Impaired Cytotoxic CD8+T Cell Response in Elderly COVID-19 Patients

Cytotoxic T cells are responsible for the elimination of infected cells and are key players in the control of viruses. CD8+T cells with an effector phenotype express cytotoxic molecules and are able to perform target cell killing. COVID-19 patients with a mild disease course were analyzed for the differentiation status and cytotoxic profile of CD8+T cells. SARS-CoV-2 infection induced a vigorous cytotoxic CD8+T cell response. However, this cytotoxic profile of T cells was not detected in COVID-19 patients over the age of 80 years. Thus, the absence of a cytotoxic response in elderly patients might be a possible reason for the more frequent severity of COVID-19 in this age group than in younger patients.