SCREENING FOR THE GENES RESPONSIBLE FOR THE SURVIVAL ADVANTAGE OF PNH CLONES

在所有PNH病例中都发现了猪- a基因的体细胞突变。因此，猪- a基因突变被认为与PNH的发生有关。然而，最近的研究表明，在健康个体中也存在罕见的PNH细胞（Araten， DJ等人，1996）。因此，我们认为除了猪- a基因突变外，PNH克隆的生长优势和/或生存优势对PNH的发展是不可或缺的。本研究的目的是阐明与PNH无性系生长优势和/或生存优势有关的基因。我们采用cDNA减法和cDNA宏阵列来筛选PNH患者CD59^-粒细胞与CD59^+粒细胞中上调的基因。半定量RT-PCR检测1例PNH患者CD59^-粒细胞中有3个基因上调2倍以上。然而，在其他3例PNH患者中，我们没有发现这些基因在CD59^-粒细胞中比CD59^+粒细胞中有显著的上调趋势。此前已有4个基因在PNH患者中被报道上调。我们用半定量RT-PCR检测了这4个基因在7例PNH患者和5例健康供体中的表达。我们没有发现这4个基因在我们的PNH患者中上调的趋势。

Somatic mutations in the PIG-A gene have been found in all PNH cases. Therefore PIG-A gene mutation has been considered to be responsible for the development of PNH. However, recent study revealed that rare PNH cells are present also in healthy individuals (Araten, DJ et al. 1996). Therefore, it is postulated that growth advantage and/or survival advantage of PNH clones is indispensable for the development of PNH, in addition to PIG-A gene mutation. The purpose of this study is to clarify the genes concerned in growth advantage and/or survival advantage of PNH clones. We performed a cDNA subtraction and a cDNA macro array to screen for the genes up-regulated in CD59^- granulocytes of PNH patient compared to CD59^+ granulocytes of PNH patient. Three genes were up-regulated more than 2 times in CD59^- granulocytes of one PNH patient by semi-quantitative RT-PCR assay. However we could not find remarkable tendency that these genes are up-regulated in CD59^- granulocytes compared to CD59^+ granulocytes in 3 other PNH patients. Already, 4 genes were reported up-regulated in PNH patients before. We have checked the expression of these 4 genes in 7 PNH patients and in 5 healthy donors by semi-quantitative RT-PCR. We could not find tendency that these 4 genes were up-regulated in our PNH patients.