CCL18 and COVID-19: While some genes involved in monocyte and lymphocyte migration and function were expressed in the COVID-19(+) TV group (CCL13, CCL8, and CCL20), a greater number of these genes were expressed in the COVID-19(-) PU control group (CCL19, CCL18, CXCL13, CCL4, CCL5, CXCL9).