Clinical information and genotypes of HLA-DRB1 and -DPB1 alleles were available from 528 MS and 183 NMO/NMOSD patients based on the 2010 revised McDonald criteria25 and NMO and NMOSD criteria advocated by Wingerchuk in 2006 and 200726,27, respectively. Here, HLA-DRB1 is linked to neuromyelitis optica.