Search

.83 ht 1 Abbreviations: IgG, immunoglobulin G; IgRT, immunoglobulin replacement therapy; IQR, interquartile range. We demonstrate that, in previously stable patients, IgRT dose reductions lead to a reduction in trough IgG, which is associated with an increased frequency of infections requiring outpatient antibiotic use. [Extracted from the article]

Detecting antibody responses during and after SARS‐CoV‐2 infection is essential in determining the seroepidemiology of the virus and the potential role of antibody in disease. Scalable, sensitive and specific serological assays are essential to this process. The detection of antibody in hospitalized patients with severe disease has proven relatively straightforward; detecting responses in subjects with mild disease and asymptomatic infections has proven less reliable. We hypothesized that the suboptimal sensitivity of antibody assays and the compartmentalization of the antibody response may contribute to this effect. We systematically developed an ELISA, optimizing different antigens and amplification steps, in serum and saliva from non‐hospitalized SARS‐CoV‐2‐infected subjects. Using trimeric spike glycoprotein, rather than nucleocapsid, enabled detection of responses in individuals with low antibody responses. IgG1 and IgG3 predominate to both antigens, but more anti‐spike IgG1 than IgG3 was detectable. All antigens were effective for detecting responses in hospitalized patients. Anti‐spike IgG, IgA and IgM antibody responses were readily detectable in saliva from a minority of RT‐PCR confirmed, non‐hospitalized symptomatic individuals, and these were mostly subjects who had the highest levels of anti‐spike serum antibodies. Therefore, detecting antibody responses in both saliva and serum can contribute to determining virus exposure and understanding immune responses after SARS‐CoV‐2 infection. [ABSTRACT FROM AUTHOR]

Although anti-S IgA and IgG were more similar in children and adult COVID-19 patients, anti-N IgA and IgG antibodies were higher in ITU patients (Figure 1C,D). Since antibody isotypes can reflect recent infection (IgM), or more historic infections (IgG and IgA), we examined individual antibody isotypes and presented these results as area under the curve (AUC). Therefore, children with Kawasaki-like inflammatory syndrome, negative by PCR, can have IgG1, IgG3, and IgA antibody levels to SARS-CoV-2 in the absence of maintained IgM responses. Screening of sera, diluted 1:40, to detect IgG, IgA, and IgM demonstrated that all children had antibodies against the SARS-CoV-2 S glycoprotein (Figure 1A). [Extracted from the article]