CD4 and COVID-19: While, further data are needed to better clarify the role of adaptative immunity in the pathogenesis of COVID-19 and c-ARDS, several lines of evidence show that the three main components of the adaptive immune system, such as CD4+ T cells, CD8+ T cells, and B cells producing neutralizing antibodies, all contribute to controlling SARS-CoV-2 infection during the acute phase and regulate immune memory [1, 81].