慢性嗜酸粒细胞白血病／高嗜酸粒细胞综合征临床和实验室特征研究

Studying of clinical and laboratory features of chronic eosinophilic leukemias/hypereosinophilic syndrome

目的探讨慢性嗜酸粒细胞白血病（CEL）／高嗜酸粒细胞综合征（HES）的临床和实验室特征。方法回顾性分析20例CEL／HES患者，用筑巢式RT—PCR方法检测FIP1L1-PDGFRA融合基因；等位基因特异性聚合酶链反应（ASP—PCR）联合测序分析检测JAK2 V617F，PCR-限制性片段长度多态性（RFLP）检测JAK2V617F突变状态；PCR法检测TCRγ重排。比较CEL与HES的临床和实验室特征。结果20例患者男：女为19：1，中位年龄33（20～57）岁。12例FIP1L1-PDGFRA检测阳性，测序证实FIP1L1断裂位点位于内含子10～12，PDGFRA断裂位点位于外显子12。1例HES患者存在JAK2 V617F，突变状态分析显示为杂合子突变。6例检出TCRγ基因重排，其中CEL4例，HES2例。CEL患者以呼吸道症状起病者多见，易合并循环系统损害及神经系统症状。CEL患者脾脏肿大发生率明显高于HES（分别为92．5％和42．5％，P=0．031），发生贫血及骨髓纤维化的比例亦高于后者。外周血嗜酸粒细胞绝对值、白细胞计数、血小板计数、骨髓嗜酸粒细胞比例、骨髓原始细胞比例二组之间差异无统计学意义。嗜酸粒细胞形态学异常更多见于CEL患者，主要表现为嗜酸性颗粒减少，嗜碱性颗粒增多及胞质空泡等。结论①嗜酸粒细胞增多男性好发，以年轻人为主；②CEL患者主要表现为循环系统、呼吸道及消化道症状，易发生贫血和血小板减少，常规检查对CEL与HES鉴别意义不大，骨髓涂片形态学检查对CEL诊断有一定帮助；③部分HES患者存在JAK2 V617F突变，进一步研究其在HES发病中的作用有助于今后此类患者的诊断及开展新的靶向药物治疗；④部分CEL FIP1L1-PDGFRA融合基因TCRγ重排同时存在，二者在HES发病中的关系需进一步研究。

Objective To investigate the clinical and laboratory features of chronic eosinophilic leu- kemias（CEL） and hypereosinophilic syndrome（HES）. Methods The clinical manifestations, laboratory pa- rameters were retrospectively analyzed in 20 patients with HES/CEL. Detection of the FIP1L1-PDGFRA fusion gene was performed by nested RT-PCR. JAK2 V617F mutation screening was processed through allelespecific PCR combined with sequence analysis. PCR-RFLP was used to discriminate homozygous from heterozygous mutation patterns. TCRγ rearrangement was detected by PCR. Results Of the 20 patients, 19 were males and one female, with a median age of 33（20 to 57） years. The FIP1L1-PDGFRA fusion gene positivity in bone marrow mononuclear cells in 12 cases was identified. All the breakpoints were identified by direct sequencing of cloned RT-PCR products in FIP1L1 intron 10 - 12 and in PDGFRA exon 12. In CEL the most common involved organs were lungs, heart and nervous system. Splenomegaly was significantly more frequent in CEL than in HES （92. 5% vs 42.5% , P =0. 031）. Anemia and myelofibrosis were common in CEL. There was no significant difference in circulating absolute eosinophil, leukocyte, platelet counts, hemoglobin level and percentages of eosinophil and blast cell in bone marrow between CEL and HES. The morphological abnormalities of eosinophils on bone marrow smear were easily found in CEL, including hypogranularity, and cytoplasmic vacuolization, increased basophilic granule. One patient with HES was found to have heterozygous JAK2 V617F mutation. Six patients had TCRγ rearrangement, including 4 CEL and 2 HES. Conclusions （1）There is a male predominance in HES/CEL, and the median age was in the thirties. （2）The most common involved organs in CEL were lung, heart and nervous system. Bone marrow morphology might be of a little help in diagnosis of CEL. （3）JAK2 V617F may be involved in the pathogenesis of HES. （4）Patients with CEL carried the FIP1L1-PDGFRA fusion gene and TCRγ rearrangement concurrently, their relationship worrants further study.