银屑病患者白介素-20基因多态性和临床表型研究

目的：研究银屑病患者中自介素-20（IL-20）基因启动子区-1679位点单核苷酸多态性与上呼吸道感染（URI）间的相关性。方法：采用序列特异引物聚合酶链反应（PCR—SSP）检测上海周边地区340例汉族银屑病患者及193名正常对照者的IL-20基因多态性。并将银屑病患者按是否与URI相关分组，其中以URI为诱发或加重因素者为106例；不以URI为诱发或加重因素者234例，2组分别与对照组进行比较。结果：①银屑病患者与正常对照者间启动子区-1679位点的基因型和等位基因组成差异有统计学意义（分别为P〈0．05，P〈0．01）。（爹以UR]为诱发或加重因素的银屑病患者与正常对照者间在此位点的基因型和等位基因的分布差异亦均有统计学意义（分别是P〈0．05，P〈0．01）；而与URI无关的银屑病患者与对照者间在此位点的基因型和等位基因的分布差异均无统计学意义（P〉0．05）。结论：①上海周边地区汉族人群中，IL-20基因-1679位点的C等位基因可能具阻止银屑病发生的作用，而G等位基因可能增加其银屑病易感性。与URI相关的银屑病患者与正常对照者相比，G等位基因的频率明显增加，提示G等位基因可能使正常人在微生物感染后更易诱发银屑病或使银屑病患者原有疾病加重。

Analysis of single nucleotide polymorphism of interleukin-20 gene in psoriatic patients

Objective To investigate the single nucleotide polymorphism(SNP)in promoter region of interleukin- 20(IL-20)gene in 340 Shanghai patients with psoriasis.Methods In this case-control study of the 340 patients with psoriasis and 193 normal controls,DNA was extracted from peripheral blood samples and amplified by polymerase chain reaction with sequence specific primer(PCR-SSP),then analyzed the genotype of IL-20 gene polymorphism and allele frequency of promotor region-1679 C>G,and assessed the correlation between risk of psoriasis and upper respiratory infection.The patients were divided into two groups:those having correlation with upper respiratory infection and those not.The genotype distribution and allele frequency of-1679 C>G were compared between normal control and patient group,and between the two patient groups.Results The genotype distribution and allele frequency of this SNP was statistically different between patients with psoriasis and normal control group(P<0.05 and P<0.01,respectively).Statistical difference was found between normal control group and psoriasis patients having correlation with upper respiratory infection(P<0.05 and P<0.01,respectively).However,no significantly difference was seen between normal control group and psoriatic Shanghai patients having no correlation with upper respiratory infection(P>0.05).Conclusions C allele of IL-20 gene-1679 locus might have the ability to prevent the pathogenesis of psoriasis,while G allele could enhance the susceptibility of psoriasis.The higher frequency of G allele at this locus occurred in psoriatic patients having correlation with upper respiratory infection,suggesting that G allele at this locus could enhance the induction or aggravation of psoriasis by microbial infection.