ABSTRACT
The World Health Organization has declared SARS-CoV-2 virus outbreak a world-wide pandemic. Individuals infected by the virus exhibited different degrees of symptoms, the basis of which remains largely unclear. Currently, though convalescent individuals have been shown with both cellular and humoral immune responses, there is very limited understanding on the immune responses, especially adaptive immune responses, in patients with severe COVID-19. Here, we examined 10 blood samples from COVID-19 patients with acute respiratory distress syndrome (ARDS). The majority of them (70%) mounted SARS-CoV-2-specific humoral immunity with production of neutralizing antibodies. However, compared to healthy controls, the percentages and absolute numbers of both NK cells and CD8+ T cells were significantly reduced, accompanied with decreased IFN{gamma} expression in CD4+ T cells in peripheral blood from severe patients. Most notably, we failed in detecting SARS-CoV-2-specific IFN{gamma} production by peripheral blood lymphocytes from these patients. Our work thus indicates that COVID-19 patients with severe symptoms are associated with defective cellular immunity, which not only provides insights on understanding the pathogenesis of COVID-19, but also has implications in developing an effective vaccine to SARS-CoV-2.
Subject(s)
COVID-19ABSTRACT
Objective: To analyze the differences between clinical evaluation and the detailed imaging features in the time course of lung changes in diverse clinical types.Methods: 73 patients with COVID-19 pneumonia were retrospectively collected from three institutions in China. Radiographic features, CT score were analyzed and compared between non-emergency group (mild- and common-type) and emergency group (severe- and fatal-type).Results: In non-emergency group, the disease slowly aggravated within the first two weeks, peaked during the 2nd week (median superimposed involvement CT score: 9.5), while in emergency group, the disease peaked in the 2nd week rapidly, and the superimposed involvement CT score(median: 20) was higher than that in non-emergency group. Both two groups began to decline in the 4th week, and persistence of high levels. In emergency group, the residual lung lesions were mostly reticular (median single reticular CT score: 10) and consolidation (median single consolidation CT score:7). By contrast, most residual lung lesions in non-emergency group were GGO (median single GGO CT score: 7) and reticular (median single reticular CT score: 4). In both non-emergency and emergency groups, GGO pattern was dominant in the first week, and the proportion in emergency group was higher [20 (65%) and (18 (72%), respectively], the consolidation pattern peaked in the second week, which were 9 (32%) and 19 (73%), respectively, reticular pattern became dominant in and after 4 weeks (both over 40%).Conclusion: The disease in non-emergency and emergency group peaks in the second week. In the non-emergency group, the residual lesions are dominated by GGO and reticular, while those in the emergency group are mainly reticular and consolidation. The transiently CT manifestations of emergency and non-emergency follow certain patterns at different time points of the disease course.
Subject(s)
COVID-19 , PneumoniaABSTRACT
The WHO has declared SARS-CoV-2 outbreak a public health emergency of international concern. However, to date, there was hardly any study in characterizing the immune responses, especially adaptive immune responses to SARS-CoV-2 infection. In this study, we collected blood from COVID-19 patients who have recently become virus-free and therefore were discharged, and analyzed their SARS-CoV-2-specific antibody and T cell responses. We observed SARS-CoV-2-specific humoral and cellular immunity in the patients. Both were detected in newly discharged patients, suggesting both participate in immune-mediated protection to viral infection. However, follow-up patients (2 weeks post discharge) exhibited high titers of IgG antibodies, but with low levels of virus-specific T cells, suggesting that they may enter a quiescent state. Our work has thus provided a basis for further analysis of protective immunity to SARS-CoV-2, and understanding the pathogenesis of COVID-19, especially in the severe cases. It has also implications in designing an effective vaccine to protect and treat SARS-CoV-2 infection.