LAUSR

genotyping methods. The molecular method used for GM genotyping must be validated by the serological determination of these determinants [16]. This is important because the expression of certain GM allotypes may be conformational [17] and not depend entirely on particular nucleotide substitutions. Data on GM alleles cannot be extracted from the GWAS of MS because, as mentioned before, these studies do not interro-gate/impute GM alleles. General linear regression models could be used to determine whether seropositivity to EBV is associated with MS development, and whether this association is modified by the expression of alternative GM haplotypes. Results of this investigation are likely to shed light on the mechanisms underlying the disparity between EBV seroprevalence and the prevalence of MS in the popula-tion. They may also help unify the genetic and viral aetiology of this autoimmune disease.