Parallel to its increase in the CSF, increased serum IL-6 was observed in patients with NMO [229] Further, IL-6 induces the differentiation and maturation of B-lymphocytes into plasmablasts further increasing the production of AQP4 antibodies, and the differentiation of naïve T-cells into TH17 cells. The gene discussed is AQP4; the disease is neuromyelitis optica.