CD4 and COVID-19: Natural infection may mediate some chronic symptoms by strong induction of virus-specific CD4+ and CD8+ T and B cells. Significant alterations in T, B, and NK cell quantities have been reported in COVID-19 survivors.Consistently elevated IgGs have been described in long-COVID patients.Autoantibodies may mediate both severe disease and chronic inflammation in some long COVID cases.Persistent circulation of the SARS-CoV-2 spike protein could be a putative antigen mediating chronic manifestations.