VDR and COVID-19: Moreover, in the adaptive immune system, VDR activation inhibits antigen presentation by dendritic cells, reduces the number of T helper 1 (Th1) cells and promotes the transition to Th2 and T-regulatory (Treg) cells, inducing a shift from an inflammatory to a more tolerogenic status by moderating the intensity of the local and systemic inflammatory immune response from a severe COVID-19 evolution to a more favorable clinical evolution [28,32].