IL15 and COVID-19: Additionally, we observed 3 (IL-7, IL-6 and IL-17A) and 1 (IL-17A) correlations between NK cell-derived cfDNA and cytokines; 1 (Eotaxin-3) and 2 (MIP-1α and IL-17A) correlations between B cell-derived cfDNA and cytokines; and 5 (IL-15, TNF-β, IL-7, IL-8, and VEGF) and 1 (IL-13) correlations between erythroblast-derived cfDNA and cytokines levels in SOT and Non-SOT COVID-19 patients, respectively.