目的：近来有研究认为某些自身免疫性疾病可能与甘露糖结合凝集素(MBL)缺陷有关。MBL基因多态性影响MBL水平。过敏性紫癜(Henoch-Schnlein purpura, HSP)是一种全身性血管炎综合征，其病因被认为可能与免疫损伤有关。该研究探讨MBL基因第54号密码子多态性与中国汉族儿童过敏性紫癜(HSP)的关系。方法：应用聚合酶链反应-限制性内切酶片段长度多态性分析，对160例健康中国汉族儿童及104例过敏性紫癜(HSP)患儿的MBL基因多态性进行检测。结果：①HSP患儿MBL基因GGC/GAC基因型频率明显高于健康对照组(51.9% vs 25.0%)(P<0.05)，而GGC/GGC基因型频率显著低于健康对照组(46.2% vs 73.8%)(P<0.05)。HSP患儿GAC等位基因频率明显高于健康对照组(0.279 vs 0.138)(P<0.05)，而GGC等位基因频率明显低于健康对照组(0.721 vs 0.862)(P<0.05)；GAC等位基因与HSP的发病明显相关(OR=2.46，95% CI=1.32-4.48，P<0.05)。②在HSP患儿中，GAC型等位基因携带者中有前驱感染史者明显多于GGC纯合子(P<0.05)。结论：HSP发病受遗传背景影响，MBL第54号密码子基因多态性可能是HSP易感性标志。

OBJECTIVE: Henoch Schnlein purpura (HSP) is an autoimmune vasculitis syndrome of unknown etiology. Recently, some research has shown that the polymorphisms of Mannose binding lectin (MBL) gene can decrease the serum MBL level, and MBL deficiency may be associated with increased susceptibility to infection and autoimmune diseases. This study aims at exploring the correlation between MBL codon 54 polymorphism and HSP in Han nationality children. METHODS: One hundred and four children with HSP and 160 healthy controls were enrolled in this study. The genotypes of MBL gene 54 codon were detected by Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR RFLP). RESULTS: The genotype frequency of heterozygote (GGC/GAC) in the HSP group was significantly higher than that in the healthy controls ( 51.9% vs 25.0% ) (P< 0.05 ), whereas that of homozygote (GGC/GGC) in the former was significantly lower than that of the latter (46.2% vs 73.8%) (P< 0.05 ). The allele frequency of GAC was higher in HSP patients than that in controls ( 0.279 vs 0.138 ) (P< 0.05 ), whereas that of GGC in HSP patients was lower than that in controls ( 0.721 vs 0.862 ) (P< 0.05 ). The variant allele (GAC) was markedly associated with onset of HSP (OR= 2.46 , 95% CI= 1.32 - 4.48 ; P< 0.05 ). In addition, in the HSP group more patients carrying the variant allele (GAC) had episodes of upper respiratory or gastrointestinal infections before onset of HSP compared with those with GGC homozygote (P< 0.05 ). CONCLUSIONS: MBL gene condon 54 mutation might be related to the pathogenesis of HSP.