TNF and COVID-19: Based on the notion that elevated levels of CXCL10 are found in both autoimmune thyroid disease and COVID-19, and considering that the synergism between TNF-α and IFN-γ would: (i) promote a more severe course of COVID-19; (ii) strongly increase the secretion of CXCL10 by thyroid cells, the further subsequent hypothesis to be tested was whether a synergic effect could be exerted by IFN-γ and TNF-α also in the induction of ACE-2 expression by thyroid cells.