CCL4 and COVID-19: Moreover, there is a link between the hyperinflammatory syndrome and aberrant monocyte activation in COVID-19 patients, which was demonstrated by the dysregulated balance in monocyte populations with a preference for inflammatory CD14+ monocytes expressing IL-1β, JUN, FOS, JUNB, KLF6, CCL4 and CXCR4 in the circulation (58).