An imbalance in von Willebrand factor (VWF) may either lead to bleeding (von Willebrand disease, VWD) or thrombosis. Both disorders have shortcomings in the currently available treatments. VWF... Show moreAn imbalance in von Willebrand factor (VWF) may either lead to bleeding (von Willebrand disease, VWD) or thrombosis. Both disorders have shortcomings in the currently available treatments. VWF itself could be a potential therapeutic target because of its role in both bleeding and thrombosis. Inhibiting VWF gene expression through allele-selective silencing of VWF with small interfering RNAs (siRNAs) could be a personalized approach to specifically inhibit mutant VWF in VWD or to normalize increased VWF levels in thrombotic disorders without complete VWF knockdown. Therefore, we investigated a method to allele-selectively silence the VWF gene in mice as a therapeutic strategy. Fourteen candidate siRNAs targeting murine Vwf of either the C57BL/6J (B6) or the 129S1/SvImJ (129S) strain were tested in vitro in cells expressing B6- and 129S-Vwf for inhibitory effect and allele-selective potential. Together with a nonselective siVwf, 2 lead candidate siRNAs, siVwf.B6 and siVwf.129S, were further tested in vivo in B6 and 129S mice. Efficient endothelial siRNA delivery was achieved by siRNA encapsulation into 7C1 oligomeric lipid nanoparticles. Treatment with the nonselective siVwf resulted in dose-dependent inhibition of up to 80% of both lung messenger RNA and plasma VWF protein in both mouse strains. In contrast, the allele-selective siVwf.B6 and siVwf.129S were shown to be effective in and selective solely for their corresponding mouse strain. To conclude, we showed efficient endothelial delivery of siRNAs that are highly effective in allele-selective inhibition of Vwf in mice, which constitutes an in vivo proof of principle of allele-selective VWF silencing as a therapeutic approach. Show less
Despite high cure rates in classic Hodgkin lymphoma (cHL), relapses are observed. Whether relapsed cHL represents second primary lymphoma or an underlying T-cell lymphoma (TCL) mimicking cHL is... Show moreDespite high cure rates in classic Hodgkin lymphoma (cHL), relapses are observed. Whether relapsed cHL represents second primary lymphoma or an underlying T-cell lymphoma (TCL) mimicking cHL is underinvestigated. To analyze the nature of cHL recurrences, in-depth clonality testing of immunoglobulin (Ig) and T-cell receptor (TCR) rearrangements was performed in paired cHL diagnoses and recurrences among 60 patients, supported by targeted mutation analysis of lymphoma-associated genes. Clonal Ig rearrangements were detected by next-generation sequencing (NGS) in 69 of 120 (58%) diagnoses and recurrence samples. The clonal relationship could be established in 34 cases, identifying clonally related relapsed cHL in 24 of 34 patients (71%). Clonally unrelated cHL was observed in 10 of 34 patients (29%) as determined by IG-NGS clonality assessment and confirmed by the identification of predominantly mutually exclusive gene mutations in the paired cHL samples. In recurrences of >2 years, ∼60% of patients with cHL for whom the clonal relationship could be established showed a second primary cHL. Clonal TCR gene rearrangements were identified in 14 of 125 samples (11%), and TCL-associated gene mutations were detected in 7 of 14 samples. Retrospective pathology review with integration of the molecular findings were consistent with an underlying TCL in 5 patients aged >50 years. This study shows that cHL recurrences, especially after 2 years, sometimes represent a new primary cHL or TCL mimicking cHL, as uncovered by NGS-based Ig/TCR clonality testing and gene mutation analysis. Given the significant therapeutic consequences, molecular testing of a presumed relapse in cHL is crucial for subsequent appropriate treatment strategies adapted to the specific lymphoma presentation. Show less
Bergen, C.A.M. van; Kloet, S.L.; Quinten, E.; Yáñez, J.H.S.; Menafra, R.; Griffioen, M.; ... ; Veelken, H. 2023
Alemtuzumab (anti-CD52 antibody) is frequently prescribed to children with nonmalignant diseases undergoing allogeneic hematopoietic stem cell transplantation (HSCT) to prevent graft failure (GF)... Show moreAlemtuzumab (anti-CD52 antibody) is frequently prescribed to children with nonmalignant diseases undergoing allogeneic hematopoietic stem cell transplantation (HSCT) to prevent graft failure (GF) and acute graft-versus-host disease (aGVHD). The aim of this multicenter study was the characterization of alemtuzumab population pharmacokinetics to perform a novel modelbased exposure-response analysis in 53 children with nonmalignant immunological or hematological disease and a median age of 4.4 years (interquartile range [IQR], 0.8-8.7). The median cumulative alemtuzumab dose was 0.6 mg/kg (IQR, 0.6-1) administered over 2 to 7 days. A 2-compartment population pharmacokinetics model with parallel linear and nonlinear elimination including allometrically scaled bodyweight (median, 17.50 kg; IQR, 8.76-33.00) and lymphocyte count at baseline (mean, 2.24 x 10(9)/L; standard deviation +/- 1.87) as significant pharmacokinetic predictors was developed using nonlinear mixed effects modeling. Based on the model-estimated median concentration at day of HSCT (0.77 mu g/mL; IQR, 0.33-1.82), patients were grouped into a low- (<= 0.77 mu g/mL) or high- (>0.77 mu g/mL) exposure groups. High alemtuzumab exposure at day of HSCT correlated with delayed CD4(+) and CD8(+) T-cell reconstitution (P value <.0001) and increased risk of GF (P value =.043). In contrast, alemtuzumab exposure did not significantly influence the incidence of aGVHD grade >= 2, mortality, chimerism at 1 year, viral reactivations, and autoimmunity at a median follow-up of 3.3 years (IQR, 2.5-8.0). In conclusion, this novel population pharmacokinetics model is suitable for individualized intravenous precision dosing to predict alemtuzumab exposure in pediatric allogeneic HSCT for nonmalignant diseases, aiming at the achievement of early T-cell reconstitution and prevention of GF in future prospective studies. Show less
Patients with cancer have an increased risk of developing venous thromboembolism (VTE), and this combination is reported to result in poorer survival compared with cancer alone. This study aimed to... Show morePatients with cancer have an increased risk of developing venous thromboembolism (VTE), and this combination is reported to result in poorer survival compared with cancer alone. This study aimed to investigate the impact of VTE on the survival of patients with cancer in a general population. The Scandinavian Thrombosis and Cancer (STAC) cohort, a population-based cohort including 144 952 participants without previous VTE or cancer, was used. During follow-up, cancer and VTE incidences were registered. "Cancer-related VTE" was defined as VTE diagnosed in patients with overt or occult cancer. The survival of participants without cancer and/or VTE ("disease-free") was compared with the survival of participants with cancer and cancer-related VTE. Cox regression models with cancer and VTE as time-varying exposures were performed to calculate hazard ratios for death. Subanalyses were performed across cancer types and stages and VTE type (deep vein thrombosis or pulmonary embolism). During follow-up (mean, 11.7 years), 14 621 participants developed cancer, and 2444 developed VTE, of which 1241 were cancer-related. The mortality rates (per 100 person years) for disease-free participants, VTE only, cancer only, and cancer-related VTE were 0.63, 5.0, 9.2, and 45.3, respectively. Compared with patients with cancer only, the risk of death for patients with cancer-related VTE was increased 3.4-fold. Within all cancer types, the occurrence of VTE increased the mortality risk 2.8-to 14.7-fold. In a general population, patients with cancer with VTE had a 3.4-fold higher mortality risk than patients with cancer without VTE, independent of cancer type. Show less
Complement-mediated (CM) autoimmune hemolytic anemia (AIHA) is characterized by the destruction of red blood cells (RBCs) by autoantibodies that activate the classical complement pathway. These... Show moreComplement-mediated (CM) autoimmune hemolytic anemia (AIHA) is characterized by the destruction of red blood cells (RBCs) by autoantibodies that activate the classical complement pathway. These antibodies also reduce transfusion efficacy via the lysis of donor RBCs. Because C1-inhibitor (C1-INH) is an endogenous regulator of the classical complement pathway, we hypothesized that peritransfusional C1-INH in patients with severe CM-AIHA reduces complement activation and hemolysis, and thus enhances RBC transfusion efficacy. We conducted a prospective, single-center, phase 2, open-label trial (EudraCT2012-003710-13). Patients with confirmed CM-AIHA and indication for the transfusion of 2 RBC units were eligible for inclusion. Four IV C1-INH doses (6000, 3000, 2000, and 1000 U) were administered with 12-hour intervals around RBC transfusion. Serial blood samples were analyzed for hemolytic activity, RBC opsonization, complement activation, and inflammation markers. Ten patients were included in the study. C1-INH administration increased plasma C1-INH antigen and activity, peaking at 48 hours after the first dose and accompanied by a significant reduction of RBC C3d deposition. Hemoglobin levels increased briefly after transfusion but returned to baseline within 48 hours. Overall, markers of hemolysis, inflammation, and complement activation remained unchanged. Five grade 3 and 1 grade 4 adverse event occurred but were considered unrelated to the study medication. In conclusion, peritransfusional C1-INH temporarily reduced complement activation. However, C1-INH failed to halt hemolytic activity in severe transfusion-dependent-CM-AIHA. We cannot exclude that posttransfusional hemolytic activity would have been even higher without C1-INH. The potential of complement inhibition on transfusion efficacy in severe CM-AIHA remains to be determined. Show less
Cancer enhances the risk of venous thromboembolism, but a hypercoagulant microenvironment also promotes cancer progression. Although anticoagulants have been suggested as a potential anticancer... Show moreCancer enhances the risk of venous thromboembolism, but a hypercoagulant microenvironment also promotes cancer progression. Although anticoagulants have been suggested as a potential anticancer treatment, clinical studies on the effect of such modalities on cancer progression have not yet been successful for unknown reasons. In normal physiology, complex formation between the subendothelial-expressed tissue factor (TF) and the blood-borne liver-derived factor VII (FVII) results in induction of the extrinsic coagulation cascade and intracellular signaling via protease-activated receptors (PARs). In cancer, TF is overexpressed and linked to poor prognosis. Here, we report that increased levels of FVII are also observed in breast cancer specimens and are associated with tumor progression and metastasis to the liver. In breast cancer cell lines, tumor-expressed FVII drives changes reminiscent of epithelial-to-mesenchymal transition (EMT), tumor cell invasion, and expression of the prometastatic genes, SNAI2 and SOX9. In vivo, tumorexpressed FVII enhanced tumor growth and liver metastasis. Surprisingly, liver-derived FVII appeared to inhibit metastasis. Finally, tumor-expressed FVII-induced prometastatic gene expression independent of TF but required a functional endothelial protein C receptor, whereas recombinant activated FVII acting via the canonical TF:PAR2 pathway inhibited prometastatic gene expression. Here, we propose that tumor-expressed FVII and liverderived FVII have opposing effects on EMT and metastasis. Show less
Adoptive cellular therapies with T cells are increasingly used to treat a variety of conditions. For instance, in a recent phase 1/2 trial, we prophylactically administered multivirusspecific T... Show moreAdoptive cellular therapies with T cells are increasingly used to treat a variety of conditions. For instance, in a recent phase 1/2 trial, we prophylactically administered multivirusspecific T-cell products to protect recipients of T-cell-depleted allogeneic stem cell grafts against viral reactivation. To establish treatment efficacy, it is important to determine the fate of the individual transferred T-cell populations. However, it is difficult to unequivocally distinguish progeny of the transferred T-cell products from recipient- or stem cell graft-derived T cells that survived T-cell depletion during conditioning or stem cell graft manipulation. Using messenger RNA sequencing of the T-cell receptor beta-chains of the individual virus-specific T-cell populations within these T-cell products, we were able to track the multiple clonal virus-specific subpopulations in peripheral blood and distinguish recipient- and stem cell graft-derived virus-specific T cells from the progeny of the infused T-cell products. We observed in vivo expansion of virus-specific T cells that were exclusively derived from the T-cell products with similar kinetics as the expansion of virus-specific T cells that could also be detected before the T-cell product infusion. In addition, we demonstrated persistence of virus-specific T cells derived from the T-cell products in most patients who did not show viral reactivation. This study demonstrates that virus-specific T cells from prophylactically infused multiantigen-specific T-cell products can expand in response to antigen encounter in vivo and even persist in the absence of early viral reactivation. Show less
Langerhans cell histiocytosis (LCH) is a rare neoplastic disorder caused by somatic genetic alterations in hematopoietic precursor cells differentiating into CD1a+/CD207+ histiocytes. LCH clinical... Show moreLangerhans cell histiocytosis (LCH) is a rare neoplastic disorder caused by somatic genetic alterations in hematopoietic precursor cells differentiating into CD1a+/CD207+ histiocytes. LCH clinical manifestation is highly heterogeneous. BRAF and MAP2K1 mutations account for ∼80% of genetic driver alterations in neoplastic LCH cells. However, their clinical associations remain incompletely understood. Here, we present an international clinicogenomic study of childhood LCH, investigating 377 patients genotyped for at least BRAFV600E. MAPK pathway gene alterations were detected in 300 (79.6%) patients, including 191 (50.7%) with BRAFV600E, 54 with MAP2K1 mutations, 39 with BRAF exon 12 mutations, 13 with rare BRAF alterations, and 3 with ARAF or KRAS mutations. Our results confirm that BRAFV600E associates with lower age at diagnosis and higher prevalence of multisystem LCH, high-risk disease, and skin involvement. Furthermore, BRAFV600E appeared to correlate with a higher prevalence of central nervous system (CNS)–risk bone lesions. In contrast, MAP2K1 mutations associated with a higher prevalence of single-system (SS)-bone LCH, and BRAF exon 12 deletions seemed to correlate with more lung involvement. Although BRAFV600E correlated with reduced event-free survival in the overall cohort, neither BRAF nor MAP2K1 mutations associated with event-free survival when patients were stratified by disease extent. Thus, the correlation of BRAFV600E with inferior clinical outcome is (primarily) driven by its association with disease extents known for high rates of progression or relapse, including multisystem LCH. These findings advance our understanding of factors underlying the remarkable clinical heterogeneity of LCH but also question the independent prognostic value of lesional BRAFV600E status. Show less
Patients with type 1 and type 2 von Willebrand disease (VWD) can be treated with desmopressin. Although a previous study has shown that the location of the causative VWF gene variant is associated... Show morePatients with type 1 and type 2 von Willebrand disease (VWD) can be treated with desmopressin. Although a previous study has shown that the location of the causative VWF gene variant is associated with desmopressin response in type 1 VWD, the association between variants in the VWF gene and desmopressin response is not yet fully understood. Our primary aim was to compare desmopressin response in type 1 VWD patients with and without a VWF gene variant. Secondly, we investigated whether desmopressin response depends on specific VWF gene variants in type 1 and type 2 VWD. We included 250 patients from the Willebrand in the Netherlands study: 72 type 1 without a VWF gene variant, 108 type 1 with a variant, 45 type 2A, 16 type 2M, and 9 type 2N patients. VWF gene was analyzed with ion semiconductor sequencing and Multiplex Ligation-dependent Probe Amplification. Complete response to desmopressin was observed in all type 1 VWD patients without a variant, 64.3% of type 1 patients with a variant, and 31.3% of type 2 patients (P<.001). Despite a large interindividual variability in desmopressin response, patients with the same variant had comparable desmopressin responses. For instance, in 6 type 1 patients with exon 4 to 5 deletion, mean VWF activity at 1 hour after desmopressin was 0.81 IU/mL, with a coefficient of variation of 22.9%. In conclusion, all type 1 VWD patients without a VWF gene variant respond to desmopressin. In type 1 and type 2 VWD patients with a VWF variant, desmopressin response highly depends on the VWF gene variants. Show less
It is unknown how lower-leg injury and knee arthroscopy, both associated with venous thromboembolism (VTE), affect coagulation. To study the effect of (1) lower-leg trauma and (2) knee arthroscopy... Show moreIt is unknown how lower-leg injury and knee arthroscopy, both associated with venous thromboembolism (VTE), affect coagulation. To study the effect of (1) lower-leg trauma and (2) knee arthroscopy on coagulation, plasma samples of the Prevention of Thrombosis following CAST immobilization (POT-CAST, #NCT01542762) and Prevention of Thrombosis following Knee Arthroscopy (POT-KAST, #NCT01542723) trials were used, which were collected shortly after lower-leg trauma and before/ after (,4 hours) knee arthroscopy. For aim 1, 1204 lower-leg injury patients were compared with preoperative samples of 1001 controls. Mean differences/ratios (if ln-retransformed because of skewedness) were adjusted for sex, age, body mass index, comorbidity, malignancy, and oral contraceptives using linear regression. For aim 2, perioperative mean changes of 715 arthroscopy patients were calculated. Plasma levels of fibrinogen, factor (F)VIII, FIX, FXI, von Willebrand Factor (VWF), and D-dimer were measured in all individuals. Parameters of underlying mechanisms (tissue factor, interleukin-6 [IL-6], myeloperoxidase DNA, cell-free DNA) were measured in especially FVIII, VWF, and D-dimer, that is, adjusted mean differences: FVIII 26.8% (95% confidence interval [CI], 23.7-29.9), FIX 13.8% (95% CI, 11.9-15.6), FXI 5.1% (95% CI, 3.3-7.0), VWF 29.8% (95% CI, 26.0-33.6), fibrinogen 32.5 mg/dL (95% CI, 25.8-39.2), and D-dimer (mean ratio) 3.3 (95% CI, 3.1-3.6). Remaining parameters were unchanged, except for increased IL-6 levels. After arthroscopy, all parameters decreased. Lower-leg trauma is associated with increased procoagulant factor levels in contrast to knee arthroscopy. This suggests that, in both situations, different pathways are involved in development of VTE. Show less
Background: COVID-19-related critical illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines of the American Society of Hematology ... Show moreBackground: COVID-19-related critical illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in decisions about the use of anticoagulation for patients with COVID-19. Methods: ASH formed a multidisciplinary guideline panel, including 3 patient representatives, and applied strategies to minimize potential bias from conflicts of interest. The McMaster University Grading of Recommendations Assessment, Development and Evaluation (GRADE) Centre supported the guideline development process, including performing systematic evidence reviews (up to January 2022). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the GRADE approach to assess evidence and make recommendations, which were subject to public comment. This is an update to guidelines published in February 2021 and May 2021 as part of the living phase of these guidelines. Results: The panel made 1 additional recommendation: a conditional recommendation for the use of prophylactic-intensity over therapeutic-intensity anticoagulation for patients with COVID-19-related critical illness who do not have suspected or confirmed VTE. The panel emphasized the need for an individualized assessment of thrombotic and bleeding risk. Conclusions: This conditional recommendation was based on very low certainty in the evidence, underscoring the need for additional, high-quality, randomized controlled trials comparing different intensities of anticoagulation for patients with COVID-19-related critical illness. Show less
Background: COVID-19-related acute illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines from the American Society of Hematology ... Show moreBackground: COVID-19-related acute illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines from the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in making decisions about the use of anticoagulation in patients with COVID-19. Methods: ASH formed a multidisciplinary guideline panel that included patient representatives and applied strategies to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process and performed systematic evidence reviews (through November 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess evidence and make recommendations, which were subject to public comment. This is an update to guidelines published in February 2021 as part of the living phase of these guidelines. Results: The panel made one additional recommendation. The panel issued a conditional recommendation in favor of therapeutic-intensity over prophylactic-intensity anticoagulation in patients with COVID-19-related acute illness who do not have suspected or confirmed VTE. The panel empha-sized the need for an individualized assessment of risk of thrombosis and bleeding. The panel also noted that heparin (unfractionated or low molecular weight) may be preferred because of a preponderance of evidence with this class of anticoagulants. Conclusion: This conditional recommendation was based on very low certainty in the evidence, underscoring the need for additional, high-quality, randomized controlled trials comparing different intensities of anticoagulation in patients with COVID-19-related acute illness. Show less
Amini, S.N.; Nelson, V.S.; Porcelijn, L.; Netelenbos, T.; Zwaginga, J.J.; Haas, M. de; ... ; Kapur, R. 2022
Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder with an incompletely understood pathophysiology, but includes platelet-clearance in the spleen and liver via T-cells and/or platelet... Show moreImmune thrombocytopenia (ITP) is an autoimmune bleeding disorder with an incompletely understood pathophysiology, but includes platelet-clearance in the spleen and liver via T-cells and/or platelet-autoantibodies. Strikingly, thrombopoietin (TPO) levels remain low in ITP. Platelet-glycoprotein (GP)Ibα has been described to be required for hepatic TPO generation, however, the role of GPIb-antibodies in relation to platelet hepatic sequestration and TPO-levels, with consideration of platelet counts, remains to be elucidated. Therefore, we performed a study in which we included 53 chronic and non-splenectomized ITP patients for which we conducted indium labeled autologous platelet scintigraphy, measured platelet-antibody profiles and TPO-levels. Upon stratification towards the severity of thrombocytopenia, no negative association was observed between GPIb/IX-antibodies and TPO levels, suggesting that GPIb/IX-antibodies do not inhibit or block TPO levels. Surprisingly, we observed a positive association between GPIb/IX-antibody levels and TPO levels, and GPIb/IX-antibodies and platelet hepatic sequestration, in patients with severe thrombocytopenia, but not in patients with mild or moderate thrombocytopenia. In addition, platelet hepatic sequestration and TPO levels were positively associated. This collectively indicates that GPIb/IX-antibodies may be associated with an increased platelet hepatic sequestration and elevated TPO levels in severe thrombocytopenic ITP patients, however, further research is warranted to elucidate the pathophysiological mechanisms. Show less
The presence of blood flow influences the interaction between von Willebrand factor (VWF) and blood cells, affecting characteristics of forming blood clots. The interactions between coagulation and... Show moreThe presence of blood flow influences the interaction between von Willebrand factor (VWF) and blood cells, affecting characteristics of forming blood clots. The interactions between coagulation and inflammation have mainly been studied in thrombosis models, but it remains unclear whether these interactions might also play a role in reduced bleeding in patients with bleeding disorders. In this systematic review, we provide an overview of the literature investigating the interactions between VWF and blood cells in flow models. For article selection, a systematic search was performed in Embase, Medline-Ovid, Cochrane Library, Web of Science databases, and Google Scholar. After selection, 24 articles were included. These articles describe direct or platelet-dependent interactions between VWF and neutrophils, monocytes, erythrocytes, or lymphocytes under different flow conditions. Almost all the described interactions required the presence of activated platelets. Only erythrocytes, monocytes, and natural killer cells were capable of directly binding the VWF multimers. Overall, interactions between VWF and blood cells mainly occurred in the presence of platelets. Because of the large variation in study design and used flow rates, further research is necessary to compare the results between studies and draw firm conclusions on when and under what conditions these interactions can occur. After our findings, many questions remained unanswered. This review might provide a starting point for future research. Extended knowledge on the influence of blood flow on VWF and blood cell interactions can contribute to improved understanding of the variation in bleeding in patients with bleeding disorders. Show less
von Willebrand Disease (VWD) is associated with significant morbidity because of excessive bleeding. Early diagnosis and treatment are important to prevent and treat these symptoms. We... Show morevon Willebrand Disease (VWD) is associated with significant morbidity because of excessive bleeding. Early diagnosis and treatment are important to prevent and treat these symptoms. We systematically reviewed the accuracy of any von Willebrand factor (VWF) activity assay in the diagnosis and classification of patients for VWD. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 and the certainty of evidence using the GRADE framework. We pooled estimates of sensitivity and specificity. The review included 77 studies that evaluated the use of newer tests of VWF platelet binding activity (VWF:GPIbR, VWF:GPIbM) and VWF:RCo for the diagnosis of VWD (13 studies), VWF propeptide to VWF:Ag ratio, and desmopressin trial for the diagnosis of type 1C VWD (5 studies), VWF multimer analysis and VWF:CB/VWF:Ag ratio for the classification of type 2 VWD (11 studies), genetic testing and ristocetin-induced platelet aggregation to diagnose type 2B VWD (14 studies), genetic testing and FVIII:VWF binding to diagnose type 2N VWD (17 studies). Based on available diagnostic test accuracy, there appear to be comparable test accuracy results between newer tests of platelet binding activity of VWF function and VWF:RCo. The findings of these reviews support VWF multimer analysis or VWF:CB/VWF:Ag to diagnose type 2 VWD. The desmopressin trial test with 1- and 4-hour postinfusion blood work is the test of choice to confirm increased VWF clearance in patients with suspected VWD type 1C. Additionally, genetic testing is most useful in diagnosing type 2B VWD and has a role in the diagnostic algorithm of suspected type 2N VWD. Show less
We prospectively studied clofarabine-fludarabine-busulfan (CloFluBu)-conditioning in allogeneic hematopoietic cell therapy (HCT) for lymphoid and myeloid malignancies and hypothesized that CloFluBu... Show moreWe prospectively studied clofarabine-fludarabine-busulfan (CloFluBu)-conditioning in allogeneic hematopoietic cell therapy (HCT) for lymphoid and myeloid malignancies and hypothesized that CloFluBu provides a less toxic alternative to conventional conditioning regimens, with adequate antileukemic activity. All patients receiving their first HCT, from 2011-2019, were included and received CloFluBu. The primary endpoint was event-free survival (EFS). Secondary endpoints were overall survival (OS), graft-versus-host disease (GvHD)-relapse-free survival (GRFS), treatment-related mortality (TRM), cumulative incidence of relapse (CIR), acute and chronic GvHD (aGvHD and cGvHD), and veno-occlusive disease (VOD). Cox proportional hazard and Fine and Gray competing-risk models were used for data analysis. One hundred fifty-five children were included: 60 acute lymphoid leukemia (ALL), 69 acute myeloid leukemia (AML), and 26 other malignancies (mostly MDS-EB). The median age was 9.7 (0.5 to 18.6) years. Estimated 2-year EFS was 72.0% +/- 6.0 in ALL patients, and 62.4% +/- 6.0 in AML patients. TRM in the whole cohort was 11.0% +/- 2.6, incidence of aGvHD 3 to 4 at 6 months was 12.3% +/- 2.7, extensive cGvHD at 2 years was 6.4% +/- 2.1. Minimal residual disease-positivity prior to HCT was associated with higher CIR, both in ALL and AML. CloFluBu showed limited toxicity and encouraging EFS. CloFluBu is a potentially less toxic alternative to conventional conditioning regimens. Randomized prospective studies are needed. Show less
Amini, S.N.; Porcelijn, L.; Sobels, A.; Kartachova, M.; Haas, M. de; Zwaginga, J.J.; Schipperus, M.R. 2022
Antiglycoprotein (anti-GP) antibodies play an important role in the pathophysiology of immune thrombocytopenia (ITP). The sequestration pattern of platelets in the spleen and liver can be studied... Show moreAntiglycoprotein (anti-GP) antibodies play an important role in the pathophysiology of immune thrombocytopenia (ITP). The sequestration pattern of platelets in the spleen and liver can be studied with In-111-labeled autologous platelet scans. No studies have investigated the role of anti-GP antibodies in sequestration patterns in ITP patients. In this study, we examined the association between antibodies and (1) platelet sequestration site and (2) clearance rate of platelets. All ITP patients receiving an In-111-labeled autologous platelet study between 2014 and 2018 were included. Antibodies were measured using the direct MAIPA method to determine the presence and titer of anti-GPIIb/IIIa, anti-GPIb/IX, and anti-GPV antibodies. Multivariate regression models were used to study the association between anti-GP antibodies, sequestration site, and clearance rate. Seventy-four patients were included, with a mean age of 36 years. Forty-seven percent of the patients showed a predominantly splenic sequestration pattern, 29% mixed, and 25% a hepatic pattern. In 53% of the patients, anti-GP antibodies were detected. Regression models showed a significant association between splenic sequestration and GPV autoantibodies. Furthermore, in patients where antibodies were present, the clearance rate was higher in patients with a splenic sequestration. Anti-GPV antibodies are associated with a splenic sequestration pattern in ITP patients. These associations provide insight into the possible pathophysiological mechanisms of ITP, which may lead to better detection and treatment of this partly idiopathic and prevalent disease. Show less
Vaccination guidelines for patients treated for hematological diseases are typically conservative. Given their high risk for severe COVID-19, it is important to identify those patients that benefit... Show moreVaccination guidelines for patients treated for hematological diseases are typically conservative. Given their high risk for severe COVID-19, it is important to identify those patients that benefit from vaccination. We prospectively quantified serum immunoglobulin G (IgG) antibodies to spike subunit 1 (S1) antigens during and after 2-dosemRNA-1273 (Spikevax/Moderna) vaccination in hematology patients. Obtaining S1 IgG >= 300 binding antibody units (BAUs)/mLwas considered adequate as it represents the lower level of S1 IgG concentration obtained in healthy individuals, and it correlates with potent virus neutralization. Selected patients (n = 723) were severely immunocompromised owing to their disease or treatment thereof. Nevertheless, >= 50% of patients obtained S1 IgG >= 300 BAUs/mL after 2-dosemRNA-1273. All patients with sickle cell disease or chronicmyeloid leukemia obtained adequate antibody concentrations. Around 70% of patients with chronic graft-versus-host disease (cGVHD), multiple myeloma, or untreated chronic lymphocytic leukemia (CLL) obtained S1 IgG >= 300 BAUs/mL. Ruxolitinib or hypomethylating therapy but not high-dose chemotherapy blunted responses inmyeloidmalignancies. Responses in patients with lymphoma, patients with CLL on ibrutinib, and chimeric antigen receptor T-cell recipients were low. The minimal time interval after autologous hematopoietic cell transplantation (HCT) to reach adequate concentrations was <= 2months formultiplemyeloma, 8months for lymphoma, and 4 to 6 months after allogeneic HCT. Serum IgG4, absolute B- and natural killer-cell number, and number of immunosuppressants predicted S1 IgG >= 300 BAUs/mL. Hematology patients on chemotherapy, shortly after HCT, or with cGVHD should not be precluded fromvaccination. Show less
Rijneveld, A.W.; Holt, B. van der; Weerdt, O. de; Biemond, B.J.; Loosdrecht, A.A. van de; Wagen, L.E. van der; ... ; Dutch-Belgian HOVON Cooperative Gr 2022
Clofarabine (CLO) is a nucleoside analog with efficacy in relapsed/refractory acute lymphoblastic leukemia (ALL). This randomized phase 3 study aimed to evaluate whether CLO added to induction and... Show moreClofarabine (CLO) is a nucleoside analog with efficacy in relapsed/refractory acute lymphoblastic leukemia (ALL). This randomized phase 3 study aimed to evaluate whether CLO added to induction and whether consolidation would improve outcome in adults with newly diagnosed ALL. Treatment of younger (18-40 years) patients consisted of a pediatric-inspired protocol, and for older patients (41-70 years), a semi-intensive protocol was used. Three hundred and forty patients were randomized. After a median follow-up of 70 months, 5-year event-free survival (EFS) was 50% and 53% for arm A and B (CLO arm). For patients <= 40 years, EFS was 58% vs 65% in arm A vs B, whereas in patients >40 years, EFS was 43% in both arms. Complete remission (CR) rate was 89% in both arms and similar in younger and older patients. Minimal residual disease (MRD) was assessed in 200 patients (60%). Fifty-four of 76 evaluable patients (71%) were MRD- after consolidation 1 in arm A vs 75/81 (93%) in arm B (P = .001). Seventy (42%) patients proceeded to allogeneic hematopoietic stem cell transplantation in both arms. Five-year overall survival (OS) was similar in both arms: 60% vs 61%. Among patients achieving CR, relapse rates were 28% and 24%, and nonrelapse mortality was 16% vs 17% after CR. CLO-treated patients experienced more serious adverse events, more infections, and more often went off protocol. This was most pronounced in older patients. We conclude that, despite a higher rate of MRD negativity, addition of CLO does not improve outcome in adults with ALL, which might be due to increased toxicity. This trial was registered at www.trialregister.nl as #NTR2004. Show less
