Acute promyelocytic leukemia: a curable disease

The Second International Symposium on Acute Promyelocytic Leukemia (APL) was held in Rome in 12-14 November 1997. Clinical and basic investigators had the opportunity to discuss in this meeting the important advances in the biology and treatment of this disease achieved in the last 4 years, since the First Roman Symposium was held in 1993. The first part of the meeting was dedicated to relevant aspects of laboratory research, and included the following topics: molecular mechanisms of leukemogenesis and of response/resistance to retinoids, biologic and therapeutic effects of new agents such as arsenicals and novel synthetic retinoids; characterization of APL heterogeneity at the morphological, cytogenetic and immunophenotypic level. The updated results of large cooperative clinical trials using variable combinations of all-trans retinoic acid (ATRA) and chemotherapy were presented by the respective group chairmen, and formed the 'core' part of the meeting. These studies, which in most cases integrated the molecular assessment of response to treatment, provided a stimulating framework for an intense debate on the most appropriate frontline treatment options to be adopted in the future. The last day was dedicated to special entities such as APL in the elderly and in the child, as well as the role of bone marrow transplantation. The prognostic value of molecular monitoring studies was also discussed in the final session of the meeting. In this article, we review the major advances and controversial issues in APL biology and treatment discussed in this symposium and emerging from very recent publications. We would like to credit the successful outcome of this meeting to the active and generous input of all invited speakers and to participants from all over the world who provided constructive and fruitful discussions.     

Strongly increased efficiency of altered peptide ligands by mannosylation

Altered peptide ligands (APL) have the potential to modulate pathogenic T cell reactivity. High concentrations of APL, however, are required to achieve efficient blocking of the T cell response. We have therefore investigated whether improved delivery of APL to professional antigen-presenting cells (APC) can lead to more efficient application of such peptides. For this purpose APL were bis-mannosylated in order to facilitate their uptake by mannose receptor-positive dendritic cells (DC) in vitro. We present evidence that a 100- to 1000-fold lower concentration of bis-mannosylated APL was sufficient for complete blocking of the proliferative T cell response against the agonist peptide compared to the non-mannosylated APL. Moreover, bis-mannosylated APL were similarly effective in the inhibition of the T cell response against whole protein antigens. In contrast, unrelated, bis-mannosylated class II binding peptides were ineffective, indicating that the increased efficiency of the mannosylated APL was not due to competition for binding to class II molecules. Furthermore, a strong increase in the efficiency of presentation of APL was also observed when macrophages and peripheral blood mononuclear cells were used as APC. Thus, bis-mannosylation of APL greatly increases their potency to inhibit proliferative T cell responses. Moreover, it is likely that the use of bis-mannosylated APL will result in preferential presentation by mannose receptor-positive, professional APC. These results may be of relevance for more effective use of APL for immunoregulation in vivo.     

Placental pathology and antiphospholipid antibodies: a descriptive study

We described placental pathology in antiphospholipid antibody (APL) syndrome, APL and no history of recurrent pregnancy loss, and in treated and untreated pregnancies of APL syndrome. Thirty-nine pregnancies of 28 patients were studied: 23 placentas delivered from 23 women with APL (13 with APL syndrome and 10 with serological APL); 8 untreated miscarriages before APL diagnosis from 6 of the 13 patients with APL syndrome and 1 of 10 with serological APL; and 8 miscarriages by 5 additional women before APL syndrome diagnosis. Histopathology was reviewed by a pathologist blinded except to gestational age. Contingency tables and analysis of variance (ANOVA) considered p < 0.05 significant. Comparing the placentas delivered at > 18 weeks' gestation, excessive perivillous coagulation, avascular terminal villi, and chronic villitis/uteroplacental vasculitis tended to be more common in treated APL syndrome than serological APL cases (p = 0.07). Of the 16 miscarriages before diagnosis of APL, 11 were lost at < 18 weeks' gestation. None had pathology typical of APL, but 4 of 11 (36%) had chronic intervillositis. Five of 16 miscarriages before the diagnosis of APL were miscarried between 18-22 weeks. Three of 5 (60%) miscarried after 18 weeks had multifocal uteroplacental thromboses, compared to 6 of 13 (46%) treated pregnancies with APL syndrome and 0 of 10 cases with serological APL.     

治疗急性早幼粒细胞白血病的几个问题

急性早幼粒细胞白血病(APL)为急性髓系白血病的一个亚型,以进展快,易发生弥散性血管内凝血(DIC)和死亡率高为特征.95%以上APL患者有典型染色体易位t(15;17)形成PMLRARα融合基因.1986年以来,中国首创以全反式维甲酸(ATRA)和亚砷酸(ATO)治疗APL,使APL的转归大大改观,成为仅用药物可治愈的AML.结合作者经验讨论治疗APL中的有关问题.     

Negative regulation of the neu promoter by the SV40 large T antigen

We investigated the effect of transforming growth factor-beta 1 (TGF beta) on the proliferation and differentiation of cultured acute promyelocytic leukemia (APL) cells with the chromosomal t(15;17) translocation obtained from four patients to determine the role of TGF beta on growth and differentiation of APL cells. DNA synthesis, determined by 3H-thymidine uptake, was inhibited in the presence and absence of granulocyte colony-stimulating factor (G-CSF) in a dose-dependent manner by TGF beta in APL cells obtained from three of the four cases. TGF beta and G-CSF did not significantly affect the differentiation of APL cells, but all-trans retinoic acid (RA) induced morphological and functional differentiation in all APL cells tested. G-CSF markedly enhanced RA-induced granulocytic differentiation in APL cells obtained from all four cases. In cells in which TGF beta inhibited DNA synthesis, it also inhibited RA-induced granulocytic differentiation of APL cells and, to a greater degree, granulocytic differentiation induced by RA plus G-CSF. These results suggest that TGF beta is a negative regulator of the proliferation and differentiation of APL cells. The significance of TGF beta as an endogenous regulator in differentiation therapy with RA of APL patients is discussed.     

Epidemiology of acute promyelocytic leukemia

BACKGROUND: The estimated incidence of acute promyelocytic leukemia (APL) is approximately 6 cases per 10 million people per year with no apparent differences between sexes. The age of APL cases is younger than that of other acute myeloid leukemias (AML). Spatial and temporal clusters of APL have been reported. These observations suggest a possible selective role for environmental and/or occupational factors in APL development. METHODS: A multicenter case-control study was carried out on risk factors for acute leukemias and preleukemias. In this report data related to APL are selectively analyzed from the larger study to identify specific risk factors. RESULTS: The case-control study on 38 cases of APL showed a strong association with shoemaking (odds ration 6.3, 95% confidence interval 1.3-31.1). A moderate leukemogenic effect from living in houses built with tuff, a polous building material containing gamma-emitting radionuclides and having a high radon concentration, and from using hair dyes was also suggested. CONCLUSIONS: These data, together with the reported spatial and temporal clustering of APL, support the hypothesis of specific environmental and/or occupational risk factors for APL among other AML subtypes and indicate the need for additional ad hoc multicenter studies.     

Potentiated maturation with a high proliferating activity of acute promyelocytic leukemia induced in vitro by granulocyte or granulocyte/macrophage colony-stimulating factors in combination with all-trans retinoic acid

All-trans retinoic acid (ATRA) induces differentiation of acute promyelocytic leukemia (APL), but the effect of cytokines regulating myeloid differentiation on ATRA-induced APL cells is poorly understood. In this study, maturation and proliferation of fresh APL cells were examined when induced in vitro by granulocyte or granulocyte/macrophage colony-stimulating factors (G-CSF or GM-CSF) in combination with ATRA. APL cells showed a low proliferating activity when induced by ATRA alone. In contrast, cells induced by G-CSF or GM-CSF alone showed increased DNA syntheses, the levels of which were not significantly affected by the combination of ATRA with CSFs. Interestingly, G-CSF or GM-CSF potentiated the capability of ATRA-induced cells to reduce nitroblue tetrazolium (NBT), while G-CSF or GM-CSF alone induced no NBT reduction. Furthermore, in several patients examined, APL cells induced by ATRA with G-CSF showed an increased activity of chemotaxis and CD11a expression. These findings suggest that G-CSF or GM-CSF can potentiate differentiation of ATRA-induced APL cells while stimulating their proliferating activity as well, and that G-CSF, rather than GM-CSF, may be a useful adjunct to promote ATRA-induced differentiation of APL.     

High frequency of acute promyelocytic leukemia among Latinos with acute myeloid leukemia

A high frequency (24%) of acute promyelocytic leukemia (APL) was noted among acute myelocytic leukemia (AML) cases at the Los Angeles County-University of Southern California (LAC-USC) Medical Center, in comparison with the expected frequency of 5% to 15%. Because of the high proportion of Latinos in this center, we questioned if APL is more common in this ethnic group. The proportion of APL among the 80 AML patients of Latino origin was significantly higher (30; 37.5%) when compared with the 62 non-Latinos (4; 6.5%) (P = .00001). In an attempt to verify this finding on a larger group of patients, we analyzed 276 pathologically verified cases of AML in patients aged 30 to 69 years from the entire County of Los Angeles, registered on an ongoing population-based epidemiologic study of AML. APL was more frequent among the 47 Latinos (24.3%) than in the 229 non-Latinos (8.3%) (P = .0075). APL is seen in younger patients with AML, but Latino AML patients also had a higher frequency of APL after accounting for their younger age (age-adjusted odds ratio for APL among Latinos in LAC-USC Medical Center, 9.4 [95% confidence interval (CI) 2.9, 30] P = .0002; among Latinos in the population-based study, 3.0 [95% CI 1.3 to 6.9] P = .01). The different ethnic distribution of AML was found to be due to a higher proportion of APL cases per se, and not to a lower proportion of any other French-American-British subtype (P = .0004). These results, from two different populations of AML patients, indicate that Latinos with AML have a higher likelihood of the APL subtype of disease, which may suggest a genetic predisposition to APL and/or exposure to distinct environmental factor(s).     

Use of trans-retinoic acid in the treatment of acute promyelocytic leukemia

OBJECTIVE: To discuss acute promyelocytic leukemia (APL) and review the literature concerning differentiation treatment of APL with trans-retinoic acid (t-RA). DATA SOURCES: English-language articles concerning APL or its treatment with t-RA were identified with a MEDLINE search. STUDY SELECTION: All studies available at the time of article preparation, which addressed t-RA treatment in APL, were selected. DATA EXTRACTION: Data extraction and assessment were performed subjectively by the authors. An extensive discussion of specific study details is included in the article. DATA SYNTHESIS: APL is a unique subset of acute myelogenous leukemia and is typified by an accumulation of malignant promyelocytes in the bone marrow. Within the granulocyte cell cycle of a patient with APL, differentiation has been halted at the level of the promyelocyte, preventing formation of mature granulocytes. Upon treatment with traditional cytotoxic chemotherapy, complete remission rates of approximately 70 percent, with a five-year survival ranging from 25 to 40 percent have been achieved. In most patients with APL, a characteristic chromosomal t(15q+;17q-) translocation has been found, which may be responsible for the production of an aberrant retinoic acid receptor-alpha. Therefore, t-RA induction therapy has been investigated and has produced promising results. Administration of t-RA in dosages of 45-100 mg/m2/d has induced complete remissions. The apparent mechanism of t-RA is the induction of promyelocyte differentiation and maturation. The most common adverse effects noted have been dry skin, cheilitis, and headaches. CONCLUSIONS: Upon consideration of the initial trials, t-RA appears to be a promising and unique treatment for APL.     

不锈钢带材退火酸洗技术在宝甬特钢厂的应用

不锈钢带材冷热兼用退火酸洗机组是正在建设中的宝甬特钢厂的主要生产机组之一，介绍了该机组的生产能力，产品方案、主要生产工艺和设备及所采用的新技术。     

A PMLRARalpha transgene initiates murine acute promyelocytic leukemia

The malignant cells of acute promyelocytic leukemia (APL) contain a reciprocal chromosomal translocation that fuses the promyelocytic leukemia gene (PML) with the retinoic acid receptor alpha gene (RAR alpha). To test the hypothesis that the chimera PMLRAR alpha plays a role in leukemogenesis, we expressed a PMLRAR alpha cDNA in myeloid cells of transgenic mice. PMLRAR alpha transgenic mice exhibited impaired neutrophil maturation early in life, which progressed at a low frequency over the course of several months to overt APL. Both the preleukemic state and the leukemia could be transplanted to nontransgenic mice, and the transplanted preleukemia could progress to APL. The APL recapitulated features of the human disease, including a response to retinoic acid. Retinoic acid caused the leukemic cells to differentiate in vitro and in vivo, eliciting remissions of both the preleukemic state and APL in mice. Our results demonstrate that PMLRAR alpha impairs neutrophil differentiation and initiates the development of APL. The transgenic mice described here provide an apparently accurate model for human APL that includes clear evidence of tumor progression. The model should be useful for exploring the molecular pathogenesis of APL and the mechanisms of the therapeutic response to retinoic acid, as well as for preclinical studies of therapeutic regimens.     

Total hip arthroplasty with use of an acetabular reinforcement ring in patients who have congenital dysplasia of the hip. Results at five to fifteen years

In this report, we explore the mechanisms underlying cell cycle progression in T cells stimulated with an altered peptide ligand (APL) versus wild-type peptide. APL stimulation did not induce proliferation compared to wild-type peptide stimulation. To determine the point at which cell cycle progression is blocked, we have examined molecules responsible for regulating the retinoblastoma tumor suppressor gene product, pRb, which in its active state prevents G1/S progression. The majority of cells stimulated with an APL did not progress beyond G1; however, a small population did make the G1/S transition. These few cells passed the late G1 restriction point, divided and subsequently arrested at the next G1 phase. The lack of sustained signaling events following stimulation with an APL failed to induce cyclin E:cdk2 activity, a regulator which hyper-phosphorylates and inactivates pRb. Exogenous IL-2 addition did not compensate for the lack of proliferation following APL stimulation. Furthermore, the inability of the cells to enter S phase during partial T cell activation cannot be accounted for by p27Kip1 inhibition of cyclin E:cdk2 complexes. Upon APL stimulation, an increase in association of p27Kip1 with cyclin E:cdk2 complex was not observed, suggesting that instead, decreased cyclin E:cdk complex formation might contribute to the failure to progress from G1/S. Therefore, while for a majority of cells, wild-type stimulation results in cell cycle progression, APL stimulation is not sufficient to drive cells beyond G1.     

Intra-amniotic infection and premature rupture of the membranes

Antiphospholid antibodies (APL) have a notable association with recurrent miscarriages, arterial and venous thrombosis and thrombocytopenia. Analysis of the potential pathogenic effects of such human antibodies has been hampered by the considerable difficulty in producing IgG as opposed to IgM monoclonal immunoglobulins. We have developed four human monoclonal IgG APL (LJ1, AH2, DA3 and UK4) by fusing the peripheral blood lymphocytes of three patients with SLE with a mouse human heteromyeloma cell line, CB-F7. These antibodies bind to a variety of anionic phospholipids, two (LJ1 and AH2) bind total histones but none binds to ssDNA or dsDNA. Binding to beta 2 GPI is non-specific. UK4 alone demonstrates lupus anticoagulant activity. All four have lambda light chains, two are IgG1 (AH2 and UK4) and two are IgG3 (LJ1 and DA3). These APL utilize VH genes present in the fetally restricted repertoire and multiple somatic mutations in the CDR suggest an antigen-driven process. In contrast, there is no restriction in V lambda gene usage and only one lambda chain is extensively mutated. Two clonally related hybridomas were isolated from a single patients. This supports the theory that clonal expansion is the mechanism whereby antigen selects high affinity mutations.     

赊销风险分析及应对措施探索

介绍了赊销的概念,总结了赊销的特征及赊销的主要形式,分析了在市场经济环境下赊销可能面临的各种风险。针对赊销存在的风险,提出了应对赊销风险的相关措施和降低赊销风险的几条建议,以规避或消除赊销过程中所产生的风险。     

Fine specificity of the myelin-reactive T cell repertoire: implications for TCR antagonism in autoimmunity

The use of altered peptide ligands (APL) to modulate T cell responses has been suggested as a means of treating T cell-mediated autoimmune disorders. We have assessed the therapeutic potential of TCR antagonist peptides in autoimmunity using murine experimental autoimmune encephalomyelitis (EAE) as a model. The Tg4 transgenic mouse expresses an MHC class II-restricted TCR specific for the immunodominant encephalitogenic epitope of myelin basic protein, Ac1-9 (acetylated N-terminal nonamer). We have used T cell lines derived from Tg4 mice to define the TCR contact residues within Ac1-9. APL with appropriate substitutions at the primary TCR contact residue were effective antagonists of Tg4 T cells. These antagonist APL, however, were found to induce EAE in susceptible, nontransgenic strains of mice. Underlying this, the Ac1-9-specific T cell repertoire of normal mice, rather than reflecting the Tg4 phenotype, showed considerable diversity in fine specificity and was able to respond to the Tg4 antagonist APL. Defining antagonist APL in vitro using T cell clones, therefore, was not a reliable approach for the identification of APL with EAE-suppressing potential in vivo. Our findings highlight the complexities of the autoreactive T cell repertoire and have major implications for the use of APL in autoimmune diseases.     

Professionalism as ideology: a socio-historical analysis of the discourse of professionalism in nursing

We studied 18 patients with acute promyelocytic leukaemia and 13 with relapsed APL. We found a significantly elevated EGF in acute leukaemia, especially in APL, being 418.59 +/- 19.2 micrograms in the 24-h urine that was much higher than that of the normal controls. When eight APL patients achieved complete remission by RA treatment, the EGF value decreased to 149.9 +/- 27.3 micrograms in the 24-h urine near to normal. In 13 patients with relapsed APL, EGF rose to 446.9 +/- 82.6 micrograms in the 24-h urine. Most interestingly, this elevated EGF could be detected before the relapse by 5 +/- 0.84 months in seven out of eight APL with relapse. We suggest that the unaccountably elevated EGF during remission period may be an indicator of the occurrence of relapse.