In response to IL-13 monocytes obtained from NMO patients secrete chitinases that increase in vitro chemotaxis of eosinophils, macrophages and T cells across the BBB by promoting the secretion of various cytokines IL-8, RANTES (CCL5), MCP1 (CCL2), and eotaxins by monocytes [121]. Here, CCL5 is linked to neuromyelitis optica.