IL6 and COVID-19: Two different IL-6 concentrations were employed: a) 20 pg/mL (similar to the maximum plasma level detected in the total (66) COVID-19 patients recruited; Media= 22,88 pg/mL), and b) 20 ng/mL (the plasmatic concentration in severe-to-critical COVID-19 disease, recommended for tocilizumab treatment (31)).