title: HLA-patterns in patients with multiple sclerosis and type I diabetes mellitus: evidence for possible mutual exclusion of both diseases.
abstract: BACKGROUND
  Type I diabetes mellitus (T1DM) and multiple sclerosis (MS), both immune-mediated diseases, rarely co-exist in the same individual or co-segregate in families. HLA susceptibility genes for T1DM (DRB1*0401, DRB1*0404, DQB1*0302, DRB1*0301, DQB1*0201) rarely occur in MS patients. HLA genes known to confer "resistance" to T1DM (DRB1*1501, DQB1*0602-DQA1*0102) predispose to MS. To test the hypothesis of mutually exclusive HLA patterns, patients affected by T1DM plus MS were compared to those of patients affected by either of the diseases alone in a case-control study.
  
  
  METHODS
  Blood was sampled for analysis of HLA class I and class II alleles from 66 patients of German ancestry, of whom 33 had T1DM plus MS, and 33 had MS-only. For comparison to patients with T1 DM-only we referred to published data. HLA typing was performed using conventional serology (immuno-magnetic beads) and genotyping (SSP-PCR Dynal(R) SSP low/high resolution kits).
  
  
  RESULTS
  Individuals with co-existing MS plus T1DM displayed the expected T1DM associated HLA-pattern (75.8% carried DRB1*04, 69.7% carried DQB1*0302, 42% were DR4, DR3 heterozygous), but failed to display the expected MS associated HLA-pattern (0% carried DQB1*0602, 3.1% carried DQA1*0102). The expected MS associated HLA-pattern of Caucasoid patients, however, was found in the MS-only patients (42% carried DRB1*1501-DQB1*0602, 58% carried DQA1*0102), while the prevalence of T1DM susceptibility and 'resistance' alleles was not different from the general population. The allele frequency of DRB1*1501 was 16/66, 24.2% in the 33 MS-only patients, and 0% in the 33 MS plus T1DM patients. The allele frequency of DQB1*0602 was 16/66, 24.2% in the 33 MS-only patients, and 0% in the 33 MS plus T1DM patients. The allele frequency of DQA1*0102 was 18/66, 27.3%, in the 33 MS-only patients, and 1/66 1.5% in the 33 MS plus T1DM patients.
  
  
  CONCLUSIONS
  These data confirm the hypothesis of mutually exclusive HLA-patterns of T1DM and MS, and are consistent with a low rate of co-morbidity of both diseases.
authors.affiliation: Department of Metabolic Diseases and Nutrition, Heinrich-Heine-University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, German.
authors.forename: B M
authors.initials: BM
authors.lastname: Lobnig
authors.forename: E
authors.initials: E
authors.lastname: Chantelau
authors.forename: G
authors.initials: G
authors.lastname: Vidgrén
authors.forename: A A L
authors.initials: AA
authors.lastname: Van Landeghem
authors.forename: L
authors.initials: L
authors.lastname: Kinnunen
authors.forename: E
authors.initials: E
authors.lastname: Tuomilehto-Wolf
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006680:HLA Antigens / Q000032:analysis*; D006681:HLA-D Antigens / Q000097:blood; D015395:Histocompatibility Antigens Class I / Q000097:blood; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000235:genetics / Q000276:immunology*
chemical_list: D006680:HLA Antigens; D006681:HLA-D Antigens; D015395:Histocompatibility Antigens Class I