伴ASXL1和U2AF1突变年轻不典型慢性粒细胞白血病患者临床分析

Atypical chronic myeloid leukemia patient with ASXL1 and U2AF1 mutations:a clinical analysis of young patients

目的探讨不典型慢性粒细胞白血病(aCML)的临床特点及诊断方法。方法对四川省宜宾市第二人民医院南岸院区收治的1例年轻aCML患者的临床资料、骨髓形态学、免疫学、遗传学及分子生物学特点进行分析。结果患者骨髓涂片示:粒细胞系明显增生,占0.875,伴显著发育异常和不成熟的粒细胞增多,原始粒细胞占0.170,成熟粒细胞胞质内颗粒明显增多、增粗;骨髓穿刺活组织检查示:骨髓增生极度活跃,幼稚粒细胞增多,网状纤维广泛增生(骨髓纤维化2~3级);左腹股沟淋巴结切除活组织检查病理示:淋巴结结构破坏,组织细胞背景中可见巨核细胞及不成熟粒细胞,符合髓外造血;骨髓流式细胞免疫表型示:粒细胞群约占有核细胞81.6%,异常表达CD56、CD14dim,粒细胞系发育模式异常;白血病中常见30种融合基因筛查均为阴性;聚合酶链反应(PCR)检测示:BCR-ABL1融合基因p210型、BCR-ABL1融合基因p190型、BCR-ABL1融合基因p230型、CALR基因第9号外显子、JAK2 V617F突变均为阴性。Sanger测序示:MPL-W515基因突变、CSF3R基因第14号和17号外显子、BRAF基因突变、SRSF2均为阴性;二代测序示:ASXL1基因突变阳性,NM_015338.5:c.2077C>T(p.R693*),突变频率为47.7%;U2AF1基因突变阳性,NM_006758.2:c.101C>A(p.S34V),突变频率为51%;PDGFRA、PDGFRB、SETBP1、SF3B1、STAT3、STAT5B等均为阴性。染色体核型分析示:47,XX,add(5)(q33),+8,-10,+mar[8]。综合诊断为aCML,BCR-ABL1阴性。结论BCR-ABL1阴性aCML的诊断依赖于形态学、免疫学、遗传学和分子生物学综合诊断,二代测序在鉴别诊断及靶向药物治疗方面尤为重要;年轻患者的早期诊断及治疗极具挑战性,应引起临床医生重视。

Objective To explore the clinical features and diagnosis methods of atypical chronic myeloid leukemia(aCML).Methods The clinical data,bone marrow morphology,immunology,genetics and molecular biology characteristics of a young aCML patient in Nan'an Branch of the Second People's Hospital of Yibin City in Sichuan Province were analyzed.Results The bone marrow smear showed that 0.875 of the granulocyte system showed obvious proliferation,accompanied by significant dysplasia and immature granulocytosis;blasts accounted for 0.170,and the intracytoplasmic granules of mature granulocytes were significantly increased and thickened.Bone marrow puncture biopsy showed bone marrow hyperplasia was extremely active,immature granulocytes were increased,and reticular fiber was extensively proliferated(marrow fibrosis grade 2-3);biopsy pathology results of left inguinal lymph node showed lymph node structure was destroyed,megakaryocytes and immature granulocytes could be seen in the background of histiocytes,in line with the marrow external hematopoiesis;bone marrow flow cytometry immunophenotype showed granulocyte population accounted for 81.6%of nuclear cells,abnormal expression of CD56 and CD14dim,abnormal growth pattern of granulocyte system;30 common fusion genes in leukemia screening were negative.Polymerase chain reaction(PCR)method showed BCR-ABL1 fusion gene p210 type,BCR-ABL1 fusion gene p190 type,BCR-ABL1 fusion gene p230 type,CALR gene exon 9,JAK2 gene V617F mutation were all negative.Sanger sequencing showed MPL-W515 gene mutation,CSF3R gene exons 14 and 17,BRAF gene mutation,SRSF2 were all negative.Second-generation sequencing showed ASXL1 gene mutation was positive,NM_015338.5:c.2077C>T(p.R693*)and mutation frequency was 47.7%;U2AF1 gene mutation was positive:NM_006758.2:c.101C>A(p.S34V)and mutation frequency was 51%;PDGFRA,PDGFRB,SETBP1,SF3B1,STAT3,STAT5B were all negative.Karyotype analysis showed 47,XX,add(5)(q33),+8,-10,+mar[8].The integrated examination was diagnosed as aCML with negative BCR-ABL1.Conclusions The diagnosis of aCML with negative BCR-ABL1 depends on the comprehensive diagnosis of morphology,immunology,genetics and molecular biology.Second-generation sequencing is particularly important in the differential diagnosis and targeted drug therapy.Early diagnosis and treatment of young patients is extremely challenging and should be paid more attention for clinicians.