MMP9 and infection: Following infection, expression levels of the immunomodulatory cytokines C-C motif chemokine 22 (CCL22), CCL1, IL-23α, IL-3, IL-4, matrix metalloproteinase 9 (MMP9), IL-21, C-X-C motif chemokine 2 (CXCL2), and CCL2 were increased.