Genetic and functional studies in multiple sclerosis patients from Martinique attest for a specific and direct role of the HLA-DR locus in the syndrome

• Published in: Tissue antigens 2003-02, Vol.61 (2), p.166-171
• Main Authors: Quelvennec, E., Bera, O., Cabre, P., Alizadeh, M., Smadja, D., Jugde, F., Edan, G., Semana, G.
• Format: Article
• Language: English
• Subjects: Alleles; Case-Control Studies; Cell Line; Gene Frequency; genetics; histocompatibility complex; HLA-DQ Antigens - genetics; HLA-DQ beta-Chains; HLA-DR Antigens - genetics; HLA-DRB1 Chains; Humans; Martinique; multiple sclerosis; Multiple Sclerosis - genetics; Multiple Sclerosis - immunology; myelin basic protein; Myelin Basic Protein - immunology; Peptide Fragments - immunology; peptide presentation; T-Lymphocytes - immunology
• ISSN: 0001-2815; 1399-0039
• DOI: 10.1046/j.0001-2815.2002.00008.x

: Among candidate genes involved in multiple sclerosis (MS) genetic susceptibility, MHC genes and particularly HLA‐DRB1*1501–DQB1*0602 haplotype play a major role. Based on the strong linkage disequilibrium observed in Caucasians between DRB1*1501 and DQB1*0602 alleles, it is still impossible to draw a firm conclusion about the DRB1 or DQB1 locus involvement. In order to address this issue a strategy associating a genetic and a functional approach was conducted in a population of‐non‐Caucasian MS patients. We observed that in Martinicans (55 MS and 100 controls), the DRB1*15 and DRB1*07 alleles were positively associated with the disease. However in Martinicans the most common DRB1*15 subtype was *1503 and not *1501. Moreover, in Martinicans, the frequency of DQB1*0602, found in association with other DRB1 alleles than DRB1*15 (42% of DQB1*0602 haplotypes), was not increased in DRB1*15‐negative MS patients, suggesting a neutral role of DQB1*0602 in MS genetics. In a second step, we demonstrated the capability of the DRB1*1503 allele associated with MS in Martinicans to present the immunodominant autoantigen MBP 85–99 peptide to a DRB1*1501 restricted MBP specific T cell line. Interestingly, structural features of DRB1*1501 or DRB1*1503 molecules are in good fit with the hypothesis that *1501 and *1503 molecules may act similarly in MS development by presenting the same immunodominant MBP peptide. On the whole, our results show a prominent role of the DRB1 locus (DRB1*1501 and/or DRB1*1503 alleles) in the immunodominant MBP 85–99 peptide presentation to genetically different MS patients and suggest a neutral role of the DQB1 encoded molecule in MS susceptibility.