CXCL13 and Lyme disease: In a study of Rhesus macaques with induced CNS Borrelia burgdorferi infection, CSF samples showed elevated levels of proinflammatory cytokines, specifically interleukin 8 (IL-8), C–C Motif Chemokine Ligand 2 (CCL2), and C-X-C motif Chemokine ligand 13 (CXCL13), which are potent immune cell attractants [25].