(A–E) Absolute counts of CD3+CD4+CD45+ lymphocytes (A), CD3+CD8+CD45+ lymphocytes (B), CD3+CD16+CD56+CD45+ lymphocytes (C), CD3−CD16+CD56+CD45+ cells (D), and CD19+CD45+ lymphocytes (E) among healthy volunteers, patients with CAP caused by the 2009H1N1 influenza virus, and patients with CAP caused by COVID-19. Patients with COVID-19 are classified into three states of immune activation: intermediate, dysregulation, and MAS.