ABSTRACT
Coronavirus disease 2019 (COVID-19) expresses a wide spectrum of disease severity. We investigated the profile of IgG and IgG subclass antibody responses to SARS- CoV-2 in Tunisian patients with COVID-19 according to disease severity (86 patients with severe disease and 63 with mild to moderate disease). Two in house developed ELISA with excellent performance were used to test for antibodies to the nucleocapsid (N) protein and the receptor-binding domain of the spike antigen (S-RBD) of SARS-CoV-2. IgG, IgG1 and IgG3 antibodies were significantly higher in patients with severe disease compared to non-severe disease. Antibodies to S-RBD or the N protein were dominated by IgG1 and IgG3 or IgG1/IgG3 and IgG2 subclasses respectively. In patients with severe disease, IgG antibodies appearance to S-RBD was delayed compared to the N protein. IgG subclass imbalance may reflect the pathophysiology of COVID-19 and may herald disease aggravation. This study brings information on the immune responses to SARS-CoV-2 in North African patients and completes the picture drawn on COVID-19 in different African populations and worldwide.
ABSTRACT
Type I hypersensitivity is a major problem in public health, often requiring numerous investigations which aim to diagnose atopy and identify the causative allergen. Among these investigations, several blood tests, mostly using immunoenzymatic methods, can be performed to measure total and specific IgE levels. Type I hypersensitivity can also be investigated with assays which quantitate several mediators released after cellular activation induced by allergens.
