von Willebrand factor and thrombin activation in children with newly diagnosed acute lymphoblastic leukemia: an impact of peripheral blasts

A cohort study on blood coagulation in childhood cancer survivors

Cancer survivors are at an increased risk of thromboembolism compared to the general pediatric population. Anticoagulant therapy decreases the risk of thromboembolism in cancer patients. We hypothesized that pediatric cancer survivors are in a chronically hypercoagulable state compared to healthy controls. Children who survived for more than five years from cancer diagnosis at the UT Health Science Center at San Antonio Cancer Survivorship Clinic were compared to healthy controls. The exclusion criteria were recent NSAID use or a history of coagulopathy. Coagulation analysis included platelet count, thrombin-antithrombin complexes (TAT), plasminogen activator inhibitor (PAI), routine coagulation assays, and thrombin generation with and without thrombomodulin. We enrolled 47 pediatric cancer survivors and 37 healthy controls. Platelet count was significantly lower in cancer survivors at a mean of 254 × 10⁹/L (95%CI: 234-273 × 10⁹/L) compared at 307 × 10⁹/L (283-331 × 10⁹/L) in healthy controls (p < 0.001), although not outside the normal range. Routine coagulation assays showed no differences, except for a significantly lower prothrombin time (PT) in cancer survivors (p < 0.004). Cancer survivors has significantly elevated biomarkers of the procoagulant state, such as TAT and PAI, compared to healthy controls (p < 0.001). A multiple logistic regression model controlling for age, BMI, gender, and race/ethnicity documented that a low platelet count, short prothrombin clot time, and higher procoagulant biomarkers (TAT and PAI) were significantly associated with past cancer therapy. Survivors of childhood cancer have a persistent procoagulant imbalance for more than five years after diagnosis. Further studies are needed to establish whether procoagulant imbalance increases the risk of thromboembolism in childhood cancer survivors.

Predictors of thrombosis in children receiving therapy for acute lymphoblastic leukemia: Results from Dana-Farber Cancer Institute ALL Consortium trial 05-001

BACKGROUND/OBJECTIVES

Although thromboembolism (TE) is a serious complication in patients with acute lymphoblastic leukemia (ALL), thromboprophylaxis is not commonly used due to the inherent bleeding risk in this population. Identifying prothrombotic risk factors will help target thromboprophylaxis to those at highest thrombotic risk. We aimed to define predictors and the impact of TE on ALL outcome in children (1-18 years) treated on the Dana-Farber Cancer Institute ALL 05-001 trial.

METHODS

Clinical and laboratory data including TE events were prospectively collected. PCR-based allelic discrimination assay identified single-nucleotide polymorphisms (SNP) for prothrombin G20210A (rs1799963) and Factor V G1691A (rs6025). Univariate and multivariable competing risk regression models evaluated the effect of diagnostic clinical (age, sex, body mass index, ALL-immunophenotype, risk group) and laboratory variables (presenting leukocyte count, blood group, SNPs) on the cumulative incidence of TE. Cox regression modeling explored the impact of TE on survival.

RESULTS

Of 794 patients [median age 4.97 (range, 1.04-17.96) years; males 441], 100 developed TE; 25-month cumulative incidence 13.0% (95% CI, 10.7%-15.5%). Univariate analyses identified older age (≥10 years), presenting leucocyte count, T-ALL, high-risk ALL, and non-O blood group as risk factors. Age and non-O blood group were independent predictors of TE on multivariable regression; the blood group impact being most evident in patients 1-5 years of age (P = 0.011). TE did not impact survival. Induction TE was independently associated with induction failure (OR 6.45; 95% CI, 1.64-25.47; P = 0.008).

CONCLUSION

We recommend further evaluation of these risk factors and consideration of thromboprophylaxis for patients ≥10 years (especially those ≥15 years) when receiving asparaginase.

COVID-19 in Children With Cancer: A Single Low-Middle Income Center Experience

BACKGROUND

Coronavirus disease-2019 (COVID-19) could be associated with morbidity and mortality in immunocompromised children.

OBJECTIVE

The objective of this study was to measure the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among hospitalized children with cancer and to detect the associated clinical manifestations and outcomes.

METHODOLOGY

A prospective noninterventional study including all hospitalized children with cancer conducted between mid-April and mid-June 2020 in Ain Shams University Hospital, Egypt. Clinical, laboratory, and radiologic data were collected. SARS-CoV-2 infection was diagnosed by reverse transcription polymerase chain reaction tests in nasopharyngeal swabs.

RESULTS

Fifteen of 61 hospitalized children with cancer were diagnosed with SARS-CoV-2. Their mean age was 8.3±3.5 years. Initially, 10 (66.7%) were asymptomatic and 5 (33.3%) were symptomatic with fever and/or cough. Baseline laboratory tests other than SARS-CoV-2 reverse transcription polymerase chain reaction were not diagnostic; the mean absolute lymphocyte count was 8.7±2.4×109/L. C-reactive protein was mildly elevated in most of the patients. Imaging was performed in 10 (66.7%) patients with significant radiologic findings detected in 4 (40%) patients. Treatment was mainly supportive with antibiotics as per the febrile neutropenia protocol and local Children Hospital guidance for management of COVID-19 in children.

CONCLUSIONS

Pediatric cancer patients with COVID-19 were mainly asymptomatic or with mild symptoms. A high index of suspicion and regular screening with nasopharyngeal swab in asymptomatic hospitalized cancer patients is recommended.

Von Willebrand factor and cancer; metastasis and coagulopathies

Von Willebrand factor (VWF) is a multimeric procoagulant plasma glycoprotein that mediates platelet adhesion along the endothelium. In addition to its role maintaining normal hemostasis, more recently novel biological functions for VWF have been described, including inflammation, angiogenesis, and metastasis. Significantly increased plasma VWF levels have been reported across a variety of cancer patient cohorts. Given that VWF is established as a risk factor for venous thrombosis, this is of direct clinical importance. Moreover, elevated VWF has also been observed localized within the tumor microenvironment, correlating with advanced disease stage and poorer clinical outcome. Critically, evidence suggests that elevated VWF levels in cancer patients may not only contribute to cancer associated coagulopathies but may also mediate cancer progression and metastasis. Studies have shown that VWF can promote pro-inflammatory signaling, regulate angiogenesis and vascular permeability, which may facilitate tumor cell growth and extravasation across the vessel wall. Endothelial secreted VWF multimers contribute to the adhesion and transendothelial migration of tumor cells key for tumor dissemination. In support of this, VWF inhibition attenuated metastasis in vivo. Perhaps most intriguingly, specific tumor cells have been reported to acquire de novo VWF expression which increases tumor-platelet heteroaggregates and confers enhanced metastatic activity. Current knowledge on the roles of VWF in cancer and in particular its contribution to metastasis and cancer associated coagulopathies is summarized in this review.

Recipient ADAMTS13 Single-Nucleotide Polymorphism Predicts Relapse after Unrelated Bone Marrow Transplantation for Hematologic Malignancy

Relapse remains a major obstacle to the survival of patients with hematologic malignancies after allogeneic hematopoietic stem cell transplantation. A disintegrin-like and metalloprotease with a thrombospondin type 1 motif (ADMATS13), which cleaves von Willebrand factor multimers into less active fragments, is encoded by the ADAMTS13 gene and has a functional single-nucleotide polymorphism (SNP) rs2285489 (C > T). We retrospectively examined whether ADAMTS13 rs2285489 affected the transplant outcomes in a cohort of 281 patients who underwent unrelated human leukocyte antigen (HLA)-matched bone marrow transplantation for hematologic malignancies. The recipient ADAMTS13 C/C genotype, which putatively has low inducibility, was associated with an increased relapse rate (hazard ratio [HR], 3.12; 95% confidence interval [CI], 1.25–7.77; P = 0.015), resulting in a lower disease-free survival rate in the patients with a recipient C/C genotype (HR, 1.64; 95% CI, 1.01–2.67; P = 0.045). Therefore, ADAMTS13 rs2285489 genotyping in transplant recipients may be a useful tool for evaluating pretransplantation risks.

Impact of baseline clinical and laboratory features on the risk of thrombosis in children with acute lymphoblastic leukemia: A prospective evaluation

BACKGROUND

Children with acute lymphoblastic leukemia (ALL) have increased risk of thromboembolism (TE). However, the predictors of ALL-associated TE are as yet uncertain.

OBJECTIVE

This exploratory, prospective cohort study evaluated the effects of clinical (age, gender, ALL risk group) and laboratory variables (hematological parameters, ABO blood group, inherited and acquired prothrombotic defects [PDs]) at diagnosis on the development of symptomatic TE (sTE) in children (aged 1 to ≤18) treated on the Dana-Farber Cancer Institute ALL 05-001 study.

PROCEDURES

Samples collected prior to the start of ALL therapy were evaluated for genetic and acquired PDs (proteins C and S, antithrombin, procoagulant factors VIII (FVIII:C), IX, XI and von Willebrand factor antigen levels, gene polymorphisms of factor V G1691A, prothrombin gene G20210A and methylene tetrahydrofolate reductase C677T, anticardiolipin antibodies, fasting lipoprotein(a), and homocysteine).

RESULTS

Of 131 enrolled patients (mean age [range] 6.4 [1-17] years) 70 were male patients and 20 patients (15%) developed sTE. Acquired or inherited PD had no impact on the risk of sTE. Multivariable analyses identified older age (odds ratio [OR] 1.13; 95% confidence interval [CI]: 1.01, 1.26) and non-O blood group (OR 3.64, 95% CI: 1.06, 12.51) as independent predictors for development of sTE. Patients with circulating blasts had higher odds of developing sTE (OR 6.66; 95% CI: 0.82, 53.85).

CONCLUSION

Older age, non-O blood group, and presence of circulating blasts, but not PDs, predicted the risk of sTE during ALL therapy. We recommend evaluation of these novel risk factors in the development of ALL-associated TE. If confirmed, these easily accessible variables at diagnosis can help develop a risk-prediction model for ALL-associated TE.

Von Willebrand Factor and Factor VIII levels in Egyptian children with newly diagnosed acute lymphoblastic leukemia in relation to peripheral blast cells and steroid therapy

BACKGROUND

Endothelial dysfunction has been reported in children with acute lymphoblastic leukemia (ALL). The aim of this study is to assess Von Willebrand Factor antigen (VWF antigen) and Factor VIII (FVIII) in newly diagnosed ALL patients, in relation to peripheral blast (PB) cells, steroid therapy, and any prognostic potential.

PROCEDURE

VWF antigen and FVIII were assessed initially (D0) and at day 8 (D8) steroid therapy for 32 newly diagnosed ALL patients with and without peripheral blood blast cells.

RESULTS

At diagnosis, patients with PBs had a significantly higher levels of VWF antigen (102.7 ± 22.9% vs. 56.9 ± 8%, P<0.001) and FVIII (93.4 ± 15.9% vs. 6 62.6 ± 18.1%, P<0.001) than those without. Following steroid therapy, both factors decreased in those with PBs, whereas an increase above baseline was observed in those without PBs. Furthermore, there was a significant positive correlation between PBs and both VWF antigen (P<0.001) and FVIII levels (P=0.002). High-risk patients were comparable with standard-risk group in mean values of VWF antigen (P=0.234) and FVIII (P=0.891) at diagnosis. After 12 months from diagnosis, all patients without PB achieved and maintained complete remission. Those with initial PB reported relapse (12.5%) or death (4.2%) during follow-up.

CONCLUSIONS

Markers of endothelial dysfunction namely VWF and FVIII were related to circulating blast cells and steroids therapy through lysis of lymphoblasts results in reduction of both factors, with risk of thrombosis during induction with marked disintegration of malignant cells.

Alterations in Procoagulant, Anticoagulant, and Fibrinolytic Systems Before and After Start of Induction Chemotherapy in Children With Acute Lymphoblastic Leukemia

Induction chemotherapy is associated with increased thrombosis risk in children with acute lymphoblastic leukemia (ALL). In this prospective study, we explored the effects of ALL and induction chemotherapy on the procoagulant, anticoagulant, and fibrinolytic systems in 20 children with ALL. The levels of d-dimer, factor VIII, von Willebrand factor, protein C, antithrombin III, and thrombin-activated fibrinolysis inhibitor (TAFI) were elevated at diagnosis. These changes were not related with peripheral blast count. The levels of fibrinogen, d-dimer, coagulation inhibitors, and plasminogen decreased, whereas the levels of tissue factor pathway inhibitor and plasminogen activator inhibitor 1 increased progressively following prednisolone monotherapy, administration of vincristine plus daunorubicin, and l-asparaginase. The levels of factor VIII, d-dimer, and TAFI remained elevated during the study period. In conclusion, coagulation activation and impaired fibrinolysis already exist at diagnosis, whereas induction chemotherapy leads to reactivation of coagulation and progressive impairment in fibrinolytic and anticoagulant capacities in childhood ALL.