Abdallah A M, Renzoni E A, Anevlavis S, Lagan A L, Munkonge F M, Fonseca C, Black C M, Briggs D, Wells A U, Marshall S E, McHugh N, du Bois R M, Welsh K I
Clinical Genomics Group, National Heart and Lung Institute, Imperial College London, UK.
Int J Immunogenet. 2006 Jun;33(3):155-61. doi: 10.1111/j.1744-313X.2006.00580.x.
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.
系统性硬化症（SSc）是一种病因不明的结缔组织疾病，其特征为皮肤和内脏纤维化、血管异常及体液自身免疫。在SSc的亚组中发现了强烈的T细胞依赖性自身抗体与HLA的关联。由抗原呈递细胞表达的共刺激分子CD86在初始淋巴细胞致敏过程中起关键作用。我们推测SSc或其中一个疾病亚组可能与CD86基因的单核苷酸多态性相关。使用序列特异性引物-聚合酶链反应（SSP-PCR）方法，我们评估了来自英国的221例SSc患者和227名健康对照者的四种CD86多态性。通过推断构建单倍型，并使用PHASE算法进行确认。我们发现SSc与一种特定单倍型（单倍型5）之间存在强烈关联，该单倍型在患者中的发生率高于对照组（29%对15%，OR = 2.3，χ² = 12，P = 0.0005）。这种关联可能归因于新发现的-3479启动子多态性；与对照组相比，SSc患者中CD86 -3479 G等位基因的分布存在显著差异（43.7%对32.4%，OR = 1.7，χ² = 12.1，P = 0.0005）。TRANSFAC分析表明，CD86 -3479T等位基因包含假定的GATA和TBP位点，而G等位基因则不包含。我们使用电泳迁移率凝胶迁移试验（EMSA）在体外评估了-3479多态性的相对DNA-蛋白质结合活性，结果表明-3479G等位基因与T等位基因相比，对核蛋白的结合亲和力较低。这些发现突出了共刺激途径在SSc发病机制中的重要性。
