Deep NPM1 Sequencing Following Allogeneic Hematopoietic Cell Transplantation Improves Risk Assessment in Adults with NPM1-Mutated AML

Relapse is the major cause of death in patients with acute myeloid leukemia (AML) after allogeneic hematopoietic cell transplantation (HCT). Measurable residual disease (MRD) detected by multiparameter flow cytometry (MFC) before and after HCT is a strong, independent risk factor for relapse. As next-generation sequencing (NGS) is increasingly applied in AML MRD detection, it remains to be determined if NGS can improve prediction of post-HCT relapse. Herein, we investigated pre-HCT MRD detected by MFC and NGS in 59 adult patients with NPM1-mutated AML in morphologic remission; 45 of the 59 had post-HCT MRD determined by MFC and NGS around day 28. Before HCT, MRD detected by MFC was the most significant risk factor for relapse (hazard ratio [HR],?4.63; P?<?.001), whereas MRD detected only by NGS was not. After HCT, MRD detected by either MFC or NGS was significant risk factor for relapse (HR, 4.96, P?=?.004 and HR, 4.36, P?=?.002, respectively). Combining pre- and post-HCT MRD provided the best prediction for relapse (HR, 5.25; P?<?.001), with a sensitivity at 83%. We conclude that NGS testing of mutated NPM1 post-HCT improves the risk assessment for relapse, whereas pre-HCT MFC testing identifies a subset of high-risk patients in whom additional therapy should be tested.     

The use of PCR technology for detecting minimal residual disease in patients with leukemia

The study of minimal residual disease (MRD) aims to understand the biology and clinical significance of leukemia that persists in patients who are in complete pathologic remission. The detection of MRD most consistently has been associated with subsequent relapse in childhood acute lymphoblastic leukemia (ALL), t(15;17) acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) following marrow transplantation. However, in several settings, MRD has been detected in patients enjoying long-term remission. The study of MRD is thus evolving from identifying patients at high risk of relapse to explaining how leukemia can persist for years in an otherwise "cured" patient.     

Lineage switch at relapse of childhood acute leukemia: a report of four cases

Lineage switch in acute leukemia is an uncommon event at relapse, and therefore rarely reported in the literature. Here, we have described the clinical laboratory features of four cases in which the cell lineage switched from acute lymphoblastic leukemia (ALL) to acute myeloid leukemia (AML). One patient was initially diagnosed with B-ALL, switched to T-ALL at the first relapse, and eventually, AML at the second relapse. A lineage switch represented either relapse of the original clone with heterogeneity at the morphologic level or emergence of a new leukemic clone. Further sequential phenotypic and cytogenetic studies may yield valuable insights into the mechanisms of leukemic recurrence, with possible implications for treatment selection.     

Minimalna choroba resztkowa w ostrych białaczkach u dzieci i dorosłych

Biological and genetic heterogeneity of acute leukemias is a major cause of therapeutic difficulties. Response to chemotherapy is one of the most important prognostic factors in this group of diseases. In acute lymphoblastic leukemia (ALL), and progressively more in acute myeloid leukemia (AML), the best parameter of that response is the presence of minimal residual disease (MRD). MRD monitoring is performed based on the flow cytometer analysis of leukemic immunophenotypes or detection of gene rearrangement by PCR. Both methods are characterized by high sensitivity and specificity, which clearly distinguishes them from the standard morphologic examination. This review presents the current state of knowledge of the importance and use of MRD in children and adults, in ALL and AML, emphasizing similarities and differences. Current opinions show that the MRD is the most important prognostic factor in ALL and an important factor in AML. Based on current data in children and adults, it seems that in acute lymphoblastic leukemia, presence of MRD is a continuous variable; the older the patient, the higher the risk of MRD and therapy failure. This paper presents also a new insight to the concept of MRD, because of the presence of leukemic stem cells that survive chemotherapy in AML and any of the maturational stages of leukemia-propagating cells in ALL. This idea combines the phenomenon of drug resistance of tumor stem cells and the presence of residual cells undetectable by methods of optical microscopy after applied chemotherapy. The concept of leukemic stem cells explains the occurrence of resistant clones both in ALL and AML. Based on studies of genetic profiles, there is growing evidence to suggest that acute leukemia is a highly heterogeneous disease, which goes hand in hand with the hierarchy of leukemic stem cells and leukemia initiating cells. In the light of the current knowledge based on MRD, it seems necessary to review the concept of complete remission in MRD-positive leukemic patients.     

急性髓系白血病患者化疗后微小残留病与多药耐药基因表达相关

目的明确急性髓系白血病(AML)中微小残留病(MRD)与多药耐药基因表达的相关性。方法收集初诊AML患者骨髓52例,用real-time PCR检测患者化疗前ABCB1、ABCC1、ABCC4及ABCG2 4种多药耐药基因的表达,同时用多参数流式细胞术(MFC)检测患者诱导化疗后和化疗3、6和9个月后的MRD表达水平。结果 52例AML患者MRD表达水平与ABCB1(P0.01)、ABCC1(P0.01)、ABCC4(P0.01)和ABCG2(P0.01)的mRNA表达水平具有明显相关性。持续监测9个月后,MRD再次转阳者ABC基因表达水平显著高于持续阴性者:ABCB1(P0.05)、ABCC1(P0.05)、ABCC4(P0.01)和ABCG2(P0.01)。结论 MRD表达水平与多药耐药基因表达水平显著正相关。     

Extramedullary Relapse of Acute Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation: Different Characteristics between Acute Myelogenous Leukemia and Acute Lymphoblastic Leukemia

Extramedullary relapse (EMR) of acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a contributor to post-transplantation mortality and remains poorly understood, especially the different characteristics of EMR in patients with acute myelogenous leukemia (AML) and those with acute lymphoblastic leukemia (ALL). To investigate the incidence, risk factors, and clinical outcomes of EMR for AML and ALL, we performed a retrospective analysis of 362 patients with AL who underwent allo-HSCT at the First affiliated Hospital of Soochow University between January 2001 and March 2012. Compared with patients with AML, those with ALL had a higher incidence of EMR (12.9% versus 4.6%; P = .009). The most common site of EMR was the central nervous system, especially in the ALL group. Multivariate analyses identified the leading risk factors for EMR in the patients with AML as advanced disease status at HSCT, hyperleukocytosis at diagnosis, history of extramedullary leukemia before HSCT, and a total body irradiation–based conditioning regimen, and the top risk factors for EMR in the patients with ALL as hyperleukocytosis at diagnosis, adverse cytogenetics, and transfusion of peripheral blood stem cells. The prognosis for EMR of AL is poor, and treatment options are very limited; however, the estimated 3-year overall survival (OS) was significantly lower in patients with AML compared with those with ALL (0 versus 18.5%; P = .000). The characteristics of post–allo-HSCT EMR differed between the patients with AML and those with ALL, possibly suggesting different pathogenetic mechanisms for EMR of AML and EMR of ALL after allo-HSCT; further investigation is needed.     

Loss or downregulation of HLA class I expression at the allelic level in acute leukemia is infrequent but functionally relevant, and can be restored by interferon

Human leukocyte antigen (HLA) class I expression at the allelic level was analyzed in 397 acute myeloid leukemia (AML) and 186 acute lymphoid leukemia (ALL) using a complement-dependent cytotoxicity assay. Impaired recognition possibly due to HLA downregulation was observed in 2% of the patients with AML and ALL in complete remission, and in 8%-15% in the groups with blasts. In 15 instances of diminished cytotoxicity, leukemic cells and control PHA blasts from the same patients were further analyzed using flow cytometry. In 4/6 ALL and 4/9 AML patients HLA downregulation or complete loss (2 patients) of cell surface expression could be confirmed. No genomic abnormalities were observed. In addition, 12 AML and 13 ALL patients were tested during relapse using flow cytometry. In 1/12 AML patients and 1/13 ALL patients allelic downregulation of cell surface expression was found. In two patients tested, downregulation or loss of cell surface expression of HLA class I antigens corresponded with impaired T cell mediated lysis by HLA restricted cytotoxic T lymphocyte.Treatment of the cells with alpha- or gamma-interferon could restore HLA class I expression and T-cell recognition. In conclusion, downregulation of cell surface expression of HLA class I expression at the allelic level in AML and ALL is infrequent but functionally relevant. HLA downregulation was reversible and T-cell recognition could be restored by alpha- or gamma-interferon.     

What can We Learn from Leukemia as for the Process of Lineage Commitment in Hematopoiesis?

Most contemporary models of hematopoiesis assume lineage fidelity of early progenitor cells. Along with this concept normal hematopoietic cells and the majority of leukemias express exclusively myeloid or lymphoid specific antigens. On the other hand, growing evidence exists challenging the lineage fidelity model. Chronic myeloid leukemia (CML) in the blast crisis may switch to acute lymphoblastic leukemia (ALL) and as a result of the chemotherapy ALL may converse to acute myeloid leukemia (AML). Furthermore, a substantial portion of leukemia cases, named acute mixed-lineage leukemia (AMLL), show simultaneous expression of both myeloid and lymphoid antigens. Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements, correlating with myeloidlymphoid immunophenotype in AMLL, support the hypothesis of lineage infidelity of early progenitor cells, rather than the aberrant antigen expression. Based on a detailed characterization of AMLL we present a modified model of a “common myeloid/lymphoid progenitor cell”. This hypothetical very early hematopoietic progenitor cell shows a transient expression of myeloid and B-or T-lymphoid antigen and may also have rearranged its Ig and/or TCR genes. Subsequently, myeloid or lymphoid markers are downregulated and the hematopoietic cell enters either myeloid, T-lymphoid or B-lymphoid differentiation pathway.     

MLL-CBP fusion transcript in a therapy-related acute myeloid leukemia with the t(11;16)(q23;p13) which developed in an acute lymphoblastic leukemia patient with Fanconi anemia

We describe a boy with Fanconi anemia (FA) who developed acute lymphoblastic leukemia (ALL) (FAB-LI) followed by acute myeloid leukemia (AML) (FAB-M5) at relapse. The patient was diagnosed with early pre-B-cell ALL without preceding aplastic anemia and was treated with ALL-oriented chemotherapy which included doxorubicin (a total dose of 140 mg/m(2) administered), which is a topoisomerase II inhibitor. Complete remission was obtained, but after 38 weeks AML developed. The karyotype of ALL cells at diagnosis showed 46,XY, and that of AML cells at relapse was 46,XY, t(11;16)(q23;p13). An MLL gene rearrangement and MLL-CBP chimeric mRNA were found in AML, but not in ALL. A diagnosis of FA was confirmed by an increased number of chromosomal breaks and rearrangements in peripheral blood lymphocytes cultured with mitogen in the presence of mitomycin C. We conclude that this FA patient developed ALL followed by a therapy-related t(11;16)-AML resulting in an MLL-CBP fusion. Further examination of such patients would shed light on leukemogenesis in FA patients. Genes Chromosomes Cancer 27:264-269, 2000.     

What can we learn from leukemia as for the process of lineage commitment in hematopoiesis?

Most contemporary models of hematopoiesis assume lineage fidelity of early progenitor cells. Along with this concept normal hematopoietic cells and the majority of leukemias express exclusively myeloid or lymphoid specific antigens. On the other hand, growing evidence exists challenging the lineage fidelity model. Chronic myeloid leukemia (CML) in the blast crisis may switch to acute lymphoblastic leukemia (ALL) and as a result of the chemotherapy ALL may converse to acute myeloid leukemia (AML). Furthermore, a substantial portion of leukemia cases, named acute mixed-lineage leukemia (AMLL), show simultaneous expression of both myeloid and lymphoid antigens. Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements, correlating with myeloid-lymphoid immunophenotype in AMLL, support the hypothesis of lineage infidelity of early progenitor cells, rather than the aberrant antigen expression. Based on a detailed characterization of AMLL we present a modified model of a "common myeloid/lymphoid progenitor cell". This hypothetical very early hematopoietic progenitor cell shows a transient expression of myeloid and B- or T-lymphoid antigen and may also have rearranged its Ig and/or TCR genes. Subsequently, myeloid or lymphoid markers are downregulated and the hematopoietic cell enters either myeloid, T-lymphoid or B-lymphoid differentiation pathway.     

Premature chromosome condensation as a predictive indicator of relapse in children and adolescents with acute leukemia: initial observations

Premature chromosome condensation has been used to determine a proliferative potential index (PPI) in a study of children in leukemia remission at varying times during the disease. Values 35% and greater were considered predictive of relapse. Such values preceded relapse with a mean of 5 months in acute lymphoblastic leukemia (ALL) patients who had previously relapsed and in myeloid leukemia patients. ALL patients followed from diagnosis and children off therapy had fluctuating and false predictive PPI values preceding long courses of continued remission. This study suggests that the PPI as a predictive indicator for relapse may be useful for patients with ALL who have previously relapsed and for patients with myeloid leukemias. Future exploration to further evaluate this mechanism of prediction is to be attempted by investigating the ability to obtain similar and more detailed information through the use of peripheral blood rather than bone marrow samples.     

CD117在急性白血病中的表达及临床意义

目的探讨CD117在急性白血病中的表达及其临床意义。方法应用CD45/SSC设门,直接荧光标记法,经流式细胞术对73例急性髓系白血病（AML）和47例急性淋巴细胞白血病（ALL）进行CD117的检测。结果对照组、ALL及AML3组CD117的表达阳性率差异有统计学意义（χ2=41.681,P﹤0.01）。AML组CD117的表达阳性率（58.9%）明显高于对照组（0）及ALL组（8.5%）。CD117/CD34的共表达率ALL组明显低于AML组（4.3%vs45.2%,P﹤0.05）。AML组CD117＋患者的CR率为60.5%,CD117-患者为76.7%,两者比较差异无统计学意义（P〉0.05）;而CD117＋/CD34＋患者的CR率为54.5%,明显低于CD117-/CD34-患者的CR率（88.2%,P﹤0.05）。结论 CD117可作为辅助诊断AML的髓系标志抗原,CD34＋/CD117＋可作为进一步排除ALL的指标。CD117＋/CD34＋可能是AML中一类预后不良的特殊亚型,可以作为AML预后判断的指标之一。     

Immunophenotyping of acute leukemias using paraffin-embedded tissue sections

In a study of 55 patients with either acute lymphoid leukemia (ALL; 25 cases) or acute myeloid leukemia (AML; 30 cases), paraffin-embedded bone marrow particle sections were examined with a panel of monoclonal and polyclonal antibodies reactive toward lymphoid and myeloid-associated antigens, using the alkaline phosphatase-anti-alkaline phosphatase (APAAP) technique. All cases were previously classified according to the French-American-British (FAB) Co-operative Group, and cases of ALL were immunophenotyped by flow cytometry. Results indicated that myeloid-associated antibodies (Mac 387, KP 1 [CD68], antielastase, antilactoferrin, and antilysozyme) did not react with any case of ALL, M1-AML, or M6-AML, whereas at least one of these antibodies reacted with 20 of 21 (95%) cases of M2, M3, M4, and M5-AML. Anti-glycophorin C marked cases of M6-AML, whereas anti-CD3 labeled T-cell ALL. None of the antibodies tested specifically identified cases of B-cell ALL. The authors conclude that use of a selected panel of antibodies on paraffin-embedded bone marrow particle sections may be of value in the diagnosis and immunophenotypic classification of many cases of acute leukemias.     

The proportion of abnormal karyotypes in acute leukemia samples related to method of preparation

Bone marrow and peripheral blood were studied from 200 patients with acute leukemia [109 with acute myeloid leukemia (AML), 91 with acute lymphoblastic leukemia (ALL)] who had samples cultured for varying times and who had a mixture of chromosomally abnormal and normal cells. The mean percentage of abnormal metaphase cells increased with culture time. The peak was reached at 48 hours and declined slightly after 72 hours in culture for ALL patients. The mean percentage of abnormal cells increased up to 72 hours in culture for AML patients. In 68 patients (31 AML and 37 ALL), cytogenetic data were available from samples processed with both direct preparations and culture methods. The percentage of abnormal cells increased after culture in 49 patients (23 AML and 26 ALL), while it decreased or remained at the same level in 19 patients. For AML patients, the mean percentage of abnormal cells was significantly different between direct (38%) and cultured preparations (63%), (p less than 0.001). Seven of 9 patients with AML who showed a greater than 50% increase in abnormal cells after culture had either a t(8;21), t(15;17), or abnormalities involving 11q23. The two patients who showed a significant decrease in abnormal cells both had a translocation involving 11q13. Compared with ALL, more AML patients showed greater than 80% abnormal bone marrow metaphase cells at diagnosis or at relapse.     

CD64在急性白血病免疫分型中的意义

目的探讨CD64在急性白血病免疫分型中的意义。方法应用直接荧光标记法,经流式细胞术对116例急性髓系白血病(AML)和70例急性淋巴细胞白血病(ALL)进行免疫表型的检测。结果 AML组CD64的表达阳性率明显高于ALL组(41.4%vs 2.9%,P<0.01)。CD64在M5和M4的表达阳性率最高,分别为77.1%和55.6%。CD64的阳性表达率在M0(0)、M1(0)、M2(7.9%)明显低于M3(47.1%)、M4与M5(P<0.01)。各亚型CD64阳性病例中,M4、M5的CD64阳性细胞表达率分别为(62.5±24.7)%、(68.7±25.9)%,均明显高于M2(28.3%±5.7%)、M3(34.3%±6.3%)(P<0.01)。CD64对诊断AML的灵敏度优于CD14,其特异度优于CD117、CD33及CD13。虽然CD64诊断M4\M5的特异度较CD14稍差(82.5%vs 100%),但是灵敏度高于CD14(69.8%vs 41.5%)。结论 CD64可作为辅助诊断AML的髓系标志抗原,有助于提高M4/M5的检出率及其与其他AML亚型的鉴别诊断。     

Unrelated Cord Blood Transplantation for Acute Leukemia Diagnosed in the First Year of Life: Outcomes and Risk Factor Analysis

Infant acute leukemia still has a poor prognosis, and allogeneic hematopoietic stem cell transplantation is indicated in selected patients. Umbilical cord blood (UCB) is an attractive cell source for this population because of the low risk of chronic graft-versus-host disease (GVHD), the strong graft-versus-leukemia effect, and prompt donor availability. This retrospective, registry-based study reported UCB transplantation (UCBT) outcomes in 252 children with acute lymphoblastic leukemia (ALL; n?=?157) or acute myelogenous leukemia (AML; n?=?95) diagnosed before 1 year of age who received a single-unit UCBT after myeloablative conditioning between 1996 and 2012 in European Society for Blood and Marrow Transplantation centers. Median age at UCBT was 1.1 years, and median follow-up was 42 months. Most patients (57%) received a graft with 1 HLA disparity and were transplanted in first complete remission (CR; 55%). Cumulative incidence function (CIF) of day 100 acute GVHD (grades II to IV) was 40%?±?3% and of 4-year chronic GVHD was 13%?±?2%. CIF of 1-year transplant-related mortality was 23%?±?3% and of 4-year relapse was 27%?±?3%. Leukemia-free-survival (LFS) at 4 years was 50%?±?3%; it was 40% and 66% for those transplanted for ALL and AML, respectively (P?=?.001). LFS was better for patients transplanted in first CR, regardless of diagnosis. In multivariate model, diagnosis of ALL (P?=?.001), advanced disease status at UCBT (<.001), age at diagnosis younger than 3 months (P?=?.012), and date of transplant before 2004 were independently associated with worse LFS. UCBT is a suitable option for patients diagnosed with infant acute leukemia who achieve CR. In this cohort, patients with AML had better survival than those with ALL.     

Measurable residual disease testing for personalized treatment of acute myeloid leukemia

This review summarizes – with the practicing hematologist in mind – the methods used to determine measurable residual disease (MRD) in everyday practice with some future perspectives, and the current knowledge about the prognostic impact of MRD on outcome in acute myeloid leukemia (AML), excluding acute promyelocytic leukemia. Possible implications for choice of MRD method, timing of MRD monitoring, and guidance of therapy are discussed in general and in some detail for certain types of leukemia with specific molecular markers to monitor, including core binding factor (CBF)‐leukemias and NPM1‐mutated leukemias.     

Flow cytometric detection of CD79a expression in T-cell acute lymphoblastic leukemias

We evaluated the lineage specificity of CD79a in acute leukemias using 3-color flow cytometry in 58 consecutive cases. A panel of cell-surface antigens, including myeloid-associated markers, B-cell-associated markers, and T-cell-associated markers, was used. All cases of acute myeloid leukemia were CD79a-, whereas all cases of B-lineage acute lymphoblastic leukemia (ALL) were CD79a+. Three of 8 cases of T-cell ALL showed variable CD79a expression, indicating the presence of a blast subset expressing a relatively high level of CD79a. We investigated the clinical and pathologic characteristics of these 3 cases. All 3 cases had L1 or L2 morphology and expressed surface CD3. None of the other B-cell-associated markers were positive, although 1 case expressed CD13 and CD33. Uncommon random karyotypic abnormalities were identified in all 3 cases. Molecular studies demonstrated monoclonal gene rearrangement of T-cell receptor gamma in 2 of 3 cases. All 3 patients were 18 years old or younger; 1 patient did not enter remission, and 1 had disease relapse in 8 months. Our findings provide further support for the existence of a subset of T-cell ALL coexpressing CD3 and CD79a. Further study of the clinical and biologic significance of this subset may be warranted.     

Impact of cellular CD71 (transferrin receptor 1) expression in Egyptian acute leukemia: correlation with clinicopathologic features

Cellular transferrin receptor 1 (CD71) has been identified as a proliferation marker. Inferior outcome with higher expression was observed in many solid tumors. This study objected to assess the expression of CD71 in patients with acute leukemia and to address its prognostic significance and relations to clinicopathologic features. The study included 34 acute myeloid leukemia (AML) and 64 acute lymphoblastic leukemia (ALL) newly diagnosed cases from Mansoura Oncology Center. CD71 was analyzed on blast cells by flow cytometry. CD71 expression was significantly elevated in both AML and ALL. Antigen expression apparently increased in T-ALL, while in AML there was a trend toward a gradual increase of antigen expression in relation to maturation evidence of myeloid subtypes. CD71 expression correlated positively with total leukocyte count in ALL cases and negatively with platelet count in AML cases. In ALL, higher CD71 expression was associated with higher relapse rate and was an independent prognostic factor of overall survival (HR 1.8; 95 % CI 1.2–4.1). In conclusion, CD71 is overexpressed in acute leukemia; it predicts adverse clinical outcome in ALL. In addition, CD71 antagonism could be a possible therapeutic target in acute leukemia.