Differences in Clinical and Imaging Features between Asymptomatic and Symptomatic COVID-19 Patients.

Objectives: The clinical and imaging features of asymptomatic carriers of severe acute respiratory syndrome coronavirus 2 and symptomatic COVID-19 patients. Methods: The clinical and chest computed tomography imaging data of 47 asymptomatic carriers and 36 symptomatic COVID-19 patients were derived. All patients underwent 4-6 CT scans over a period of 2-5 days. Results: The bulk of asymptomatic carriers who developed symptoms and most of the COVID-19 patients were older than 18 years of age with a decreased lymphocyte count, abnormal hepatic and renal function, and increased D-dimer and C-reactive protein. In the early stage, the pulmonary lesion involved mostly 1-2 lobes at the peripheral area in asymptomatic carriers but more than three lobes at both the central and peripheral areas in COVID-19 patients. In the progression stage, the lesion of asymptomatic carriers extended from the peripheral to the central area, and no significant difference was found in the lesion range compared with the symptomatic control group. In early improvement stage, the lesion was rapidly absorbed, and lesions were located primarily at the peripheral area in asymptomatic carriers; contrastingly, lesions were primarily located at both the central and peripheral areas in symptomatic patients. Asymptomatic carriers reflected a significantly shorter duration from disease onset to peak progression stage compared with the symptomatic. Conclusions: Asymptomatic carriers are a potential source of transmission and may become symptomatic COVID-19 patients despite indicating less severe pulmonary damage, earlier improvement, and better prognosis. Early isolation and intervention can eliminate such carriers as potential sources of transmission and improve their prognosis.

Pyroptosis in the lung and spleen of patients died from COVID-19

The purpose of this study was to investigate the expression of pyroptosis-related factors (NLRP3, IL-18, NF-κB, HMGB-1, and GSDMD) in patients who died of COVID-19. The expression levels of NLRP3, IL-18, NF-κB, HMGB-1, and GSDMD in lung and spleen tissues of the COVID-19 group and the control group were detected by tissue immunofluorescence. The control group includes lung tissues and spleen tissues of two patients who died unexpectedly without SARS-CoV-2 infection, and the COVID-19 group includes the lung and spleen tissues of three patients who died of SARS-CoV-2 virus infection. The positive rates of NF-κB, NLRP3, IL-18, and GSDMD in the lung tissues from the control group and COVID-19 group were 9.8% vs 73.4% (p = 0.000), 5.5% vs 63.6% (p = 0.000), 24.4% vs 76.2% (p = 0.000), and 17.5% and 46.8% (p = 0.000) respectively. The positive rates of NF-κB, NLRP3, IL-18, HMGB-1, and GSDMD in the spleen tissues from the control group and COVID-19 group were 20.6% vs 71.2% (p = 0.000), 18.9% vs 72.0% (p = 0.000), 15.2% vs 64.8% (p = 0.000), 27.6% vs 69.2% (p = 0.000), and 23% and 48.8% (p = 0.000), respectively. The positive rates of SARS-CoV-2 spike protein in the CD68 positive cells of the lung and spleen in the control group and COVID-19 group were 2.5% vs 56.8% (p = 0.000);3.0% vs 64.9% (p = 0.000) respectively. The rates of NF-κB positive nuclei in the control group and COVID-19 group were 13.4% vs 51.4% (p = 0.000) in the lung and 38.2% vs 59.3% (p = 0.000) in the spleen. The rates of HMGB-1 positive cytoplasm in the control and the COVID-19 group were 19.7% vs 50.3% (p = 0.000) in the lung and 12.3% vs 45.2% (p = 0.000) in the spleen. The targets of SARS-CoV-2 are the lung and spleen, where increased macrophages could be involved in the up-regulation of pyroptosis-related inflammatory factors such as NF-κB, HMGB-1, NLRP3, IL-18, and GSDMD.

Cell death and pathological findings of the spleen in COVID-19 patients.

The coronavirus disease 2019(COVID-19) is recognized as systemic inflammatory response syndrome. It was demonstrated that a rapid increase of cytokines in the serum of COVID-19 patients is associated with the severity of disease. However, the mechanisms of the cytokine release are not clear. By using immunofluorescence staining we found that the number of CD11b positive immune cells including macrophages in the spleens of died COVID-19 patients, was significantly higher than that of the control patients. The incidence of apoptosis as measured by two apoptotic markers, TUNEL and cleaved caspase-3, in COVID-19 patients' spleen cells is higher than that in control patients. By double immunostaining CD11b or CD68 and SARS-CoV-2 spike protein, it was found that up to 67% of these immune cells were positive for spike protein, suggesting that viral infection might be associated with apoptosis in these cells. Besides, we also stained the autophagy-related molecules (p-Akt、p62 and BCL-2) in spleen tissues, the results showed that the number of positive cells was significantly higher in COVID-19 group. And compared with non-COVID-19 patients, autophagy may be inhibited in COVID-19 patients. Our research suggest that SARS-CoV-2 may result in a higher rate of apoptosis and a lower rate of autophagy of immune cells in the spleen of COVID-19 patients. These discoveries may increase our understanding of the pathogenesis of COVID-19.

CT features of coronavirus disease 2019 (COVID-19) in the original district of this disease (Wuhan): a pictorial review.

On December 31, 2019, the Wuhan Health Commission reported the discovery of an "unexplained" pneumonia for the first time; the pathogen was confirmed as novel coronavirus pneumonia (2019-nCoV) on January 7, 2020. As one of the important examination methods for the Corona Virus Disease 2019 (COVID-19), Computed Tomography (CT) examination plays an important role in the clinical discovery of suspected cases, diagnosis, and treatment review. This paper reviews the published papers in order to offer help in early clinical screening, disease diagnosis, disease severity determination and post-treatment review.

CT characteristics and diagnostic value of COVID-19 in pregnancy.

OBJECTIVE: To investigate the computed tomography (CT) characteristics and diagnostic value of novel coronavirus pneumonia (NCP or COVID-19) in pregnancy. METHODS: This study included ten pregnant women infected with COVID-19, treated in the Zhongnan Hospital of Wuhan University from January 20, 2020 to February 6, 2020. Clinical and chest CT data were collected and clinical symptoms, laboratory indicators, and CT images were analyzed to explore CT characteristics and diagnostic value for COVID-19 during pregnancy. RESULTS: Laboratory examination showed that white blood cell count was normal in nine patients, and slightly higher in one patient (10.23 × 109). The lymphocyte ratio decreased in two patients by 12% and 14%, respectively. The levels of C-reactive protein was elevated in seven patients (range, 21.16-60.3 mg/L) and the levels of D-dimer was increased in eight patients (range, 507-2141 ng/mL). Six patients had low levels of total protein (range, 35.3-56.5 mg/L). Two patients showed small patchy ground glass opacity (GGO) involving single lung, while eight patients showed multilobe GGO in both the lungs, with partial consolidation. Peripheral and non-peripheral lesion distributions were seen in ten (100%) and four (40%) patients, respectively. There were four patients who had signs of intra-bronchial air-bronchogram, six patients had small bilateral pleural effusions, while none had lymphadenopathy. Dynamic observations were performed in four patients after COVID-19 treatment. Among these four patients, one patient showed normal on the initial examination, and new lesions were observed after 3 days; 1 patient showed progression after 7 days of treatment, with expansion of the lesion area; and the other 2 patients showed improvement after 14 days of treatment, with reduction in the density and area of lesions and appearance of linear opacity. CONCLUSIONS: The CT characteristics of COVID-19 in pregnancy were mainly observed in early and progressive stages, and multiple new lesions were common. And there were consolidations of varying sizes and degrees within the lesion. Moreover, the original ground glass lesions could be fused or partially absorbed. Six patients had small bilateral pleural effusion. In summary, CT scans can play an important role in early screening, dynamic observation, and efficacy evaluation of suspected or confirmed cases of pregnant women with COVID-19.