Evaluation of Humoral Immunity to SARS-CoV-2: Diagnostic Value of a New Multiplex Addressable Laser Bead Immunoassay.

Despite efforts to develop anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody (Ab) immunoassays, reliable serological methods are still needed. We developed a multiplex addressable laser bead immunoassay (ALBIA) to detect and quantify anti-Spike S1 and nucleocapsid N Abs. Recombinant S1 and N proteins were bound to fluorescent beads (ALBIA-IgG-S1/N). Abs were revealed using class-specific anti-human Ig Abs. The performances of the test were analyzed on 575 serum samples including 192 from SARS-CoV-2 polymerase chain reaction-confirmed patients, 13 from seasonal coronaviruses, 70 from different inflammatory/autoimmune diseases, and 300 from healthy donors. Anti-S1 IgM were detected by monoplex ALBIA-IgM-S1. Comparison with chemiluminescent assays or enzyme-linked immunosorbent assays was performed using commercial tests. Multiplex ALBIA-IgG-S1/N was effective in detecting and quantifying anti-SARS-CoV-2 IgG Abs. Two weeks after first symptoms, sensitivity and specificity were 97.7 and 98.0% (anti-S1), and 100 and 98.7% (anti-N), respectively. Agreement with commercial tests was good to excellent, with a higher sensitivity of ALBIA. ALBIA-IgG-S1/N was positive in 53% of patients up to day 7, and in 75% between days 7 and 13. For ALBIA-IgM-S1, sensitivity and specificity were 74.4 and 98.7%, respectively. Patients in intensive care units had higher IgG Ab levels (Mann-Whitney test,

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Copyright © 2020 Drouot, Hantz, Jouen, Velay, Lamia, Veber, Sibilia, Lotellier, Candon, Alain, Fafi-Kremer and Boyer.

Déclaration de conflit d'intérêts

LD and OB are designated as inventors for the European Patent application EP 20315157.6 filed on April 14, 2020 in the names of Inserm, Université de Rouen and CHU de Rouen and entitled “methods for detecting the presence of coronavirus-specific antibodies in a subject.” The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.