A mass spectrometry analysis of the cerebrospinal fluid (CSF) of macaques that are infected with simian immunodeficiency virus (SIV) and that develop neurological disorders has revealed clues about mechanisms of the nervous system diseases and could lead to new therapeutic treatments (J. Clin. Invest., DOI: 10.1172/JCI34138). SIV in monkeys or human immunodeficiency virus in people can infiltrate the central nervous system and cause "neuroAIDS" conditions such as dementia and encephalitis. Howard S. Fox, Gary Siuzdak, and coworkers William R. Wikoff and Gurudutt Pendyala at Scripps Research Institute used capillary reversed-phase liquid chromatography and electrospray ionization MS to analyze the CSF metabolites of SIV-infected macaques. Only one other such MS-based metabolomics study has ever been carried out. The researchers found increased levels of carnitines, fatty acids, and phospholipids that were specific to macaques that developed SIV-induced encephalitis. In related work, they observed increased expression of phospholipases, including one that catalyzes fatty acid production. "The identification of specific metabolites, as well as mechanisms of their increase, illustrates the potential of mass-based metabolomics" to study nervous system biochemistry and virology and neurodegenerative diseases, the researchers note.