The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a pandemic of the respiratory disease
coronavirus disease 2019 (COVID-19). Antibody testing is essential to identify persons exposed to the virus and potentially in predicting disease immunity. 183
COVID-19 patients (68 of whom required
mechanical ventilation) and 41 controls were tested for plasma
IgG,
IgA and
IgM against the SARS-CoV-2 S1, S2, receptor binding domain (RBD) and N
proteins using the MILLIPLEX® SARS-CoV-2
Antigen Panel. Plasma
cytokines were concurrently measured using the MILLIPLEX® MAP Human
Cytokine/
Chemokine/
Growth Factor Panel A. As expected the 183
COVID-19 positive patients had high levels of
IgG,
IgA and
IgM anti-SARS-CoV-2
antibodies against each of the
viral proteins. Sensitivity of anti-S1
IgG increased from 60% to 93% one week after symptom onset. S1-IgG and S1-IgA had specificities of 98% compared to the 41
COVID-19 negative patients. The 68 ventilated
COVID-19 positive patients had higher antibody levels than the 115
COVID-19 positive patients who were not ventilated.
IgG antibody levels against S1
protein had the strongest positive correlation to days from symptom onset. There were no statistically significant differences in
IgG,
IgA and
IgM antibodies against S1 based on age. We found that patients with the highest levels of anti-SARS-CoV-2
antibodies had the lowest viral load in the nasopharynx. Finally there was a correlation of high plasma
IL-10 with low anti-SARS-CoV-2
antibodies. Anti-SARS-CoV-2 antibody levels, as measured by a novel
antigen panel, increased within days after symptom onset, achieving > 90% sensitivity and specificity within one week, and were highest in patients who required
mechanical ventilation. Antibody levels were inversely associated with viral load but did not differ as a function of age. The correlation of high
IL-10 with low antibody response suggests a potentially suppressive role of this
cytokine in the humoral immune response in
COVID-19.