In the pool of intermediate CD14++CD16+ monocytes the mean of fluorescence intensity of the activation marker CD64 was significantly increased in COVID-19 patients compared to healthy subjects, respectively 599 ± 43 vs 556 ± 39, p = 0.04 (Supplementary Fig. 2, positively associated to the amount of IL-6, (respectively, r-square = 0.42, p = 0.04 and r-square = 0.79, p = 0.04, data not shown). Here, IL6 is linked to COVID-19.