The expression of many important CRS cytokines has been associated with the dysfunction of macrophages; some are excessively secreted by macrophages, including IL-1, IL-18, IL-6, and TNF, whereas others lead to the recruitment and activation of macrophages, including granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemo-attractant protein-1 (MCP-1), and interferon (IFN)14,19,22,23. Here, IL6 is linked to congenital rubella syndrome.