ATX levels in serum are increased in patients with severe COVID-19; increased serum levels of ATX are corelated with increased serum levels of IL-6, as well as endothelial dysfunction markers, such as soluble E-selectin, soluble P-selection, ICAM-1, and angiopoietin 2 [5] (Figure 3). Here, ENPP2 is linked to endothelial dysfunction.