Objective: To study the association between the single nucleotide polymorphisms (SNPs) of the ninth exon Val279Phe of platelet-activating factor acetylhydrolase (PAF-AH) gene and gastrointestinal bleeding in children with Henoch-Schönlein purpura (HSP).
Methods: A total 516 children with HSP were enrolled, among whom 182 had gastrointestinal bleeding and 334 had no gastrointestinal bleeding. PCR was used to investigate the distribution of genotypes and alleles in the SNPs of Val97Phe. The plasma PAF-AH activity was measured, as well as the levels of platelet-activating factor (PAF), granular membrane protein-140 (GMP-140), β-thromboglobulin (β-TG), and platelet factor 4 (PF4).
Results: The Val279Phe genotype and allele frequencies were in Hardy-Weinberg equilibrium, and the homozygous genotype TT and heterozygotes accounted for 0.97% and 6.05% respectively. The gastrointestinal bleeding group had a significantly higher allele frequency than the control group (5.22% vs 3.33%; P<0.01). The HSP patients with GG genotype in the gastrointestinal bleeding group had significantly higher levels of plasma PAF and GMP-140 than those in the non-gastrointestinal bleeding group (P<0.05), while the non-gastrointestinal bleeding group had a significantly higher PAF-AH activity than the gastrointestinal bleeding group (P<0.05). There were no significant differences in β-TG and PF4 between the two groups (P>0.05).
Conclusions: Val279Phe gene polymorphisms in PAF-AH are associated with PAF-AH activity and PAF and GMP-140 levels and may be a risk factor for HSP with gastrointestinal bleeding.
目的: 从基因水平探讨血小板活化因子乙酰水解酶（PAF-AH）基因第9号外显子Val297Phe单核苷酸多态性与过敏性紫癜（HSP）消化道出血的关系。
方法: 选取516例HSP患者，其中合并消化道出血的182例、非消化道出血的334例，应用聚合酶链式反应（PCR）检测Val279Phe多态性位点的基因型及等位基因分布情况，并测定血浆PAF-AH活性、血小板活化因子（PAF）、α颗粒膜糖蛋白140（GMP-140）、β-血小板球蛋白（β-TG）和血小板第4因子（PF4）的水平。
结果: Val279Phe基因型及等位基因频率分布符合Hardy-Weinberg平衡，纯合突变基因型TT占0.97%、杂合子占6.05%。等位基因频率在消化道出血组为5.22%，明显高于对照组（3.33%），差异有统计学意义（P < 0.01）。合并消化道出血的GG基因型HSP患者的血浆PAF和GMP-140水平高于非出血组（P < 0.05），PAF-AH活性以非出血组较高（P < 0.01），而β-TG和PF4在两组间的差异没有统计学意义（P > 0.05）。
结论: PAF-AH Val279Phe基因多态性与血浆PAF-AH活性、PAF及GMP-140水平有关，PAF-AH Val279Phe基因多态性可能是HSP合并消化道出血的一个风险因素。