内蒙古汉族儿童过敏性紫癜与HLA-DQA1基因的关联性研究

目的 探讨内蒙古汉族儿童HLA－DQA1等位基因与过敏性紫癜（anaphylactoid purpura,AP）的遗传易感性及其与临床特点的关系。方法 用聚合酶链反应－序列特异性引物技术，对70例内蒙古汉族儿童AP和90名健康儿童HLA－DQA1等位基因进行对比分析。结果 （1）病例组DQA1＊0301基因频率为33.4%，明显高于对照组（10.6%）（P＜0.01）；DQA1＊0302基因频率为6.7%，明显低于对照组（19％）（P＜0.01)。（2）单纯皮肤紫癜病例组与对照组DQA1＊0301和0302基因频率比较，差异无显著性（P＞0.05）；伴有胃肠、关节、肾脏损害病例DQA1＊0301基因频率分别为26.7%、28.5%和29.3%，均明显高于对照组（10.6%）（P均＜0.01）；而DQA1＊0302基因频率分别为3.9%、5.7%和9.6%，分别与对照组（19％）比较，肾脏损害组差异无显著性（P＞0.05），胃肠和关节损害组均明显降低（P均＜0.01）。结论 HLA－DQA1＊0301等位基因可能是内蒙古汉族儿童AP发病单体型中一个遗传易感基因，具此基因者可能更易出现胃肠、关节和肾脏损害；而DQA1＊0302等位基因可能为其遗传保护基因，对出现胃肠、关节损害可能有拮抗作用。

Correlation between HLA-DQA1 allele and anaphylactoid purpura in juvenile Hans residing in Inner Mongolia

OBJECTIVE: To analyze the genetic susceptibility of HLA-DQA1 allele to anaphylactoid purpura(AP)and its association with the clinical features in juvenile Hans residing in Inner Mongolia. METHODS: Seventy children with AP and ninety normal controls of Hans in Inner Mongolia were subjected to HLA-DQA1 genotyping with the use of polymerase chain reaction-sequence specific primer (PCR-SSP) technique. RESULTS: (1) The gene frequency of HLA-DQA1*0301 of AP group (33.4%) was significantly higher than that (10.6%) of control group (chi square=21.899, P<0.01). On the other hand, the gene frequencies of HLA-DQA1*0302 were 6.7% and 19% in the AP group and the control group respectively; a significant difference between them was seen (chi square=9.786, P<0.01); (2)The gene frequencies of both DQA1*0301 and DQA1*0302 in the cutaneous purpura simplex cases and the controls were not significantly different (P>0.05). The gene frequencies of DQA1*0301 of the cutaneous purpura cases associated with gastrointestinal, joint and renal impairment were 26.7%, 28.5% and 29.3% respectively, which were higher than that of the control group (10.6%); the differences were statistically significant (P<0.01, 0.01, 0.01; respectively). The gene frequencies of HLA-DQA1*0302(3.9%, 5.7% and 9.6%) for the cutaneous purpura cases associated with gastrointestinal, joint and renal impairment were significantly lower than that (19%) of the controls except renal impairment(P<0.01, 0.01, respectively). CONCLUSION: The allele of HLA-DQA1*0301 was probably a susceptible gene while HLA-DQA1*0302 was the protective one in AP of the children who were Han inhabitants in Inner Mongolia. The results of this study also revealed that patients with the allele of HLA-DQA1*0301 tended to involve gastrointestinal, joint and renal impairment.