IL6 and neuromyelitis optica: It has been reported that serum and cerebrospinal fluid (CSF) levels of IL-6 are elevated in the acute period of NMO.[10,11] Further, Chihara et al have reported that a B cell subpopulation exhibiting the CD19int/CD27high/CD38high/CD180− phenotype is selectively increased in the peripheral blood of patients with NMO.[13] These B cells displayed the morphological and phenotypical characteristics of plasmablasts and were further expanded during NMO relapse.