CD4 and COVID-19: COVID-19, especially severe forms, is associated with an aberrant inflammatory response with exuberant innate immunity activation, and hyperinflammation as well as increased levels of pro inflammatory mediators, cytokines and chemokines, CRP, ferritin, and D-dimers in parallel with lymphocytopenia, decreased CD4+, CD8+ T and natural killer (NK) and B cells [58,59,60,61].