对过继免疫治疗中外周血单个核细胞采集术的探讨

目的观察细胞表面分化抗原CD117在急性髓细胞白血病(AML)与急性淋巴细胞白血病(ALL)的表达差异及其意义,评价其作为髓系抗原的特异性。方法采用CD45/SSC双参数散点图设门法进行三色流式细胞术分析。直接免疫荧光标记法标记20种细胞表面分化抗原,经流式细胞仪测定,对286例白血病患者骨髓或外周血白血病细胞CD117及其他表面抗原的表达结果进行分析。结果CD117在ALL中表达率极低,仅占2%,在AML中表达率为56.9%,2者差异有统计学意义(P<0.05)。在AML各型中,CD117在M3亚型中的表达率最低,为23.1%。本组数据统计结果显示CD117的髓系特异度为0.98(SE=0.014),髓系敏感度为0.57(SE=0.04),统计结果表明CD117比CD13、CD33更具髓系特异性(P<0.05)。结论与CD13和CD33相比较,CD117在作为髓系标记的敏感度不如前两者高,但它更具有髓系特异度,因而可作为排除ALL及辅助诊断AML的标志。     

CD33 directed bispecific antibodies in acute myeloid leukemia

Despite the approval of a number of new targeted therapies for acute myeloid leukemia (AML), median overall survival still remains poor, ranging from 12 to 18 months in most patients. Based on the success of blinatumomab, the CD19-targeted bispecific antibody for the treatment of acute lymphoblastic leukemia, the development of several CD33-targeted bispecific antibodies for AML are being investigated in clinical trials. In this review article of CD33-targeted bispecific antibodies, we describe the rationale for targeting CD3 x CD33, summarize the data from four ongoing phase 1 studies, review the major toxicity associated with CD33-targeted bispecific antibody therapy of cytokine release syndrome (CRS) and steps to mitigate CRS, and describe possible mechanisms of resistance to CD33-targeted bispecific antibody therapy. Future development to try to improve outcomes include combination therapies to reduce the tumor burden prior to starting treatment, combining with immune checkpoint inhibition therapy such as anti-PD-1/PDL1 antibodies, and the use of second generation bispecific antibodies that target two different antigens and recruit other effector cells such as nature killer cells and macrophages.     

CD56 expression in myeloperoxidase-negative FAB M5 acute myeloid leukemia

CD56 is a natural killer (NK) cell marker that has been identified in approximately 15-20% of acute myeloid leukemia (AML) cases, where it has been associated with monocytic morphology and chromosomal abnormalities such as trisomy 8, t(8;21), t(15;17), and 11q23 rearrangements. The clinical presentation, chromosomal abnormalities as detected by fluorescent in-situ hybridization (FISH), and clinical outcomes of 7 patients with AML are presented. These cases were characterized by French-American-British (FAB) M5 morphology, myeloperoxidase (MPO) negativity, and co-expression of myelomonocytic and NK cell-associated antigens (CD11c(+), CD13(+), CD15(+), CD33(+), HLA-DR(+), and CD56(+)). All patients presented lymph node, hepatic, or splenic involvement at diagnosis. Despite the homogeneous morphologic and immunophenotypic characteristics the outcomes varied considerably. Two patients died during induction therapy, but the other five patients attained complete remission (CR). Of these five patients, 4 have received a bone marrow transplantation (autologous or allogeneic) and 3 of them are in CR (median follow-up: 45 months). The three patients with 11q23 rearrangements had a poor outcome and died of their disease within 1 year of diagnosis. Further studies with a larger group of patients would help establish the actual prognostic value of these morphologic, immunophenotypic and cytogenetic features.     

Prognostic significance of CD56 antigen expression in acute myeloid leukemia

BACKGROUND AND OBJECTIVES. CD56 antigen expression has been reported in several hematologic malignancies. In acute myeloid leukemia (AML)M2 with t(8;21) and acute promyelocytic leukemia (APL) it has been found to be consistently associated with an unfavorable prognosis, whereas in other AML subtypes its role remains uncertain. We investigated CD56 expression in a cohort of AML patients in order to assess its frequency and prognostic relevance. DESIGN AND METHODS. Immunophenotypic analysis including that of CD56 antigen was available for 171 consecutive AML patients (139 with AML and 32 with APL), enrolled between December 1995 and December 1999 at a single institution. A sample of fresh bone marrow cells taken at diagnosis was recorded as positive when at least 20% of the cells double-stained with specific monoclonal antibodies against CD56 and CD33 antigens. RESULTS. CD56 positivity was demonstrated in 37 cases (21.6%). Its frequency was lower in M4 (6%) and higher in M5 (37%). The median percentage for CD56+ blasts was 56% (range 21-99%). CD56 positivity did not correlate with age, sex, blast count, favorable or unfavorable cytogenetics at diagnosis, nor did it influence the outcome in terms of complete remission (CR) duration (606 vs. 417 days, p=n.s.) or overall survival (OS) (210 vs. 277 days, p= n.s.). In the APL subgroup a significant difference in relapse rate was found at 3 years (71.4% in the CD56 positive group vs. 12% in the CD56 negative group, p=0.005). INTERPRETATION AND CONCLUSIONS. Our data confirm that CD56 positivity in APL patients at diagnosis is associated with a worse prognosis, suggesting that close molecular monitoring is necessary in CD56 positive APL patients. In contrast, the prognostic role of CD56 remains uncertain in the other AML subtypes.     

Biologic and clinical significance of CD7 expression in acute myeloid leukemia

CD7 antigen, a T-cell lineage associated antigen, is expressed in a minority of patients with acute myeloid leukemia (AML). The biologic and clinical significance of this finding is not clearly established. In this retrospective study of patients with de novo acute myeloid leukemia, we have identified CD7 expression and analyzed its association with markers expressed early in hemopoietic ontogeny and clinical parameters. Among 60 consecutive AML patients, we found six (10%) expressing CD7 on leukemic cells. There were five males and one female and the mean age was 59.6 years (age range: 32–76 years) with no demographic peculiarities. The FAB subtypes were: M0 (2), M1 (1), M2 (1), and M4 (2). CD7 expression was associated with immature antigens CD34, HLA-DR, and terminal deoxynucleotidyl transferase (TdT) and antigen receptor gene rearrangements (rearrangements of T-cell receptor gamma chain in 6/6 and immunoglobulin heavy chain in 2/6). Hepatomegaly was present in three and this was associated with splenomegaly with lymphadenopathy in one patient. Mediastinal or central nervous system involvement was absent. Complete remission was achieved in two patients with standard chemotherapy; one of these is in remission and alive (5 years later), while one died following relapse 9 months later. Three patients had significantly lower response to standard therapeutic regimen (two died during induction and one died 7 months later without ever achieving complete remission). One patient has been excluded in determining the prognostic significance of CD7 due to early death. Our results suggest origin of CD7+ AML from early hemopoietic precursors and indicate biologic aggressiveness in a significant proportion of patients. We suggest evaluation of CD7 in all patients with AML at the time of diagnosis in view of poor clinical outcome. Am. J. Hematol. 58:278–284, 1998. © 1998 Wiley-Liss, Inc.     

Long-term leukemia-initiating capacity of a CD34-subpopulation of acute myeloid leukemia

Acute myeloid leukemia (AML) proliferation in vivo is maintained by a small fraction of progenitor cells. These cells have been assumed to express an immature phenotype and to produce most colony-forming units (CFU-AML). For one case of AML (French-American-British [FAB] M1, normal cytogenetics), we examined the capacity of the CD34+ (25% of unseparated AML cells) and CD34- fractions to initiate leukemia in severe combined immunodeficient (SCID) mice. In addition, the production of CFU-AML and nucleated cells (NC) of these subsets was investigated in long-term bone marrow culture (LTBMC). The frequencies of cobblestone area-forming cells (CAFC) were also estimated; early appearing cobblestone areas (CAs) are indicative of relatively mature progenitors and late CAs represent the progeny of primitive progenitors. In mice transplanted with CD34- (98% pure) or CD34+ (98% pure) grafts, similar AML cell growth was seen throughout an observation period of 106 days. The capacity to establish long-term growth from the CD34- cells was confirmed by renewed outgrowth after retransplantation. In vitro, the CD34- fraction contained both immature and mature CAFCs and produced high numbers of CFU-AML and NC in LTBMC. The CD34+ fraction produced only small numbers of CFU-AML, NC, and mature CAFCs. Therefore, the expression of CD34 and the content of CFU- AML were not associated with long-term growth of AML. However, similar frequencies of primitive CAFCs were observed in both fractions. Thus, both CD34- and CD34+ subsets of this AML sample contained immature progenitors with the capacity to initiate long-term AML growth as characterized in vivo (in SCID mice) as well as in vitro (in CAFC assay), indicating asynchrony between functional and immunophenotypical maturation of AML progenitor cell compartments.     

CD7-positive acute myeloid leukemia: further evidence of cellular immaturity

Summary Among 63 cases of acute myeloid leukemia (AML), 14 were found to express the CD7 antigen, a cell surface marker usually found at an early stage during T lineage differentiation. The CD7-positive AML cases consisted of 5 cases of M1, 3 cases of M2, 3 cases of M4, 1 case of M5, 1 case of M6 and 1 case of M7. Among these 63 cases, the proportion of blast cells expressing the CD34 antigen was examined. The proportion of CD34-stained cells among the CD7-positive AML cases, although varying, was significantly larger than that among the CD7-negative AML cases (P<0.05). As the CD34 antigen was expressed on hematopoietic progenitor cells and was considered to reflect an early hematopoietic stage, the high proportion of cells expressing CD34 among the CD7-positive AML cases may support the notion that CD7-positive AML cells are immature.Abbreviations AML acute myeloid leukemia - CD clusters of differentiation Partly supported by grants-in-aid from the Ministry of Education, Culture and Science of Japan (03252102, 63015063, 02256102, and 03670325) and from theFukuoka Anti-Cancer Society     

Angiogenesis and acute myeloid leukemia

Background

Angiogenesis is a word of Greek origin, ‘angeio’ refers to blood vessel, and genesis refers to creation, meaning the generation of new blood vessels. This process is essential for vertebrate development and plays a key role in human diseases. Angiogenesis is generally understood to be essential for the growth and metastasis of solid tumors and is also important in acute myeloid leukemia (AML).

Methods

This review summarizes the essential features of physiological and tumoral angiogenesis and the methods used for their assessment.

Results

Technologies for evaluating angiogenesis in AML are discussed and the prognostic significance of angiogenic factors is considered in the context of optimizing treatment.

Conclusion

As acute myelogenous leukemia and endothelial cells depend on each other for survival and proliferation, therapy directed against several pro-angiogenic factors might help to enhance the AML outcome.     

Treatment of acute myeloid leukemia

The treatment of acute myeloid leukemia has improved in the last ten years, and in this perspective article Dr. Estey examines the recent progress in this field. See related articles on pages 54 and 102.Ten years ago therapy of newly-diagnosed acute myeloid leukemia (AML) was largely invariant. Patients received daunorubicin or idarubicin for 3 days and cytarabine (ara-C) at a dose of 100 mg/m² daily for 7 days as a continuous infusion, a regimen commonly known as “3+7”. Nowadays, however, guidelines, such as those in the paper by Morra et al.,¹ recommend that many older patients be given investigational therapies at diagnosis. This change reflects the greater availability of new treatments, often thought to be targeted to specific abnormalities in AML blasts. The advent of a broader range of investigational therapies and increased knowledge about the molecular biology of AML has raised several questions, which I address here: (i) which patients are candidates for investigational therapy¿ (ii) should cytogenetic and molecular information be used to plan initial therapy¿ (iii) what is the current role of allogeneic hematopoietic stem cell transplant (HSCT)¿ (iv) regarding targeted therapy - are responses less than a complete response worthwhile, how long should therapy be continued before failure is declared, should combinations with chemotherapy or other targeted agents be explored sooner than is currently the case, and should these agents be reserved for a specific population or used more broadly¿ and (v) given the increasing recognition of the biological and prognostic heterogeneity of AML, should we depart from standard clinical trial methodology, which could lead to missing potentially important therapeutic advances as described in the paper by Schlenk et al.²     

Age and acute myeloid leukemia

We conducted a retrospective analysis of 968 adults with acute myeloid leukemia (AML) on 5 recent Southwest Oncology Group trials to understand how the nature of AML changes with age. Older study patients with AML presented with poorer performance status, lower white blood cell counts, and a lower percentage of marrow blasts. Multidrug resistance was found in 33% of AMLs in patients younger than age 56 compared with 57% in patients older than 75. The percentage of patients with favorable cytogenetics dropped from 17% in those younger than age 56 to 4% in those older than 75. In contrast, the proportion of patients with unfavorable cytogenetics increased from 35% in those younger than age 56 to 51% in patients older than 75. Particularly striking were the increases in abnormalities of chromosomes 5, 7, and 17 among the elderly. The increased incidence of unfavorable cytogenetics contributed to their poorer outcome, and, within each cytogenetic risk group, treatment outcome deteriorated markedly with age. Finally, the combination of a poor performance status and advanced age identified a group of patients with a very high likelihood of dying within 30 days of initiating induction therapy. The distinct biology and clinical responses seen argue for age-specific assessments when evaluating therapies for AML.     

Familial CEBPA-mutated acute myeloid leukemia

Familial CEBPA-mutated acute myeloid leukemia (AML) represents a recognized leukemia predisposition syndrome, with several families described in the literature since the initial report in 2004. The pathological features and long-term survival of individuals with familial CEBPA-mutated AML are reminiscent of sporadic CEBPAdm AML.  Germline mutations predominantly localize to the N-terminal and are associated with near complete penetrance, with age of AML onset from 2–50 years, frequently accompanied by the acquisition of a second CEBPA mutation in C-terminal domain.  Patients appear to have a significant risk of late AML recurrence and these typically represent independent leukemic episodes, characterized by a unique molecular profile that is distinct from that of the preceding tumor.  While these patients respond well to salvage therapies, allogeneic hematopoietic stem cell transplantation (HSCT) should be considered for patients with high-risk features at presentation or recurrent disease, with the aim of eradicating the germline mutation and improving long-term survival. In contrast, inherited C-terminal CEBPA mutations occur less frequently and appear to demonstrate reduced penetrance, impeding clinical detection and surveillance.     

Gefitinib induces myeloid differentiation of acute myeloid leukemia

Cure rates for patients with acute myeloid leukemia (AML) remain low despite ever-increasing dose intensity of cytotoxic therapy. In an effort to identify novel approaches to AML therapy, we recently reported a new method of chemical screening based on the modulation of a gene expression signature of interest. We applied this approach to the discovery of AML-differentiation-promoting compounds. Among the compounds inducing neutrophilic differentiation was DAPH1 (4,5-dianilinophthalimide), previously reported to inhibit epidermal growth factor receptor (EGFR) kinase activity. Here we report that the Food and Drug Administration (FDA)-approved EGFR inhibitor gefitinib similarly promotes the differentiation of AML cell lines and primary patient-derived AML blasts in vitro. Gefitinib induced differentiation based on morphologic assessment, nitro-blue tetrazolium reduction, cell-surface markers, genome-wide patterns of gene expression, and inhibition of proliferation at clinically achievable doses. Importantly, EGFR expression was not detected in AML cells, indicating that gefitinib functions through a previously unrecognized EGFR-independent mechanism. These studies indicate that clinical trials testing the efficacy of gefitinib in patients with AML are warranted.     

Altered expression of CD45 isoforms in differentiation of acute myeloid leukemia.

Specific expression of different CD45 isoforms can be seen in various stages of differentiation of normal nucleated hematopoietic cells. Association of membrane expression of CD45 isoforms and differential levels of leukemia cells was studied in 91 cases with de novo acute myeloid leukemia (AML). Membrane expression of CD45RA and CD45RO was analyzed by flow cytometry and their expression patterns were compared with AML subtypes classified according to the French-American-British (FAB) classification. CD45RA was essentially expressed in all of the FAB myelocytic subtypes (M0-M3). Its expression in percentage was lower in the most differentiated subtype of AML (M3) when compared with other myelocytic subtypes. CD45RO expression was rarely observed in cases with myelocytic subtypes (1/56 cases of M0, M1, M2, and M3) except for the minimally differentiated myelocytic subtype (M0) or those with potential for differentiation to T-cell lineage where three of 12 cases showed CD45RO expression. When leukemia cells of an M3 case were differentiated to mature granulocytes by treatment of all-trans-retinoic acid, they showed increasing expression of CD45RO. In subtypes with a monocytic component (M4 and M5), both of CD45RA and CD45RO expression were observed and mutually exclusive. When 10 cases of M5 were subdivided by the differential level into undifferentiated (M5a) and differentiated monocytic leukemia (M5b), expression of CD45RA and CD45RO was strictly restricted to cases with M5a and M5b, respectively. These results suggest that CD45 isoform expression in AML characterizes differential levels both in myelocytic and monocytic lineages and specifically disturbed in each subtype. The assessment of CD45 isoform expression appears to provide an insight on biological characteristics and a useful supplementary test for differential diagnosis of AML subtypes.