Evaluation of Antibody Response in Symptomatic and Asymptomatic COVID-19 Patients and Diagnostic Assessment of New IgM/IgG ELISA Kits.

Hadeel T Al-Jighefee,Sara Taleb,Mohamed Mohamedali,Hassen Maatoug,Gheyath K Nasrallah,Ali A Hssain,Maryam A Al-Nesf,Hadi M Yassine,Ahmed S Mohamed

doi:10.3390/pathogens10020161

Abstract

This study aims to study the immune response and evaluate the performances of four new IgM and five IgG enzyme-linked immunosorbent assay (ELISA) kits for detecting anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies against different antigens in symptomatic and asymptomatic coronavirus disease 2019 (COVID-19) patients. A total of 291 samples collected from symptomatic and asymptomatic RT–PCR-confirmed patients were used to evaluate the ELISA kits’ performance (EDI, AnshLabs, DiaPro, NovaLisa, and Lionex). The sensitivity was measured at three different time-intervals post symptoms onset or positive SARS-CoV-2 RT–PCR test (≤14, 14–30, >30 days). The specificity was investigated using 119 pre-pandemic serum samples. The sensitivity of all IgM kits gradually decreased with time, ranging from 48.7% (EDI)–66.4% (Lionex) at ≤14 days, 29.1% (NovaLisa)–61.8% (Lionex) at 14–30 days, and 6.0% (AnshLabs)–47.9% (Lionex) at >30 days. The sensitivity of IgG kits increased with time, peaking in the latest interval (>30 days) at 96.6% (Lionex). Specificity of IgM ranged from 88.2% (Lionex)–99.2% (EDI), while IgG ranged from 75.6% (DiaPro)–98.3% (Lionex). Among all RT–PCR-positive patients, 23 samples (7.9%) were seronegative by all IgG kits, of which only seven samples (30.4%) had detectable IgM antibodies. IgM assays have variable and low sensitivity, thus considered a poor marker for COVID-19 diagnosis. IgG assays can miss at least 8% of RT–PCR-positive cases.

Highlights

The current coronavirus disease 2019 (COVID-19) pandemic has imposed an unpreceded challenge on the health and economy of millions of people
The development of accurate and reliable diagnostic serological assays that can be readily applicable is crucial [1,2]. These assays should provide guidance to determine the seroprevalence of antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the individual and community levels, identify immune presumptive protected persons who can serve as potential plasma donors, and for vaccine development [1]
This study evaluated the antibody immune response in symptomatic and asymptomatic RT–PCR-confirmed COVID-19 patients using different CE-marked IgM and IgG enzyme-linked immunosorbent assay (ELISA) kits coated with different SARS-CoV-2 antigens

Summary

Introduction

The current coronavirus disease 2019 (COVID-19) pandemic has imposed an unpreceded challenge on the health and economy of millions of people. Serology assays are expected to play a critical role in testing the currently approved vaccines’ efficiency by measuring the level of produced antibodies, determining their durability, and identifying thresholds of protection [3,4]. This is important since it is still unknown how long immunity against SARS-CoV-2 lasts after vaccination [3]. NAT may not be the best choice for large-scale screening of populations infected with SARS-CoV-2 [6]

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Discussion

Conclusion