Characterization of the immune response to SARS-CoV-2 in individuals with asymptomatic, mild/moderate and severe disease.

Coronavirus disease 2019 (COVID-19), a disease caused by the novel coronaviius SARS-CoV-2, emerged in Wuhan and rapidly spread throughout the world, including Kuwait. Patients infected with SARS-CoV-2 can be asymptomatic, but most develop mild/moderate symptoms, and some succumb to severe/critical disease. The severe cases have mostly occurred among the elderly and those with pre-existing conditions such as diabetes, cardiovascular disease and hypertension. In patients with COVID-19, increased total neutrophils, reduced total lymphocytes, and high levels of c-reactive protein and pro-inflammatory cytokines have been reported. Effective innate immune responses against viral infections relies heavily on type 1 interferon (IFN) responses and its downstream cascade, which culminates in the control of viral replication and induction of effective adaptive immunity. Helper T cells play a major role in the adaptive immune response to viral infections, while cytotoxic T cells are critical in killing virally infected cells. The humoral immune response, which includes antigen-specific antibody production, plays a protective role by limiting infection and preventing re-infection. Currently, limited information is available on the innate and adaptive immune response to SARS-CoV-2. In the present study, we propose to characterize the humoral and cellular immune responses to SARS-CoV-2 in infected individuals, including those with no symptoms, and those with mild/moderate or severe/critical disease. Moreover, we will elucidate the effect of certain medicines, used for pre-existing conditions, on the immune response.