CCL2 and COVID-19: Several studies have demonstrated the sex bias for male COVID-19 patients enhancing the disease severity (32, 44), and IL-8, IL-18, CCL5 are the cytokines associated with sex bias (45), our cohort suggests multiple cytokines including IL-1β, IFN-α2, MCP-1, and MCP-3 are also involved in sex bias of COVID-19 patients.