 54/203). The time from disease onset to hospital admission was 5.8 days (1.0 to 20.0 days). Among 203 enrolled patients, 107(52.7%) were divided into severe group and 96(47.3%) were non-severe group. The age in severe group was 60 years (23 to 91 years), which was significantly older than non-severe group (47 years (20 to 86 years)), the difference was statistically significant ( Z=-6.12, P<0.01). There were 63.6%(68/107) patients in severe group with at least one underlying disease, which was significantly more than non-severe group (20.8% (20/96)), the difference was statistically significant ( χ2=37.60, P<0.01). The proportions of patients with increased white blood cells, decreased lymphocytes and albumin, elevated alanine aminotransferase, aspartate aminotransferase, creatinine, lactic acid dehydrogenase, creatine kinase, fasting blood glucose, D-dimer, erythrocyte sedimentation rate, C-reactive protein, interleukin-6, and procalcitonin in severe group were all higher. On admission, 172 patients (84.7%) had bilateral patchy shadows or ground glass opacity in the lungs on chest imaging study, 20(9.9%) presented pleural effusion. Fifty-five cases (27.1%) showed progressions of lung lesions on computed tomography (CT) rescan at an average interval of five days. Among 203 patients, 123(60.6%) were given oxygen therapy upon admission, 107(52.7%) were given short-term glucocorticoid therapy, and 131(64.5%) received antiviral therapy; and 26(12.8%) died. The hospital stay was 11.0 days (1.0 to 45.0 days). Conclusions:Fever is the most common symptoms in COVID-19 patients.Elderly and patients with underlying diseases are risk factors for progression to severe cases. The elderly patients should be strengthened early monitoring, paid attention to the control of underlying diseases, and reduce the occurrence of critical diseases.
ABSTRACT
Objective:To study the immunological characteristics of recombinant Rv3425 protein,to evaluate its diagnosis value and the role in the pathogenicity. Methods: Rv3425 gene was cloned into pET28a vector,the recombinant protein was induced and purified;we analyzed the antigenicity and specificity of Rv3425 by ELISA ( Enzyme-linked immuno sorbent assay) and Western blot methods,apoptosis effect of Rv3425 to macrophage was deteced by FCM ( Flow cytometry method ) . Results: Purified prokaryotic expressed protein Rv3425 was acquired,we found Rv3425 could elicit high level of IFN-γin spleen cells and combine with the serum of iH37Rv (inactivated mycobacterium tuberculosis) immunized mice;the specific IgG and IgM antibodies of TB (Tuberculosis) patients were significantly higher than healthy donors;Rv3425 also could induce the necrosis of macrophage. Conclusion:Our study found that Rv3425 had strong antigenicity and could induce the apoptosis of macrophage,these findings were very important for the research of TB diagnosis and pathogenicity.
