Relationship between TET2 Gene SNP rs3733609 C/T and JAK2V617F Allele Burden in Patients with Myeloproliferative Neoplasms / 中国实验血液学杂志

OBJECTIVE@#To investigate the relationship between the polymorphism of TET2 gene SNP rs3733609 and JAK2V617F allele burden in patients with myeloproliferative neoplasms (MPN).@*METHODS@#The exon 9 of TET2 gene was amplified by RT-PCR, and the nucleotide sequence of SNP rs3733609 site was analyzed by gene sequencing. The MGB Taqman probe PCR method was used to detect the JAK2V617F allele burden. The correlation of TET2 gene SNP rs3733609 C/T with the JAK2V617F allele burden and clinical parameters was analyzed.@*RESULTS@#TET2 gene rs3733609 C/T heterozygosity (normal T/T) could be detected in 19 cases of 85 cases of JAK2V617F positive MPN (22.4%) patients, while the TET2 gene rs3733609 C/T heterozygosity could be detected only in 9 of the 106 healthy volunteers, and the incidence was only 8.5% (9/106). Compared with the negative group (TET2 rs3733609 T/T), there was no significant difference in the median age, hemoglobin level and platelet count in the patients with TET2 gene SNP rs3733609 (CT/TC) positive, but the WBC count of peripheral blood and JAK2V617F allele burden significantly increased. In JAK2V617F high allele burden group, TET2 gene SNP rs3733609 was positive in 7 cases (36.8%, 7/19), the ratio was higher than that in the low allele burden group(18.2%, 12/66).@*CONCLUSION@#TET2 SNP rs3733609 C/T may be a new susceptible allelee, which affects the clinical characteristics and clonal evolution of MPN patients.

The frequency of JAK2 V617F mutation, expression level of phosphorylated JAK/STATs proteins and their clinical significance in myeloproliferative disorders patients / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the frequency of JAK2 V617F mutation in 145 myeloproliferative disorders (MPDs) patients, analyze the correlation between JAK2 V617F mutation and clinical features.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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 V617F-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.</p><p><b>CONCLUSIONS</b>MPDs patients display higher frequency of JAK2 V617F mutation. JAK2 V617F mutation positive patients predispose to a thrombosis tendency.</p>

The dynamic analysis and the clinical significance of vascular endothelial cell markers and hemolysis parameters in thrombotic thrombocytopenic purpura / 中华血液学杂志

<p><b>OBJECTIVE</b>To monitor the changes of hemolysis parameters and endothelial cell markers in thrombotic thrombocytopenic purpura (TTP) and reveal the clinical significance of these changes.</p><p><b>METHODS</b>vWF-cleaving protease (vWF-CP) activity in 3 cases of TTP was detected by Western blot. The percentages of fragmented red cells (FRC) were counted throughout the entire clinical course. Levels of plasma thrombomodulin were detected by Western blot combined with density screening in TTP and healthy individuals (n = 3). Concentration of plasma VEGF was measured by enzyme-linked immunosorbent assay in TTP and healthy individuals (n = 9). Fundus fluorescein angiography was performed to search the evidence of microvascular thrombosis in one TTP patient with impaired visual acuity.</p><p><b>RESULTS</b>The lower vWF-CP activity was observed in TTP patients; the percentages of FRC in 3 cases of TTP were 1.65%, 2.50%, 3.32% respectively with an average of 2.49% at the onset of and decreased with the improvement of the disease. The levels of plasma TM and VEGF were significantly elevated in TTP than those in healthy individuals, and related to the severity of TTP. Fundus photography in one TTP patient with impaired visual acuity revealed vascular occlusion in fundus arteriole and venulae.</p><p><b>CONCLUSIONS</b>A decreased vWF-CP activity is in favour of TTP diagnosis. Dynamic monitoring of plasma TM and VEGF as well as percentages of FRC are useful indexes for reflecting the severity and evaluating therapeutic response of TTP. Selective fundus fluorescein angiography is useful for the judgement of microvascular thrombosis in TTP.</p>