title: Strong linkage disequilibrium between HLA-Dw2 and and BfS in multiple sclerosis and in the normal population.
abstract: An increased frequency of the S allele of Properdin factor B (BfS) was found amongst 162 patients with multiple sclerosis (MS) compared with 470 normal controls. This increase was shown to be due to a strong linkage disequilibrium (LD) between BfS and HLA-Dw2 in 77 patients typed for both systems (delta = 3.84%, P = .0002). The same LD was demonstrated amongst 100 normal controls (delta = 2.24%, P = .0049) and 31 patients with idiopathic demyelination of the peripheral nervous system (IDPN). A total of 70 haplotypes with HLA-Dw2 were encountered (40 MS, seven IDPN and 23 normal controls) and all contained BfS. In the MS patient group, a much weaker association was noted between BfS and HLA-B7 suggesting either that the Bf locus is musch closer to the HLA-D than the HLA-B locus or (and) that HLA-D and Bf products selectively interact (perhaps on the surface of B lymphocytes) with evolutionary advantage or disadvantage resulting from certain allelic combinations. Strong associations between BfS1 and HLA-Bw21 (P = .0000) and BfF1 and HLA-B18 (P = .0001), both previously reported, were confirmed in the current study. No increase in the frequency of a glyoxalase (GLO) allele was found amongst the MS patients and no LD was encountered between HLA-Dw2 and a GLO allele. The possibility that the HLA-Dw2, BfS disequilibrium has resulted from a selective advantage conferred on the general community but at the expense of increasing susceptibility to MS should be considered.
mesh_terms: D002874:Chromosome Mapping; D011415:Complement Factor B / Q000235:genetics*; D004792:Enzyme Precursors / Q000235:genetics*; D000939:Epitopes; D005260:Female; D005787:Gene Frequency; D008040:Genetic Linkage; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000235:genetics* / Q000276:immunology; D010641:Phenotype; D011115:Polyneuropathies / Q000235:genetics / Q000276:immunology
chemical_list: D004792:Enzyme Precursors; D000939:Epitopes; D006680:HLA Antigens; D011415:Complement Factor B