Immunologic classification of acute lymphoblastic leukemia

The study of cell surface antigens in acute lymphoblastic leukemia (ALL) has provided the basic information for classification of ALL into B cell or T cell lineage. Each immunologic type may present at an immature or more mature stage of maturation. This classification has prognostic significance since mature B cell and T cell ALL phenotypes have a worse prognosis, compared to common acute lymphoblastic leukemia-associated antigen (CALLA) positive leukemias that belong to an immature B cell lineage and have the best prognosis. By performing these immunologic studies together with those of molecular biology, it is now possible to establish the precise level of cell differentiation, the point at which the malignant transformation occurred. Further studies may allow correlation of these different maturation stages, thus providing insight into the biologic behavior of lymphoblastic leukemia.     

Immunodiagnosis and immunotherapy of childhood malignancies

Recent advances in immunologic techniques have allowed the generation of monoclonal antibodies against antigens on tumor cells and their normal counterparts. Monoclonal antibodies useful for diagnosing and defining subtypes of acute leukemias and neuroblastoma have been prepared, although the prognostic significance of the subtypes defined by such antibodies remains to be determined. The usefulness of these reagents for therapeutic purposes either ex vivo, in association with autologous bone marrow transplantation, or in vivo, as carriers of cytotoxic agents, is currently under investigation.     

Myelopoiesis in immunologically classified subgroups of childhood acute lymphocytic leukemia

Soft agar culture studies of 43 immunologically characterized patients with childhood acute lymphocytic leukemia (ALL) are presented. The immunologic subsets studied include “null”-cell, pre-B-cell, and T-cell leukemias. Abnormal myelopoiesis, including high peripheral blood and low marrow, colony-forming cell numbers, low colony-stimulating activity, and normal maturation of colony-forming cells in vitro was noted in each group as previously described for immunologically uncharacterized ALL. We conclude that immunologic subsets of childhood lymphoblastic leukemia cause similar abnormalities of myelopoiesis. Lack of differences in growth characteristics among immunologic subsets of ALL make it impossible to use this tissue culture technique in sub-classification of these leukemic disorders.     

Cytogenetic Abnormalities in Childhwood Acute Lymphoblastic Leukemias

From the early 1950s to the mid 1970s all childhood acute lymphoblastic leukemias were treated according to an unique protocol. It became evident that some parameters had prognostic significance: age, white blood cells count, lymphoma syndrome, initial meningeal involvement, mediastinal mass, treatment efficacy, and more recently immune markers and cytogenetics. Multivariate analysis demonstrated that karyotype is one independent prognostic factor for survival even when age, white cell count, tumor burden, and immunologic parameters are considered.     

Establishment of leukaemia cell lines and their significance for clinical and experimental oncology (author's transl)]

Permanent in vitro growing leukemic cell lines have been established from all types of immunologically classified childhood leukemias. Essential characteristics of primary blasts and cultured cells are identical. In contrast to lymphoblastoid, non-leukemic cell lines, the Epstein-Barr-virus specific nuclear angiten (EBNA) is not detected. Up to now 8 Non-B-non-T cell lines (6 of them were derived from children with acute lymphoblastic leukemia, 2 from patients with chronic myeloid leukemia), 8 T-lines and one B-line have been established. Three Non-B-non-T lines from children with acute lymphoblastic leukemia (KM-3, RU-3, MH-3) and one T-cell line (JM) were cultivated by ourselves. Cultured blasts represent a pure tumor material which can be propagated in large quantities. Leukemic cell lines reveal a new approach for the search after leukemia-associated proteins and represent another possibility for the experimental investigation of the etiology of leukemia.     

Myeloid lineage switch following chimeric antigen receptor T‐cell therapy in a patient with TCF3‐ZNF384 fusion‐positive B‐lymphoblastic leukemia

A pediatric patient diagnosed initially with B‐lymphoblastic leukemia (B‐ALL) relapsed with lineage switch to acute myeloid leukemia (AML) after chimeric antigen receptor T‐cell (CAR‐T) therapy and hematopoietic stem cell transplant. A TCF3‐ZNF384 fusion was identified at diagnosis, persisted through B‐ALL relapse, and was also present in the AML relapse cell population. ZNF384‐rearrangements define a molecular subtype of B‐ALL characterized by a pro‐B‐cell immunophenotype; furthermore, ZNF384‐rearrangements are prevalent in mixed‐phenotype acute leukemias. Lineage switch following CAR‐T therapy has been described in patients with KMT2A (mixed lineage leukemia) rearrangements, but not previously in any patient with ZNF384 fusion.     

Five Chinese pediatric patients with leukemias possibly arising from immature natural killer cells: clinical features and courses

Leukemias arising from immature nature killer (NK) cells have been proposed as distinct entities and are rare. Treatment and prognosis of these diseases are controversial, and data on children are limited. According to the literature, one of these distinct leukemias may be myeloid/NK cell precursor acute leukemia (MNKPL), with the blasts being cytochemically myeloperoxidase negative (MPO(-)) and phenotypically CD56(+)CD3(-)CD7(+)CD34(+) and myeloid antigens(+). The other may be myeloid/NK cell acute leukemia (MNKL), in which the blasts were cytochemically MPO(dim) and phenotypically CD56(+)CD16(-)CD3(-)CD33(+)HLA-DR(-). Between 2005 and 2008, 4 MNKPL and 1 MNKL children aged 1.3 to 12.5 years were encountered in the First Affiliated Hospital of Sun Yat-Sen University. In those with MNKPL, remarkable extramedullary involvement usually occurring in adults was not observed; however, myelofibrosis was found in 2 children. The child with MNKL abandoned treatment. Those with MNKPL were treated with a protocol designed for childhood high-risk acute lymphoblastic leukemia (ALL) containing cytarabine, mitoxantrone, etoposide, l-asparaginase, and methotrexate according to the myeloid and lymphoid characteristics of MNKPL. They responded slowly to chemotherapy and were in complete remission (CR) for 26 to 63 months, except 1 who died in CR from pneumonia. They had longer survival and seemed to have a better outcome than those reported previously. In conclusion, childhood leukemias with immature NK cell markers may have different characteristics from their adult counterparts. A protocol including agents used for acute myeloid leukemia combined with those for ALL is seemingly effective for treatment of MNKPL. However, a modified treatment strategy designed more specifically for MNKPL and longer observations are needed.     

Immunological Classification of Childhood Acute Lymphoblastic Leukemia

Seven hundred and forty-four newly diagnosed patients with acute leukemias between 1978 and 1990 were classified on the basis of immunological phenotypes. The majority of the patients were enrolled in the Tokyo Children's Cancer Study Group (TCCSG) studies. The incidence of subclassification of acute leukemias in this study was as follows: 522 patients with ALL (70%), 139 patients with ANLL (18%), 29 patients with biphenotypic leukemia, 8 patients with Ph1-positive acute leukemia (Ph^-AL), and 45 patients with infant leukemia. ALLs were classified into common ALL (cALL, 77%), T-ALL (15%), B-ALL (4%), and unclassified ALL (3%). The incidence of ALL subtypes in this study reflected those of TCCSG. Biphenotypic leukemias were categorized into 4 groups as follows; 1) cALL with positive myelomonocytic antigen(s) (N = 11), 2) unclassified ALL with positive myelomonocytic antigen(s) (N = 5), 3) ANLL with positive B-lymphoid antigen(s) (N = 4), and 4) acute leukemia with positive T-lymphoid and myeloid antigen(s). Infant leukemias were classified into ALL type (N = 27) and ANLL type (N = 18). In this present study, clinical features and immunological phenotypes of the acute leukemias with a poor prognosis, i.e. biphenotypic leukemia, Ph^-AL, and infant leukemia are analyzed and discussed.     

Tumefactive intracranial presentation of precursor B-cell acute lymphoblastic leukemia

In children, leukemia is the most common malignancy, and approximately 75% of leukemias are acute lymphoblastic leukemia (ALL). Central nervous system leukemia is found at diagnosis in fewer than 5% of children with ALL. Leukemic intracranial masses have been described with acute myeloid leukemia, but ALL presenting as a mass lesion is rare. We describe a unique case of an intracranial confirmed precursor B cell (pre-B) ALL mass in a 13-year-old girl that was diagnosed by brain CT, MRI and cerebral angiography, and confirmed by biopsy. This report details pertinent history and distinguishing imaging features of an intracranial ALL tumefaction.     

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.     

Undifferentiated acute leukemia and lineage infidelity (difficulties in classification and management)

The acute leukemias have been considered to represent a clonal expansion of a malignant transformed hematopoietic progenitor cell with adherence to either the myeloid or lymphoid lineage--"lineage fidelity." Lineage fidelity has been challenged by the demonstration of lineage switching or mixed-lineage leukemias. We describe a 7 year old male who presented with undifferentiated acute leukemia and nasopharyngeal and cervical masses. His blasts had the morphologic appearance of myeloblasts (FAB M1) and were positive solely for the myeloid antigen CD15. He entered a complete remission (CR) with acute nonlymphocytic leukemia therapy. At first relapse he had evidence of mixed-lineage leukemia with B-cell lymphoid and myeloid phenotypes. He again relapsed from a second CR with Burkitt-cell leukemia. Cytogenetic findings showed a consistent 14q+, 17p+ abnormality in the blasts and nasopharyngeal mass. The t(8;14) associated with Burkitt's lymphoma was found in the mass tissue only following passage in the nude mouse. Our patient demonstrates that limitations still exist in our ability to classify acute leukemia. That leukemic transformation occurred in a multipotential progenitor cell leading to undifferentiated leukemia at diagnosis and/or that chemotherapy can influence the genetic programs of leukemic cells leading to the evidence of mixed-lineage leukemia and lineage switching is supported.     

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.     

Heterogeneity Among the Acute Nonlymphocytic Leukemias: Value of Immunophenotype for Diagnosis, Prognosis, and Therapy

Immunophenotyping of acute nonlymphocytic leukemia has confirmed previous observations on the heterogeneity of this disease. The lack of leukemia-specific monoclonal antibodies as well as antibodies reactive with early myeloid cells is reflected in poor correlation of morphologically and cytochemically defined FAB classes with the immunophenotype of the leukemic cells. Possible exceptions are the microgranular variant of FAB-M3, megakaryocytic leukemia (FAB-M7), and early erythroid leukemias (FAB-M6). The use of antibody panels can alleviate the differential diagnosis of acute lymphoid and myeloid leukemias, especially those occurring in infants, and the discrimination of FAB-L2 and FAB-MI. Also, the immunophenotyping of presumptive hybrid leukemias can help to resolve the many questions about these leukemias with a particularly poor prognosis. The challenge for multiinstitutional groups is to define those clinically relevant subgroups of acute nonlymphocytic leukemia in children that have general acceptance and could provide the basis for new treatment strategies.     

Cytologic diagnosis of the acute nonlymphoid leukemias. II. Flow cytometry, surface markers, cytogenetics, and use of cell culture techniques

Part I of this two-part article discussed the use of morphologic, histochemical, and ultrastructural studies for the diagnosis and classification of ANLL variants of acute nonlymphoid leukemia. However, a small proportion of acute leukemias are not amenable to definition by these techniques and have, in the past, been classified as acute undifferentiated leukemias. The use of supplemental techniques such as flow cytometry, surface marker analysis, cytogenetics, and in vitro growth patterns will often identify the correct cellular lineage for these cases.     

儿童急性淋巴细胞白血病抗原错译表达的临床意义

目的 研究儿童急性淋巴细胞白血病(ALL)抗原错译表达的临床意义。方法 对54例ALL患儿的骨髓标本分别进行细胞形态学及细胞化学染色，确定其FAB类型，运用一组相关的单克隆抗体，采用流式细胞仪及直接免疫荧光标记技术进行免疫分型，采用吉姆萨G显带技术进行核型分析。结果 儿童ALL54例髓系抗原阳性表达率为29.63％，其中CD13为25．93％，CD33为20．37％，CD14为11．11％。T—ALL和B—ALL髓系抗原阳性表达差异无统计学意义(30．77％vs529．27％ P＝0.918)。CD34表达阳性ALL髓系抗原阳性表达率明显高于CD34表达阴性ALL髓系抗原阳性表达率(40.63％vs13.64％P＝0．039)；ALL髓系抗原阳性表达与髓系抗原阴性表达的完全缓解(CR)率差异无统计学意义(81．25％vs94．74％ P＝0．148)；但生存率曲线比较分析，ALL髓系抗原阳性表达的生存时间短(P＝0.031)。结论 儿童ALL的抗原错译表达率为29．63％；CD34阳性的ALL抗原错译表达率明显高于CD34表达阴性的ALL抗原错译表达率；ALL髓系抗原阳性表达的生存时间短；ALL髓系相关抗原阳性表达可能是影响ALL患儿预后的不利因素。     

Simultaneous immunoglobulin/T-cell receptor gene rearrangements and multiclonality in childhood acute lymphoblastic leukemia

Twenty-five children less than 16 years of age with acute lymphoblastic leukemia (ALL) were investigated with immunologic, cytogenetic and molecular genetic techniques at diagnosis. All pre-B-cell ALL showed clonal rearrangements in the immunoglobulin heavy chain gene (J_H and/or Cμ). A very high proportion of the pre-B-cell leukemias (17 of 23 cases) also snowed clonal rearrangements in T-cell receptor genes (Tγ and/or Tβ). The two T-cell leukemias exhibited clonal T-cell receptor gene rearrangements and in one Jh and kappa light chain rearrangments also. The T-cell receptor gene rearrangements found in pre-B-cell leukemias appeared to occur randomly with respect to the Tβ and Tγ genes. A significant proportion of the leukemias (at least 24%) seemed to harbor more than one malignant (sub)clone at diagnosis. Cytogenetic studies revealed a clonal abnormality in 10 cases. Only 2 showed hyperdiploidy (> 50 chromosomes). The only correlation between cytogenetic findings and rearrangement patterns was extra bands corresponding to a possible trisomy of chromosome 14. Our data indicate, in line with previous studies, that childhood ALL has complex rearrangement patterns not useful for lineage sub-classification. For this purpose immunophenotyping appears to be superior. However, molecular analysis can reveal the presence of more than one clone not detected by immunophenotyping or karyotyping, and distribution of clones in different compartments. In this study no correlation with clinical outcome was observed.     

Clofarabine induced durable complete remission in heavily pretreated adolescents with relapsed and refractory leukemia

Current treatments for relapsed/refractory leukemias are unable to achieve extended remissions in most patients even with multiagent chemotherapy. Clofarabine is a new nucleoside analog that has demonstrated clinical benefit in phase I-II studies, and is currently being studied in children and adults with leukemias and has been approved for the treatment of children with relapsed or refractory acute lymphocytic leukemia. We report the experience of three adolescents, two with acute lymphocytic leukemia in 3rd relapse and one with relapsed/refractory acute myeloid leukemia, who achieved complete remission with clofarabine. The remissions were sustained with repeated cycles of monotherapy for 47, 59, and 64 weeks, respectively.