AQP4 and neuromyelitis optica: HDL, high-density lipoprotein; LDL, low-density lipoprotein; dsDNA, double-stranded deoxyribonucleic acid; NMO, neuromyelitis optica; AQ-4, aquaporin-4; MOG, myelin oligodendrocyte glycoprotein; HIV, human immunodeficiency virus; VDRL, venereal disease research laboratory test; TPHA, treponema pallidum hemagglutination assay; HBs, hepatitis B surface; HBc, hepatitis B core; HC, hepatitis C; CMV, cytomegalovirus