CXCL10 and COVID-19: Although increased expression levels of several cytokines and chemokines mediated via monocytes, macrophages, DCs, NK cells, or neutrophils have been observed within the severe patients (13, 18), only a few among them such as CRP, CXCL8, CCL20, IL-6, IL-8, IL-10, PTX3, MCP-3, and IP-10 (85–88) serve as “biomarkers” and indicate a “cytokine storm” underlying COVID-19 severity.