Detection of IgM and IgG antibodies in patients with coronavirus disease 2019

Abstract

Objectives. This study aimed to determine the IgM and IgG responses against severe acute respiratory syndrome coronavirus (SARS-CoV)-2 in coronavirus disease 2019 (COVID-19) patients with varying illness severities. Methods. IgM and IgG antibody levels were assessed via chemiluminescence immunoassay in 338 COVID-19 patients. Results. IgM levels increased during the first week after SARS-CoV-2 infection, peaked 2 weeks and then reduced to near-background levels in most patients. IgG was detectable after 1 week and was maintained at a high level for a long period. The positive rates of IgM and/or IgG antibody detections were not significantly different among the mild, severe and critical disease groups. Severe and critical cases had higher IgM levels than mild cases, whereas the IgG level in critical cases was lower than those in both mild and severe cases. This might be because of the high disease activity and/or a compromised immune response in critical cases. The IgM antibody levels were slightly higher in deceased patients than recovered patients, but IgG levels in these groups did not significantly differ. A longitudinal detection of antibodies revealed that IgM levels decreased rapidly in recovered patients, whereas in deceased cases, either IgM levels remained high or both IgM and IgG were undetectable during the disease course. Conclusion. Quantitative detection of IgM and IgG antibodies against SARS-CoV-2 quantitatively has potential significance for evaluating the severity and prognosis of COVID-19.

Clinical characteristics of 134 convalescent patients with COVID-19 in Guizhou, China

“…Similar to a recent study [30] , we found that the antibody positivity rate was not signi cantly different between severe and non-severe patients with COVID-19. Our data showed that positive rates of IgG and IgM were 69.1% and 5.5%, respectively.…”

“…Thus, recovered patients had lower positive rates of IgM in this study. IgG is produced later than IgM and is typically maintained at a high level for 2 months [30] . Therefore, the levels of IgG and IgM can roughly re ect the disease stage.…”

Antibody seroconversion in asymptomatic and symptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)

“…[18][19][20][21][22][23][24] Because of their convenience and cost-efficiency, new serological assays of IgG and IgM antibodies have been recognised as a promising diagnostic tool to complement viral nucleic acid screening in the atrisk populations. 25 Of note, IgG/IgM seroconversion can be observed in many patients after their infections with SARS-CoV-2, 4,18,20,23,26 and serological responses are associated with disease severity. 19 For instance, an observational study of 32 critically ill and 141 noncritically ill patients reported IgM and IgG seroconversion rates of 82.7% and 64.7%, respectively.…”

No evidence of Re-infection or Human-to-Human Transmission in Cured COVID-19 Patients, a Retrospective Cohort Study

“…Studies found that IgG and IgM have a good diagnostic value in the early stage of the disease [6][7][8]. However, the value of IgG and IgM in the diagnosis of cured COVID-19 patients is not clear.…”

“…However, in patients with COVID-19, the relevance of IgM and IgG antibodies has not been clarified. Researches demonstrated that IgM and IgG could be identified during the early stage of COVID-19, and thus could have a high diagnostic value in patients with acute infection [6][7][8]. Compared with real-time reverse transcriptase polymerase chain reaction (RT-PCR), the detection of antibodies by ELISA is faster, less expensive, and easier to perform.…”