伴WT1、MLL-PTD、EVI1基因的幼儿急性巨核细胞白血病的表型与遗传学分析

Phenotypic and genetic analysis of acute megakaryoblastic leukemia in young children with WT1,MLL-PTD and EVI1 genes

目的探讨伴WT1、MLL-PTD、EVI1基因幼儿急性巨核细胞白血病(acute mega-karyoblastic leukemia,AMKL)的表型与遗传学特征。方法采集静脉血进行血常规及血细胞形态分析;抽取骨髓进行细胞形态学、免疫表型、染色体核型及融合基因分析。结果血常规白细胞计数12.3×109/L、血红蛋白73 g/L、血小板计数13×109/L;血细胞形态分析发现幼稚细胞胞体大小似原始幼稚淋巴细胞,呈圆形或不规则形,部分可见明显伪足;胞质嗜碱性,着色不均,内有颗粒;核染色质细致,可见核仁1~3个,此类细胞约占40%;骨髓细胞形态分析符合急性白血病,过氧化物酶染色阴性,酯酶双染色AS-DNCE阴性,α-NBE阴性;流式细胞免疫分型结果可见约52%的原始细胞,伴明显的巨核细胞相关标记表达(cCD41+,CD61+部分,CD36+);染色体核型为46,XX,der(3)add(3)(p21)add(3)(q25),add(9)(q22),-13,+mar[4]/46,XX,del(13)(q12q22)[3]/46,XX[3];融合基因WT1过表达、MLL-PTD阳性、EVI1阳性。结论急性巨核细胞白血病具有独特且复杂的表型特点及遗传学特征。

Objective To explore the phenotypic and genetic characteristics of acute megakaryoblastic leukemia(AMKL)in young children accompany by WT1,MLL-PTD and EVI1,in order to improve the diagnosis level of AMKL.Methods EDTA-K2 anticoagulation venous blood was collected for blood routine and morphological analysis of blood cells;bone marrow was extracted for cell morphology,immunophenotype,chromosome karyotype and fusion gene analysis.Results White blood cell count was 12.3×109/L,hemoglobin was 73 g/L,and platelet count was 13×109/L.The morphological analysis of blood cells showed that the size of immature cells was like that of primitive immature lymphocytes,which was circular or irregular and part of them with obvious pseudopodia.The cytoplasm is basophilic with heterogeneous coloration and granules.Nuclear chromatin is fine and even,1-3 nucleoli can be seen,this immature cells account for about 40%;the morphology of bone marrow cells was consistent with acute leukemia,negative for peroxidase staining,negative for AS-DNCE staining andα-NBE staining.Flow cytometry results showed that the protocells account for about 52%and significant expression of megakaryocytes related markers(cCD41+,CD61+,CD36+).Chromosome karyotype is 46,XX,der(3)add(3)(p21)add(3)(q25),add(9)(q22),-13,+mar[4]/46,XX,del(13)(q12q22)[3]/46,XX[3].The fusion gene WT1 was overexpressed,MLL-PTD and EVI1 were positive.Conclusion Acute megakaryocytic leukemia has unique and complex phenotypic and genetics characteristics.