Abstract
The coronavirus disease 2019 (COVID-19) emerged around December 2019 and have become a global epidemic disease currently. Specific antibodies against SAS-COV-2 could be detected in COVID-19 patients’ serum or plasma, but the clinical values of these antibodies as well as the effects of clinical drugs on humoral responses have not been fully demonstrated. In this study, 112 plasma samples were collected from 36 patients diagnosed with laboratory-confirmed COVID-19 in the Fifth Affiliated Hospital of Sun Yat-sen University. The IgG and IgM antibodies against receptor binding domain (RBD) and spike protein subunit 1 (S1) of SAS-COV-2 were detected by ELISA. We found that COVID-19 patients generated specific antibodies against SARS-CoV-2 after infection, and the levels of anti-RBD IgG within 2 to 3 weeks from onset were negatively associated with the time of positive-to-negative conversion of SARS-CoV-2 nucleic acid. Patients with severe symptoms had higher levels of anti-RBD IgG in 2 to 3 weeks from onset. The use of chloroquine did not significantly influence the patients’ antibody titer but reduced C-reaction protein (CRP) level. Using anti-viral drugs (lopinavir/ritonavir or arbidol) reduced antibody titer and peripheral lymphocyte count. While glucocorticoid therapy developed lower levels of peripheral lymphocyte count and higher levels of CRP, lactate dehydrogenase (LDH), α-Hydroxybutyrate dehydrogenase(α-HBDH), total bilirubin (TBIL), direct bilirubin (DBIL). From these results, we suggested that the anti-RBD IgG may provide an early protection of host humoral responses against SAS-COV-2 infection within 2 to 3 weeks from onset, and clinical treatment with different drugs displayed distinct roles in humoral and inflammatory responses.
Highlights
The coronavirus disease 2019 (COVID-19) emerged around December 2019 [1]
The present study included a cohort of 36 COVID-19 patients admitted to the Fifth Affiliated Hospital of Sun Yat-sen University between Jan 22, 2020 to March 7, 2020
N protein is abundant in coronaviruses and is a highly immunogenic protein that participates in genome replication and cell signaling pathway regulation
Summary
The coronavirus disease 2019 (COVID-19) emerged around December 2019 [1]. The infectious pathogen has been identified a SARS-related coronavirus and named as SARS-COV-2. Viral-specific antibodies play an important role in blocking viral infection. The SAS-COV-2 specific antibodies could be detected in patients’ serum or plasma, and has been used as a diagnose marker for COVID-19 [3, 4]. Transfusion plasma or serum from recovered patients has been applied as a potential therapy in clinical trials [5]. Fan Wu et al detected specific antibodies against SARS-COV-2 in COVID-19 patients within three weeks from onset, and found that elderly and middle-age patients had significantly higher plasma neutralizing Ab titers [6]. Whether the antibody titers correlated with disease progression has not been fully explored
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