title: Response to letter from Dr Hongliang Zhang entitled 'B-cell activating factor in the cerebrospinal fluid of neuromyelitis optica and multiple sclerosis'.
authors.affiliation: Neurology Department, Multiple Sclerosis and Immunobiology Research, Hadassah University Hospital, Jerusalem, Israel.
authors.forename: Adi
authors.initials: A
authors.lastname: Vaknin-Dembinsky
authors.affiliation: Neurology Department, Multiple Sclerosis and Immunobiology Research, Hadassah University Hospital, Jerusalem, Israel.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Karussis