骨髓增殖性疾病患者JAK2基因V617F突变频率、磷酸化JAK／STAT蛋白表达水平及临床意义

The frequency of JAK2 V617F mutation, expression level of phosphorylated JAK/STATs proteins and their clinical significance in myeloproliferative disorders patients

目的探讨145例骨髓增殖性疾病患者JAK2基因V617F突变率；并分析JAK2基因V617F突变阳性患者的临床特点及意义。方法应用PCR产物直接测序和等位基因特异性PCR技术检测145例骨髓增殖性疾病患者JAK2基因V617F突变，并应用Westernblot方法测定JAK2基因V617F突变阳性患者JAK2蛋白、磷酸化JAK2蛋白及磷酸化STAT5蛋白表达；对JAK2基因V617F突变阳性与突变阴性的骨髓增殖性疾病患者临床资料进行比较，评价JAK2基因V617F突变阳性的临床意义。结果①本组病例真性红细胞增多症（PV）、特发性骨髓纤维化（ET）、原发性血小板增多症（IMF）患者JAK2基因V617F突变率分别为92％（64例中59例）、58％（43例中25例）和50％（38例中19例），等位基因特异性PCR检测较PCR产物直接测序有更高的JAK2基因V617F检出率『PV84％（64例中53例）、MIF44％（43例中19例）、ET39％（38例中15例）]。（2）JAK2基因V617F突变阳性患者外周血单个核细胞磷酸化JAK2及磷酸化STAT5蛋白表达较突变阴性者明显增高（P〈0．05）。（3）JAK2基因V617F突变阳性骨髓增殖性疾病患者发病平均年龄偏大；平均白细胞计数高于突变阴性患者；血小板计数小于突变阴性患者；脾脏较突变阴性患者小；JAK2基因V617F突变阳性PV、ET和IMF患者血栓性事件发生率分别为17％、32％和16％；而突变阴性PV、ET和IMF患者血栓性事件发生率分别为0、16％和5％。结论骨髓增殖性疾病患者有较高的JAK2基因V617F突变发生率，且JAK2基因V617F突变阳性患者易发生血栓事件。

Objective To investigate the frequency of JAK2 V617F mutation in 145 myeloproliferative disorders（MPDs） patients, analyze the correlation between JAK2 V617F mutation and clinical features. Methods The JAK2 V617F mutation was detected by direct DNA sequencing of PCR product and allele-specific PCR respectively. The expression of JAK2, phospho-JAK2 and phospho-STAT5 proteins was determined by Western blot. The clinical data of MPDs patients with or without JAK2 V617F mutation was collected and analyzed for evaluating the clinical significance of JAK2 V617F mutation. Results （1） The frequency of JAK2 V617F mutation for PV, IMF, ET was 92% ,58% ,50 % respectively. Compared with conventional DNA sequencing （ PV 84% , IMF 44% , ET 39% , respectively） , allele-specific PCR exhibited a higher sensitivity in JAK2 V617F mutation detection.（2）The expression levels of phospho-JAK2 and phospho-STAT5 in peripheral blood mononuclear cells （PBMNCs） were upregulated significantly in JAK2 V617 F-positive patients than in JAK2 V617F negative patients. （3） Compared with the patients with no JAK2 V617F mutation, the JAK2 V 617F-positive patients＇ features were as follows： older age of onset,higher mean leukocyte counts, lower platelet counts and smaller spleen volume. Frequency of thrombosis events in PT,ET, IMF was 17%, 32%, 16% respectively for JAK2 V617F positive group, and 0% （PV）, 16% （ET） ,5% （IMF） for JAK2 V617F negative group. Conclusions MPDs patients display higher frequency of JAK2 V617F mutation.JAK2 V617F mutation positive patients predispose to a thrombosis tendency.