title: A polymorphism in the promoter region of the CD86 (B7.2) gene is associated with systemic sclerosis.
abstract: Systemic sclerosis (SSc) is a connective tissue disease of unknown aetiology characterized by fibrosis of the skin and internal organs, vascular abnormalities and humoral autoimmunity. Strong T-cell-dependent autoantibody and HLA associations are found in SSc subsets. The co-stimulatory molecule, CD86, expressed by antigen-presenting cells, plays a crucial role in priming naïve lymphocytes. We hypothesized that SSc, or one of the disease subsets, could be associated with single-nucleotide polymorphisms of the CD86 gene. Using sequence specific primer-polymerase chain reaction (SSP-PCR) methodology, we assessed four CD86 polymorphisms in 221 patients with SSc and 227 healthy control subjects from the UK. Haplotypes were constructed by inference and confirmed using PHASE algorithm. We found a strong association between SSc and a specific haplotype (haplotype 5), which was more prevalent in patients than in controls (29% vs 15%, OR = 2.3, chi(2) = 12, P = 0.0005). This association could be attributed to the novel -3479 promoter polymorphism; a significant difference was observed in the distribution of the CD86 -3479 G allele in patients with SSc compared to controls (43.7% vs. 32.4%, OR = 1.7, chi(2) = 12.1, P = 0.0005). TRANSFAC analyses suggest that the CD86-3479T allele contains putative GATA and TBP sites, whereas G allele does not. We assessed the relative DNA protein-binding activity of the -3479 polymorphism in vitro using electromobility gel shift assays (EMSA), which showed that the -3479G allele has less binding affinity compared to the T allele for nuclear proteins. These findings highlight the importance of co-stimulatory pathways in SSc pathogenesis.
authors.affiliation: Clinical Genomics Group, National Heart and Lung Institute, Imperial College London, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Abdallah
authors.forename: E A
authors.initials: EA
authors.lastname: Renzoni
authors.forename: S
authors.initials: S
authors.lastname: Anevlavis
authors.forename: A L
authors.initials: AL
authors.lastname: Lagan
authors.forename: F M
authors.initials: FM
authors.lastname: Munkonge
authors.forename: C
authors.initials: C
authors.lastname: Fonseca
authors.forename: C M
authors.initials: CM
authors.lastname: Black
authors.forename: D
authors.initials: D
authors.lastname: Briggs
authors.forename: A U
authors.initials: AU
authors.lastname: Wells
authors.forename: S E
authors.initials: SE
authors.lastname: Marshall
authors.forename: N
authors.initials: N
authors.lastname: McHugh
authors.forename: R M
authors.initials: RM
authors.lastname: du Bois
authors.forename: K I
authors.initials: KI
authors.lastname: Welsh
mesh_terms: D000465:Algorithms; D000483:Alleles; D051940:B7-2 Antigen / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide / Q000235:genetics* / Q000276:immunology; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D020218:Response Elements / Q000235:genetics* / Q000276:immunology; D012595:Scleroderma, Systemic / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D012984:Software; D006113:United Kingdom
chemical_list: D051940:B7-2 Antigen; C497964:CD86 protein, human; D004268:DNA-Binding Proteins