Immunogenotypic and clonal culture studies in Philadelphia chromosome-positive acute leukemia

Molecular analysis and blast colony assay were performed on patients with Philadelphia chromosome-positive acute leukemia (Ph+ AL). All patients were diagnosed as ALL- L2 and 3 were My+ ALL. Nine of the 12 cases had rearranged immunoglobulin heavy chain, and 4 had rearranged TCR beta. TCR gamma rearrangement was noted in 3 patients, and TCR delta involvement was also noted in 6 patients. Clonal culture analysis revealed that leukemia cells of M-BCR rearranged Ph+ AL cases had a potential to proliferate by myelopoietic CSFs and ILs, however, M-BCR nonrearranged Ph+ AL did not. These results indicate biological and immunogenotypic heterogeneity of Ph+ AL.     

Cytogenetic and molecular aspects of Ph-positive leukemia

Cytogenetic and molecular aspects of Ph-positive leukemia are described in comparison with those of Ph-positive CML. Chromosomal characteristics of Ph+AL are; 1) mixture of a normal karyotype at diagnosis, 2) frequent combination with +Ph, +21, +6, +8, or -7, 3) recovery of a normal karyotype at remission. Additional chromosome changes at myeloid blast crisis (BC) of CML are characterized by +Ph, i(17q), +8, or +19. Meanwhile, lymphoid BC exhibits +Ph, +21, but not i(17q) or +19. There seems no cytogenetic difference between Ph+AL and lymphoid BC of CML, but i(17q) may be specific for CML BC. Eight patients with Ph+AL were studied with pulsed-field gel electrophoresis (PFGE) to examine the break site within ABL and BCR genes. One case had a M-BCR rearrangement and the remainder a rearrangement upstream of M-BCR. Minor-BCR rearrangement occurs seldom in CML but is detected in approximately a half of the reported cases of Ph+AL. ABL was rearranged within 1st or 2nd intron in all 8 cases. ABL breakpoints appear randomly distributed between exons 1b and 2 in both Ph+AL and CML.     

Detection of minimal residual leukemia after bone marrow transplantation in patients with chronic myeloid leukemia using the polymerase chain reaction

We have utilized the polymerase chain reaction (PCR) to sensitively detect the minimal residual leukemia in 24 patients who were hematologically normal and were negative for Ph1 chromosome after bone marrow transplantation (BMT). None of the patient showed breakpoint cluster region (BCR) gene rearrangement by Southern blot analysis, however, PCR technique revealed the bcr/abl mRNA in 13 of 24 patients. In patients who received CY + TBI as a conditioning regimen, 6 out of 8 patients were detected bcr/abl mRNA by PCR. On the other hand, patients who received high dose AraC+ CY + TBI or busulfan + CY as a conditioning, bcr/abl mRNA was detected in 4 out of 9 patients and 1 out of 5 patients, respectively. There was no clear association between the presence or absence of graft versus host disease and the detection of bcr/abl mRNA by PCR.     

Philadelphia chromosome-positive adult acute lymphocytic leukemia

The CML-specific Philadelphia (Ph1) chromosome is relatively common cytogenetic abnormality of ALL, which has been shown 20% of adult ALL and 5% of child ALL. We analysed here the 12 patients of Ph1-positive ALL, aged 35 to 69-years old, who were experienced in our hospital for latest eight years. In comparison with Ph1-negative ALL, these 12 patients were elder and showed high peripheral and bone marrow leukemic cell counts. Of these, seven patients had 100% Ph1 abnormality in the bone marrow and another five patients showed mosaic marrow patterns of Ph1 and normal chromosomes. Remissioned eight cases had no more Ph1 abnormalities in their bone marrows. Our Ph1-positive ALL revealed B-cell lineage leukemia, since their surface phenotype were Ia+ and CD10+ and they have rearranged immunoglobulin JH genes. Four out of these nine patients had such gene rearrangement in the 5.8kb bcr (major BCR: M-BCR) as CML's patient had. Eight out of twelve Ph1-positive ALL patients (66.7%) achieved complete remission, but the prognosis was so bad since they had shorter remission duration (median 6.7 mos) and survival months (median 11.9 mos) than those of Ph1-negatives.     

Expression of c-abl in Philadelphia-positive acute myelogenous leukemia

The identical cytogenetic marker, t(9;22)(q34;q11) (Philadelphia [Ph] translocation), is found in approximately 90%, 20%, and 2% of adult patients with chronic myelogenous leukemia (CML), acute lymphoblastic leukemia (ALL), and acute myelogenous leukemia (AML), respectively. In CML, the molecular events resulting from the Ph translocation include a break within the bcr locus on chromosome 22, transfer of the c-abl protooncogene from chromosome 9 to 22, and formation of an aberrant 210- kD bcr-abl fusion protein (p210bcr-abl). Recently, the absence of bcr rearrangement and expression of a distinct aberrant 190-kd abl protein (p190c-abl) has been described in Ph-positive ALL, with the suggestion that the two abl variants may be pathogenetically associated with myeloid v lymphoid leukemogenesis. Here we report that the genomic configuration and translation product of Ph-positive AML can be similar to that of Ph-positive ALL: the break at 22q11 may occur outside the 5.8 kb bcr region and result in expression of a 190-kD abl protein lacking these bcr sequences. Phosphokinase enzymatic activity, a fundamental property of p210bcr-abl, was also associated with AML- derived p190c-abl. Our current observations indicate that p190c-abl can be found in cells of lymphoid or myeloid lineage and is therefore unlikely to play a specific role in the development of lymphoid leukemias. Formation of p190c-abl instead of p210bcr-abl appears to be a characteristic of the acute rather than the chronic Ph-positive leukemic state.     

Rearrangement of the breakpoint cluster region and expression of P210 BCR-ABL in a "masked" Philadelphia chromosome-positive acute myeloid leukemia

The Philadelphia (Ph) translocation t(9;22)(q34;q11) occurs frequently in chronic myeloid leukemia (CML) but is less common in acute lymphoblastic leukemia (ALL) and rare in acute myeloid leukemia (AML). In most cases of CML and some cases of Ph+ ALL the protooncogene ABL from 9q34 is translocated to the breakpoint cluster region (bcr) of the BCR gene at 22q11 to form a chimeric gene encoding a novel 210-kd protein (P210 BCR-ABL) with enhanced tyrosine kinase activity. In other patients with Ph+ ALL and Ph+ AML, the breakpoint probably occurs in the first intron of the BCR gene; this results in a smaller chimeric gene which encodes a P190 BCR-ABL. We studied a patient with AML (FAB M6) arising de novo who had a "masked" Ph chromosome in association with extensive karyotypic changes. The leukemic cells initially showed rearrangement of the bcr, presence of a hybrid mRNA, and expression of the P210 BCR-ABL. These changes were absent in remission. These results support the concept that the BCR-ABL chimeric gene plays a crucial role in leukemogenesis but suggest that factors other than the position of the breakpoint in the BCR gene determine the lineage of the target cell for malignant transformation.     

老年白血病bcr/abl融合基因的表达及其临床意义

目的　观察bcr/abl融合基因在老年白血病的表达及其临床意义。　 方法 　应用逆转录聚合酶链反应 (RT PCR)一步法检测 62例老年白血病患者bcr/abl融合基因的表达。　 结果 　 62例患者中bcr/abl融合基因阳性 5 3例 ,阳性率 85 5 % ,其中急性淋巴细胞白血病 (ALL) 17例 ,阳性 9例 (5 2 9% ) ;慢性粒细胞白血病 (CML)45例 ,阳性 44例 (97 88% )。DOCP方案治疗 7例bcr/abl ALL患者完全缓解 (CR)率 2 8 6% ,6例bcr/abl-ALL患者CR率 66 7% (P <0 0 1)。　 结论　bcr/abl融合基因检测有助于CML和ALL的临床诊断、治疗选择、微小残留病变 (MRD)监测以及预后判断 ;老年ALLbcr/abl融合基因阳性率较高 ,可能是其治疗效果较差的原因之一 ;bcr/abl ALL患者CR率明显低于bcr/abl-ALL患者 ;RT PCR一步法特异性好、敏感性高、简便快速 ,尤其适用于MRD的临床监测。     

Variable Philadelphia breakpoints and potential lineage restriction of bcr rearrangement in acute lymphoblastic leukemia

Philadelphia (Ph1) chromosome breakpoints in acute lymphoblastic leukemia (ALL) are of two kinds: those within the breakpoint cluster region (bcr+), as in chronic myeloid leukemia (CML), and those outside it (bcr-). These encode different c-abl messenger RNAs (mRNAs), p210 and p190, respectively. It has been suggested that one class of Ph+ ALL (bcr+) may be a variant of CML arising in a multipotent stem cell, the other (bcr-) de novo ALL initiated in a lymphoid-committed progenitor. Thirty-two cases of ALL (12 Ph1+, ten chromosomally normal, and ten non-mitotic cases) were investigated for bcr involvement. Breakpoints were found within five Ph1+ and in one normal case. There was no difference in clinical features, common ALL antigen (CALLA) positivity, cytogenetics, or response to treatment between the 6 bcr+ and 7 Ph1+ bcr- patients. Myeloid antigen expression was found in 2 bcr+ cases. Bcr rearrangement appeared to be restricted to the lymphoblastic component of marrow or blood in at least four bcr+ cases. In one case, separated myeloid and lymphoid cell fractions were both bcr+. Potential heterogeneity of the Ph1+ target cell, as seen in this study, may be more important in determining disease outcome than the precise location of the Ph breakpoint.     

Ｐh染色体阳性的急性白血病免疫表型及临床特征分析

目的探讨Ph染色体阳性的急性白血病(Ph     

格列卫治疗单倍体骨髓移植后复发的难治性急性淋巴细胞白血病缓解 1例报告

目的：探讨格列卫治疗Ph^1阳性儿童急性淋巴细胞性白血病单倍体骨髓移植后复发的疗效。方法：用格列卫，300mg，1次／d，顿服治疗1例单倍体骨髓移植后复发难治性急性淋巴细胞白血病。治疗前后观察血常规、骨髓象、BCR／ABL融合基因。结果：治疗4周后达完全缓解，BCR／ABL基因转阴。结论：格列卫治疗Ph^1阳性儿童急性淋巴细胞性白血病单倍体骨髓移植后复发有效。     

Basophilic differentiation of leukemic cells in a patient with acute leukemia carrying minor bcr/abl chimeric mRNA

A 77-year-old woman was referred to our hospital because of leukocytosis and leukoblastosis in September 1999. She was healthy except for hypertension, and no abnormal findings in the peripheral blood had been observed up to December 1998. Physical examination revealed neither hepatosplenomegaly nor superficial lymphadenopathy. A bone marrow film showed massive proliferation of blast cells (87.8%), some of which contained coarse basophilic granules (38.6%). The cells were negative for peroxidase and esterase (alpha-naphtyl butyrate and ASD-chloroacetate) staining, but the granules showed metachromasia upon toluidine blue staining. As immunophenotypic analysis of the cells showed double positive for CD13/CD19 but negativity for CD33, this case did not meet the diagnostic criteria for biphenotypic acute leukemia. Chromosome and gene analysis showed positivity for the Ph1 chromosome with minor bcr/abl chimeric mRNA. A homogenate of the peripheral mononuclear cells demonstrated a high concentration of histamine. Electron microscopy analysis confirmed that some of the blast cells contained dense granules, which closely resembled "immature basophil granules" morphologically. These results suggested that the blast cells showed basophilic differentiation. As the clinical course and peripheral blood findings were different from blastic crisis of chronic myelogenous leukemia (CML) and CML with minor bcr/abl chimeric mRNA, the present case was diagnosed as "multiphenotypic acute leukemia", a type of acute basophilic leukemia classified by Duchayne.     

Prognostic efficacy for measurement of real-time quantitative PCR-based major bcr/abl mRNA in patients with Philadelphia chromosome-positive leukemia

Evaluation of minimal residual disease (MRD) provides prognostic information on various hematological malignancies. We describe here the prognostic efficacy of real-time quantitative polymerase chain reaction (RQ-PCR)-based analysis of major bcr/abl mRNA in cases of Philadelphia chromosome-positive leukemia (Ph-leukemia). Twenty-one patients with Ph-leukemia were enrolled as subjects to determine the usefulness of RQ-PCR-based measurement of bcr-abl/abl ratios. Imatinib mesylate (imatinib) was administered to seven of the 21 patients before allogeneic stem cell transplantation (SCT). Hematological relapse or failure of treatment with SCT was observed in 2 of those patients who showed bcr-abl/abl ratios of more than 0.002%, and 5 of the 7 patients showed both RQ-PCR and RT-PCR negativity immediately after SCT. All of the 5 patients who did not receive imatinib before allogeneic SCT showed RQ-PCR negativity immediately after SCT, but the results of RT-PCR were positive in 3 patients at the same time points, and those became negative after donor lymphocyte infusion or the appearance of graft-versus-host disease. Administration of imatinib before SCT was thought to induce an early remission. On the other hand, 8 patients who received imatinib without SCT showed a remarkable decrease in bcr-abl/abl ratios. The ratio gradually rose in one patient with Ph+ALL, enabling prediction of the hematological relapse preceding detection by fluorescence in situ hybridization (FISH) analysis. Standardization of RQ-PCR analysis of bcr-abl mRNA will help to predict early hematological relapse in patients with MRD. In conclusion, it is thought that measurement of RQ-PCR-based major bcr/abl mRNA in patients who were given imatinib and were treated with SCT is useful for the evaluation of MRD and in deciding additional treatment.     

Philadelphia chromosome‐positive mixed phenotype acute leukemia in the imatinib era

Although the introduction of imatinib dramatically improved the outcomes for patients with Philadelphia chromosome‐positive B‐cell precursor acute lymphoblastic leukemia (Ph+BCP‐ALL), the survival benefit of imatinib has not been assessed in the context of Ph+ mixed phenotype acute leukemia (Ph+MPAL). To clarify this important issue, we studied 42 Ph+ acute leukemia (Ph+AL) patients who received intensive chemotherapy and concurrent administration of imatinib. Of the 42 Ph+AL patients, 13 (31%) patients were categorized as Ph+MPAL (positive for both myeloid and B‐cell lineage), 27 (64%) were categorized as Ph+BCP‐ALL, and two (5%) were categorized as Ph+ acute myeloid leukemia. The complete remission rates after the initial induction therapy were not significantly different when comparing Ph+MPAL and Ph+BCP‐ALL patients (100% vs. 85%, respectively, P = 0.14). Likewise, there were no significant differences in the 5‐yr overall survival (OS) or disease‐free survival (DFS) rates when comparing the MPAL and BCP‐ALL groups (OS: 55% vs. 53%, respectively, P = 0.87, DFS: 46% vs. 42%, respectively, P = 0.94). These findings suggest that concurrent imatinib administration with chemotherapy improved the outcomes of Ph+MPAL patients to the level seen in Ph+BCP‐ALL patients and should, therefore, be considered as the standard therapy for these patients.     

Lineage switch and multilineage involvement in two cases of pH chromosome-positive acute leukemia: evidence for a stem cell disease

Philadelphia chromosome-positive acute leukemias (Ph+ AL) show variable cytologic features, possibly reflecting heterogeneous stem cell involvement. Morphologic, immunologic and cytogenetic studies were performed in two cases of Ph+ acute lymphoblastic leukemia (ALL) in order to better delineate the clinicobiological features of this cytogenetic subset of AL. Sequential cytoimmunologic studies in patient 1 documented a lineage switch from pro-B ALL with a minor myeloid component at diagnosis to minimally differentiated acute myeloid leukemia (AML) at relapse. In this patient the major breakpoint cluster region (M-bcr) was in a rearranged configuration and all metaphase cells showed t(9;22)(q34;q11), both at diagnosis and at relapse. In patient 2 a diagnosis of Ph+ early T-cell ALL with minor myeloid component was made. In this patient the M-bcr was in a germline configuration. Cytogenetic studies documented the presence of the Ph chromosome in all metaphases from a lymphoid cell population obtained by fine-needle aspiration of an enlarged lymph node, and from a bone marrow cell fraction enriched in granulocyte precursors. This finding suggests multilineage involvement in this patient. Lineage switch and multilineage involvement in two patients suggest that a pluripotent stem cell may be affected rather frequently in patients with Ph+ AL. These findings show that biologically Ph+ AL may resemble chronic myelogenous leukemia blast crisis, since it may originate from an undifferentiated stem cell carrying the t(9;22) translocation.     

异基因造血干细胞移植治疗高危恶性血液病

目的 分析HLA配型相合同胞供者异基因造血干细胞移植（allo-HSCT）治疗高危恶性血液病的疗效及影响疗效的相关因素。方法 回顾性分析90例有高危因素的恶性血液病患者,其中急性髓细胞白血病（AML）43例,急性淋巴细胞性白血病（ALL）28例,急性混合细胞性白血病（AHL）2例;移植前处于第1次完全缓解期（CR1）11例,均为Ph染色体阳性,第二次及以上CR期23例,未缓解／复发39例;骨髓增生异常综合征（MDS）-难治性贫血伴原始细胞增多或难治性贫血伴原始细胞增多一转化型17例。预处理方案采用全身照射加环磷酰胺（CY／TBI）方案11例,白消安加环磷酰胺方案79例。干细胞来源包括骨髓移植（BMT）27例,外周血造血干细胞移植（PBSCT）30例,BMT＋PBSCT33例;移植物抗宿主病（GVHD）预防采用经典环孢素A加短程甲氨蝶呤（MTX）。平均随访时间为15个月。结果 至随访终点,62．2％（56／90）存活,55．5％（50／90）无病存活,31．1％（28／90）复发。HSCT后预计4年累积总体生存率（OS）为45．5％,无病生存率（DFS）为34．9％。移植前处于CR、未缓解／复发和MDS患者HSCT后4年的累积0s分别为54．0％、28．2％和70．1％（P=0．027）。发生0～Ⅰ和Ⅱ～Ⅳ度GVHD的患者HSCT后的4年OS分别为57．6％和26．7％（P=0．015）,而患者性别、年龄、移植前有无脑膜白血病、预处理方案、干细胞来源均不是OS,DFS及复发的影响因素。多因素分析表明,移植前处于CR期者长期生存率明显提高,而ALL长期生存率明显低于AML／MDS。结论 对有高危因素的血液系统恶性肿瘤患者,选择allo—HSCT可使部分患者延长无病生存乃至根治。移植前处于CR期者长期生存率明显提高,ALL复发率明显高于AML／MDS。对于急性白血病挽救性治疗争取在取得CR后移植;对于MDS患者一经诊断,无需化疗,可尽早移植。     

Ph1-positive, bcr-negative acute leukemias: clustering of breakpoints on chromosome 22 in the 3' end of the BCR gene first intron

About 50% of the Philadelphia-positive acute leukemias undergo molecular rearrangements outside the now classical bcr sequence (or M-BCR-1) rearranged in chronic myeloid leukemia (CML). Most of the breakpoints on chromosome 22 have been shown to be clustered in a 10.8-kb region of the first intron of the BCR gene (called bcr2 or m-BCR-1). In this report we examined two cases of Ph1 acute lymphoblastic leukemia in adult patients that exhibited breakpoints in a 5-kb segment of the BCR gene first intron, 16 kb upstream of the previously described cluster, suggesting the possibility of a second minor breakpoint cluster. In addition, the breakpoints on chromosome 9 were located in a region just 5' of the c-abl exon la.