JAK2不同外显子突变真性红细胞增多症二例并文献复习

目的:探讨JAK2 exon12和JAK2 exon13突变真性红细胞增多症的临床特征及诊断。方法:回顾性分析宁夏回族自治区人民医院2例JAK2 exon12及JAK2 exon13基因突变真性红细胞增多症患者的临床特征及诊疗经过，并进行相关文献复习。结果:例1骨髓活组织检查提示粒红系增生活跃，巨核细胞形态大小不一，可见集簇现象；JAK2 exon13突变阳性。例2骨髓活组织检查示巨核细胞可见集簇现象，纤维组织增殖明显，骨小梁增厚；JAK2 exon12突变阳性。结合临床表现及相关检查结果，2例患者分别诊断为JAK2 exon12及JAK2 exon13突变真性红细胞增多症，给予间断放血及羟基脲治疗。结论:JAK2 exon12及JAK2 exon13突变真性红细胞增多症临床少见，不同外显子突变导致的真性红细胞增多症的临床特征和疾病演变需进一步观察。     

BCR-ABL阴性骨髓增殖性肿瘤JAK2 V617F基因突变状态及负荷的临床意义

目的探讨JAK2 V617F基因突变状态及负荷对BCR-ABL阴性骨髓增殖性肿瘤(MPN)的影响。方法回顾性分析2015年9月至2020年1月河北省沧州市中心医院199例MPN患者的临床资料。分析JAK2 V617F突变负荷与MPN患者临床病理特征及预后评分的关系。结果199例BCR-ABL阴性MPN患者中JAK2 V617F突变阳性138例(69.4%);其中,72例真性红细胞增多症(PV)患者中突变阳性64例(88.9%),101例原发性血小板增多症(ET)患者中突变阳性54例(53.5%),25例骨髓纤维化(MF)患者中突变阳性20例(80.0%),1例嗜酸粒细胞增多症(HES)患者突变阳性。JAK2 V617F突变高负荷者占55.1%(76/138)。突变负荷最高的类型为PV,MF次之,ET最低,3组突变负荷分别为(73.9±18.3)%、(59.9±25.2)%、(25.0±16.5)%。JAK2 V617F突变负荷与PV、ET、MF患者的白细胞计数均呈正相关(r值分别为0.626、0.675、0.796,均P<0.01)。JAK2 V617F突变负荷与PV、ET患者的预后评分均呈正相关(r值分别为0.296、0.404,均P<0.05)。结论BCR-ABL阴性MPN患者JAK2 V617F突变负荷与临床病理因素相关,JAK2 V617F突变高负荷患者预后不良。     

原发性血小板增多症、真性红细胞增多症和骨髓纤维化：目前的处理和靶向治疗

最近发现JAK2和／或MPL突变对真性红细胞增多症（PV）、原发性血小板增多症（ET）和原发性骨髓纤维化（PMF）的诊断和治疗产生着重大影响。例如,JAK2突变目前认为是诊断PV的必要条件,WHO分类系统最近修订的PV、ET和PMF诊断标准中包括JAK2和MPL（血小板生成素受体）突变作为克隆性标记。从治疗学的观点,JAK—STAT信号途径现已确定为研发骨髓增殖性新生物治疗新药的合理靶途径。本文简述ET、PV和PMF目前的处理,并复习抗JAK2小分子药物临床前和临床活性的有关资料。     

实时定量聚合酶链反应检测慢性骨髓增殖性疾病患者JAK2 V617F基因突变

 目的　观察实时定量聚合酶链反应（PCR）检测慢性骨髓增殖性疾病（CMPD）中JAK2基因V617F点突变情况。方法　采用实时定量PCR法检测56例CMPD患者JAK2 V617F基因突变类型及突变转录水平。其中,真性红细胞增多症（PV）26例、原发性血小板增多症（ET）24例、原发性骨髓纤维化（CIMF） 5例、高嗜酸粒细胞综合征（HES）1例。结果　56例CMPD患者JAK2 V617F基因突变率为51.79 ％（29／56）,PV 65.38 %（17／26）、ET 37.50 %（9／24）、IMF 60.00 %（3／5）;杂合性突变率为41.07 %（23／56）,包括PV 53.85 %（14／26）、ET 29.17 %（7／24）、CIMF 40.0 %（2／5）;纯合性突变率为10.71 %（6／56）, 包括PV 11.54 %（3／26）、ET 8.33 %（2／24）、CIMF 20.00 %（1／5）;1例HES患者为野生型。PV、ET和CIMF突变患者拷贝数分别为2.14×102～1.5×107、9.80×102～4.4×107和4.10×103～3.70×106。结论　实时定量PCR检测JAK2 V617F基因简便、快捷, 并且易于定量, 检测阳性率与国外报道相似, 适合临床用于CMPD的诊断和疗效评估。     

血红蛋白及血小板增多患者的JAK2 V617F突变检测及临床意义分析

骨髓增殖性肿瘤（myeloproliferative neoplasm,MPN）是以一系或多系分化相对成熟的骨髓细胞克隆性增殖异常为特点的疾病,其分类中的真性红细胞增多症（polycythemia vera,PV）、原发性血小板增多症（essentialthrombocythemia,ET）等疾病中存在JAK2V617F点突变。有研究表明,在检测MPN患者JAK2V617F突变中,PV发生率在90％以上、ET发生率为50％-70％。JAK2V617F基因突变已作为诊断MPN的必要指标之一。本研究目的是对血红蛋白及血小板增多临床怀疑MPN者进行JAK2V617F突变检测,并结合临床资料进行分析,为血红蛋白及血小板增高患者的诊断提供依据。     

JAK2基因突变与骨髓增生性疾病的关系

 骨髓增生性疾病（MPD）中真性红细胞增多症（PV）、特发性血小板增多症（ET）、特发性骨髓纤维化（IMF）发现蛋白酪氨酸激酶（JAK2）基因上有一个碱基突变JAK2 V617F,突变明显与PV、ET和IMF的发生有关,这一发现可能成为诊断这类综合征的一种方式,也为寻找新的药物治疗MPD提供了明确的作用目标,同时还为研究细胞生长紊乱和细胞功能紊乱提供新的研究思路。     

潜匿性真性红细胞增多症与真性红细胞增多症鉴别诊断

目的：对比分析潜匿性真性红细胞增多症（mPV）和真性红细胞增多症（PV）的特点,探讨mPV 早期诊断的方法。方法收集符合诊断标准的男性初诊 PV、mPV 患者各100例,均行促红细胞生成素（EPO）、中性粒细胞碱性磷酸酶（NAP）、 JAK2 V617F 基因检测及骨髓组织活组织检查（BMB）。半年后追踪未经特殊治疗两组患者的血红蛋白（Hb）及 JAK2 V617F 基因突变负荷量变化情况。结果PV 组与 mPV 组 EPO 分别为（3.4±0.7）、（3.2±0.6） U／ml,NAP 积分分别为（276±20）、（278±21）分, BMB 造血容积分别为（78±10）%、（76±9）%,巨核细胞数分别为（53±6）、（51±5）个／张切片,差异均无统计学意义（均 P＞0.05）。 JAK2 V617F 基因突变负荷量分别为（89.2±9.4）%、（78.1±8.6）%,差异有统计学意义（P＜0.05）。 mPV 组中未经特殊治疗的半年后达 PV 水平（Hb≥185 g／L）的37例患者 Hb 平均水平为（194±8）g／L,JAK2 V617F 负荷量为（90.7±9.1）%。结论 PV、mPV 患者的 EPO、NAP 积分及骨髓组织形态学无差异,而 JAK2 V617F 基因突变负荷量有差异。未经特殊治疗的 mPV 患者 Hb 水平半年后多数可达到典型 PV 的诊断水平,JAK2 V617F 基因突变负荷量随之增加。     

真性红细胞增多症27例临床分析

目的 对真性红细胞增多症（Pv）患者的临床特征进行分析,进一步了解其特点,为临床诊治提供帮助.方法 对2001年5月至2012年12月收治并确诊为PV的27例患者的临床资料进行回顾性分析.结果 对27例患者中合并血栓性疾病15例（55.6％）,行JAK2 V617F基因突变检测15例中,12例出现阳性,阳性率为80.0％.结论 JAK2 V617F基因突变在PV患者中的发生率高,对PV早期诊断、治疗及预防血栓事件的发生具有重要的临床意义.     

132例BCR-ABL融合基因阴性骨髓增殖性肿瘤患者JAK2、CALR及MPL基因突变的临床分析

目的:探讨BCR-ABL融合基因阴性的骨髓增殖性肿瘤(myeloproliferative neoplasms,MPN)患者JAK2、CALR及MPL基因突变情况及临床特征。方法:选取132例BCR-ABL融合基因阴性的MPN患者,其中真性红细胞增多症(polycythemia vera,PV)27例,原发性血小板增多症(essential thrombocythemia,ET)97例,原发性骨髓纤维化(primary myelofibrosis,PMF)8例。骨髓抽提DNA,荧光定量PCR检测JAK2、CALR及MPL基因突变情况并分析临床特征,JAK2基因包含JAK2V617F、JAK2 N542_E543del、E543_D544del和JAK2 K539L1/L2;CALR基因包含CALR L367fs*46和CALR K385fs*47,MPL基因包含MPL W515K/A/L/R1/R2/S和MPL S505N。结果:在132例BCR-ABL融合基因阴性的MPN患者中,仅有JAK2V617F、MPL W515K/A/L/R1/R2/S、CALR L367fs*46和CALR K385fs*47突变,突变率分别为48.48%(64/132)、0.76%(1/132)、10.61%(14/132)和6.06％(8/132),并且这几种突变不同时出现。PV中仅有JAK2V617F突变,突变率为74.07%（20/27）,ET中JAK2V617F、CALR L367fs*46和CALR K385fs*47突变率分别为42.27%（41/97）、13.40%（13/97）、8.25%（8/97）,PMF中 JAK2V617F、CALR L367fs*46和MPL W515K/A/L/R1/R2/S突变率分别为37.50%（3/8）、12.50%（1/8）和12.50%（1/8）。在PV患者中,JAK2V617F突变阳性患者的白细胞（white blood cell,WBC）显著高于阴性患者（P<0.05）。在ET患者中,JAK2V617F突变阳性患者的血红蛋白（hemoglobin,Hb）显著高于阴性患者（P<0.05）,CALR突变阳性患者的血小板（platelet,PLT）显著高于阴性患者（P<0.05）。结论:基因检测为MPN的诊断及预后能提供更加方便、准确地依据,为相关的治疗提供更多的帮助。     

BCR-ABL阴性骨髓增殖性疾病患者

目的：检测BCRABL融合基因阴性的骨髓增殖性疾病（myeloproliferative disorders,MPD）患者的JAK2 V617F突变率,探讨其与MPD患者临床特征间的关系。方法：选择山东大学附属省立医院确诊的56例BCRABL阴性的MPD患者为研究对象,其中真性红细胞增多症（polycythaemia vera,PV）20例、原发性血小板增多症（essential thrombocythaemia,ET）26例,特发性骨髓纤维化（idiopathic myelofibrosis,IMF）10例。应用等位基因特异性PCR（allelespecific polymerase chain reaction,ASPCR）和基因测序检测MPD患者JAK2 V617F突变情况,分析各组MPD患者JAK2 V617F突变与MPD临床特征间的关系。结果：56例MPD患者中36例检出JAK2 V617F突变,突变率分别为ET患者53.8%（14/26）,PV患者85%（17/20）,IMF患者50%（5/10）。JAK2 V617F突变阳性的MPD患者与突变阴性者相比,在血象方面：PV患者的白细胞（P= 0.018）、血小板计数（P= 0.021）;ET患者的白细胞计数（P= 0.001）、血红蛋白（P= 0.007）;IMF患者的白细胞计数（P= 0.026）差异均有统计学意义。在并发症方面：ET组中JAK2 V617F突变阳性的患者出血、血栓并发症的发生率更高（P= 0.016）,PV及IMF组中差异无统计学意义。结论：ASPCR可有效检测JAK2 V617F突变的发生,JAK2 V617F突变阳性的MPD患者与突变阴性者在临床特征上有较明显的差异。     

Characterization and Prognosis Significance of JAK2 (V617F), MPL,and CALR Mutations in Philadelphia-Negative Myeloproliferative Neoplasms

Background: The discovery of somatic acquired mutations of JAK2 (V617F) in Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPNs) including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) has not only improved rational disease classification and prognostication but also brings new understanding insight into the pathogenesis of diseases. Dosage effects of the JAK2 (V617F) allelic burden in Ph-negative MPNs may partially influence clinical presentation, disease progression, and treatment outcome. Material and Methods: Pyrosequencing was performed to detect JAK2 (V617F) and MPL (W515K/L) and capillary electrophoresis to identify CALR exon 9.0 mutations in 100.0 samples of Ph-negative MPNs (38.0 PV, 55 ET, 4 PMF, and 3 MPN-U). Results: The results showed somatic mutations of JAK2 (V617F) in 94.7% of PV, 74.5% of ET, 25.0% of PMF, and all MPN-U. A high proportion of JAK2 (V617F) mutant allele burden (mutational load > 50.0%) was predominantly observed in PV when compared with ET. Although a high level of JAK2 (V617F) allele burden was strongly associated with high WBC counts in both PV and ET, several hematological parameters (hemoglobin, hematocrit, and platelet count) were independent of JAK2 (V617F) mutational load. MPL (W515K/L) mutations could not be detected whereas CALR exon 9.0 mutations were identified in 35.7% of patients with JAK2 negative ET and 33.3% with JAK2 negative PMF. Conclusions: The JAK2 (V617F) allele burden may be involved in progression of MPNs. Furthermore, a high level of JAK2 (V617F) mutant allele appears strongly associated with leukocytosis in both PV and ET.     

JAK2V617F allele burden is associated with transformation to myelofibrosis

Abstract The JAK2V617F mutation has emerged in recent years as a diagnostic as well as treatment target in patients with polycythemia vera (PV). We analyzed JAK2V617F allele burden (JAK2(V617F)) in a Jewish population with PV. Results were correlated with disease symptoms and complications. Median JAK2(V617F) was 48% and 54% in patients of Ashkenazi and non-Ashkenazi origin, respectively (p =0.75). Higher JAK2(V617F) was seen in patients with imaging-proven splenomegaly (p =0.01). A correlation between JAK2(V617F) and the weekly hydoxyurea dose needed for disease control was found (p =0.043). In addition, a trend for higher allele burden in patients with longer disease duration (p =0.064) and those treated with cytoreductive drugs other than hydroxyurea (p =0.056) was noted. Higher JAK2(V617F) was seen in patients with transformation to myelofibosis (p =0.0001), but not in patients with vascular complications. JAK2(V617F) may assist in prognostic stratification of patients with PV.     

Influence of JAK2 46/1 haplotype in the natural evolution of JAK2V617F allele burden in patients with myeloproliferative neoplasms

JAK2V617F allele burden was prospectively measured in untreated patients with polycythaemia vera (PV, n=26) or essential thrombocythaemia (ET, n=36) and compared according to JAK2 46/1 haplotype status. The mean increase in JAK2V617F allele burden per year was 1%, 0.8% and 6% for PV patients with the JAK2 46/1 haplotype in negative, heterozygous and homozygous status, respectively (p<0.001). The JAK2 46/1 haplotype had no influence in JAK2V617 allele burden in ET. In conclusion, untreated PV patients homozygous for the JAK2 46/1 haplotype show a progressive increase in the JAK2V617F allele burden during the evolution of the disease.     

原发血小板增多症患者 JAK2 V617F 突变与凝血功能的相关性

目的：探讨原发血小板增多症（ET）患者 JAK2 V617F 突变及其突变负荷与血常规及凝血功能之间的相关性。方法回顾性分析2008年1月至2015年12月收治的90例 ET 患者临床及实验室资料,用等位基因特异性聚合酶链反应行 JAK2 V617F 点突变检测,实时定量特异性聚合酶链反应行JAK2 V617F 检测突变负荷,分析 JAK2 V617F 突变及突变负荷与血常规及凝血功能的相关性。结果90例ET 患者中,50例患者检出 JAK2 V617F 突变,突变率为55.6%。 JAK2 V617F 突变组红细胞计数[（4.67±0.89）×109／L 比（4.04±0.99）×109／L, P＝0.003]、白细胞计数[（11.64±5.20）×109／L 比（9.11±4.11）×109／L, P＝0.014]、血细胞比容[（0.41±0.07）比（0.36±0.07）,P＝0.005]均较野生型组高,凝血酶原时间较野生型组长[（13.18±1.63） s 比（12.02±1.24） s,P＝0.000]。 JAK2 V617F 突变负荷为（29.91±18.63）%,JAK2 V617F 突变负荷与血常规之间未见相关性（均 P＞0.05）,与纤维蛋白降解产物（FDP）之间存在相关性（r＝0.456,P＝0.001）。结论 ET 患者存在较高的 JAK2 V617F 突变率,临床早期检测JAK2 V617F 突变及突变负荷可能对 ET 患者血管性事件早期预防具有重要的临床价值。     

Prospective identification of high-risk polycythemia vera patients based on JAK2(V617F) allele burden.

The aim of this study was to determine whether the burden of JAK2(V617F) allele correlated with major clinical outcomes in patients with polycythemia vera (PV). To this end, we determined JAK2 mutant allele levels in granulocytes of 173 PV patients at diagnosis. The mean (+/-s.d.) mutant allele burden was 52% (+/-29); 32 patients (18%) had greater than 75% mutant allele. The burden of JAK2(V617F) allele correlated with measurements of stimulated erythropoiesis (higher hematocrit, lower mean cell volume, serum ferritin and erythropoietin levels) and myelopoiesis (higher white cell count, neutrophil count and serum lactate dehydrogenase) and with markers of neutrophil activation (elevated leukocyte alkaline phosphatase and PRV-1 expression). As compared to those with less than 25% mutant allele, patients harboring greater than 75% JAK2(V617F) allele were at higher relative risk (RR) of presenting larger spleen (RR 4.7; P<0.001) or suffering from pruritus (RR 3.1; P<0.001). In these patients, the risk of requiring chemotherapy (RR 1.8; P=0.001) or developing major cardiovascular events (RR 7.1; P=0.003) during follow up were significantly increased. We conclude that a burden of JAK2(V617F) allele greater than 75% at diagnosis points to PV patients with high-risk disease.     

Somatic JAK-2 V617F Mutational Analysis in Polycythemia Rubra Vera: a Tertiary Care Center Experience

Background: Polycythemia rubra vera (PV), being a primary polycythemia, is caused by neoplastic proliferation of erythroid, megakaryocytic and granulocytic lineages which result in panmyelosis. PV patients have a somatic acquired mutation in the Janus kinase (JAK2) pathway, rendering cell proliferation independent of the normal regulatory mechanisms that regulate erythropoiesis. The rational of this study was to determine the prevalence of the JAK-2 V617F mutation in Pakistani patients with PV. Materials and Methods: In this cross sectional study, 26 patients with PV were enrolled from January 2010 to December 2014. Patients were diagnosed based on WHO criteria for PV. All were screened for G-T point mutation (V617F) in the JAK2 gene on chromosome 9 by an allele specific PCR. Results: The mean age was 53.49.31 years (range 36-72) and the male to female ratio was 2:1. The frequency of JAK2 V617F positivity in our PV patients was found to be 92.3%. Overall 30.7% of patients were asymptomatic and remaining 69.3% presented with symptomatic disease. The mean hemoglobin was 18.11.9g/dl with the mean hematocrit of 55.68.3%. The mean total leukocyte count was 12.87.1x109/l and the platelet count was 511341.9x109/l. A positive correlation of JAK2 V617F mutation was established with high TLC count (P=0.01). No correlation of JAK2 V617F could be established with age or gender (P>0.05). Conclusions: The JAK2 V617F mutation frequency in our PV patients was similar to those reported internationally. Screening for the mutation in all suspected PV cases could be beneficial in differentiating patients with reactive and clonal erythrocytosis.     

The V617F JAK2 mutation and the myeloproliferative disorders

The discovery this year of a single mutation in the Janus Kinase (JAK)-2 gene in a high percentage of cases of polycythaemia vera (PV), essential thrombocythaemia (ET) and myelofibrosis suggests that it maybe the underlying molecular mechanism for these disorders. Different approaches from the inhibition of the tyrosine kinase JAK2, widespread search for mutations in tyrosine kinases, and investigation of the short arm of chromosome 9 where JAK2 is located all led to the discovery of the V617F JAK2 mutation. Substitution of a valine for a phenylalanine destabilizes the JH2 domain of JAK2 causes loss of the auto-inhibitory activity of this domain and explains some of the biological phenomena observed in patients with myeloproliferative disorders (MPD). The V617F JAK2 mutation can be detected by PCR-direct sequencing using DNA from the granulocyte lineage or with increased sensitivity by the amplification refractory mutation system using DNA from unfractionated blood. Pyrosequencing assays can be used to quantitate allele ratios to accurately define homozygote and heterozygote status. This single mutation is widespread having been detected in related MPD and other haematological malignancies. This leads to a number of further questions about the role of this single mutation in the clinical pattern of disease.