['The current 2006 neuromyelitis optica (NMO) criteria is useful for diagnosing NMO, however this criteria seemed to be insufficient at early stage of NMO. Hence, the development of diagnostic marker besides anti-aquaporin 4 antibody at early stage of NMO may be required. Our main aim of this study is to test the usefulness of measuring cerebrospinal fluid (CSF) interleukin (IL)-6 and glial fibrillary acidic protein (GFAP) concentrations as early diagnostic markers during initial NMO attacks.', 'We investigated CSF IL-6 and GFAP concentrations in 13 NMO spectrum disorder (NMOSD) patients at initial attacks, 24 idiopathic central nervous system inflammatory disease patients (9 optic neuritis, 9 myelitis and 6 encephalitis) and 20 other non-inflammatory neurological disorders (ONNDs) patients, retrospectively.', 'The mean CSF IL-6 and GFAP concentrations during the initial NMOSD attack were 91.4 pg/ml and 369.3 ng/ml, respectively, and were significantly higher than in ONNDs, idiopathic optic neuritis and myelitis patients (P<0.01). The sensitivity of high CSF IL-6 during initial NMO attack was 76.9% and that of high CSF GFAP was 84.6%, respectively.'] Are cerebrospinal fluid interleukin-6 and glial fibrillary acidic protein levels increased during initial neuromyelitis optica attacks?