GP IIb三种基因多态性之间的关系及GP IIb T13959 G在血小板输注耐受中的作用

目的:研究血小板膜糖蛋白Ⅱb (GP Ⅱb)三种基因多态性之间的关系及GP Ⅱb T13959 G在血小板输注耐受中的作用.方法:聚合酶链反应-单链构型多态性分析检测110例正常人GP Ⅱb基因第26和30外显子(Exon 26, Exon30)及21内含子(Intron21)基因多态性,进行基因序列分析,研究这些基因多态性是否存在连锁关系;应用Fok1酶切法对147例血液病人人类血小板抗原-3(human platelet antigen-3, HPA-3)基因进行分型,并与110例正常人进行比较;将接受单采血小板输注的44例血液病人随机分为HPA-3同型输注组和对照组,血小板输注3次以后检测血小板抗体.结果:正常人GP Ⅱb存在基因多态性,表现分别为gDNA 13 959位点T→G,16 977位点C→T,11 996～12 004位点9个碱基缺失,且三者具有同步性.Fox1酶切分析结果表明,正常人和血液病人的HPA-3a基因频率分别为83.6%(92/110)和81.9%(119/147),HPA-3b基因频率分别为16.4%(18/110)和19.1%(28/147),两者之间差异无统计学意义(P＞0.05).血液病人接受单采血小板输注后, HPA-3同型输注组血小板抗体阴性,而对照组有2例存在血小板抗体,其中1例为HPA-3a抗体.结论:(1)GP Ⅱb基因存在gDNA 13 959位点T→G,16 977位点C→T,11 996～12 004位点9个碱基缺失,这3个位点的多态性可能存在完全连锁关系;(2)血液病人与正常人的HPA-3基因频率相同;(3)HPA-3系统可能是我国人群产生血小板输注耐受的原因之一.

3 polymorphisms of gene GP IIb and the function of GP IIb T13959 Gin the platelet transfusion refractoriness

OBJECTIVE: To investigate the relationship among 3 polymorphisms of GP IIb and the function of GP IIb T13959 G in the platelet transfusion refractoriness(PTR). METHODS: The 26th exon, the 30th exon and the 21st intron of gene GP IIb in 110 individuals were amplified by polymerase chain reaction (PCR), and the PCR products were analyzed with single-strand conformation polymorphism(SSCP) and sequenced to investigate whether there was linkage among the polymorphisms of the gene. Human platelet antigen-3 (HPA-3) gene frequency was detected by Fok I enzyme in 147 patients with hematologic diseases, and was compared with that in 110 normal individuals. Forty-four patients who received apheresis platelet transfusion repeatedly were randomly divided into the HPA-3 homotype group and the control group. The antibodies of the platelet were detected after 3 times of platelet transfusion. RESULTS: There were polymorphisms of gene GP IIb in the 26th, 30th exon and the 21st intron, and the mutations were: T changed into G in 13,959 th of the 26th exon; C changed into T in 16,997 th of the 30th exon; the 9 bps deletion occurred in 11,996-12,004 th of the 21st intron. The 3 polymorphisms had synchronization in the individuals. The results of Fok I enzyme indicated that the frequency of HPA-3a was 83.6% (92/110)and 81.9%(119/147), and that of HPA-3b was 16.4%(18/110) and 19.1%(28/147) in the normal individuals and the patients respectively. There was no significant difference between the patients and normal individuals (P>0.05). After the platelet transfusion, the antibodies of all the cases of the homotype platelet transfusion were negative, but the antibodies in 2 cases of the control group were positive, and there was antibody to HPA-3a in one of the antibodies positive cases. Conclusion (1)There is close linkage among the polymorphisms of gene GP IIb, which is T->G in 13 959 th of the 26th exon, C->T in 16,997 th of the 30th exon, and the 9 bps deletion in 11,996-12,004 th in the 21st intron. (2)The gene frequency of HPA-3a/3b is similar in the normal individuals and patients with hematologic diseases. (3) HPA-3 system may be one of the reasons for PTR in Chinese.