title: Relevant residues of DRbeta1 third hypervariable region contributing to the expression and to severity of rheumatoid arthritis (RA) in Mexicans.
abstract: Rheumatoid arthritis (RA) is a chronic autoimmune disease leading to destruction of the joints. Residues at positions 67-74 of the DRB1 third hypervariable region are involved in susceptibility (S) and resistance (P) to RA. DNA from 83 patients and 175 controls, all of them Mexican Mestizos were oligotyped using PCR-SSOP and PCR-SSP. The (S) alleles are DRB*0404 (p = 0.000004), *0401 (p = 0.007) and *1001 (p = 0.008). Those associated with P are DRB1*0701 (p = 0.0001); *1101 (p = 0.01); *1503 (p = 0.02); *0801 (p = 0.04); *1401 (p = 0.04). Susceptibility/protection are recessive traits; SS genotypes are increased in the patients (p = 0.0003) while PP genotypes are decreased in them (p = 0.00004). The motif at 67-74 and the valine or glycine at position 86 are relevant in the development and severity of RA in Mexicans. The associations suggest that residues 67, 70, 71 are central for susceptibility. The P alleles have D-70 or carry V-86 in the absence of D-70. Thus, susceptibility/protection depends on the combination of basic residues at these positions and a non-polar aa at 86 contributes to resistance. Severity is also HLA influenced. DQA1*03011-DQB1*0302 are associated to severe lesions in the presence of any DR4 subtype. Analyzing different ethnic groups is essential to elucidate the etiopathogenesis of RA.
authors.affiliation: Department of Immunogenetics, Instituto Nacional de Diagnostico y Referencia Epidemiologicos, SSA, Mexico City, Mexico.
authors.forename: H
authors.initials: H
authors.lastname: Debaz
authors.forename: A
authors.initials: A
authors.lastname: Olivo
authors.forename: M N
authors.initials: MN
authors.lastname: Vazquez Garcia
authors.forename: G
authors.initials: G
authors.lastname: de la Rosa
authors.forename: A
authors.initials: A
authors.lastname: Hernandez
authors.forename: L
authors.initials: L
authors.lastname: Lino
authors.forename: R
authors.initials: R
authors.lastname: Burgos
authors.forename: M
authors.initials: M
authors.lastname: Fernandez-Viña
authors.forename: P
authors.initials: P
authors.lastname: Stastny
authors.forename: C
authors.initials: C
authors.lastname: Gorodezky
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000208:ethnology* / Q000276:immunology*; D001327:Autoimmune Diseases / Q000208:ethnology* / Q000276:immunology*; D004198:Disease Susceptibility; D005260:Female; D005838:Genotype; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D007198:Indians, North American / Q000235:genetics; D008297:Male; D008800:Mexico; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D044465:White People / Q000235:genetics
chemical_list: D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D007135:Immunoglobulin Variable Region