Classical drug digitoxin inhibits influenza cytokine storm, with implications for COVID-19 therapy.

Influenza viruses, corona viruses and related pneumotropic viruses cause sickness and death partly by inducing a hyper-proinflammatory response by immune cells and cytokines in the host airway. Here we show that the cardiac glycoside digitoxin suppresses this response induced by influenza virus strain A/Wuhan/H3N2/359/95 in the cotton rat lung. The cytokines TNF, GRO/KC, MIP2, MCP1, TGF{beta}, and IFN{gamma}. are significantly and differentially reduced. Since the hyper-proinflammatory expression of cytokines is a host response, we suggest that digitoxin may have therapeutic potential for not only influenza and but also for coronavirus infections.