Lippert Eric, Boissinot Marjorie, Kralovics Robert, Girodon François, Dobo Irène, Praloran Vincent, Boiret-Dupré Nathalie, Skoda Radek C, Hermouet Sylvie
Laboratoire d'Hématologie du CHU de Bourdeaux, France.
Blood. 2006 Sep 15;108(6):1865-7. doi: 10.1182/blood-2006-01-013540. Epub 2006 May 25.
We determined the allelic frequency of the JAK2-V617F mutation in DNA and assessed the expression levels of the mutant and wild-type JAK2 mRNA in granulocytes from 60 patients with essential thrombocythemia (ET) and 62 patients with polycythemia vera (PV) at the time of diagnosis. Using allele-specific quantitative polymerase chain reaction (qPCR), we detected JAK2-V617F in 75% of ET and 97% of PV at diagnosis. The total JAK2 mRNA levels were elevated in ET, PV, and secondary and idiopathic erythrocytosis, suggesting that hyperactive hematopoiesis alters JAK2 expression. The expression levels of JAK2-V617F mRNA were variable but strongly correlated with the allelic ratio of JAK2-V617F determined in DNA. Thus, differences in JAK2-V617F expression, markedly lower in ET than in PV, reflected different percentages of granulocytes carrying the mutation. Moreover, allelic ratios higher than 50% JAK2-V617F, indicating the presence of granulocytes homozygous for JAK2-V617F, were found in 70% of PV at diagnosis but never in ET.
我们测定了60例原发性血小板增多症（ET）患者和62例真性红细胞增多症（PV）患者诊断时DNA中JAK2-V617F突变的等位基因频率，并评估了粒细胞中突变型和野生型JAK2 mRNA的表达水平。采用等位基因特异性定量聚合酶链反应（qPCR），我们在诊断时检测到75%的ET患者和97%的PV患者存在JAK2-V617F。ET、PV、继发性和特发性红细胞增多症患者的总JAK2 mRNA水平均升高，提示造血功能亢进会改变JAK2的表达。JAK2-V617F mRNA的表达水平存在差异，但与DNA中测定的JAK2-V617F等位基因比例密切相关。因此，JAK2-V617F表达的差异（ET患者明显低于PV患者）反映了携带该突变的粒细胞百分比不同。此外，诊断时70%的PV患者中发现JAK2-V617F等位基因比例高于50%，表明存在JAK2-V617F纯合的粒细胞，而ET患者中从未发现这种情况。
