Objectives: To explore the influential factors and titer trend of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific IgG antibody in convalescent patients with coronavirus disease 2019 (COVID-19), and to provide theoretical basis for the feasibility of clinical treatment of convalescent plasma.
Methods: Colloidal gold immunochromatography assay was used to detect the SARS-CoV-2 specific IgG antibody and its titer in 113 convalescent patients with COVID-19 who were followed up from February 19, 2020 to April 6, 2020. The basic characteristics and treatment factors of patients in the high titer group (antibody titer≥1꞉160, n=22) and the low titer group (antibody titer <1꞉160, n=91) were analyzed. The IgG antibody titer in the high titer group was continuously monitored and the trend of titer was analyzed.
Results: The difference in the clinical type of COVID-19, onset time, first admission C-reactive protein, absolute value of lymphocyte, absolute value of CD19+CD3- lymphocytes, and the treatment of glucocorticoid were not statistically significant between the patients in the high titer group and the low titer group (all P>0.05). The male patients in the high titer group were more than those in the low titer group (P<0.05). The titer of SARS-CoV-2 specific IgG antibody in the high titer group decreased to less than 1꞉160 28 d after discharge.
Conclusions: Male COVID-19 patients might be more likely to produce high titer SARS-CoV-2 specific IgG antibodies than female. The peak level of SARS-CoV-2 specific IgG antibody in convalescent patients is maintained for a short period. Using plasma from convalescent COVID-19 patients for treatment should be within 28 d after discharge.
目的: 探讨2019冠状病毒病(coronavirus disease 2019，COVID-19)康复者严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2，SARS-CoV-2)特异性IgG抗体的影响因素及效价变化趋势，为康复者恢复期血浆临床治疗的可行性提供理论依据。方法: 采用胶体金免疫层析法检测2020年2月19日至4月6日期间随诊的113例COVID-19康复者SARS-CoV-2特异性IgG抗体及其效价，分析高效价组(抗体效价≥1꞉160)与低效价组(抗体效价<1꞉160)病例的基本特征及治疗因素差异；连续监测高效价组特异性IgG抗体效价，分析效价变化趋势。结果: 高效价组与低效价组患者年龄、ABO血型分布、COVID-19临床分型、发病时间、入院后首次C-反应蛋白、淋巴细胞绝对值、CD19+CD3-淋巴细胞绝对值及病程中是否接受糖皮质激素治疗差异均无统计学意义(均P>0.05)，高效价组男性占比高于低效价组(P<0.05)；高效价组SARS-CoV-2特异性IgG抗体效价在患者出院28 d后全部下降至1꞉160以下。结论: 男性COVID-19患者较女性患者可能更容易产生高效价SARS-CoV-2特异性IgG抗体。康复者SARS-CoV-2特异性IgG抗体效价峰值维持时间较短，用于临床治疗的康复者血浆应在患者康复出院后28 d内采集。.
Keywords: IgG antibody; antibody titer; convalescent plasma; coronavirus disease 2019.