Johns Hopkins School of Medicine, Baltimore, Maryland (G.C., J.M., B.M.H., P.C.).
Ann Intern Med. 2020 Oct 20;173(8):614-622. doi: 10.7326/M20-2889. Epub 2020 Jul 6.
The clinical utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies remains undefined.
To determine the clinical validity and utility of SARS-CoV-2 antibodies.
Case-control study.
First month of testing for coronavirus disease 2019 (COVID-19) by using a nucleic acid amplification test (NAAT) on nasopharyngeal swabs at the Johns Hopkins Hospital, Baltimore, Maryland (11 066 persons).
Of the 11 066 tested persons, 115 (1%) were hospitalized adults investigated for COVID-19. Clinical record review was performed to classify them into a COVID-19 case group ( = 60) or a non-COVID-19 control group ( = 55). The laboratory control groups comprised 513 persons not tested by NAAT: 160 healthy laboratory employees, 101 persons positive for IgG antibodies against Epstein-Barr virus capsid antigen, 215 positive for thyroperoxidase antibody, and 37 positive for rheumatoid factor.
Serum IgG and IgA antibodies against SARS-CoV-2 spike protein were detected by using enzyme-linked immunosorbent assay.
Sensitivity and specificity of the SARS-CoV-2 IgG assay were 0.976 (95% CI, 0.928 to 0.995) and 0.988 (CI, 0.974 to 0.995), respectively, when performed 14 days or later after symptom onset, but sensitivity decreased at earlier time points. Immunoglobulin G developed rapidly and was sustained at high levels throughout follow-up (up to 58 days). Antibodies to SARS-CoV-2 predicted the odds of developing acute respiratory distress syndrome, which increased by 62% (CI, 48% to 81%; < 0.001) for every 2-fold increase in IgG. Of 11 066 NAAT-tested patients, 457 were repeatedly NAAT-negative, and serum samples were obtained for 18 such patients (6 COVID-19 case patients and 12 non-COVID-19 control patients). Antibodies were present in 5 of 6 case patients and none of the 12 control patients ( = 0.001).
The study was retrospective and performed at a single center; the sample was small; follow-up was limited; and selection bias may have occurred.
Antibodies to SARS-CoV-2 demonstrate infection when measured at least 14 days after symptom onset, are associated with clinical severity, and provide valuable diagnostic support in patients who test negative by NAAT but remain clinically suspicious for COVID-19.
Clinical Immunology Laboratory, Department of Pathology, Johns Hopkins Hospital.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）抗体的临床效用仍未确定。
确定 SARS-CoV-2 抗体的临床有效性和实用性。
病例对照研究。
马里兰州巴尔的摩市约翰霍普金斯医院使用鼻咽拭子进行的针对 2019 年冠状病毒病（COVID-19）的核酸扩增检测（NAAT）的检测的第一个月（11066 人）。
在接受检测的 11066 人中，有 115 名（1%）住院成年人因 COVID-19 接受调查。进行临床记录审查以将他们分为 COVID-19 病例组（n=60）或非 COVID-19 对照组（n=55）。实验室对照组由 513 名未通过 NAAT 检测的人组成：160 名健康实验室员工、101 名针对 Epstein-Barr 病毒衣壳抗原 IgG 抗体阳性、215 名针对甲状腺过氧化物酶抗体阳性和 37 名针对类风湿因子阳性。
通过酶联免疫吸附试验检测 SARS-CoV-2 刺突蛋白的血清 IgG 和 IgA 抗体。
当在症状出现后 14 天或之后进行 SARS-CoV-2 IgG 检测时，该检测的敏感性和特异性分别为 0.976（95%CI，0.928 至 0.995）和 0.988（CI，0.974 至 0.995），但在较早的时间点敏感性降低。免疫球蛋白 G 迅速发展，并在整个随访期间（长达 58 天）保持高水平。针对 SARS-CoV-2 的抗体预测了发生急性呼吸窘迫综合征的几率，每增加 2 倍 IgG，几率就会增加 62%（95%CI，48%至 81%；<0.001）。在接受了 11066 次 NAAT 检测的患者中，有 457 次重复进行了 NAAT 检测呈阴性，并且对 18 名这样的患者获得了血清样本（6 名 COVID-19 病例患者和 12 名非 COVID-19 对照患者）。在 6 名病例患者中有 5 名患者存在抗体，而在 12 名对照患者中均不存在抗体（=0.001）。
该研究是回顾性的，并且仅在一个中心进行；样本量小；随访时间有限；并且可能发生选择偏倚。
在症状出现后至少 14 天测量时，针对 SARS-CoV-2 的抗体可证明存在感染，与临床严重程度相关，并为通过 NAAT 检测呈阴性但仍对 COVID-19 具有临床怀疑的患者提供有价值的诊断支持。
约翰霍普金斯医院病理学系临床免疫学实验室。
