REPORT FROM THE 26TH CONGRESS OF THE EUROPEAN COMMITTEE FOR TREATMENT AND RESEARCH IN MS (ECTRIMS), GOTHENBURG, SWEDEN, OCTOBER 13-16, 2010 – Recent papers have speculated that environmental factors, such as vitamin D status, may interact directly with genetic factors to increase the susceptibility to MS (Handunnetthi et al. Neurology 2010; 74: 1905-1910). Of particular interest is the HLA DRB1*1501 allele, which has been shown in numerous studies to influence MS risk (Link et al. J Neuroimmunol 2010; 226: 172-176).