Dataset Information

The kinetics of viral load and antibodies to SARS-CoV-2.

ABSTRACT:

Objectives

The aim was to understand persistence of the virus in body fluids the and immune response of an infected host to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), an agent of coronavirus disease 2019 (COVID-19).

Methods

We determined the kinetics of viral load in several body fluids through real time reverse transcription polymerase chain reaction, serum antibodies of IgA, IgG and IgM by enzyme-linked immunosorbent assay and neutralizing antibodies by microneutralization assay in 35 COVID-19 cases from two hospitals in Guangdong, China.

Results

We found higher viral loads and prolonged shedding of virus RNA in severe cases of COVID-19 in nasopharyngeal (1.3 × 10⁶ vs 6.4 × 10⁴, p < 0.05; 7∼8 weeks) and throat (6.9 × 10⁶ vs 2.9 × 10⁵, p < 0.05; 4∼5 weeks), but similar in sputum samples (5.5 × 10⁶ vs 0.9 × 10⁶, p < 0.05; 4∼5 weeks). Viraemia was rarely detected (2.8%, n = 1/35). We detected early seroconversion of IgA and IgG at the first week after illness onset (day 5, 5.7%, n = 2/35). Neutralizing antibodies were produced in the second week, and observed in all 35 included cases after the third week illness onset. The levels of neutralizing antibodies correlated with IgG (r_s = 0.85, p < 0.05; kappa = 0.85) and IgA (r_s = 0.64, p < 0.05; kappa = 0.61) in severe, but not mild cases (IgG, r_s = 0.42, kappa = 0.33; IgA, r_s = 0.32, kappa = 0.22). No correlation with IgM in either severe (r_s = 0.17, kappa = 0.06) or mild cases (r_s = 0.27, kappa = 0.15) was found.

Discussion

We revealed a prolonged shedding of virus RNA in the upper respiratory tract, and evaluated the consistency of production of IgG, IgA, IgM and neutralizing antibodies in COVID-19 cases.

SUBMITTER: Sun J

PROVIDER: S-EPMC7474805 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description: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.