Lei Li

In recent months, the novel coronavirus disease 2019 (COVID-19) pandemic has become a major public health crisis with takeover more than 1 million lives worldwide. The long-lasting existence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has not yet been reported. Herein, we report a case of SARS-CoV-2 infection with intermittent viral polymerase chain reaction (PCR)-positive for >4 months after clinical rehabilitation. A 35-year-old male was diagnosed with COVID-19 pneumonia with fever but without other specific symptoms. The treatment with lopinavir-ritonavir, oxygen inhalation, and other symptomatic supportive treatment facilitated recovery, and the patient was discharged. However, his viral PCR test was continually positive in oropharyngeal swabs for >4 months after that. At the end of June 2020, he was still under quarantine and observation. The contribution of current antivirus therapy might be limited. The prognosis of COVID-19 patients might be irrelevant to the virus status. Thus, further investigation to evaluate the contagiousness of convalescent patients and the mechanism underlying the persistent existence of SARS-CoV-2 after recovery is essential. A new strategy of disease control, especially extending the follow-up period for recovered COVID-19 patients, is necessary to adapt to the current situation of pandemic.

The outbreak of the novel coronavirus disease 2019 (COVID-19) infection began in December 2019 in Wuhan, and rapidly spread to many provinces in China. The number of cases has increased markedly in Anhui, but information on the clinical characteristics of patients is limited. We reported 75 patients with COVID-19 in the First Affiliated Hospital of USTC from Jan 21 to Feb 16, 2020, Hefei, Anhui Province, China. COVID-19 infection was confirmed by real-time RT-PCR of respiratory nasopharyngeal swab samples. Epidemiological, clinical and laboratory data were collected and analyzed. Of the 75 patients with COVID-19, 61 (81.33%) had a direct or indirect exposure history to Wuhan. Common symptoms at onset included fever (66 [88.0%] of 75 patients) and dry cough (62 [82.67%]). Of the patients without fever, cough could be the only or primary symptom. The most prominent laboratory abnormalities were lymphopenia, decreased percentage of lymphocytes (LYM%), decreased CD4 ⁺ and CD8 ⁺ T cell counts, elevated C-reactive protein (CRP) and lactate dehydrogenase (LDH). Patients with elevated interleukin 6 (IL-6) showed significant decreases in the LYM%, CD4 ⁺ and CD8 ⁺ T cell counts. Besides, the percentage of neutrophils, CRP, LDH and Procalcitonin levels increased significantly. We concluded that COVID-19 could cause different degrees of hematological abnormalities and damage of internal organs. Hematological profiles including LYM, LDH, CRP and IL-6 could be indicators of diseases severity and evaluation of treatment effectiveness. Antiviral treatment requires a comprehensive and supportive approach. Further targeted therapy should be determined based on individual clinical manifestations and laboratory indicators.

Hydrodynamic injection (HI) of hepatitis B virus (HBV) mouse model is an useful tool for HBV related research in vivo. However, only 40% of C57/BL6 mice injected with 10 μg HBV genome contained plasmid (pAAV-HBV1.2), serum HBsAg more than 6 months and none of the BALB/c mice injected with 10 μg pAAV-HBV1.2 plasmid DNA, serum HBsAg positive more than 4 weeks in the previous study. In this study, C57/BL6 and BALB/c mice were hydrodynamic injected with different doses of pAAV-HBV1.2 plasmid DNA. HBV related serum markers were detected by ELISA. ALT levels in the serum were measured using full automated biochemistry analyzer. HBcAg positive cells in the liver were detected by immunohistochemical staining. The mRNA levels of IRF3, ISGs including ISG15, OAS, PKR and immune factors including IFNγ, TNFα, TGFβ, IL-6, IL-10, PDL1 in liver of the mice were quantified by qRT-PCR. The results showed that the mice injected with 100 μg high-concentration or 1 μg low-concentration of pAAV-HBV1.2 plasmid DNA did not excert dominant influence on HBV persistence. In contrast, injection of 5 μg intermediate-dose of pAAV-HBV1.2 plasmid DNA led to significant prolonged HBsAg expression and HBV persistence in both C57/BL6 (80% of the mice with HBsAg positive more than 6 months) and BALB/c (60% of the mice with HBsAg positive more than 3 months) mice. IFNγ was significant up-regulated in liver of the mice injected with 1 μg or 100 μg pAAV-HBV1.2 plasmid DNA. TNFα was up-regulated significantly in liver of the mice injected with 100 μg pAAV-HBV1.2 plasmid DNA. Moreover, PDL1 was significant up-regulated in liver of the mice injected with 5 μg pAAV-HBV1.2 plasmid DNA. In this paper we demonstrated that, in the HBV HI mouse model, the concentration of injected pAAV-HBV1.2 plasmid DNA contributes to the diverse kinetics of HBsAg and HBeAg in the serum as well as HBcAg expression level in the liver, which then determined the HBV persisternce, while the antiviral factors IFNγ, TNFα as well as immune negative regulatory factor PDL1 play important roles on HBV persistence.