CD4 and COVID-19: The abundance of naïve B cells, follicular helper T cells, Tregs, activated NK cells, monocytes, and activated mast cells decreased, while the abundance of plasma cells, CD4 naïve T cells, activated CD4 memory T cells, γδ T cells, resting dendritic cells, and activated dendritic cells increased, potentially demonstrating the relevance of COVID-19 initiation and development.