CXCL16 and COVID-19: They found that EVs of serious cases of COVID-19 carried higher levels of cytokines, including the IL-6 family, TNF superfamily, chemokines (MCP-1 and CXCL16), and proteases and peptidases (Cathepsin L1), compared with that of patients with moderate COVID-19 or asymptomatic individuals (Krishnamachary, et al., 2020).