IL6 and COVID-19: Patients presented with increased renalase/decreased IL-6 (established marker of mortality in COVID-19) plasma levels had the best survival compared to other evaluated groups, while decreased renalase concentration (“blunted response”) experienced worse outcomes, as defined by higher mortality, greater hypoxia, a longer length of stay, higher intensive care unit admission, use of vasopressors, and cardiopulmonary resuscitation rate [91].