Coronavirus disease 2019 in critically ill patients: can we re-program the immune system? A primer for Intensivists.

In December 2019, Coronavirus disease 2019 (COVID-19) emerged in Wuhan and rapidly spread around the word. The immune response is essential to control and eliminate CoV infections, however, multiorgan damage might be due to direct SARS-CoV2 action against the infected organ cells, as well as an imbalanced host immune response. In effect, a "cytokines storm" and an impaired innate immunity were found in the COVID-19 critically ill patients. In this review, we summarized the virus immune response steps, underlying the relevance of introducing the measurement of plasma cytokine levels and of circulating lymphocyte subsets in clinical practice for the follow-up of critically ill COVID-19 patients and support new therapy.