A Case of T‐cell Acute Lymphoblastic Leukemia Relapsed As Myeloid Acute Leukemia

A 4‐year‐old male with the diagnosis of T‐cell acute lymphoblastic leukemia (T‐ALL) relapsed after 19 months with an acute myeloid leukemia (AML). Immunoglobulin and T‐cell receptor gene rearrangements analyses reveal that both leukemias were rearranged with a clonal relationship between them. Comparative genomic hybridization (Array‐CGH) and whole‐exome sequencing analyses of both samples suggest that this leukemia may have originated from a common T/myeloid progenitor. The presence of homozygous deletion of p16/INK4A, p14/ARF, p15/INK4B, and heterozygous deletion of WT1 locus remained stable in the leukemia throughout phenotypic switch, revealing that this AML can be genetically associated to T‐ALL.     

Lineage Switch in MLL‐Rearranged Infant Leukemia Following CD19‐Directed Therapy

Rearrangements of the mixed lineage leukemia (MLL) gene occur frequently in infants with both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Conversions of leukemia cell lineage are rare, but occur most commonly in the setting of MLL‐rearrangement. Blinatumomab is a bidirectional antibody targeting CD19 with significant activity in relapsed B‐precursor ALL. We report an infant with ALL with t(4;11)(q21;q23) refractory to cytotoxic chemotherapy who was treated with blinatumomab. Following rapid initial clearance of peripheral lymphoblasts, bone marrow evaluation demonstrated a leukemic lineage switch to CD19‐negative monoblastic AML. Complete remission was achieved with myeloid‐directed chemotherapy.     

Lineage switch under blinatumomab treatment of relapsed common acute lymphoblastic leukemia without MLL rearrangement

Blinatumomab is a bispecific T‐cell engaging αCD19 antibody used in refractory or relapsed B‐cell precursor acute lymphoblastic leukemia (ALL). Recently, lineage switch to a myeloid phenotype has been described following CD19 targeting treatment in three pediatric patients with mixed lineage leukemia (MLL) rearranged ALL. We report the case of a female who received blinatumomab for a first relapse of ALL without MLL alterations. She suffered from a second relapse early after hematopoietic stem cell transplantation and was treated with blinatumomab again. During this treatment, the leukemia lost CD19 expression as well as nearly all other B‐cell markers, while still harboring the initial minimal residual disease marker, and switched to a myeloid phenotype.     

Psychosocial care for children receiving chimeric antigen receptor (CAR) T‐cell therapy

Chimeric antigen receptor (CAR) T‐cell therapy has transformed the treatment of relapsed/refractory B‐cell acute lymphoblastic leukemia (ALL). However, this new paradigm has introduced unique considerations specific to the patients receiving CAR T‐cell therapy, including prognostic uncertainty, symptom management, and psychosocial support. With increasing availability, there is a growing need for evidence‐based recommendations that address the specific psychosocial needs of the children who receive CAR T‐cell therapy and their families. To guide and standardize the psychosocial care offered for patients receiving CAR T‐cell therapy, we propose the following recommendations for addressing psychosocial support.      

Chimeric antigen receptor T‐cell therapy in patients with neurologic comorbidities

Chimeric antigen receptor T cells (CAR‐T) are an effective and potentially durable treatment for refractory and multiply relapsed B‐cell acute lymphoblastic leukemia. Neurotoxicity is frequent after CAR‐T cell therapy. Mechanisms driving neurotoxicity are incompletely understood, and symptoms can range from transient and mild to severe and life‐threatening. Providers have exercised caution in providing CAR‐T to patients with neurological comorbidities or extramedullary disease. Here, we report three patients with prior significant neurologic morbidity who safely tolerated CAR‐T cell infusion after bridging therapy with conventional chemotherapy.     

Acute nonlymphoblastic leukemia in children treated for acute lymphoblastic leukemia with an intensive regimen including teniposide

Some cases of conversion from acute lymphoblastic leukemia (ALL) to acute nonlymphoblastic leukemia (ANLL) at relapse have been reported recently. We report three cases initially diagnosed as having ALL and showing morphological, cytochemical, and immunophenotypic features of ANLL at relapse (lineage switch). Conversion was observed among 14 patients who developed bone marrow relapse while undergoing intensive treatment with our ALL protocol, which includes teniposide, and that had been administered to 62 patients. The three cases converted at first relapse, with a mean time of 20 months (13–29 months). Clinical and immunologic characteristics of T-cell leukemia were present in one patient. Changes documented in cytogenetic studies are discussed. The underlying mechanisms for the lineage switch remain unclear as does its relation with mixed lineage leukemias, but we believe that drugs employed in our therapy protocol could have had an influence on this conversion.     

Acute nonlymphoblastic leukemia in children treated for acute lymphoblastic leukemia with an intensive regimen including teniposide.

Some cases of conversion from acute lymphoblastic leukemia (ALL) to acute nonlymphoblastic leukemia (ANLL) at relapse have been reported recently. We report three cases initially diagnosed as having ALL and showing morphological, cytochemical, and immunophenotypic features of ANLL at relapse (lineage switch). Conversion was observed among 14 patients who developed bone marrow relapse while undergoing intensive treatment with our ALL protocol, which includes teniposide, and that had been administered to 62 patients. The three cases converted at first relapse, with a mean time of 20 months (13-29 months). Clinical and immunologic characteristics of T-cell leukemia were present in one patient. Changes documented in cytogenetic studies are discussed. The underlying mechanisms for the lineage switch remain unclear as does its relation with mixed lineage leukemias, but we believe that drugs employed in our therapy protocol could have had an influence on this conversion.     

Lineage switch and translocation t(9;11) in acute leukemia

A boy with acute lymphoblastic leukemia (ALL) who underwent lineage switch at relapse is reported. The second leukemia was myeloid in nature (acute myeloid leukemia, AML), characterized by predominantly My 9 positive blasts at first and at second relapse. Cytogenetic studies at second relapse revealed the translocation (9;11) (p21;q23) in all examined blasts. This is typical for myelomonocytic leukemia. The nature of the relapse and the occurrence of t(9;11) translocations in acute leukemia are discussed.     

Evidence for BCR/ABL1‐positive T‐cell acute lymphoblastic leukemia arising in an early lymphoid progenitor cell

BCR‐ABL1‐positive leukemias have historically been classified as either chronic myelogenous leukemia or Ph+ acute lymphoblastic leukemia. Recent analyses suggest there may be a wider range of subtypes. We report a patient with BCR‐ABL1 fusion positive T‐cell ALL with a previously undescribed cell distribution of the fusion gene. The examination of sorted cells by fluorescence in situ hybridization showed the BCR‐ABL1 fusion in the malignant T cells and a subpopulation of the nonmalignant B cells, but not nonmalignant T cells or myeloid or CD34+ progenitor cells providing evidence that the fusion may have occurred in an early lymphoid progenitor.     

多色流式细胞术在222例儿童急性白血病免疫分型中的应用

目的　探讨多色流式细胞术在儿童急性白血病 (AL)免疫分型中的应用价值 ,了解儿童AL抗原表达规律和免疫亚型的分布情况。方法　采用CD45/侧散射 (SSC)双参数散点图设门方法进行三色或四色流式细胞术细胞表面及浆内分化抗原的分析。结果　 2 2 2例儿童白血病免疫分型可分为 4类 :未分化型占 0 9% ,急性髓细胞性白血病 (AML)占 35 1% ,急性淋巴细胞白血病 (ALL)占5 5 9% ,混合型急性白血病占 8 1%。 12 4例儿童ALL中 ,B淋巴细胞白血病 (B ALL)占 75 8% ,T淋巴细胞白血病 (T ALL)占 2 4 2 %。AML伴淋巴系抗原表达为 2 4 4 % ,主要表达CD7(12 8% ) ,其次为CD19(6 4 % )和CD2 (5 1% )。B ALL及T ALL伴髓系抗原表达分别为 36 2 %及 30 0 % ,主要表达CD13(18 5 % ) ,其次为CD15(11 3% )、CD11b(6 5 % )和CD3 3 (4 3% )。CD117和CD56主要在AML中表达 ,分别为 73 3%和 38 6 % ,而在ALL中表达率极低 ,仅为 2 0 % (P <0 0 1)。胞浆内抗原CD2 2 、CD3 及髓过氧化物酶 (MPO)分别特异地表达在B ALL、T ALL及AML ,并比胞膜抗原检测更为敏感。结论　应用多色流式细胞术几乎能对所有儿童急性白血病进行准确分型 ,对儿童白血病患者的治疗方案选择及预后判断等均有重要价值。     

Rapid Capture Next‐Generation Sequencing in Clinical Diagnostics of Kinase Pathway Aberrations in B‐Cell Precursor ALL

Comprehensive next‐generation sequencing (NGS) applications have recently identified various recurrent kinase and cytokine receptor rearrangements in Ph‐like B‐cell precursor (BCP) acute lymphoblastic leukemia (ALL) amenable to tyrosin kinase inhibitor treatment. For rapid diagnostics of kinase pathway aberrations in minimal residual disease (MRD) high‐risk BCP‐ALL, we developed a PCR‐independent NGS custom enrichment capture panel targeting recurrent genomic alterations, which allows for the identification of unknown 5′ fusion partner genes and precise mapping of variable genomic breakpoints. Using a standardized bioinformatics algorithm, we identified kinase and cytokine receptor rearrangements in the majority of ALL patients with high burden of postinduction MRD and enrichment of IKZF1 mutation or deletion (IKZF1^del).     

T-cell acute lymphoblastic leukemia relapsing as acute myelogenous leukemia

We present the unusual case of a 16-year-old girl with T-cell acute lymphoblastic leukemia (ALL) with an early thymocyte immunophenotype without myeloid markers, who after 13 months of complete hematological remission relapsed as acute myelogenous leukemia (AML) with minimal differentiation and died of her disease. Whether the AML represented a relapse with lineage switch of the original immature T-cell clone or a new secondary malignancy, could not be proven due to the absence of molecular or clonal markers. This report suggests that a subset of CD7+ T-cell leukemias without mature T-cell antigens (CD4-, CD8-) are minimally differentiated and can relapse as AML.     

Successful acute lymphoblastic leukemia‐type therapy in two children with mixed‐phenotype acute leukemia

Mixed‐phenotype acute leukemia (MPAL) is a rare type of leukemia expressing both myeloid and lymphoid markers. There is limited information, especially on pediatric cases. Therefore, the optimal therapeutic approach to pediatric MPAL has not been defined. Here, we report two pediatric cases of MPAL. According to the 2008 World Health Organization (WHO) classification and European Group for the Immunological Characterization of Leukemias (EGIL) criteria, patient 1 was diagnosed with overt MPAL positive for the myeloid marker myeloperoxidase (MPO), and B‐lymphoid markers. Patient 2 was diagnosed with T‐cell acute lymphoblastic leukemia (T‐ALL) using EGIL criteria. According to the 2008 WHO classification, however, patient 2 was diagnosed with overt MPAL positive for CD3, T‐lymphoid markers and MPO. We chose an ALL‐type therapy consisting of both lymphoid‐ and myeloid‐directed agents; these patients have maintained complete remission following treatment. Further information on pediatric MPAL is needed to establish an appropriate therapeutic strategy including stem cell transplantation for this rare condition.     

急性混合谱系融合基因阳性急性白血病患儿的临床特点

目的分析混合谱系白血病(MLL)融合基因阳性的急性白血病(AL)患儿临床特点,探讨其治疗措施及其预后相关因素。方法选取细胞形态学、分子生物学、免疫分型及巢式反转录聚合酶链反应(RT-PCR)检测MLL融合基因阳性AL患儿51例,对其临床表现、治疗及预后进行回顾性分析。结果51例MLL融合基因阳性AL患儿中急性淋巴细胞白血病(ALL)37例,急性髓细胞白血病(AML)14例。42例涉及11号染色体改变;RT-PCR检测有36例MLL基因重排,15例为串联重复。32例接受正规治疗的AL患儿中24例完全缓解,其中ALL19例,AML5例;缓解时间持续2 a以上者ALL5例,AML仅1例;持续缓解存活者仅16例,ALL12例,AML4例;10例MLL融合基因已转阴,并持续存活。在随访6 a中,32例中复发6例,均为骨髓复发,死亡6例。结论MLL融合基因阳性AL患儿发生率低,化疗效果差,易复发,预后差。少数对化疗敏感的AL患儿MLL融合基因可转阴,并持续存活。     

Next‐generation sequencing of PTEN mutations for monitoring minimal residual disease in T‐cell acute lymphoblastic leukemia

Minimal residual disease (MRD) analysis has become a powerful indicator to refine therapy in acute lymphoblastic leukemia (ALL). Here, we present an MRD detection based on the next‐generation sequencing of PTEN exon 7 mutations (NGS‐PTEN) in 30 pediatric T‐cell ALL patients. By comparing the NGS‐PTEN results with current quantitative PCR of antigen receptor gene rearrangements (qPCR‐Ig/TR), an overall concordance of 80% was found between the two methods. However, the NGS‐PTEN qualified a lower number of high‐risk patients than qPCR‐Ig/TR. These findings suggest that NGS‐PTEN is a promising tool that could potentially be used to support current MRD methodologies for T‐ALL patients.     

Development of acute lymphoblastic leukemia following treatment for acute myeloid leukemia in children with Down syndrome: A case report and retrospective review of Children's Oncology Group acute myeloid leukemia trials

Children with Down syndrome have a 150‐fold increased risk of developing acute myeloid leukemia (AML) and 20‐fold increased risk of developing acute lymphoblastic leukemia (ALL). Although the risk of developing AML and ALL is significantly increased in children with Down syndrome, the development of both malignancies in the same patient is very rare. We describe a patient with Down syndrome who developed ALL 6 years after being diagnosed with AML. We performed a literature review and Children's Oncology Group query and discovered eight published cases and five cases of ALL following AML in pediatric patients with Down syndrome, as well as six cases of ALL following AML in non‐Down syndrome patients. There was a similar cumulative incidence of ALL after treatment for AML in the Down syndrome and non‐Down syndrome populations. Overall survival in patients with Down syndrome who developed ALL after treatment for AML was comparable to overall survival for patients with Down syndrome with de novo ALL with an average follow‐up of 7 years after ALL diagnosis. Clinical data collected were used to discuss whether this phenomenon represents a secondary leukemia, second primary cancer, or mixed‐lineage leukemia.     

Molecular findings in childhood leukemia in Brazil: high frequency of MLL-ENL Fusion/t(11;19) in infant leukemia

Translocations involving chromosome 11q23 are frequently found in pediatric leukemia, especially in infants. The mixed lineage leukemia (MLL)-AF4 fusion/t(4;11) is mostly found in acute lymphoblastic leukemia (ALL) and MLL-AF9 fusion/t(9;11) in acute myeloid leukemia (AML). We study 441 consecutive new cases of childhood leukemia diagnosed in Brazil. Chromosomal translocation was determined solely by conventional polymerase chain reaction (PCR) in 72 out of 265 ALL and in 43 out of 103 AML. MLL-AF4 fusion/t(4;11) was detected in 3 out of 265 ALL and MLL-AF9 fusion/t(9;11) in 4 out of 103 of AML. MLL-rearrangements were presented in 7 out of 23 infant leukemia, whose 5 were MLL-ENL fusion/t(11;19). No fusion MLL-AF4 fusion/t(4;11) was found. Other translocation frequencies differed from that reported for an American population suggesting interethnic differences on chromosomal translocations frequencies in acute leukemia.     

Blinatumomab as a bridge to further therapy in cases of overwhelming toxicity in pediatric B‐cell precursor acute lymphoblastic leukemia: Report from the Israeli Study Group of Childhood Leukemia

Tremendous progress in the therapy of pediatric acute lymphoblastic leukemia (ALL) has been achieved through combination cytotoxic chemotherapy, leading to high cure rates, at the cost of significant life‐threatening toxicity. The bispecific T‐cell engager blinatumomab, recently approved for relapsed/refractory ALL, has a unique nonmyelotoxic toxicity profile. As blinatumomab causes B‐cell depletion, the safety of its use during severe chemotherapy‐induced toxicity is unclear. We report 11 pediatric patients with ALL, treated with blinatumomab following overwhelming chemotherapy‐associated toxicity, with recovery of all patients and successful bridging to further antileukemia therapy. Blinatumomab can be considered for rare patients who cannot tolerate cytotoxic therapy.     

三色流式细胞术在120例儿童急性白血病免疫分型中的应用

目的探讨三色流式细胞术在儿童急性白血病AL免疫分型中的应用价值,了解儿童AL抗原表达规律和免疫亚型的分布情况。方法采用CD45/侧散射(SSC)双参数散点图设门方法进行三色流式细胞术细胞表面及浆内分化抗原的分析。结果120例儿童白血病免疫分型可分为4类:未分化型占0·8%,急性髓细胞性白血病(AML)占35·0%,急性淋巴细胞白血病(ALL)占57·5%,混合型急性白血病占6·7%。69例儿童ALL中,B淋巴细胞白血病(B-ALL)占75·3%,T淋巴细胞白血病(T-ALL)占24·7%。AML伴淋巴系抗原表达为28·8%,主要表达CD5、CD7及CDl9(均为9·6%)。B-ALL伴髓系抗原CDl3、CD33表达分别为40·4%和5·8%,T-ALL伴髓系抗原CD13、CD33表达分别为35·3%和5·9%。结论应用流式细胞术几乎能对所有儿童急性白血病进行准确分型,对儿童白血病患者的治疗方案选择及预后判断等均有重要价值。     

Early T‐Cell Precursor Acute Lymphoblastic Leukemia in an Infant With an NRAS Q61R Mutation and Clinical Features of Juvenile Myelomonocytic Leukemia

Early T‐cell precursor acute lymphoblastic leukemia (ETP‐ALL) is a subtype of T‐acute lymphoblastic leukemia (T‐ALL) arising from a primitive precursor. We present a unique case of an infant with ETP‐ALL with a missense NRAS mutation in codon 61 (c.182A>G, p.Q61R). The patient also had a minor population of non‐ETP T‐ALL blasts and clinical features typically associated with juvenile myelomonocytic leukemia (JMML), namely, absolute monocytosis, splenomegaly, and elevated hemoglobin F. The treatment was initiated with chemotherapy, followed by cord blood transplantation. The patient achieved remission, but unfortunately died from transplant‐related complications. This case highlights an NRAS mutation in ETP‐ALL with JMML‐like phenotype.