ABSTRACT
Objective:To detect the levels of serum IgM and IgG antibodies against 2019-nCoV in 79 patients with COVID-19 for understanding their variation patterns in vivo. Methods:Chemiluminescence immunoassay was used to detect the levels of 2019-nCoV-specific IgM and IgG antibodies in 167 serum samples collected at different periods (≤10 d, 10<~20 d, 20<~30 d、>30 d) after disease onset from 79 clinically confirmed COVID-19 patients in Hangzhou Xixi Hospital. The results were statistically analyzed together with clinical data.Results:The average levels of IgM and IgG antibodies in severe and common cases were higher than those in mild cases [IgM: 21.77 (10.18-128.65) and 13.13 (6.08-35.14) vs 3.01(1.69-8.69), χ 2=27.442, P<0.01; IgG: (124.22±36.79) and (120.04±63.25) vs (52.31±53.68), F/χ 2=27.295, P<0.01]. The positive rates of IgM and IgG antibodies in severe and common cases were also higher than those in mild cases after recovery ( P<0.01). The levels of IgM and IgG antibodies were affected by the time of detection. The level of IgM antibody detected during 10<~20 d of the disease onset was significantly higher than that within 10 d of the disease onset ( P<0.05). The level of IgG antibody detected after 10 d of the disease onset was significantly higher than that within 10 d of the disease onset ( P<0.01). Conclusions:Higher levels of IgM and IgG antibodies were detected in patients with severe COVID-19. A significant correlation was found between the levels of IgM and IgG antibodies and the time of detection.