Dysregulated hemostasis in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is associated with a high incidence of early death, which occurs within 30 days of diagnosis. The major cause of early death in APL is severe bleeding, particularly intracranial bleeding. Although APL is known to be associated with activation of coagulation, hyperfibrinolysis, and thrombocytopenia, the precise mechanisms that cause bleeding have not yet been elucidated. I propose that a combination of four pathways may contribute to bleeding in APL: (1) tissue factor, (2) the urokinase plasminogen activator/urokinase plasminogen activator receptor, (3) the annexin A2/S100A100/tissue plasminogen activator, and (4) the podoplanin/C-type lectin-like receptor 2. A better understanding of these pathways will identify new biomarkers to determine which APL patients are at high risk of bleeding and allow the development of new treatments for APL-associated bleeding.

Tissue factor-bearing microparticles are a link between acute promyelocytic leukemia cells and coagulation activation: a human subject study

Acute promyelocytic leukemia (APL) cells constitutively express a large amount of tissue factor (TF) antigen, most of which is present in the cytoplasm. Coagulopathy may persist after induction therapy. We evaluated the overall role of circulating microparticles (MPs) in coagulation activation in APL-associated coagulopathy before and during induction therapy. Eleven adult patients with ≥ World Health Organization's (WHO) grade 2 bleeding events and 11 sex- and age-matched healthy controls were selected. All patients received arsenic trioxide alone as induction therapy. MP-associated TF (MP-TF) activity and MP procoagulant activity (MP-PCA) and 12 coagulation- and anticoagulation-associated indexes were measured before, during, and after induction therapy. Correlation between MP-associated indexes and the other 12 indexes was analyzed in patients. The MP-TF activity was negligible in controls, whereas it markedly increased in patients, dropped rapidly after treatment, and returned to normal at the end of induction therapy. The MP-PCA was similar between patients and controls. The correlation analysis revealed that TF-bearing MPs in patients mainly originated from APL cells. Partially differentiated APL cells could also release TF-bearing MPs, and the higher the degree of APL cell differentiation, the lower the ability of APL cells to release TF-bearing MPs. MP-TF was the main source of active TF in plasma and an important contributor for the coagulation activation in APL-associated coagulopathy. It was MPs released by APL cells/partially differentiated APL cells that served as the vehicle to transfer the large amount of TF to plasma to activate coagulation.

Types, Clinical Features, and Survival Outcomes of Patients with Acute Myeloid Leukemia in Thailand: A 3-Year Prospective Multicenter Study from the Thai Acute Leukemia Study Group (TALSG)

BACKGROUND

Acute myeloid leukemia (AML) is a common, challenging hematologic malignancy worldwide. Thai data on its characteristics and outcomes have never been systematically reported, to our knowledge. The objective of this study was to determine the clinical features and outcomes of Thai patients with AML.

PATIENTS AND METHODS

This was a prospective observational study of nine academic hospitals. Patients with newly diagnosed AML were invited to register online.

RESULTS

A total of 679 patients with AML were included. The presence of circulating peripheral blood blasts was correlated with a high white blood cell count. Acute promyelocytic leukemia (APL) had predominantly lower white blood cell counts and higher proportions without peripheral blood blasts compared with non-APL AML. Disseminated intravascular coagulation was commonly presented in APL (37.7%). Splenomegaly and normal platelet count were more frequently seen in patients with Philadelphia chromosome-positive AML. The median follow-up time for those who survived more than 1 year was 28.0 months. One-year overall survival rates for non-APL AML and APL were 31.9% and 88.2%, respectively; 2-year overall survival rates were 29.6% and 88.2%, respectively. Hematopoietic stem cell transplantation could improve survival in non-APL AML.

CONCLUSION

APL should be considered despite absence of peripheral blood blast. This study demonstrates poor outcome of Thai AML and more research to improve outcomes are underway. Expanding access to hematopoietic stem cell transplantation should be considered in Thailand.

Epigenetic activation of O-linked β-N-acetylglucosamine transferase overrides the differentiation blockage in acute leukemia

Background

Overriding the differentiation blockage in acute myeloid leukemia (AML) is the most successful mode-of-action in leukemia therapy – now curing the vast majority of patients with acute promyelocytic leukemia (APL) using all-trans retinoic acid (ATRA)-based regimens. Similar approaches in other leukemia subtypes, such as IDH1/2-mutated AML, are under active investigation. We herein present successful release of the differentiation blockage upon treatment with the natural (−)-Δ⁹-Tetrahydrocannabinol isomer dronabinol in vitro and in vivo.

Methods

Cellular maturation and differentiation were followed in two patients employing whole genome methylation profiling, proteome analyses, NGS deep sequencing and multispectral imaging flow cytometry. For functional studies lentiviral OGT knock-down in vitro and ex vivo cell models were created to evaluate proliferative, apoptotic and differentiating effects of OGT in acute leukemia.

Findings

In here, we provide molecular evidence that dronbinol is capable to override the differentiation blockage of acute leukemia blasts at the state of the leukemia-initiating clone. We further identify the O-linked β-N-acetyl glucosamine (O-GlcNAc) transferase (OGT) to be crucial in this process. OGT is a master regulator enzyme adding O-GlcNAc to serine or threonine residues in a multitude of target proteins. Aberrant O-GlcNAc modification is implicated in pathologies of metabolic, neurodegenerative and autoimme diseases as well as cancers. We provide evidence that dronabinol induces transcription of OGT via epigenetic hypomethylation of the transcription start site (TSS). A lentiviral OGT-knock out approach proves the central role of OGT exerting antileukemic efficacy via a dual-mechanism of action: High concentrations of dronabinol result in induction of apoptosis, whereas lower concentrations drive cellular maturation. Most intriguingly, overriding of the differentiation blockage of acute leukemia blasts is validated in vivo following two patients treated with dronabinol.

Interpretation

In conclusion, we provide evidence for overcoming the differentiation blockage in acute leukemia in subentities beyond promyelocytic and IDH1/2-mutated leukemia and thereby identify O-GlcNAcylation as a novel (drugable) field for future leukemia research.

Funding

Unrestricted grant support by the IZKF Program of the Medical Faculty Tübingen (MMS) and Brigitte Schlieben-Lange Program as well as the Margarete von Wrangell Program of the Ministry of Science, Research and the Arts, Baden-Württemberg, Germany (KKS) and Athene Program of the excellence initiative University of Tübingen (KKS).

Modeling dynamics and alternative treatment strategies in acute promyelocytic leukemia

Acute Promyelocytic Leukemia (APL) is a rare and potentially lethal condition in which risk-based therapy often leads to better outcomes. Because of its rarity and relatively high overall survival rate, prospective randomized trials to investigate alternative APL treatment schedules are challenging. Mathematical models may provide useful information in this regard. We collected clinical data from 38 patients treated for APL under the International Consortium on Acute Leukemia (ICAL) protocol and laboratory data during induction therapy. We propose a mathematical model that represents the dynamics of leukocytes in peripheral blood and the effect of ICAL treatment on the disease’s dynamics. We observe that our cohort presents demographic characteristics and clinical outcomes similar to previous clinical trials on APL. Over a follow-up period of 41.8 months, the relapse-free survival and overall survival at two years are both found to be 78.7%. For two selected patients, the model produces a good fit to the clinical data. Information such as the response to treatment and risk of relapse can be derived from the model, and this may assist in clinical practice and the design of clinical trials.

Effect of combination of all-trans retinoic acid and arsenic trioxide on apoptosis of acute promyelocytic leukemia cells

To study the effect of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) combination treatment on apoptosis of acute promyelocytic leukemia cells (NB4), inflammation and prognosis. The effect of ATRA - ATO combination on the proliferation of NB4 was determined using MTT assay. Apoptosis of NB4 cells was assessed with TUNEL assay. The effect of ATRA-As2O3 combination on the expressions of IL-6 and TNF-α in NB4 cells was determined using ELISA kits, while its effect on the quality of life of 25 acute promyelocytic leukemia patients admitted to our hospital was scored, as an index of prognosis. The combination treatment with ATRA and ATO significantly inhibited the proliferation of NB4 cells and promoted their apoptosis, relative to the model group. In addition, the combination treatment reduced serum IL-6 and TNF-α levels in patients with acute promyelocytic leukemia, and improve their quality of life and survival. Combination treatment with ATRA and ATO significantly inhibits the proliferation of NB4 cells and promotes their apoptosis, and reduces inflammatory responses in patients with acute promyelocytic leukemia, while improving their quality of life and prognosis.

The value of FDP/FIB and D-dimer/FIB ratios in predicting high-risk APL-related thrombosis

Hemorrhage is the typical manifestation of APL-related coagulopathy while thrombosis is infrequently reported. In a retrospective analysis with 33 patients with hyperleukocytic APL, we found 6 out of 33 hyperleukocytic APL patients presented with thrombosis rather than hemorrhage. A notable feature in these high-risk APL patients with thrombosis is that there were no significant abnormalities in fibrinogen (FIB), prothrombin time (PT) and activated partial thromboplastin time (APTT). Compared with the normal ranges, both the high-risk APL patients with thrombosis and the high-risk APL patients with hemorrhage had a significant increase in fibrinogen degradation product (FDP) and d-dimer levels. However, the group with hemorrhage had noticeably higher plasma levels of FDP and d-dimer than the group with thrombosis. To find a close relationship between coagulation markers and the onset of thrombotic events in patients with high-risk APL, the potential effects of FDP/FIB and d-dimer/FIB ratios as risk markers were investigated. We demonstrated that FDP/FIB and d-dimer/FIB ratios in the patients with high-risk APL with thrombosis showed higher ratios than the normal range but significantly lower ratios than the patients with high-risk APL-related hemorrhage. Our data demonstrated that the alteration in FDP/FIB and d-dimer/FIB ratios have more significant relevance than the levels of FIB, FDP or d-dimer as potential factors for predicting thrombosis and may help with designing more appropriately risk-adapted treatment protocols or personalized therapy.

Analysis of early death in newly diagnosed acute promyelocytic leukemia patients

The aim of this study was to identify risk factors for early death (ED) in acute promyelocitic leukemia (APL) patients.Clinical records of 49 APL patients who suffered ED were divided into 4 groups: death before treatment or within the first 3 days (immediate death; iED group), death during treatment at least 3 days after commencement (ED after treatment), low/intermediate risk, and high-risk groups.White blood cell (WBC) count, high-risk cases, prothrombin time (PT) prolongation, international society on thrombosis and hemostasis (ISTH) scores (P < .05), bleeding (P = .05), and death due to severe hemorrhage (P = .010) were higher in iED group than ED after treatment. And the time from onset to initial hospitalization or death was significantly shorter (P < .05) in iED patients. LDH level (P = .002), PT prolongation (P = .014), and incidence of grades 3 or 4 bleeding (P = .049) were higher in high-risk group than in ED and low/intermediate-risk groups, while the times from onset to the initial hospitalization or death were lower for ED patients in high-risk group (P = .037).We found that different types of EDs have different clinical features. A high WBC count contributes to the occurrence of more ED, which is usually not associated with delay of diagnosis and hospitalization. Current therapeutic strategies to reduce the incidence of ED in these cases are not adequate and will benefit from focused research attention.

Analysis of factors affecting hemorrhagic diathesis and overall survival in patients with acute promyelocytic leukemia

BACKGROUND/AIMS

This study investigated whether patients with acute promyelocytic leukemia (APL) truly fulfill the diagnostic criteria of overt disseminated intravascular coagulation (DIC), as proposed by the International Society on Thrombosis and Haemostasis (ISTH) and the Korean Society on Thrombosis and Hemostasis (KSTH), and analyzed which component of the criteria most contributes to bleeding diathesis.

METHODS

A single-center retrospective analysis was conducted on newly diagnosed APL patients between January 1995 and May 2012.

RESULTS

A total of 46 newly diagnosed APL patients were analyzed. Of these, 27 patients (58.7%) showed initial bleeding. The median number of points per patient fulfilling the diagnostic criteria of overt DIC by the ISTH and the KSTH was 5 (range, 1 to 7) and 3 (range, 1 to 4), respectively. At diagnosis of APL, 22 patients (47.8%) fulfilled the overt DIC diagnostic criteria by either the ISTH or KSTH. In multivariate analysis of the ISTH or KSTH diagnostic criteria for overt DIC, the initial fibrinogen level was the only statistically significant factor associated with initial bleeding (p = 0.035), but it was not associated with overall survival (OS).

CONCLUSIONS

Initial fibrinogen level is associated with initial presentation of bleeding of APL patients, but does not affect OS.

The influence of joint application of arsenic trioxide and daunorubicin on primary acute promyelocytic leukaemia cells and apoptosis and blood coagulation of cell strain

This test cultivated three groups of acute promyelocytic leukemia (APL) and NB4 cells in liquid in vitro, processed them with arsenic trioxide (ATO), daunorubicin (DNR), ATO+DNR respectively, and then set up blank control group. Apoptosis of cells in each group was observed using flow cytometry, procoagulant activity of APL and NB4 cells in each group was detected with recalcification time, and expressions of tissue factor (TF), thrombomodulin and annexin II of NB4 cells in each group were measured using ELISA method. The results showed that the apoptosis rate increased 4-8 times compared with blank control group after processing APL and NB4 cells with ATO and DNR; procoagulant activity decreased obviously; and expression of TF and annexin II of NB4 cells reduced significantly (P<0.05). We concluded that combination of ATO and DNR could promote APL and NB4 cell apoptosis effectively without aggravating blood coagulation disorders, which might improve coagulation function of APL by inhibiting coagulation and hyperfibrinolysis through reducing expression of TF and annexin II. This drug combination may be a safe and effective method in the treatment of APL of primary high white blood cells type.

Knockdown of Adhesion-Regulating Molecule 1 Inhibits Proliferation in HL60 Cells

BACKGROUND/AIMS

Adhesion-regulating molecule 1 (ADRM1), a receptor located on the 26S proteasome, is upregulated in many solid cancers. However, little is known about its role in acute leukemia (AL).

METHODS

We determined ADRM1 expression levels in both untreated AL samples and leukemia cell lines using real-time polymerase chain reaction or Western blot analysis. Growth curves, colony formation assays, cell cycle and apoptosis analyses, cell migration and invasion assays and NF-κB p65 nuclear translocation assays via Western blotting were used to examine the biological behavior of HL60 cells and the underlying mechanism.

RESULTS

ADRM1 was upregulated in both untreated AL samples and leukemia cell lines. ADRM1 knockdown significantly suppressed HL60 cell proliferation (48.82 ± 12.58%) and colony formation and caused cell cycle arrest in the G0/G1 phase. Furthermore, we confirmed that ADRM1 knockdown suppressed p65 nuclear translocation.

CONCLUSION

Our study revealed that ADRM1 was overexpressed in AL, especially in CD34+ leukemia stem and progenitor cells. ADRM1 may play a role in AL via the proteasome-ubiquitin pathway by potentially sustaining the activation of NF-κB signaling.

Comparison of newly diagnosed and relapsed patients with acute promyelocytic leukemia treated with arsenic trioxide: insight into mechanisms of resistance

There is limited data on the clinical, cellular and molecular changes in relapsed acute promyeloytic leukemia (RAPL) in comparison with newly diagnosed cases (NAPL). We undertook a prospective study to compare NAPL and RAPL patients treated with arsenic trioxide (ATO) based regimens. 98 NAPL and 28 RAPL were enrolled in this study. RAPL patients had a significantly lower WBC count and higher platelet count at diagnosis. IC bleeds was significantly lower in RAPL cases (P=0.022). The ability of malignant promyelocytes to concentrate ATO intracellularly and their in-vitro IC50 to ATO was not significantly different between the two groups. Targeted NGS revealed PML B2 domain mutations in 4 (15.38%) of the RAPL subset and none were associated with secondary resistance to ATO. A microarray GEP revealed 1744 genes were 2 fold and above differentially expressed between the two groups. The most prominent differentially regulated pathways were cell adhesion (n=92), cell survival (n=50), immune regulation (n=74) and stem cell regulation (n=51). Consistent with the GEP data, immunophenotyping revealed significantly increased CD34 expression (P=0.001) in RAPL cases and there was in-vitro evidence of significant microenvironment mediated innate resistance (EM-DR) to ATO. Resistance and relapse following treatment with ATO is probably multi-factorial, mutations in PML B2 domain while seen only in RAPL may not be the major clinically relevant cause of subsequent relapses. In RAPL additional factors such as expansion of the leukemia initiating compartment along with EM-DR may contribute significantly to relapse following treatment with ATO based regimens.

Thrombomodulin alfa treatment in patients with acute promyelocytic leukemia and disseminated intravascular coagulation: a retrospective analysis of an open-label, multicenter, post-marketing surveillance study cohort

INTRODUCTION

Patients with acute promyelocytic leukemia (APL) can develop disseminated intravascular coagulation (DIC) that results in life-threatening hemorrhagic complications. Studies regarding the safety and efficacy of thrombomodulin alfa (TM-α; recombinant human soluble thrombomodulin) in patients with APL and DIC are limited.

MATERIALS AND METHODS

A retrospective evaluation was performed on a cohort of 172 patients with APL from an open-label, multicenter, post-marketing surveillance study of TM-α.

RESULTS

Of the 172 patients, 31 were relapse/refractory APL patients, and 141 were newly diagnosed APL patients. Within the first 30 days, 24 patients (14.0%) died, and six of those deaths (3.5%) were due to hemorrhage. In total, 12 patients (7.0%) had severe hemorrhagic complications. Both the early death rate due to hemorrhage as well as the severe hemorrhage rate did not exceed those in some recent population-based studies of patients with APL. Forty-nine patients received TM-α prior to the initiation of antileukemic treatment, and one patient experienced hemorrhagic early death (ED), suggesting that early TM-α treatment appeared to result in a reduction in the hemorrhagic ED rate. Moreover, TM-α improved coagulopathy regardless of concomitant all-trans retinoic acid treatment.

CONCLUSIONS

This study confirmed the safety and efficacy of TM-α in daily clinical practice for patients with APL and DIC. TM-α appeared to reduce hemorrhagic early deaths due to DIC in patients with APL who were receiving antileukemic treatment.

[A woman with shortness of breath and butterfly shaped cell nuclei]

A 53-year-old woman with respiratory discomfort came to the Emergency Department. The blood smear, made because of a new thrombocytopenia, showed leukocytes with butterfly-shaped nuclei and fine cytoplasmic granulation. The diagnosis 'microgranular variant of acute promyelocytic leukemia' was made.

Arsenic methylation metabolism and liver injury of acute promyelocytic leukemia patients undergoing arsenic trioxide treatment

Although arsenic is effective in the treatment of acute promyelocytic leukemia (APL), as a well-known environmental toxicant, the side effects of arsenic treatment and arsenic methylation metabolism of the patients are rarely reported. In this manuscript, we investigated 23 APL patients treated with 10 mg arsenic trioxide daily, detected the arsenic metabolites in urine samples collected on the 0, 10th, and 20th day of arsenic treatment. At the same time, liver function and blood routine examination were also investigated in these APL patients. We found that, urinary monomethylated arsenic proportion (MMA%) increased, but dimethylated arsenic proportion (DMA%), the first methylation ratio (FMR) and the secondary methylation ratio (SMR) decreased with consecutive administration of arsenic trioxide. After adjustment for age impact, no statistical difference was observed in urinary arsenic concentrations and arsenic methylation capacity between male and female at the same treatment time point. During arsenic trioxide treatment of APL, transient elevation of serum aminotransferases was found in the blood samples, which indicated that liver injury occurred and probably reversible. Leukocytosis developed in 5 of the 23 patients with the administration of arsenic trioxide. No statistical difference was observed in the other blood routine examination parameters. These results demonstrated that the capacity of arsenic methylation decreased and transient liver injury occurred during arsenic trioxide treatment of APL, which indicated that the side effects of clinical arsenic treatment can not be ignored.

[Treatment of adult patients with acute promyelocytic leukemia according to the AIDA protocol]

AIM

To give the results of an investigation conducted at the Hematology Research Center (HRC), Ministry of Health of the Russian Federation (MHRF), to treat adult patients with acute promyelocytic leukemia (APL) according to the AIDA protocol elaborated by Spanish investigators.

SUBJECTS AND METHODS

The investigation enrolled 33 patients diagnosed with APL verified by cytogenetic and molecular studies, who had been treated at the HRC, MHRF, in July 2009 to January 2012. The patients classified in the low-, intermediate-, and high-risk groups were 30, 46.7; and 23.3%, respectively. The analysis was made in January 2013.

RESULTS

The number of patients who achieved complete remission, as well as the mortality rates during remission induction were wholly comparable to those previously obtained when using the 7+3+ATRA protocol: 90.3 and 9.7%, respectively. One patient in remission died (3.6% mortality rate). The likelihood of recurrence in this investigation was high (21%), which was due to gross noncompliance with maintenance therapy. On examining the clearance of the malignant clone by FISH and polymerase chain reaction, a naturally chimeric transcript identified by a molecular study was statistically significantly more frequently revealed during postinduction therapy, which was associated with different sensitivity of the techniques. Comparison of changes in the disappearance of a chimeric marker for APL with the AIDA and 7+3+ARTA programs showed that the clearance of the malignant clone was much slower.

CONCLUSION

The AIDA program is a highly effective treatment protocol for patients with APL.

[Detection of tissue factor-positive microparticles and its clinical significance in the haemostatic disorder]

Objective of this study was to detect the level of tissue factor-positive microparticles (TF(+)MP) by flow cytometry (FCM) and to analyze its clinical significance in the haemostatic disorder. TF(+) MP was detected by FCM using antibody CD142-PE in 25 cases of acute promyelocytic leukemia (APL), 20 cases of hemostatic diseases and 20 healthy adults as controls. The differences of TF(+) MP between various groups were determined. The results showed that the level of TF(+) MP in the patients with thrombotic complications was significantly higher than that in the healthy adults (P < 0.05). The TF(+) MP level was higher in the patient with APL than that in the healthy adults, especially in course before therapy (P < 0.01), but the difference was not statistically significant in the patient with APL after therapy and the healthy adults. Among these patient with APL, the level of TF(+) MP in the 18 patients who complicated with disseminated intravascular coagulation (DIC) was also higher than that in the healthy adults (P < 0.05), but the level of TF(+) MP in the other 7 patients who did not complicate with DIC was similar before and after treatment. It is concluded that the method of TF(+) MP detection by FCM is feasible and simple, it is useful for the diagnosis of thrombotic disorder, and helps evaluation for the prognosis of APL patient.

Halofuginone has anti-proliferative effects in acute promyelocytic leukemia by modulating the transforming growth factor beta signaling pathway

Promyelocytic leukemia-retinoic acid receptor alpha (PML-RARα) expression in acute promyelocytic leukemia (APL) impairs transforming growth factor beta (TGFβ) signaling, leading to cell growth advantage. Halofuginone (HF), a low-molecular-weight alkaloid that modulates TGFβ signaling, was used to treat APL cell lines and non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice subjected to transplantation with leukemic cells from human chorionic gonadotrophin-PML-RARα transgenic mice (TG). Cell cycle analysis using incorporated bromodeoxyuridine and 7-amino-actinomycin D showed that, in NB4 and NB4-R2 APL cell lines, HF inhibited cellular proliferation (P<0.001) and induced apoptosis (P = 0.002) after a 24-hour incubation. Addition of TGFβ revealed that NB4 cells were resistant to its growth-suppressive effects and that HF induced these effects in the presence or absence of the cytokine. Cell growth inhibition was associated with up-regulation of TGFβ target genes involved in cell cycle regulation (TGFB, TGFBRI, SMAD3, p15, and p21) and down-regulation of MYC. Additionally, TGFβ protein levels were decreased in leukemic TG animals and HF in vivo could restore TGFβ values to normal. To test the in vivo anti-leukemic activity of HF, we transplanted NOD/SCID mice with TG leukemic cells and treated them with HF for 21 days. HF induced partial hematological remission in the peripheral blood, bone marrow, and spleen. Together, these results suggest that HF has anti-proliferative and anti-leukemic effects by reversing the TGFβ blockade in APL. Since loss of the TGFβ response in leukemic cells may be an important second oncogenic hit, modulation of TGFβ signaling may be of therapeutic interest.

Hematopoietic stem cell transplantation in acute promyelocytic leukemia, experience in Iran

BACKGROUND

Acute promyelocytic leukemia is a rare indication for hematopoietic stem cell transplantation. Usually it is indicated as consolidation of salvage regimens following relpase. Here we report our experience with stem cell transplantation in acute promyelocytic leukemia patients.

METHODS

Between 1989 and 2011, we performed 40 hematopoietic stem cell transplantation in first complete remission or relapsed acute promyelocytic leukemia patients. Median age of patients was 23.5 years. Patients received 11 autologous and 29 allogeneic hematopoietic stem cell transplantation from their HLA fully-matched sibling donors. Different conditioning regimens were applied. A total of 24 patients received hematopoietic stem cell transplantation who were in first complete remission and the remainder with a second or more complete remission.

RESULTS

Hematopoietic stem cell engraftment was observed in all cases. There were no deaths prior to 100 days after hematopoietic stem cell transplantation. Acute graft versus host disease was mild to moderate in the majority of patients, whereas it was grade III in 4 patients. Chronic graft versus host disease was extensive in 2 cases. With a 4-year median follow up, the relapse rate was 25%. A total of 26 patients are alive. Five year overall survival was 65.5% and 46.8% for allogeneic and autologous hematopoietic stem cell transplantation, respectively.

CONCLUSION

Hematopoietic stem cell transplantation is an acceptable treatment for acute promyelocytic leukemia. Although there is a statistical difference for overall survival between allogeneic or autologous hematopoietic stem cell transplantation, the choice between autologous or allogeneic transplantation needs to have reliable methods for the detection of molecular remission before hematopoietic stem cell transplantation as well as close, reliable follow up of patients with clinical and molecular parameters.

[Blood coagulation parameters in children with acute promyelocytic leukemia, their changes during all-trans retinoic acid treatment, and causes of hemorrhagic and thrombotic events]

The specific feature of acute promyelocytic leukemia (APL) is blood coagulation impairments that appear as thrombohemorrhagic disorders with a possible fatal outcome. The pathogenesis of bleeding in APL is due to the properties of leukemic promyelocytes; however, little is known about the causes of venous thrombosis in APL. This circumstance determined the objective of the investigation, which was to study the functional state of blood coagulation over time during treatment for APL and to reveal the causes of thromboses in children with this condition. There was a relationship of the Leiden mutation in patients with APL to the development of thrombosis (p = 0.009). Vein catheterization and puncture are other provoking factors of thrombosis.

Phosphatidylserine exposure and procoagulant activity in acute promyelocytic leukemia

BACKGROUND

Acute promyelocytic leukemia (APL) frequently causes disseminated intravascular coagulation that can worsen with cytotoxic chemotherapy but improve with the therapeutic differentiating agents, all trans retinoic acid (ATRA) and arsenic trioxide (As(2)O(3)). APL cells display tissue factor but the relationship of tissue factor and other procoagulant activity to phosphatidylserine (PS) exposure is largely unknown.

METHODS

Lactadherin, a milk protein with stereospecific binding to phosphatidyl-L-serine, was used as a probe for PS exposure on an immortalized APL cell line (NB4) and on the cells of eight patients with APL. PS exposure was evaluated with flow cytometry, confocal microscopy, coagulation assays, and purified prothrombinase and factor (F) Xase assays.

RESULTS

Plasma procoagulant activity of NB4 and APL cells increased approximately 15-fold after exposure to etoposide or daunorubicin and decreased 80% after treatment with ATRA or As(2)O(3). Procoagulant activity corresponded to exposed PS on viable APL cells. PS exposure decreased after treatment with ATRA or As(2)O(3) and increased after treatment with daunorubicin or etoposide. Excess lactadherin inhibited 80-85% of intrinsic FXase, FVIIa-tissue factor and prothrombinase activities on both NB4 cells and APL cells. Confocal microscopy identified membrane patches that stained with lactadherin, but not annexin V, demonstrating focal, low-level PS exposure.

CONCLUSIONS

PS is exposed on viable APL cells and is necessary for approximately 80% of procoagulant activity.

A case of ischemic stroke in acute promyelocytic leukemia at initial presentation. Relevance of all-trans retinoic acid treatment

Acute promyelocytic leukemia (APL) is frequently associated, often from the earliest phases, with a life-threatening coagulation/bleeding syndrome; disseminated intravascular coagulation (DIC) is described in majority of patients. We report a case of 49-year-old male, without cardiovascular risk factors, who suddenly developed ischemic stroke and splenic infarction as presenting symptoms of APL and related DIC. The patient was immediately treated with all-trans retinoic acid (ATRA) and the alterations of hemocoagulation parameters promptly returned in normal range. The coagulation/bleeding syndrome of the onset of APL is associated with high mortality; both diagnostic and therapeutic approaches require special and timely consideration of this condition. Treatment with ATRA is essential.

A case of acute promyelocytic leukemia showing transient thrombocytosis caused by increased interleukin-6 and thrombopoietin after treatment with all-trans retinoic acid and chemotherapy

A patient with acute promyelocytic leukemia(APL)treated with all-trans retinoic acid(ATRA)and chemotherapy for remission induction developed marked thrombocytosis after bone marrow recovery. Thrombocytosis also occurred after post remission chemotherapies, although the degree of thrombocytosis gradually decreased. During thrombocytosis, plasma levels of interleukin-6(IL-6)were elevated while those of thrombopoietin(TPO)were not elevated. However, the plasma level of TPO was markedly elevated at the nadir after post remission chemotherapy. These findings suggest that in APL patients, thrombocytosis after treatment with ATRA and or chemotherapy may be caused by increased plasma levels of both of IL-6 and TPO.

Successful treatment by all-trans retinoic acid in a patient with acute promyelocytic leukemia complicated by liver cirrhosis and polycystic kidney

Although all-trans retinoic acid (ATRA) is widely used in acute promyelocytic leukemia (APL), there is little data as to whether or not ATRA is useful for patients with liver and renal failure. A 63-year-old APL patient, complicated by Child-Pugh class A liver cirrhosis and chronic renal failure (creatinine 3.2 mg/dL), was successfully treated with 45 mg/m(2)/day of ATRA. With three courses of chemotherapy, complete remission has been maintained for four years in this patient. Serum trough and maximum ATRA concentration, and the area under the curve (AUC) were not elevated. These observations suggest that full-dose ATRA therapy might be safely applicable to such a complicated case with APL.

As2O3enhances the anion transport activity of band 3 and the action is related with the C-terminal 16 residues of the protein

Successful application of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL) has been attracting worldwide interest, but the exact mechanism for the action of As2O3 remains somewhat obscure. In the present work, we show for the first time that As2O3 facilitates the DIDS-sensitive anion transport activity of band 3 protein in red blood cells (RBCs) isolated from normal adults and APL patients. To elucidate the effect of As2O3 on band 3 protein, constructs encoding the full length of the band 3 transmembrane domain (mdb3) and its C-terminal deletion forms were transfected into yeast cells by a yeast display system. The results demonstrate that deletion of the C-terminal 16 residues of mdb3 (mdb3-d16) does not affect anion transport activity of mdb3 or its sensitivity to DIDS, but decreases its sensitivity to As2O3 in the yeast cell. More intriguingly, the forced expression of intact mdb3 by transfection significantly induces cell apoptosis in HeLa cells, to a higher degree than in cells transfected with mdb3-d16 or empty vector. Expression of activated caspase 3 in HeLa cells also indicates that the C-terminal 16 residues are important for mdb3-mediated apoptosis in cells treated with As2O3. Our results provide the first evidence that As2O3 enhances the anion transport activity of band 3 and the action is related with the C-terminal 16 residues of the protein.

Endothelial cell annexin A2 regulates polyubiquitination and degradation of its binding partner S100A10/p11

The annexin A2 (A2) heterotetramer, consisting of two copies of A2 and two copies of S100A10/p11, promotes fibrinolytic activity on the surface of vascular endothelial cells by assembling plasminogen and tissue plasminogen activator (tPA) and accelerating the generation of plasmin. In humans, overexpression of A2 by acute promyelocytic leukemia cells is associated with excessive fibrinolysis and hemorrhage, whereas anti-A2 autoantibodies appear to accentuate the risk of thrombosis in patients with anti-phospholipid syndrome. Complete deficiency of A2 in mice leads to a lack of tPA cofactor activity, accumulation of intravascular fibrin, and failure to clear arterial thrombi. Within the endothelial cell, p11 is required for Src kinase-mediated tyrosine phosphorylation of A2, which signals translocation of both proteins to the cell surface. Here we show that p11 is expressed at very low levels in the absence of A2 both in vitro and in vivo. We demonstrate further that unpartnered p11 becomes polyubiquitinated and degraded via a proteasome-dependent mechanism. A2 stabilizes intracellular p11 through direct binding, thus masking an autonomous p11 polyubiquitination signal that triggers proteasomal degradation. This interaction requires both the p11-binding N-terminal domain of A2 and the C-terminal domain of p11. This mechanism prevents accumulation of free p11 in the endothelial cell and suggests that regulation of tPA-dependent cell surface fibrinolytic activity is precisely tuned to the intracellular level of p11.

Effect of dialysis on all trans retinoic acid levels in a child with acute promyelocytic leukemia and renal failure

All trans retinoic acid (ATRA) combined with chemotherapy has become the mainstay of treatment for patients with acute promyelocytic leukemia (APL). Renal dysfunction (RD) is commonly seen in patients with APL. We describe a patient with APL and multi-organ failure, who was on chronic veno-venous hemofiltration followed by hemodialysis (HD) and later peritoneal dialysis (PD), who received ATRA. ATRA levels were assessed as the body clearance of ATRA in children on HD and/or PD was unknown. Neither HD nor PD significantly affected ATRA levels, suggesting that dose modifications of ATRA may not be necessary for children with these forms of renal replacement therapy.

Detecting PML-RARalpha transcript in acute promyelocytic leukemia using real-time quantitative RT-PCR

BACKGROUND

Real-time quantitative RT-PCR (RQ-PCR) assay has become a vital tool to monitor residual disease of leukemia. However, the complexity and standardization of RQ-PCR should never be overlooked and the results should be interpreted cautiously in clinical conditions. We aimed to assess the methodology of RQ-PCR and its clinical applications in monitoring molecular kinetics of 36 newly diagnosed cases of acute promyelocytic leukemia patients with t (15; 17) from October 2004 to December 2005.

METHODS

All the TaqMan probe-based RQ-PCR reactions and analysis were performed on an ABI-PRISM 7,500 platform. The quantitation of PML-RARalpha transcripts was represented by the normalized quotient, that is, PML-RARalpha transcript copies divided by ABL transcript copies. According to induction therapy, the patients were classed into two groups: group 1 (n = 23), three-drug combination including arsenics, all-trans retinoic acid and mitoxantrone; and group 2 (n = 13), two-drug combination from all-trans retinoic acid, arsenics and mitoxantrone.

RESULTS

The sensitivity of RQ-PCR was 1 per 10(5) cells and 5 copies of the PML-RARalpha transcript could be reproducibly detected. No false positive results occurred in 40 non-acute promyelocytic leukemia samples. Optimal amplification efficiency could be attained, which was determined by the slope of the standard curves (slope: -3.2 - -3.7). The inter-assay and intra-assay variation coefficients of the method were 1.01% and 0.56% respectively. Although the time to attain hematological complete remission was similar in both groups, the time to achieve molecular remission of group 1 was significantly shorter than that of group 2 (61 days vs 75 days, P = 0.034). The rate of molecular remission within 70 days was higher in group 1 than in group 2 (75.00% vs 38.46%, P = 0.036). Compared with pretreatment, median reduction of the PML-RARalpha transcript before first consolidation therapy differed significantly between group 1 and group 2 (log scale, 3.15 vs 2.31, P = 0.024). Interestingly, we found that PML-RARalpha transcript levels temporarily increased in bone marrow (7 patients) and peripheral blood (22 patients) samples of patients during induction therapy in both groups.

CONCLUSIONS

The RQ-PCR assay is reliable for the detection of PML-RARalpha transcripts. Arsenics, all-trans retinoic acid and mitoxantrone triad induction treatment of acute promyelocytic leukemia is superior to two-drug combination induction therapy in terms of the molecular response.

Annexinopathies

Annexins comprise a conserved family of proteins characterised by their ability to bind and order charged phospholipids in membranes, often in response to elevated intracellular calcium. The family members (there are at least 12 in humans) have become specialised over evolutionary time and are involved in a diverse range of cellular functions both inside the cell and extracellularly Although a mutation in an annexin has never been categorically proven to be the cause of a disease state, they have been implicated in pathologies as diverse as autoimmunity, infection, heart disease, diabetes and cancer. 'Annexinopathies' were first described by Jacob H. Rand to describe the pathological sequelae in two disease states, the overexpression of annexin 2 in a patients with a haemorrhagic form of acute promyelocytic leukaemia, and the under-expression of annexin 5 on placental trophoblasts in the antiphospholipid syndrome. In this chapter we will outline some of the more recent observations in regard to these conditions, and describe the involvement of annexins in some other major causes of human morbidity.

Using quantification of the PML-RARalpha transcript to stratify the risk of relapse in patients with acute promyelocytic leukemia

BACKGROUND AND OBJECTIVES

The detection of PML-RARalpha by real-time polymerase chain reaction (RQ-PCR) is becoming an important tool for monitoring minimal residual disease (MRD) in patients with acute promyelocytic leukemia (APL). However, its clinical value remains to be determined. Our aim was to analyze any associations between the risk of relapse and RQ-PCR results in different phases of treatment, comparing these data with those yielded by conventional qualitative reverse transcriptase-PCR.

DESIGN AND METHODS

Follow-up samples from 145 APL patients treated with the PETHEMA protocols were evaluated by the RQ-PCR protocol (Europe Against Cancer program) and by the RT-PCR method (BIOMED-1 Concerted Action). Hematologic and molecular relapses and relapse-free survival were recorded. We then looked for associations between relapse risk and RQ-PCR results.

RESULTS

After induction therapy, no association was found between positive RQ-PCR results and relapse. The PCR result here did not imply any change in the scheduled therapy. After the third consolidation course, two out of three cases with positive RQ-PCR relapsed in contrast to 16 out of 119 (13%) patients with negative RQ-PCR. During maintenance therapy and out-of treatment, all patients with >10 PML-RARalpha normalized copy number (NCN) (n=19) relapsed while all patients with <1 NCN at the end of the study remained in hematologic remission (p<0.0001). In the intermediate group (NCN 1-10) (n=18), the relapse-free survival at 5 years was 60%. Hematologic relapses were predicted if a positive RQ-PCR result had been obtained in a follow-up sample within the previous 4 months.

INTERPRETATION AND CONCLUSIONS

Based on the information provided by RQ-PCR in samples obtained after the end of consolidation and subsequently, a relapse risk stratification could be established for APL patients. This stratification divides patients into three groups: those at high risk of relapse, those with an intermediate risk and those with a low risk of relapse.

Outcome of patients with acute promyelocytic leukemia failing to front-line treatment with all-trans retinoic acid and anthracycline-based chemotherapy (PETHEMA protocols LPA96 and LPA99): benefit of an early intervention

To determine prognosis of acute promyelocytic leukemia (APL) failing to front-line therapy with all-trans retinoic acid (ATRA) and anthracyclines, outcome of 52 patients (32 M/20 F; age: 37, 3-72) included in PETHEMA trials LPA96 and LPA99 who presented with either molecular failure (MOLrel, n=16) or hematological relapse (HEMrel, n=36) was analyzed. Salvage therapy consisted of ATRA and high-dose ara-C-based chemotherapy (HDAC) in most cases (83%), followed by stem-cell transplantation (autologous, 18; allogeneic, 10; syngeneic, 1). Fourteen patients with MOLrel (88%) achieved second molecular complete response (molCR), whereas 81% HEMrel patients responded to second-line treatment, with 58% molCR. After median follow-up of 45 months, four MOLrel and 18 HEMrel patients, respectively, experienced a second relapse. Outcome after MOLrel compared favorably to HEMrel, with longer survival (5-year survival: 64+/-14 vs 24+/-8%, P=0.01) and lower relapse risk (5-year relapse risk: 30+/-13 vs 64+/-9%; P=0.044). Additionally, age <or=40 and male gender were favorable variables for survival, whereas molecular response predicted longer leukemia-free survival. In conclusion, early institution of salvage therapy at molecular failure, before onset of hematological relapse, is beneficial in APL. Moreover, given the poor outcome of HEMrel managed with ATRA and HDAC, use of alternative therapeutic strategies in this setting is warranted.

Increased oxidative DNA products in patients with acute promyelocytic leukemia during arsenic therapy

Arsenic trioxide (ATO) has been used to treat acute promyelocytic leukemia (APL), but the oxidative DNA damage occurring in patients has not been fully elucidated. We measured 8-hydroxy-2'-deoxyguanosine (8-OHdG), one of the most abundant oxidative products of DNA, by enzyme-linked immunoassay, and reactive oxidative species (ROS), by luminol- and luminol-H2O2 chemiluminescence, in the plasma of four APL patients treated with ATO. After six courses of ATO therapy, the plasma 8-OHdG concentration had increased from 45.6+/-22.8 ng/mL to 310.2+/-239.6 ng/mL. The plasma chemiluminescence level did not change significantly. These findings suggest that ATO generates intracellular oxidative DNA damage, but this is not correlated with the plasma ROS level. The clinical significance of 8-OHdG during and after ATO therapy warrants further study.

[Haematological characteristics, FAB and WHO classification of 153 cases of myeloid acute leukaemia in Tunisia]

A complete blood analysis with a careful morphologic examination of peripheral blood and bone morrow smears completed by cytochemical reaction will help to classify the most acute myeloid leukaemia (AML). Actually, the study of other cytogenetis and immunophenotypic markers are now necessary to confirm diagnosis. The World Health Organisation WHO classification (2001) incorporates theses approaches. The purpose of this study is a bio-clinical review according to the WHO recommendations in 153 cases of LAM diagnosed between January 1998 and December 2003. The patients were aged 2 months to 90 years with sex ratio (M/F) of 1,22. The morphologic conclusion was difficult in 12% cases. Presence of dysplasia is noted in 50% of cases with multilineage dysplasia in 42% of cases. Our results showed cloned chromosomal abnormalities in 57% of cases (t(8;21): 12%, t(15;17) : 10%, Inv16: 1,3%, 11q23: 2,6% et complex karyotype: 14,3%). In 69% of cases with multilineage dysplasia, the karyotype was normal. 3 cases of LAM were noted at patients treated for breast cancer with chirurgic chemotherapy and radiotherapy 3, 4 et 5 years after treatment (LAM3 with t(15;17), LAM4 with genetic abnormalities of chromosomes 3, 5, 7, 8, 9, 14 et 16 et LAM 6 with genetic abnormalities of chromosomes 4, 7, 12, 14, 19 et 21). In WHO classification, cytology is essential in diagnosis of LAM even if the karytype have an important prognostic value. Research of signs of dysplasia lineage after lineage constitutes an important microscopic work and it is difficult to quantify dysplasia when the lineage is poor.

Occurrence of thrombotic events in acute promyelocytic leukemia correlates with consistent immunophenotypic and molecular features

Although the occurrence of thrombosis in acute promyelocytic leukemia (APL) has been reported during retinoic acid treatment, no studies carried out in large clinical cohorts have specifically addressed this issue. We analyzed 124 APL patients treated with the all-trans retinoic acid and idarubicin protocol and compared clinico-biologic characteristics of 11 patients who developed thrombosis with those of 113 patients who had no thrombosis. In seven patients, the events were recorded during induction, whereas in four patients deep vein thrombosis occurred in the post-induction phase. Comparison of clinico-biological characteristics of patients with and without thrombosis revealed in the former group higher median white blood cell (WBC) count (17 x 10(9)/l, range 1.2-56, P=0.002), prevalence of the bcr3 transcript type (72 vs 48%, P=0.01), of FLT3-ITD (64 vs 28%, P=0.02), CD2 (P=0.0001) and CD15 (P=0.01) expression. No correlation was found with sex, age, French-American-British subtype, all-trans-retinoic acid syndrome or with thrombophilic state that was investigated in 5/11 patients. Our findings suggest that, in APL patients consistent biologic features of leukemia cells may predict increased risk of developing thrombosis.

Effects of arsenic trioxide administration styles on leukocytosis

OBJECTIVE

To study the effects of constantly slow intravenous arsenic trioxide (As2O3) infusion regimen on decreasing leukocytosis in vivo and in vitro.

METHODS

Three kinds of leukemia cells, NB4, K562, and acute promyelocytic leukemia (APL) cells, were cultured in the media with constant concentration and varying concentrations of As2O3 respectively for 24 hours. Seventy-five patients were enrolled in two groups randomly. In trial group, 37 patients received continuously slow intravenous As2O3 infusion regimen for 24 hours with an infusion rate of 8 drips per minute and total infusion duration of about 18-21 hours daily. In control group, 38 patients received routine regimen with an infusion rate of 45-55 drips per minute and total infusion duration of about 2-3 hours daily for 24 hours. The daily As2O3 dosage was 0. 16 mg/kg. The intracellular arsenic concentration was measured by atomic fluorescence assay. The apoptosis rate of cells, CD33- CD11b+ cells, and CD33+ CD11b- cells were monitored by flow cytometry.

RESULTS

The apoptosis rates of NB4, K562, and APL leukemia cells in the media with constant As2O3 concentration were 56.6% +/- 2.4%, 27.6% +/- 3.1%, and 52.2% +/- 2.8%, respectively, which were significantly higher than those with changing As2O3 concentration (23.2% +/- 2.1%, 11.0% +/- 2.5%, and 21.0% +/- 2.5%, respectively, P < 0.01). The apoptosis rates of APL, M2 type acute myeloid leukemia (AML-M2), and chronic myeloid leukemia (CML) patients in the trial group (28.5% +/- 1.9%, 9.5% +/- 0.6%, and 12.5% +/- 1.8%) were also significantly higher than those in control group (8.5% +/- 2.2%, 2. 9% +/- 0.8%, and 4.5% +/- 1.2%; P < 0.05). The ratios of CD33 CD11b- and CD33- CD11b+ cells in control group were significantly higher than those in trial group.

CONCLUSION

The continuously slow intravenous As2O3 infusion regimen can obtain high efficiency of apoptosis and low differentiation proportion, relieve leukocytosis, and gain maximal therapeutic benefit.

Use of all-trans retinoic acid plus arsenic trioxide as an alternative to chemotherapy in untreated acute promyelocytic leukemia

We examined whether combining all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) might be an alternative to ATRA plus chemotherapy in untreated acute promyelocytic leukemia (APL). Twenty-five low-risk patients (white blood cell [WBC] count less than 10 × 109/L [10 000/μL]) received ATRA (45 mg/m2 daily) and ATO (0.15 mg/kg daily, beginning day 10 of ATRA), and in complete remission (CR) received ATO plus ATRA, without chemotherapy, unless they were reverse transcriptase–polymerase chain reaction (RT-PCR)–positive 3 months from CR date or had molecular relapse. Nineteen high-risk patients were treated identically, but received chemotherapy, generally 9 mg/m2 gemtuzumab ozogamycin (GO) on day 1 of induction. The CR rate was 39 of 44 (24 of 25 in low-risk, 15 of 19 in high-risk). Disease recurred at 9, 9, and 15 months, respectively, in 3 high-risk patients. The median follow-up time from CR date in the 36 patients alive in first CR is 16 months (15 months in low-risk, 20 months in high-risk), with 9 patients followed for at least 24 months. Each of the 36 patients was PCR-negative at last follow-up. Thus, none of the low-risk patients has received chemotherapy, and only 3 high-risk patients (the 3 with relapsed disease) have received chemotherapy past induction. ATRA plus ATO may serve as an alternative to chemotherapy in low-risk untreated APL (eg, in older patients) and, when combined with GO, may improve outcome in high-risk patients.

Single-agent arsenic trioxide in the treatment of newly diagnosed acute promyelocytic leukemia: durable remissions with minimal toxicity

Arsenic trioxide, as a single agent, has proven efficacy in inducing molecular remission in patients with acute promyelocytic leukemia (APL). There is limited long-term outcome data with single-agent As2O3 in the management of newly diagnosed cases of APL. Between January 1998 to December 2004, 72 newly diagnosed cases of APL were treated with a regimen of single-agent As2O3 at our center. Complete hematologic remission was achieved in 86.1%. At a median follow-up of 25 months (range: 8-92 months), the 3-year Kaplan-Meier estimate of EFS, DFS, and OS was 74.87% ± 5.6%, 87.21% ± 4.93%, and 86.11% ± 4.08%, respectively. Patients presenting with a white blood cell (WBC) count lower than 5 × 109/L and a platelet count higher than 20 × 109/L at diagnosis (n = 22 [30.6%]) have an excellent prognosis with this regimen (EFS, OS, and DFS of 100%). The toxicity profile, in the majority, was mild and reversible. After remission induction, this regimen was administered on an outpatient basis. Single-agent As2O3, as used in this series, in the management of newly diagnosed cases of APL, is associated with responses comparable with conventional chemotherapy regimens. Additionally, this regimen has minimal toxicity and can be administered on an outpatient basis after remission induction.