Zhang Wenyan, Liu Wei, Lin Jiawang, Jin Jing, Zhao Kefu, Zhu Liwei, Wang Xiuzhen, Wang Lijie, Tang Renshu, Zhu Yindi, Zhou Wei, You Enqing, Zhang Lei, Liu Xuxiang, Wu Jinju, Chen Lili, Wang Wenjing, Zhang Qiang, Gao Rongbao
Hefei Center for Disease Control and Prevention, Hefei, Anhui Province 230061, China.
BIOHIT Healthcare (Hefei) Co., Hefei, Anhui Province 230000, China.
Infect Dis Immun. 2022 Jul 20;2(3):193-199. doi: 10.1097/ID9.0000000000000057. eCollection 2022 Jul.
Many issues, such as severity assessment and antibody responses, remain to be answered eagerly for evaluation and understanding of COVID-19. Immune lesion is one of key pathogenesis of the disease. It would be helpful to understand the disease if an investigation on antigenemia and association was conducted in the patients with SARS-CoV-2 infection.
A total of 156 patients admitted to the First People's Hospital of Hefei or Anhui Provincial Hospital on January to February 2020 were involved in this study. SARS-CoV-2 nucleocapsid (NP) antigen, specific IgM/IgG antibodies, and RNA were detected in sequential sera from three COVID-19 patients, and additional 153 COVID-19 patients by means of NP-antigen capture enzyme-linked immunosorbent assay, colloidal gold quick diagnosis, and real-time RT-PCR, respectively. The clinical types of COVID-19 patients were classified into asymptomatic, mild, moderate, severe, and critical, following on the Chinese guideline of COVID-19 diagnosis and treatment. The demographic and clinical data of patients were obtained for comparable analysis.
NP antigen was detected in 5 of 20 sequential sera collected from three COVID-19 patients with typically clinical symptoms, and 60.13% (92/153) expanded samples collected within 17 days after illness onset. No SARS-CoV-2 RNA segment was detected in these sera. The NP positive proportion reached a peak (84.85%, 28/33) on 6 to 8 days after illness onset. Both NP concentration and positive proportion were increased with the increase of clinical severity of COVID-19. Compared to NP negative patients, NP positive patients had older age [years, medians (interquartile ranges (IQR)), 49 (6) 31 (11)], lower positive proportion of NP specific IgM [27.17% (25/92) 59.02% (36/61)], and IgG [21.74% (20/92) 59.02% (36/61)] antibodies, and longer duration [days, medians (IQR), 24 (10) 21 (13)] from illness to recovery.
SARS-CoV-2 NP antigenemia occurred in COVID-19, and presented highly prevalent at early stage of the disease. The antigenemia was related to clinical severity of the disease, and may be responsible for the delay of detectable SARS-Cov-2 IgM.
对于新型冠状病毒肺炎（COVID-19）的评估和理解，许多问题，如严重程度评估和抗体反应等，仍亟待解答。免疫损伤是该疾病的关键发病机制之一。如果对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）感染患者进行抗原血症及相关性调查，将有助于了解该疾病。
本研究纳入了2020年1月至2月在合肥市第一人民医院或安徽省立医院住院的156例患者。分别采用核衣壳（NP）抗原捕获酶联免疫吸附测定、胶体金快速诊断和实时逆转录聚合酶链反应，检测了3例COVID-19患者连续血清中的SARS-CoV-2 NP抗原、特异性IgM/IgG抗体及RNA，另外检测了153例COVID-19患者。按照中国COVID-19诊断和治疗指南，将COVID-19患者的临床类型分为无症状、轻型、普通型、重型和危重型。获取患者的人口统计学和临床数据进行比较分析。
从3例有典型临床症状的COVID-19患者采集的20份连续血清中，有5份检测到NP抗原，在发病后17天内采集的153份扩大样本中，60.13%（92/153）检测到NP抗原。这些血清中未检测到SARS-CoV-2 RNA片段。NP阳性率在发病后6至8天达到峰值（84.85%，28/33）。NP浓度和阳性率均随着COVID-19临床严重程度的增加而升高。与NP阴性患者相比，NP阳性患者年龄更大[岁，中位数（四分位间距），49（6）对31（11）]，NP特异性IgM[27.17%（25/92）对59.02%（36/61）]和IgG[21.74%（20/92）对59.02%（36/61）]抗体的阳性率更低，从发病到康复的病程更长[天，中位数（四分位间距），24（10）对21（13）]。
COVID-19患者中出现SARS-CoV-2 NP抗原血症，且在疾病早期呈现高发性。抗原血症与疾病的临床严重程度相关，可能是导致SARS-CoV-2 IgM检测延迟的原因。
