Advances in the management of coagulopathy in acute promyelocytic leukemia

Clot waveform analysis in acute promyelocytic leukemia

The aim of this study was to evaluate the activated partial thromboplastin time (APTT) and prothrombin time (PT)-based clot waveform analysis (CWA) in patients diagnosed with acute promyelocytic leukemia (APL). APTT-based and PT-based CWA parameters of patients diagnosed with APL were analyzed and compared with healthy volunteers. Four APTT-CWA parameters were noted, maximum velocity corresponding to the first peak of the first derivative (max1), maximum acceleration corresponding to the first peak of the second derivative (max2) and the corresponding peak times of max1 and max2 (Tmax1, Tmax2). For the PT-CWA, two PT-CWA parameters were noted, maximum velocity (max1') and the corresponding timing (Tmax1'). The results were expressed in medians. Mann-Whitney U test was used to compare the CWA parameters. Correlations were examined using the Spearman correlation test. Tmax1 and Tmax2 were significantly prolonged in patients with APL in comparison with healthy volunteers. Although max1 and max2 were lower in APL patients compared with healthy volunteers, no significant difference was noted. There was a strong and significant correlation between the DIC score and the parameters max1, max2 and max1' and a very strong and significant correlation between fibrinogen levels and max1, max2 and max1'. When comparing DIC patients with hypofibrinogenemia and DIC without hypofibrinogenemia, a significant difference was noted in max1, max2, Tmax1 and Tmax2. The APTT and PT-based CWA analysis is a good tool to evaluate the bleeding tendency in APL, as it offers a novel approach for evaluating global hemostasis, predicting the bleeding risk and delivering improvements to APL patients management.

How to avoid early mortality in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL), a phenotypically and genotypically unique subtype of acute myeloid leukemia, has seen unprecedented advances in its management since the introduction of all-trans retinoic acid (ATRA) and arsenic trioxide. However, the phenomenal pharmacologic conversion of this once highly fatal disease to one with a long-term survival exceeding 90% among patients who survive induction remains impaired by the significant incidence of early death (ED) reaching 30% in some real-world studies. The key driver for ED in APL is catastrophic hemorrhage with a proclivity for cranial sites. Most EDs in APL are currently considered preventable. Here, we discuss the concept of early death in APL and its characteristics. Importantly, we outline implementable strategies to reduce the incidence of ED. Early recognition of APL underpins these preventive measures as significant delays in the diagnosis increase the likelihood of ED. While early administration of ATRA is often taught to all hematology trainees, this lifesaving intervention is only possible if providers, including those in emergency departments and urgent/immediate care settings, are trained to have a high index of suspicion and competence to recognize the morphologic and clinical characteristics of the disease. Other proposed strategies tackle the complications that can be present at diagnosis or arise during induction therapy and address the issues of expert consultation and protocol adherence in the management of these patients. While some of these measures appear intuitive and others aspirational, widespread adoption could bring about an era of cure for almost every patient with APL.

Hemorrhagic Coagulation Disorders and Ischemic Stroke: How to Reconcile Both?

Coagulation and fibrinolytic system disorders are conditions in which the blood's ability to clot is impaired, resulting in an increased risk of thrombosis or bleeding. Although these disorders are the expression of two opposing tendencies, they can often be associated with or be a consequence of each other, contributing to making the prognosis of acute cerebrovascular events more difficult. It is important to recognize those conditions that are characterized by dual alterations in the coagulation and fibrinolytic systems to reduce the prognostic impact of clinical conditions with difficult treatment and often unfortunate outcomes. Management of these individuals can be challenging, as clinicians must balance the need to prevent bleeding episodes with the potential risk of clot formation. Treatment decisions should be made on an individual basis, considering the specific bleeding disorder, its severity, and the patient's general medical condition. This review aims to deal with all those forms in which coagulation and fibrinolysis represent two sides of the same media in the correct management of patients with acute neurological syndrome. Precision medicine, personalized treatment, advanced anticoagulant strategies, and innovations in bleeding control represent future directions in the management of these complex pathologies in which stroke can be the evolution of two different acute events or be the first manifestation of an occult or unknown underlying pathology.

Cerebral venous thrombosis in patients with autoimmune disease, hematonosis or coronavirus disease 2019: Many familiar faces and some strangers

BACKGROUND

Cerebral venous thrombosis, a rare stroke, is characterized by neurological dysfunction caused by bleeding and/or infarction resulting from venous sinus thrombosis, the so-called venous stroke. Current guidelines recommend anticoagulants as first-line therapy in the treatment of venous stroke. With complicated causes of cerebral venous thrombosis, treatment is difficult, especially when combined with autoimmune diseases, blood diseases, and even COVID-19.

AIMS

This review summarizes the pathophysiological mechanisms, epidemiology, diagnosis, treatment, and clinical prognosis of cerebral venous thrombosis combined with autoimmune diseases, blood diseases, or infectious diseases such as COVID-19.

CONCLUSION

A systematic understanding of particular risk factors that should not be neglected when unconventional cerebral venous thrombosis occurs and for a scientific understanding of pathophysiological mechanisms, clinical diagnosis, and treatment, thus contributing to knowledge on special types of venous stroke.

Successful Management of Acute Promyelocytic Leukemia in a Patient Who Presented With Acute Ischemic Stroke on Top of Subdural Hematoma

Acute promyelocytic leukemia (APL), a distinct subtype of acute myelogenous leukemia (AML), is commonly associated with a heightened risk of bleeding due to coagulopathy. Thrombotic events, although less frequent, have also been linked to APL. However, the occurrence of ischemic stroke as an initial presentation of APL, particularly concomitant with central nervous system (CNS) bleeding, is exceedingly rare. The combination of these two complications is not reported in APL patients and is anticipated to carry a high mortality rate even with treatment. In this report, we describe the case of a young female patient with no significant medical history, who presented with decreased consciousness and recurrent seizures. Brain magnetic resonance imaging (MRI) revealed the simultaneous occurrence of acute ischemic stroke and acute-on-chronic subdural hematoma. The subsequent bone marrow biopsy confirmed the diagnosis of APL, displaying the characteristic positive promyelocytic leukemia (PML)-retinoic acid receptor alpha (RARA) t(15;17) translocation. The patient was promptly initiated on a high-risk AML-M3 protocol, coupled with supportive treatment through platelet transfusion. Remarkably, a favorable response to treatment was observed, and a marked improvement in her neurological parameters was observed within 2 weeks duration of treatment. Subsequent assessment through a bone marrow biopsy one month later revealed complete remission, with the PML-RARA fusion gene becoming negative following a single course of consolidation therapy.

Preparation of chitosan/retinoic acid @ nanocapsules/TiO2 self-cleaning one-dimensional photonic crystals and the study of the visual detection of acute promyelocytic leukemia

Sample exposure to air during optical detection leads to the widespread dispersal of microorganisms in the air, posing a health threat to patients and healthcare workers and potentially causing numerous nosocomial infections. In this study, a TiO₂/CS-nanocapsules-Va visualization sensor was developed by alternatively spin-coating TiO₂, CS and nanocapsules-Va. The uniformly distributed TiO₂ can endow the visualization sensor with good photocatalytic performance, and the nanocapsules-Va can bind specifically to the antigen and change its volume. The research results showed that the visualization sensor cannot only detect acute promyelocytic leukemia conveniently, quickly and accurately, but also kill bacteria, decompose organic residues in blood samples under the influence of sunlight, and have an extensive application prospect in substance detection and disease diagnosis.

Primary hemostasis dysfunctions and bleeding risk in newly diagnosed acute myeloid leukemia

BACKGROUND

Acute myeloid leukaemia carries the risk of complications associated with dysfunctions in haemostasis system. The purpose of this study was to investigate the factors associated with the risk of bleeding in patients with newly diagnosed acute myeloid leukaemia (AML).

METHODS

This study involved the methods of immunoenzymatic analysis and classical coagulation studies. The number of biochemical parameters important for establishing coagulative dysfunction in acute myeloid leukaemia was determined, the main ones being the level of von Willebrand factor, the Ristocetin-cofactor activity of von Willebrand factor and factor VIII activity, prothrombin time, platelet count, and fibrinogen concentration.

RESULTS

According to the results of the present study, the reduced activity of von Willebrand factor in patients with AML was associated with severe bleeding. The authors observed an increase in the number of platelets count in patients with AML who experienced haemorrhages compared to patients with no bleeding signs. The study also established an increase in the concentration of fibrinogen in cancer patients, compared to the control sample. Symptoms and quantitative indicators for diagnosing the severity of haemorrhagic syndrome were grouped. The authors considered the advantages and disadvantages of many therapeutic preparations and focussed on specific markers of activated haemorrhage-predicting platelets.

CONCLUSION

Further studies concern the search for effective markers and therapeutic approaches to minimize haemorrhagic syndrome. The results were statistically processed using the functions ANOVA, t test, CORREL, determination of the value of reliability, and mean square deviation.

Influence of cytokines on early death and coagulopathy in newly diagnosed patients with acute promyelocytic leukemia

Introduction

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) with a better prognosis. But early death (ED) rate remains high. APL patients are simultaneously accompanied by coagulopathy and hyperinflammation at the onset. It is not known what effects cytokines have on ED and coagulopathy in these patients. Therefore, the purposes of this study are to explore the clinical differences between APL and other types of AML, the link between cytokines and coagulopathy in newly diagnosed APL, and their roles in the ED for APL.

Methods

This study retrospectively collected the information of 496 adult patients with AML (age ≥14 years at admission) newly diagnosed in the First People's Hospital of Yunnan Province between January 2017 to February 2022, including 115 APL patients. The difference of clinical manifestations between two groups [APL and AML (non-APL)] was statistically analyzed. Then, the factors affecting ED in APL patients were screened, and the possible pathways of their influence on ED were further analyzed.

Results

The results indicate APL at the onset have a younger age and higher incidence of ED and DIC than other types of AML. Intracranial hemorrhage (ICH), age, and PLT count are found to be independent factors for ED in newly APL, among which ICH is the main cause of ED, accounting for 61.54% (8/13). The levels of cytokines in newly APL are generally higher than that in AML (non-APL), and those in the group of ED for APL were widely more than the control group. IL-17A and TNF-β are directly related to the ED in newly APL, especially IL-17A, which also affects ICH in these patients. Moreover, the increase of IL-17A and TNF-β cause the prolongation of PT in APL patients, which reflected the exogenous coagulation pathway. However, they have no effect on APTT prolongation and FIB reduction. Thus, it is speculated that IL-17A leads to early cerebral hemorrhage death in newly APL by inducing tissue factor (TF) overexpression to initiate exogenous coagulation and further leading to excessive depletion of clotting factors and prolongation of PT.

Conclusions

In conclusion, compared with other types of AML, APL patients have a younger age of onset and high inflammatory state, and are more likely to develop into DIC and die early. Age, and PLT count at diagnosis are independent factors for ED of APL, especially ICH. IL-17A is confirmed to be an independent risk factor for ED and ICH of newly APL. Hence, IL-17A may serve as a predictor of ED in newly diagnosed APL patients, and controlling its expression probably reduce ED in these patients.

How to manage coagulopathies in critically ill patients

Coagulopathy is a severe and frequent complication in critically ill patients, for which the pathogenesis and presentation may be variable depending on the underlying disease. Based on the dominant clinical phenotype, the current review differentiates between hemorrhagic coagulopathies, characterized by a hypocoagulable and hyperfibrinolysis state, and thrombotic coagulopathies with a systemic prothrombotic and antifibrinolytic phenotype. We discuss the differences in pathogenesis and treatment of the common coagulopathies.

Effects of peripheral blood leukocyte count and tumor necrosis factor-alpha on early death in acute promyelocytic leukemia

BACKGROUND

Early death remains a major factor in survival in APL. We aimed to analyze the risk factors for differentiation syndrome and early death in acute promyelocytic leukemia (APL).

METHODS

The clinical data of APL patients who were newly diagnosed at Mianyang Central Hospital from January 2013 to January 2022 were retrospectively analyzed.

RESULTS

Eighty-six newly diagnosed APL patients (37 males and 49 females) were included in this study. The median age was 46 (17-75) years. Sixty-one patients (70.9%) had low/intermediate-risk APL, and 25 patients (29.1%) had high-risk APL. The incidence of differentiation syndrome (DS) was 62.4%. The multivariate analysis showed that a peak white blood cell (WBC) count ≥16 × 10^9/L was an independent risk factor (OR = 11.000, 95% CI: 2.830-42.756, P = 0.001) for DS in all APL patients, while a WBC count ≥10 × 10^9/L on Day 5 was an independent risk factor for DS in low-intermediate risk APL patients (OR = 9.114, 95% CI: 2.384-34.849, P = 0.001). There were 31 patients (36.5%) with mild DS and 22 patients (25.9%) with severe DS. The multivariate analysis showed that WBC count ≥23 × 10^9/L at chemotherapy was an independent risk factor for severe DS (OR = 10.500, 95% CI: 2.344-47.034, P = 0.002). The rate of early death (ED) was 24.4% (21/86). The multivariate analysis showed that male gender (OR = 7.578,95% CI:1.136-50.551, P = 0.036), HGB < 65 g/L (OR = 16.271,95% CI:2.012-131.594, P = 0.009) and WBC count ≥7 × 10^9/L on Day 3(OR = 23.359,95% CI:1.825-298.959, P = 0.015) were independent risk factors for ED. The WBC count at diagnosis, WBC count on Day 3 and WBC count on Day 5 had moderate positive correlations with tumor necrosis factor-α (TNF-α) at diagnosis, and the correlation coefficients were 0.648 (P = 0.012), 0.615 (P = 0.033), and 0.609 (P = 0.035), respectively. The WBC count had no correlation with IL-6.

CONCLUSION

During induction treatment, cytotoxic chemotherapy may need to be initiated to reduce the risk of DS for APL patients with a low-intermediate risk WBC count ≥10 × 10^9/L on Day 5 or for all patients with a peak WBC count ≥16 × 10^9/L. Patients with WBC > 7 × 10^9/L on Day 3 have a higher risk of ED. Leukocyte proliferation is associated with TNF-α rather than IL-6, and TNF-α may be a potential biomarker for predicting ED.

Challenging Cases in Cerebrovascular Disease

Disorders involving the vascular system of the brain are numerous and sundry. Atherosclerotic thromboembolism of large vessels and lacunar infarctions of small vessel disease are well known. Brain infarction due to cardioembolism is common as well, and even more so when diligently sought. Rupture of intracranial blood vessels results in subarachnoid and intraparenchymal hemorrhage. We present four cases of stroke of uncommon cause and remind clinicians to be open minded to the many possible causes of stroke, in particular because early recognition and treatment is often critical. Case 1 discusses a patient with inflammatory cerebral amyloid angiopathy. The presentation, ability to recur, and current treatment considerations are reviewed. Case 2 discusses microangiopathic thrombotic angiopathy. Diagnosis and treatment are considered. An association with interferon therapy and the evolving terminology of this and related conditions are discussed. Case 3 discusses intracranial hemorrhage secondary to acute promyelocytic leukemia. Patients with acute leukemias require aggressive management of their coagulopathy, thrombocytopenia, and the disease itself. Finally, Case 4 discusses ischemic stroke due to a paradoxical embolism in the setting of a patent foramen ovale (PFO). Both medical and surgical management of a PFO for stroke prevention are considered.

Predictors of early death and clinical features in newly diagnosed patients with low-intermediate risk acute promyelocytic leukemia

Background

Although most acute promyelocytic leukemia(APL) with low-intermediate risk could survive the induction treatment, early death still a big problem to have effects on overall survival in real world.This study aimed to analyze the clinical characteristics and possible predictors of early death in newly diagnosed patients with low-intermediate-risk acute promyelocytic leukemia.

Methods

Sixty patients with newly diagnosed low/intermediate-risk APL admitted to Mianyang Central Hospital from January 2013 to December 2021 were retrospectively analyzed.

Results

Sixty patients with a median age of 46 years (range, 17-75 years) were included. Fourteen patients (23.3%) were in low-risk group, and 46 patients (76.7%) were in intermediate-risk group. Fourteen patients (23.3%) died during induction treatment. Five patients died of hemorrhage, 5 of severe infection and 4 of differentiation syndrome. Multivariate analysis showed that HGB <65g/L at diagnosis (OR=38.474, 95%CI: 2.648~558.923, P=0.008) during induction treatment was an independent risk factors for early death in low- intermediate risk APL patients. In survival group, all patients achieved complete remission, the time to achieve remission was 25.87 ± 5.02 days, the average ATO dosage was 0.16 ± 0.03 mg/kg/day. In univariate analysis, there was no statistically significant difference in time span for remission when ATO dosage was in the 0.11~0.16mg/kg/day range. Compared with patients with low-risk APL, those with intermediate-risk APL had higher white blood cell counts (at diagnosis, day 3, day 5 and peak), higher level of lactate dehydrogenase, higher percentage of bone marrow promyelocytes, more platelet transfusions during treatment, and more early deaths (P<0.05). The overall survival of intermediate-risk APL patients seemed worse than those with low-risk APL (χ=5.033, P =0.025).

Conclusions

In patients with low-intermediate risk APL, HGB <65g/L at diagnosis was an independent risk factors for early death. Remission could still be achieved at low-dose ATO without affecting the required time for low-intermediate risk APL patients. Differences in clinical characteristics were found between low-risk and intermediate-risk APL. The intermediate-risk group had higher early mortality risk than the low-risk group.

Effect of Therapeutically Related Drugs on Coagulation-Anticoagulation Balance in Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) usually presents with a series of coagulation-anticoagulation disturbance. Early administration of All-trans retinoic acid (ATRA) can reduce the risk of bleeding, but the potential for thrombosis needs to be addressed in some cases. The role of arsenic agent in correcting coagulation disorder remains to be studied, but oral arsenic agent shows potential advantages in coagulation recovery compared with intravenous agent, and chemotherapy can aggravate the progress of coagulation disease. In addition to early application of ATRA, avoiding invasive procedures and transfusion support can reduce the risk of bleeding. Whether the administration of heparin, thrombomodulin, recombinant factor VIIa or antifibrinolytics reduces the risk of bleeding and thrombosis associated with APL remains to be further explored, and their routine use outside of clinical trials is not recommended. This article reviews the effects of related drugs on coagulation-anticoagulation balance in APL patients.

Neurologic complications of acute myeloid leukemia. Diagnostic approach and therapeutic modalities

Acute myeloid leukemia (AML) comprises a heterogeneous group of aggressive blood malignancies that arise from clonal expansion of malignant hematopoietic precursor cells in the bone marrow. Neurologic manifestations of these malignancies are manifolds. AML is the most common form of acute leukemia in adults and this review describes the neurologic complications in this age group. Neurologic symptoms and signs may develop in AML either from a direct neoplastic involvement of the central or the peripheral nervous system or as an indirect effect of the disease process. Direct involvement of the nervous system includes invasion of the central or the peripheral nervous system (parenchymal and leptomeningeal dissemination, myeloid sarcoma, neuroleukemiosis). Thrombotic and hemorrhagic events are common manifestations of indirect involvement of the nervous system and they are the outcome of hyperleukocytosis, thrombocytopenia and coagulopathy. Many neurologic complications are iatrogenic and include diverse categories such as lumbar puncture and intrathecal or systemic chemotherapy and targeted therapies, radiotherapy and allogeneic stem cell transplantation. Most neurologic manifestations require urgent treatment and confer a poor prognosis. This review describes the neurologic complications of acute myeloid malignancies in the era of contemporary treatment. Those manifestations require expert consideration of their origin as they are being identified with increasing frequency as patients survive longer.

LncRNA KCNQ1OT1 activated by c-Myc promotes cell proliferation via interacting with FUS to stabilize MAP3K1 in acute promyelocytic leukemia

Uncontrolled proliferation is the hallmark of cancer cells. Previous studies mainly focused on the role of protein-coding genes in cancer cell proliferation. Emerging evidence showed that long non-coding RNAs (lncRNAs) also play critical roles in cancer cell proliferation and growth. LncRNA KCNQ1OT1 is found to contribute to carcinogenesis, but its role in acute promyelocytic leukemia (APL) is unclear. In this study, by analyzing data from Gene Expression Omnibus, The Cancer Genome Atlas database and our clinical samples, we found that KCNQ1OT1 was selectively highly expressed in APL. Functional assays demonstrated that knockdown of KCNQ1OT1 reduced APL cell proliferation and increased apoptosis. Further evidence showed that KCNQ1OT1 was mainly located in the cytoplasm of APL patient-derived NB4 cells and APL patient bone marrow samples. Mechanistically, KCNQ1OT1 bound to RNA binding protein FUS, and silencing either KCNQ1OT1 or FUS reduced the expression level and stability of MAP3K1 mRNA. Whereas KCNQ1OT1 and FUS did not affect each other. Importantly, knockdown of MAP3K1 impaired APL cell proliferation. Finally, c-Myc transactivated KCNQ1OT1 in APL cells through binding to its promoter while knockdown of c-Myc decreased KCNQ1OT1 expression. Our results not only revealed that c-Myc transactivated KCNQ1OT1 and upregulated KCNQ1OT1 promoted APL cell proliferation, but also demonstrated that KCNQ1OT1 bound to FUS to synergistically stabilize MAP3K1 mRNA, thus facilitating APL cell proliferation. This study established a previously unidentified role of KCNQ1OT1 in the development of APL, and KCNQ1OT1 may serve as a potential therapeutic target for APL.

Characteristics and predictors of early hospital deaths in newly diagnosed APL: a 13-year population-wide study

Despite therapeutic advances, early death (ED) remains a major factor curtailing survival of acute promyelocytic leukemia (APL). Studies examining factors that cause early death (ED; within 30 days of admission) and the correlation of survival with the timing of administration of all-trans retinoic acid (ATRA) and hemostatic parameters are scarce. We performed a cohort analysis of nonselect patients with newly diagnosed APL who presented to the health care system in Hong Kong, where oral arsenic trioxide was used. From 1 January 2007 to 30 April 2020, 358 patients (median age, 47 [1-97] years) with newly diagnosed APL were identified. ED occurred in 56 patients (16%): 11 (3%) died in the first 2 days after admission (intracranial hemorrhage [ICH], n = 6; APL-differentiation syndrome [APL-DS], n = 4; infection, n = 1); 22 (6%) died within 3 to 7 days (ICH, n = 12; APL-DS, n = 8; infections, n = 2), and 23 (6%) died within 8 to 30 days (ICH, n = 7; APL-DS, n = 11; infection, n = 5). Factors significantly associated with ED by multivariate analysis included male sex (P = .01); presenting leukocyte count ≥10 × 109/L (P = .03); fibrinogen <1.5 g/L (P = .02); and ATRA administration >24 hours after hospital admission (P < .001). After a median follow-up of 47 (0-166) months, the 5- and 10-year overall survival (OS) was 68.6% and 61.2%, respectively. Excluding EDs, the 5- and 10-year post-30-day OS improved to 81.3% and 72.5%. Early administration of ATRA (<24 hours) and vigorous correction of hemostatic abnormalities, including hypofibrinogenemia, are key to reducing ED.

Myeloid Sarcoma Type of Acute Promyelocytic Leukemia With a Cryptic Insertion of RARA Into FIP1L1: The Clinical Utility of NGS and Bioinformatic Analyses

Background

Acute promyelocytic leukemia (APL) is characterized by the presence of coagulopathy at onset and translocation t (15; 17) (q22; 21), meanwhile, other translocation variants of APL have also been reported. The FIP1L1-RARA fusion gene has recently been reported as a novel RARA-associated fusion gene.

Objectives

We report a case of de novo myeloid sarcoma (MS) type of APL with FIP1L1-RARA found by next-generation sequencing (NGS) that was not detected by conventional analyze analysis for RARA translocations.

Methods

We performed typical morphological, magnetic resonance imaging (MRI), conventional tests for PML-RARA dual-fusion translocation probe, high-through sequencing and NGS. Meanwhile, bioinformatics analyses were done by using public repositories, including ONCOMINE, COSMIC, and GeneMANIA analysis.

Results

A 28-month-old girl with a complex karyotype that includes 46,XX,t(4;17)(q12;q22)[9]/46,idem,del(16)(q22)[3]/45,idem,-x,-4,-9,-15,del(16)(q22),+marl,+mar2,+mar3[7]/46,xx[3], c.38G>A (p.Gly13Asp) in the KRAS gene, and a cryptic insertion of RARA gene into the FIP1L1 gene was diagnosed with APL complicated by the de novo MS.

Conclusion

We report a FIP1L1-RARA fusion in a child with APL who presented with an extramedullary tumor in the skull without the classic karyotype using NGS, whom we treated with good results. NGS analysis should be considered for APL variant cases. Further experimental studies to the association between the mutation in KRAS gene and FIP1L1-RARA fusion on the clinical phenotype and progression of APL are needed to identify more effective therapeutic targets for APL.

Absolute Circulating Leukemic Cells as a Risk Factor for Early Bleeding Events in Patients with Non-High-Risk Acute Promyelocytic Leukemia

Background

Hemorrhagic complications are the most common cause of early death in patients with APL and remain a major challenge in the management of APL. Early fatal bleeding events occur not only in high-risk but also in non-high-risk acute promyelocytic leukemia (APL) patients with normal or low WBC counts.

Objectives and Methods

To demonstrate the role of the absolute number of circulating leukemic cells in early bleeding events in APL patients. Clinical and laboratory characteristics of 149 patients newly diagnosed with APL were obtained from medical records and retrospectively investigated.

Results

In this study, circulating absolute leukemic cells were positively correlated with the WBC count (r=0.9813, p<0.001) in all patients with APL, and importantly, they were strongly associated with significant bleeding events in non-high-risk patients. Multivariate logistic regression analysis showed that the absolute number of leukemia cells was an independent risk factor for significant bleeding events in APL patients. A cut-off value of 2.59×10⁹/L for circulating leukemic cells to predict significant bleeding events in APL patients was obtained by ROC curve analysis. We further confirmed that the significant bleeding rate of patients with non-high-risk APL was statistically increased when the absolute number of circulating leukemic cells was ≥2.59×10⁹/L.

Conclusion

Circulating leukemic cell content has great clinical value for predicting early bleeding events in APL patients, especially in non-high-risk APL.

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.

Evolving Chemotherapy Free Regimens for Acute Promyelocytic Leukemia

With the treatment advances over the last three decades, acute promyelocytic leukemia (APL) has evolved from being the most malignant form of acute leukemia to a leukemia with excellent long term survival rates. In the present review, we have summarized data leading to the development of the currently used treatment regimens for APL, which incorporate either none or minimal chemotherapeutic drugs. We have discussed the historical aspects of APL treatment along with the challenges associated with chemotherapy-based approaches and our experience with the use of single agent arsenic trioxide (ATO) which was one of the first successful, non-chemotherapy approaches used for APL. Subsequently, we have reviewed the data from major clinical trials in low-intermediate risk APL and high risk APL which guide the current clinical practice in APL management. With accumulating data on oral ATO, we postulate that the treatment for low-intermediate risk APL will be a completely oral ATO + ATRA regimen in the future. While for high-risk APL, we believe that minimal anthracycline use with ATO + ATRA might become the standard of care soon. A number of promising non-chemotherapy drugs with pre-clinical data would merit clinical testing in the high risk and relapsed setting, with potential to translate to a complete oral chemotherapy free combination regimen in combination with ATO and ATRA.

Cerebrovascular manifestations in hematological diseases: an update

Patients with hematological diseases often experience cerebrovascular complications including ischemic stroke, intracerebral and subarachnoid hemorrhage, microbleeds, posterior reversible encephalopathy syndrome, and dural sinus and cerebral vein thrombosis (CVT). In this update, we will review recent advances in the management of cerebrovascular diseases in the context of myeloproliferative neoplasms, leukemias, lymphomas, multiple myeloma, POEMS, paroxysmal nocturnal hemoglobinuria (PNH), thrombotic thrombocytopenic purpura (TTP), and sickle-cell disease. In acute ischemic stroke associated with hematological diseases, thrombectomy can in general be applied if there is a large vessel occlusion. Intravenous thrombolysis can be used in myeloproliferative neoplasms and sickle-cell anemia, but in other diseases, a case-by-case evaluation of the bleeding risks is mandatory. Patients with sickle-cell disease and acute stroke need very often to be transfused. In PNH, acute ischemic stroke patients must be anticoagulated. Most patients with CVT can be treated with low-molecular weight heparin (LMWH) acutely, even those with leukemias. Prevention of recurrence of cerebral thrombotic events depends on the control of the underlying disease, combined in some conditions with antithrombotic drugs. The recent introduction of specific monoclonal antibodies in the treatment of PHN and TTP has dramatically reduced the risk of arterial and venous thrombosis.

Acute Promyelocytic Leukemia in Children: A Model of Precision Medicine and Chemotherapy-Free Therapy

Acute promyelocytic leukemia (APL) represents a paradigm of precision medicine. Indeed, in the last decades, the introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) completely revolutionized the therapeutic approach to this previously highly fatal disorder. This entirely chemotherapy-free treatment, which provided excellent survival rates, has been initially validated in adults and, recently, translated in the pediatric setting. This review summarizes currently available data on the use of ATRA and ATO combination in pediatric APL, providing a particular focus on peculiar issues and challenges, such as the occurrence of pseudotumor cerebri and death during induction (early death), as well as the advantage offered by the ATO/ATRA combination in sparing long-term sequelae.