IL20 and infection: Leukocytes, especially myeloid cells, are the primary sources of IL-19 and IL-20 (22), so we performed flow cytometry by staining leukocyte markers on the cell surface and the cytokines inside the cells to quantify splenocytes expressing IL-19 or IL-20 in infected WT mice on 3 and 5 d.p.i., the time points at which EV-A71 infection significantly and slightly increased serum IL-19 and IL-20 levels, respectively.