CXCL8 and tick-borne encephalitis: Human TBE patients exhibit elevated serum levels of the pro-inflammatory cytokines interleukin (IL)-6, IL-8, IL-12, IL-17A, and IL-17F and of the chemokines CCL3, CXCL2, CXCL10, and CXCL13 and elevated CSF levels of IL-8, IL-10, IL-17F, IL-22, CCL2, CCL3, CCL5/RANTES, CXCL1-2, and CXCL10-13 [21–27].