Expression of proteins involved in inflammation and lipid transport is altered before the onset of symptoms in multiple sclerosis (MS), according to new research. Longitudinal proteomic analysis of serum samples from a population-based incident MS cohort revealed specific proteomic changes in 100 participants who went on to develop MS compared with 100 matched healthy controls. These presymptomatic alterations in the serum proteome could aid our understanding of the pathogenesis of MS.