Arias A I, Giles B, Eiermann T H, Sterry W, Pandey J P
Department of Microbiology and Immunology, Medical University of South Carolina, Charleston 29425-2230, USA.
Exp Clin Immunogenet. 1997;14(2):118-22.
Psoriasis, an inflammatory autoimmune disease, is characterized by increased level and activity of the proinflammatory cytokine TNF-alpha in affected lesions. Two promoter region polymorphisms of the TNF-alpha locus--one at position -308 and the other at -238--were examined in 99 Caucasian patients (64 with type I and 35 with type II psoriasis) and in 123 controls. A highly significant difference in the distribution of the -238 polymorphism--the TNF (G,A) genotypes--was detected between the type I psoriasis patients and controls: compared to the controls, the frequency of the homozygous TNF-G genotype was decreased (55 vs. 91%; p = 0.0000000274; corrected p = 0.0000001644; odds ratio = 0.12), whereas that of TNF-G,A heterozygotes was increased (41 vs. 8%; p = 0.000000264; corrected p = 0.000001584; odds ratio = 7.73) in patients. No significant differences were observed in the distribution of the TNF-A homozygotes. These results suggest that homozygosity of the G allele is associated with a lower relative risk (resistance), whereas heterozygosity at this locus is associated with an increased risk (susceptibility) of type I psoriasis.
银屑病是一种炎症性自身免疫性疾病，其特征是在受影响的皮损中促炎细胞因子肿瘤坏死因子-α（TNF-α）的水平和活性升高。在99名白种人患者（64例I型银屑病患者和35例II型银屑病患者）和123名对照者中，检测了TNF-α基因座的两个启动子区域多态性——一个位于-308位，另一个位于-238位。在I型银屑病患者和对照者之间，检测到-238多态性（TNF（G，A）基因型）的分布存在高度显著差异：与对照者相比，纯合TNF-G基因型的频率降低（55%对91%；p = 0.0000000274；校正p = 0.0000001644；优势比 = 0.12），而患者中TNF-G，A杂合子的频率增加（41%对8%；p = 0.000000264；校正p = 0.000001584；优势比 = 7.73）。在TNF-A纯合子的分布上未观察到显著差异。这些结果表明，G等位基因的纯合性与较低的相对风险（抗性）相关，而该基因座的杂合性与I型银屑病的风险增加（易感性）相关。
