CD4 and long COVID-19: Towards a better understanding of the pathophysiology of PASC, it has been suggested that T-cell subsets exhibit different dynamics, depending on the severity of the initial infection and the time since then; in severe convalescents, there is a tendency towards an exhausted/senescent state of CD4+ and CD8+ T cells and perturbances in CD4+ Tregs 3 months post-infection, a remodeling that is clearly visible at 6 months post-infection.