MAJOR HISTOCOMPATIBILITY COMPLEX CLASS-II ALLELES AND THE COURSE AND OUTCOME OF MS - A POPULATION-BASED STUDY

Background: The major histocompatibility complex (MHC) has been consis tently associated with susceptibility to MS and the course of several other human autoimmune diseases. A putative association between the co urse and severity of RIS and the MHC remains controversial. Methods: D R and DQ genotyping by either restriction fragment length polymorphism or sequence-specific PCR-based typing in 119 patients representing 73 .4% of the population with MS evaluated in a cross-sectional disabilit y survey and 100 healthy controls from Olmsted County, Minnesota. Resu lts: We found a positive association between MS susceptibility and the DR15-DQ6 and DR13-DQ7 haplotypes, and we found a negative association with the DR1-DQ5 haplotype. We found a trend to a positive associatio n of primary progressive MS with DR4-DQ8 and DR1-DQ5 and an associatio n of ''bout onset'' MS with DR17-DQ2. We did not find an association w ith disease severity, as defined by EDSS/duration. Conclusion: Lack of consistency between different studies may be due to regional variatio n in MS and limitations of power but likely indicate a minor effect of MHC class II genes on the course and severity of MS.