[Review of the novelties presented at the 2018 ECTRIMS Congress: 11th Post-ECTRIMS Meeting (I)].

The Post-ECTRIMS Meeting is an emblematic event in Spain which seeks to review and disseminate the main advances in multiple sclerosis presented at the ECTRIMS annual congress. In October 2018, the eleventh Post-ECTRIMS meeting was held in Madrid and was attended by the country's leading experts in multiple sclerosis. As a result of this meeting, we present two articles which outline the most interesting novelties discussed there. This first part includes the latest results obtained regarding the influence of modifiable and non-modifiable risk factors in multiple sclerosis, with emphasis on the progress made in the field of genetics, where the discovery of genes associated with multiple sclerosis has increased exponentially. The complexity of the immune system is addressed and some contributions are made on autoimmunity mechanisms, in which bidirectional relations are observed between immune cells and cells residing in the central nervous system, such as microglial cells and astrocytes. Biomarkers, both in serum and cerebrospinal fluid as well as in imaging, are gaining more and more attention due to their current and, above all, potential role in the diagnosis and prognosis of the disease and in the evaluation of the efficacy of treatments. Finally, the observations made regarding changes in structural and functional connectivity in patients and their relationship with clinical alterations are presented.