Review of the novelties presented at the 29th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) (I).

The most relevant data presented at the 29th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS), held in October 2013 in Denmark, were summarised at the sixth edition of the Post-ECTRIMS Expert Meeting, held in Madrid in October 2013, resulting in this review, to be published in three parts. This first part of the Post-ECTRIMS review presents an update on gender differences in multiple sclerosis (MS) as well as new evidence on the impact of sex hormones on the disease. We should consider that there is still much to discover with regard to the genetic components of the disease. Similarly, possible infections and lifestyle habits are added as triggers of the known environmental risk factors for MS. The interaction between genetics and the environment has been increasingly implicated as a cause of susceptibility to MS. With regard to the mechanisms of inflammation, axo-glial proteins, instead of myelin proteins, may be the early antigenic targets, and B cells have been implicated in the production of cytokines toxic to oligodendrocytes. Chitinase 3-like 1 (CHI3L1) is validated as a prognostic marker of conversion to MS, and immunoglobulin M oligoclonal bands and L-selectin could be incorporated as possible measures of the risk stratification strategy in patients treated with natalizumab.