CCL2 and neuromyelitis optica: The specific binding of NMO-IgG to AQP4 on the cytomembrane of astrocytes activated various intracellular inflammatory signaling pathways, for example the NF-κB, p38, and JAK/STAT signaling pathways, which would induce the release of several inflammatory cytokines and chemokines, such as CCL2, CXCL1, IL-1β, IL-6, IL-17A, and IL-18.