Digital PCR Improves Sensitivity and Quantification in Monitoring CAR-T Cells in B Cell Lymphoma Patients.

Chimeric antigen receptor T cells (CAR-T) has emerged as a promising therapy, over 60% of patients fail to sustain a long-term response. The underlying factors that leads to the effectiveness of this therapy are not completely understood, CAR-T cell persistence and monitoring seems to be pivotal for ensuring a successful response. Various monitoring methods such as multiparametric flow cytometry (MFC) or quantitative PCR (qPCR) have been applied. Our objective is to develop digital PCR (dPCR) assays for detection and quantification of CAR-T cells, comparing them with MFC and qPCR. Samples taken at different follow-up times from 45 patients treated with CAR-T therapy were analyzed to assess the correlation between the different methodologies. dPCR presented a high correlation with MFC and qPCR (r = 0.97 and r = 0.87, respectively), while offering a higher sensitivity (0.01%) compared to MFC (0.1%) and qPCR (1%). dPCR emerged as an alternative and highly sensitivity method for monitoring CAR-T cell dynamics. This technique is well-suited for implementation in clinical practice as a complementary technique to MFC.

Advantages of high cell concentration prior to cryopreservation of initial leukapheresis in CAR-T cell therapy.

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy is increasingly used in patients affected by B-cell lymphoma and acute lymphoblastic leukemia. For logistical reasons, initial apheresis products may be cryopreserved for shipment to manufacturing centers. Due to the characteristics of these patients, cells are often collected in large volumes, meaning more bags must be cryopreserved. This requires increased storage, time and monetary costs. In this context, we aimed to evaluate a high cell concentration cryopreservation protocol by centrifugation to standardize the initial CAR-T manufacturing procedure. MATERIALS AND METHODS: Sixty-eight processes of leukapheresis of 57 patients affected by refractory/relapsed B cell lymphoma and 9 patients affected by acute lymphoblastic leukemia who were eligible for anti-CD19 CAR-T cell treatment performed between June 2019 and October 2022 were analyzed. Whole blood count, percentage and number of T cells were assessed on the apheresis final product. The apheresis product, which was alternatively stored overnight at 4°C, was centrifuged, adjusting the volume to approximately 40 mL. The product was immediately cryopreserved to achieve a final cell concentration of 50-200×106 cells/ml for cryopreservation. RESULTS: Leukapheresis volume was reduced by almost fivefold (median: 185 to 40 mL), resulting in a higher product concentration in one bag. In addition, the number of non-target cells (monocytes, platelets and erythrocytes) was also reduced during the development of CAR T cell therapy, thereby maintaining T lymphocyte levels and providing a purer starting material. DISCUSSION: The advantages of the protocol include reducing economic costs, saving storage space, simplifying the manufacturing process, and facilitating shipping logistics. In conclusion, we present a validated, simple, and cost-effective cell enrichment processing protocol that provides high-quality cryopreserved products as starting material for the CAR-T cell manufacturing process.

Protection of haematopoietic progenitor cell donors: an updated overview of the European landscape.

Haematopoietic progenitor cell donation from bone marrow and mobilised peripheral blood obtained from related and unrelated donors is an established procedure. The donation process in general has proven to be safe, but in rare cases severe and even fatal events have been reported. The present study aimed at providing a description of the current situation of donor protection measures in Council of Europe member States. A specific questionnaire was developed to compile information on donation activities, graft sources, legal frameworks, donor protection measures, collection of donor outcome data, and long-term follow-up of paediatric and adult related and unrelated donors. The outcome of this survey served as a basis for elaborating the Recommendation CM/Rec(2020)6 of the Committee of Ministers to member States on establishing harmonised measures for the protection of haematopoietic progenitor cell donors.

Poor graft function after haploidentical stem cell transplantation with post-transplant cyclophosphamide.

This is a retrospective cohort study of consecutive adult patients who received a haploidentical-SCT (haplo-SCT) with post-transplant cyclophosphamide (PT-Cy) in a single centre. Poor graft function (PGF) was defined as the occurrence of either persistent neutropenia (ANC < 0.5 × 109/µL) with poor response to granulocyte colony-stimulating factors (G-CSF) and/or thrombocytopenia (platelets < 20 × 109/L) with transfusion dependence, with complete donor chimerism and without concurrent severe GVHD or underlying disease relapse, during the first 12 months after transplantation. Forty-four (27.5%) out of 161 patients were diagnosed with PGF. Previous CMV reactivation was significantly more frequent in patients with PGF (88.6% versus 73.5%, p = 0.04) and the number of reactivations was also higher in these patients. Besides, early CMV reactivations in the first 6 months post-SCT were also significantly more frequent among patients with PGF (88.6% versus 71.8% p = 0.025). Thirty-two percent of patients with PGF were treated with increasing doses of thrombopoietin-receptor agonists (TRA) and 7 patients were treated with a donor CD34 + selected boost. In total, 93.2% of patients reached adequate peripheral blood counts in a median time of 101 days (range 11-475) after diagnosis. PGF is a frequent complication after haplo-SCT with PT-Cy. CMV reactivation might be the most relevant factor associated to its development. Even when most patients recover peripheral counts with support therapy, there is a group of patients with persistent cytopenias who can effectively be treated with TRA and/or a boost of CD34 + selective cells.

Evaluation of the Spanish population coverage of a prospective HLA haplobank of induced pluripotent stem cells.

BACKGROUND: iPSC (induced pluripotent stem cells) banks of iPSC lines with homozygous HLA (human leukocyte antigen) haplotypes (haplobanks) are proposed as an affordable and off-the-shelf approach to allogeneic transplantation of iPSC derived cell therapies. Cord blood banks offer an extensive source of HLA-typed cells suitable for reprogramming to iPSC. Several initiatives worldwide have been undertaken to create national and international iPSC haplobanks that match a significant part of a population. METHODS: To create an iPSC haplobank that serves the Spanish population (IPS-PANIA), we have searched the Spanish Bone Marrow Donor Registry (REDMO) to identify the most frequently estimated haplotypes. From the top ten donors identified, we estimated the population coverage using the criteria of zero mismatches in HLA-A, HLA-B, and HLA-DRB1 with different stringencies: high resolution, low resolution, and beneficial mismatch. RESULTS: We have calculated that ten cord blood units from homozygous donors stored at the Spanish cord blood banks can provide HLA-A, HLA-B, and HLA-DRB1 matching for 28.23% of the population. CONCLUSION: We confirm the feasibility of using banked cord blood units to create an iPSC haplobank that will cover a significant percentage of the Spanish and international population for future advanced therapy replacement strategies.

Elafin as a Predictive Biomarker of Acute Skin Graft-Versus-Host Disease After Haploidentical Stem Cell Transplantation Using Post-Transplant High-Dose Cyclophosphamide.

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has shown favorable results in the treatment of hematological malignancies. Despite the use of post-transplant cyclophosphamide (PTCy), graft versus host disease (GVHD) remains as one of the main complications in this setting. Since the skin appears affected in up to 80% of cases of acute GVHD (aGVHD), its prognosis and diagnosis are essential for the correct management of these patients. Plasma concentration of elafin, an elastase inhibitor produced by keratinocytes, has been described elevated at the diagnosis of skin GVHD, correlated with the grade of GVHD, and associated with an increased risk of death. In this study we explored elafin plasma levels in the largest series reported of T cell-replete haplo-HSCT with PTCy. Plasma samples drawn from 87 patients at days +15 and +30 were analyzed ("discovery cohort"). Elafin levels at days +15 were no associated with chronic GVHD, non-relapse mortality, relapse, therapy-resistant GVHD, or overall survival. In our series, elafin levels at day +30 were not associated with post-transplant complications. On the other hand, elafin plasma levels at day +15 were higher in patients with severe skin aGVHD (21,313 vs.14,974 pg/ml; p = 0.01). Of note, patients with higher elafin plasma levels at day +15 presented a higher incidence of stage III-IV skin aGVHD (HR = 18.9; p < 0.001). These results were confirmed (HR = 20.6; p < 0.001) in an independent group of patients (n = 62), i.e. the "validation cohort." These data suggest that measurement of elafin in patients undergoing haplo-HSCT with PTCy might be useful for an early identification of those patients who are at higher risk of suffering severe skin aGVHD and thus, improve their treatment and prognosis.

COVID-19 in transplant recipients: The Spanish experience.

We report the nationwide experience with solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients diagnosed with coronavirus disease 2019 (COVID-19) in Spain until 13 July 2020. We compiled information for 778 (423 kidney, 113 HSCT, 110 liver, 69 heart, 54 lung, 8 pancreas, 1 multivisceral) recipients. Median age at diagnosis was 61 years (interquartile range [IQR]: 52-70), and 66% were male. The incidence of COVID-19 in SOT recipients was two-fold higher compared to the Spanish general population. The median interval from transplantation was 59 months (IQR: 18-131). Infection was hospital-acquired in 13% of cases. No donor-derived COVID-19 was suspected. Most patients (89%) were admitted to the hospital. Therapies included hydroxychloroquine (84%), azithromycin (53%), protease inhibitors (37%), and interferon-ß (5%), whereas immunomodulation was based on corticosteroids (41%) and tocilizumab (21%). Adjustment of immunosuppression was performed in 85% of patients. At the time of analysis, complete follow-up was available from 652 patients. Acute respiratory distress syndrome occurred in 35% of patients. Ultimately, 174 (27%) patients died. In univariate analysis, risk factors for death were lung transplantation (odds ratio [OR]: 2.5; 95% CI: 1.4-4.6), age >60 years (OR: 3.7; 95% CI: 2.5-5.5), and hospital-acquired COVID-19 (OR: 3.0; 95% CI: 1.9-4.9).

Three-sectioning method: A procedure for studying hard tissues and large pieces under light and electron microscopy.

The histological study of hard pieces such as tendons and calcified lesions and tissues is a field that has been gaining increased attention owing to the rapid development of implantable prostheses, among other factors. In these studies, serial sectioning is utilized to detect areas of interest throughout the entire piece, as it enables the application of the appropriate light and electron microscopy techniques in these areas. We propose the "three-sectioning method" that subjects the pieces to three consecutive cycles of embedding and sectioning to localize and study the areas of interest, as an efficient technique for these histological studies. The pieces were first embedded in epoxy resin and then cut into thick sections (approximately 300 µm) for the first cycle. Next, areas of interest selected on these thick sections were re-embedded in epoxy resin to be sectioned again (second sectioning) to obtain a series of semithin sections (1-3 µm). These semithin sections are usually studied using the most relevant techniques for light microscopy. Smaller areas of interest are selected to be cut into ultrathin sections (60-90 nm) for transmission electron microscopy. If necessary, the selected areas of the semithin sections can be embedded again, and then cut into new ultrathin sections. The different kinds of sections we have described here may also be studied using scanning electron microscopy. This systematic method facilitates correlative microscopy from lower to higher magnifications along with the usage of a broad variety of histological techniques including electron microscopy.

Clinical applications of donor lymphocyte infusion from an HLA-haploidentical donor: consensus recommendations from the Acute Leukemia Working Party of the EBMT.

Donor lymphocyte infusion has been used in the management of relapsed hematologic malignancies after allogeneic hematopoietic cell transplantation. It can eradicate minimal residual disease or be used to rescue a hematologic relapse, being able to induce durable remissions in a subset of patients. With the increased use of haploidentical hematopoietic cell transplantation, there is renewed interest in the use of donor lymphocytes to either treat or prevent disease relapse post transplant. Published retrospective and small prospective studies have shown encouraging results with therapeutic donor lymphocyte infusion in different haploidentical transplantation platforms. In this consensus paper, finalized on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, we summarize the available evidence on the use of donor lymphocyte infusion from haploidentical donor, and provide recommendations on its therapeutic, pre-emptive and prophylactic use in clinical practice.

The European Society for Blood and Marrow Transplantation (EBMT) consensus recommendations for donor selection in haploidentical hematopoietic cell transplantation.

The number of HLA-haploidentical hematopoietic cell transplants continues to increase worldwide due to recent improvements in outcomes, allowing more patients with hematological malignancies and non-malignant disorders to benefit from this procedure and have a chance to cure their disease. Despite these encouraging results, questions remain as multiple donors are usually available for transplantation, and choosing the best HLA-haploidentical donor for transplantation remains a challenge. Several approaches to haploidentical transplantation have been developed over time and, based on the graft received, can be grouped as follows: T-cell depleted haploidentical transplants, either complete or partial, or with T-cell replete grafts, performed with post-transplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis, or G-CSF-primed bone marrow graft and enhanced GVHD prophylaxis. Carefully selecting the donor can help optimize transplant outcomes for recipients of haploidentical donor transplants. Variables usually considered in the donor selection include presence of donor-specific antibodies in the recipient, donor age, donor/recipient gender and ABO combinations, and immunogenic variables, such as natural killer cell alloreactivity or KIR haplotype. Here we provide a comprehensive review of available evidence for selecting haploidentical donors for transplantation, and summarize the recommendations from the European Society for Blood and Marrow Transplantation (EBMT) on donor selection for different transplant platforms.

ST2 and REG3α as Predictive Biomarkers After Haploidentical Stem Cell Transplantation Using Post-transplantation High-Dose Cyclophosphamide.

Allogenic hematopoietic stem cell transplantation (allo-HSCT) is a curative procedure for several hematological malignancies. Haploidentical HSCT (haplo-HSCT) using high-dose post-transplantation cyclophosphamide (PTCy) makes transplantation possible for patients with no HLA-matched sibling donor. However, this treatment can cause complications, mainly infection, graft-vs.-host disease (GVHD), and conditioning-related toxicity. In recent years, different biomarkers in the form of tissue-specific proteins have been investigated; these may help us to predict complications of allo-HSCT. In this study we explored two such biomarkers, suppression of tumorigenicity 2 (ST2) and regenerating islet-derived 3α (REG3α), in the largest series reported of T cell-replete haplo-HSCT with PTCy. Plasma samples drawn from 87 patients at days +15 and +30 were analyzed. ST2 and REG3α levels at day +15 were not associated with post-transplant complications. ST2 levels at day +30 were higher in patients with grade II-IV acute GVHD, mainly those who received reduced intensity conditioning (RIC; median 2,503 vs. 1,830 ng/ml; p = 0.04). Of note, patients with higher plasma ST2 levels at day +30 also presented a higher incidence of non-relapse mortality (HR, 7.9; p = 0.004) and lower 2-year overall survival (25 vs. 44 months; p = 0.02) than patients with lower levels. Patients with REG3α levels higher than 1,989 pg/ml at day +30 presented a higher incidence of acute gastrointestinal GVHD in the whole cohort (HR, 8.37; p = 0.003) and in the RIC cohort (HR 6.59; p = 0.01). These data suggest that measurement of ST2 and REG3α might be useful for the prognosis and prediction of complications in patients undergoing haplo-HSCT with PTCy.

Novel Antibacterial and Toughened Carbon-Fibre/Epoxy Composites by the Incorporation of TiO2 Nanoparticles Modified Electrospun Nanofibre Veils.

The inclusion of electrospun nanofiber veils was revealed as an effective method for enhancing the mechanical properties of fiber-reinforced epoxy resin composites. These veils will eventually allow the incorporation of nanomaterials not only for mechanical reinforcement but also in multifunctional applications. Therefore, this paper investigates the effect of electrospun nanofibrous veils made of polyamide 6 modified with TiO2 nanoparticles on the mechanical properties of a carbon-fiber/epoxy composite. The nanofibers were included in the carbon-fiber/epoxy composite as a single structure. The effect of positioning these veils in different composite positions was investigated. Compared to the reference, the use of unmodified and TiO2 modified veils increased the flexural stress at failure and the fracture toughness of composites. When TiO2 modified veils were incorporated, new antibacterial properties were achieved due to the photocatalytic properties of the veils, widening the application area of these composites.

Factors predicting peripheral blood progenitor cell mobilization in healthy donors in the era of related alternative donors: Experience from a single center.

BACKGROUND: Poor mobilization results are unexpected after G-CSF-induced peripheral blood stem cell collection in healthy donors. However, 2%-5% of the donors are poor mobilizers. Factors predicting CD34+-cell yield after mobilization in related alternative donors are still poorly known. PATIENTS AND METHODS: Baseline characteristics and efficacy results of G-CSF induced mobilization of 159 adult healthy donors in our institution from 2008 to 2016 were retrospectively analyzed. All donors received 10 µg/kg of G-CSF once a day subcutaneously for 4 days. Leukapheresis started on the 5th day of G-CSF treatment. Donors were classified as poor mobilizers if they had less than 20 000 CD34 + cell/mL peripheral blood count in the 5th day of G-CSF treatment or if they needed three or more leukapheresis for graft collection. RESULTS: Age, weight, and platelet count before and after mobilization were significantly different between poor and good mobilizers. Poor mobilizers (n = 16) were older (50.6 vs 41.7 years, P = 0.002), weight lower (64 vs 75 kg, P = 0.00) and showed a lower platelet count before (199.5 vs 219.0 × 109 /L, P = 0.03) and after (192.5 vs 206 × 109 /L, P = 0.019) mobilization. In the multivariate analysis only the 30% of the variability of mobilization was explained by the model (sensitivity 80%, specificity 70%). CONCLUSION: In this cohort of healthy donors in a single institution, older age, less weight, and lower platelet count was associated with poorer mobilization. With clinical and analytic factors it is not possible to predict more than 30% of the variability. Further studies are needed to investigate new variables.

Bendamustine as part of conditioning of autologous stem cell transplantation in patients with aggressive lymphoma: a phase 2 study from the GELTAMO group.

We conducted a phase 2 trial to evaluate the safety and efficacy of bendamustine instead of BCNU (carmustine) in the BEAM (BCNU, etoposide, cytarabine and melphalan) regimen (BendaEAM) as conditioning for autologous stem-cell transplantation (ASCT) in patients with aggressive lymphomas. The primary endpoint was 3-year progression-free survival (PFS). Sixty patients (median age 55 [28-71] years) were included. All patients (except one who died early) engrafted after a median of 11 (9-72) and 14 (4-53) days to achieve neutrophil and platelet counts of >0.5 × 109 /l and >20 × 109 /l, respectively. Non-relapse mortality at 100 days and 1 year were 3.3% and 6.7%, respectively. With a median follow-up of 67 (40-77) months, the estimated 3-year PFS and overall survival (OS) were 58% and 75%, respectively. Patients in partial response at study entry had significantly worse PFS and OS than patients who underwent ASCT in complete metabolic remission, and this was the only prognostic factor associated with both PFS (Relative risk [RR], 0.27 [95% confidence interval {CI} [0.12-0.56]) and OS (RR, 0.40 [95% CI 0.17-0.97]) in the multivariate analysis. BendaEAM conditioning is therefore a feasible and effective regimen in patients with aggressive lymphomas. However, patients not in complete metabolic remission at the time of transplant had poorer survival and so should be considered for alternative treatment strategies.

Mononuclear cell collection for extracorporeal photopheresis by using the "off-line" system: A comparative study between COBE Spectra and Spectra Optia devices.

BACKGROUND: Extracorporeal photopheresis (ECP) is an efficient and established therapy to treat acute and chronic graft vs host disease (GVHD). Using an "off-line" method, the first step (mononuclear cell [MNC] collection) is decisive, as long as a high MNC yield and purity in the collected product is desirable. Two "off-line" devices were compared: the COBE Spectra and the Spectra Optia (Terumo BCT), using both continuous and intermittent protocols. PATIENTS AND METHODS: Twelve patients with GvHD (7 acute/5 chronic) were enrolled between June 2014 and May 2015 and were alternatively assigned for each procedure to either the COBE Spectra or the Spectra Optia cell separator. Patients characteristics and procedure/product parameters were analyzed. RESULTS: Two hundred procedures (100 per device) were included. The Spectra Optia system showed higher total nucleated cells and MNC collection efficiencies (18.6(10.2-29.7) vs 7.9(4.1-14.8)% and 43.6(20.3-59.5) vs 23.3(11.4-37.1)%, P < .001) and monocyte and lymphocyte collection efficiencies (55.2(17.7-83.2) vs 22.8(9-38.9)% and 38.3(26.7-53.4) vs 22.2(9-38.9)%, respectively, P < .001). Absolute platelet loss (PL) and PL per liter of blood processed were significantly lower in the Spectra Optia group (22.9(18.3-28.1) vs 33.6(26.5-41.1)%, P < .001 and 3.7(3.1-4.5) vs 4.3(3.5-4.2)%, P = .01, respectively). However, granulocyte contamination was higher (4.5(1.3-36) vs 1.2(0.4-5.7)%, P < .001) and a higher product haematocrit was obtained with the Spectra Optia (1(0.5-1.6) vs 0.3(0.2-0.5)%, P < .001), without an impact on irradiation time. CONCLUSIONS: In our study, Spectra Optia proved to be safe and effective in collecting MNC with high yield and purity for ECP in GvHD.

A novel predictive approach for GVHD after allogeneic SCT based on clinical variables and cytokine gene polymorphisms.

Despite considerable advances in our understanding of the pathophysiology of graft-versus-host disease (GVHD), its prediction remains unresolved and depends mainly on clinical data. The aim of this study is to build a predictive model based on clinical variables and cytokine gene polymorphism for predicting acute GVHD (aGVHD) and chronic GVHD (cGVHD) from the analysis of a large cohort of HLA-identical sibling donor allogeneic stem cell transplant (allo-SCT) patients. A total of 25 SNPs in 12 cytokine genes were evaluated in 509 patients. Data were analyzed using a linear regression model and the least absolute shrinkage and selection operator (LASSO). The statistical model was constructed by randomly selecting 85% of cases (training set), and the predictive ability was confirmed based on the remaining 15% of cases (test set). Models including clinical and genetic variables (CG-M) predicted severe aGVHD significantly better than models including only clinical variables (C-M) or only genetic variables (G-M). For grades 3-4 aGVHD, the correct classification rates (CCR1) were: 100% for CG-M, 88% for G-M, and 50% for C-M. On the other hand, CG-M and G-M predicted extensive cGVHD better than C-M (CCR1: 80% vs. 66.7%, respectively). A risk score was calculated based on LASSO multivariate analyses. It was able to correctly stratify patients who developed grades 3-4 aGVHD (P < .001) and extensive cGVHD (P < .001). The novel predictive models proposed here improve the prediction of severe GVHD after allo-SCT. This approach could facilitate personalized risk-adapted clinical management of patients undergoing allo-SCT.

Busulfan-based myeloablative conditioning regimens for haploidentical transplantation in high-risk acute leukemias and myelodysplastic syndromes.

BACKGROUND: High-risk acute leukemia (AL) and myelodysplastic syndrome (MDS) remain a therapeutic challenge. Unmanipulated haploidentical-related donor transplantation based on a myeloablative conditioning regimen (HAPLO-MAC) and post-transplant cyclophosphamide (PT-Cy) as prophylaxis against graft vs host disease (GvHD) is now a promising rescue strategy that could become universally available. OBJECTIVE: To evaluate the results of HAPLO-MAC with PT-Cy in patients with AL and MDS reported to the Haploidentical Transplantation Subcommittee of the Spanish Group for Hematopoietic Transplantation (GETH). PATIENTS AND METHODS: We report our multicenter experience using an IV busulfan-based HAPLO-MAC regimen and PT-Cy for treatment of 65 adults with high-risk AL and MDS. RESULTS: Engraftment was recorded in 64 patients (98.5%), with a median time to neutrophil and platelet recovery of 16 and 27 days, respectively. The cumulative incidence of grade II-IV acute GvHD and chronic GvHD was 28.6% and 27.5%, respectively. After a median follow-up of 31 months for survivors, the cumulative incidence of non-relapse mortality and relapse at 2 years was 18.8% and 25%, respectively. Estimated 30-month event-free survival and overall survival were 56% and 54.5%, respectively. CONCLUSION: HAPLO-MAC comprising an IV busulfan-based conditioning regimen enabled long-term disease control with acceptable toxicity in high-risk AL and MDS.

Donor Cell-Derived Hematologic Neoplasms after Hematopoietic Stem Cell Transplantation: A Systematic Review.

Development of de novo hematologic malignancies in donor cells after allogeneic stem cell transplantation (allo-SCT) provides a useful in vivo model to study the process of leukemogenesis. A systematic analysis of the cases reported in the literature was performed to identify risk factors and mechanisms involved in the pathogenesis of donor cell-derived hematologic neoplasms (DCHN) and leukemogenic transformation. Relevant data were extracted from 137 cases. Cases of DCHN show a wide heterogeneity with regard to recipient/donor age, sex mismatch, and conditioning regimen. Some characteristics, such as the type of primary disease, the type of hematologic malignancy of the DCHN, and the stem cell source used in the transplant procedure, differ from those expected. Mechanisms involved in the pathogenesis of DCHN are complex, and several hypotheses have been proposed, such as pre-existing hematologic neoplasms or premalignant clones in the donor, decreased immune surveillance, and damage to bone marrow microenvironment in the recipient. Most likely several if not all these mechanisms play a role in DCHN development. Novel approaches, such as next-generation sequencing to study consecutive samples after allo-SCT in these patients, appear to be promising to decipher the mechanisms of leukemogenesis.

Effect of Different Types of Electrospun Polyamide 6 Nanofibres on the Mechanical Properties of Carbon Fibre/Epoxy Composites.

Delamination and brittle matrix fracture have long since been the biggest problems in fibre-reinforced composites. Recently, the incorporation of electrospun nanofibre veils has been shown to be an effective method for improving the mechanical properties of these composites, without causing process problems and negatively affecting other mechanical properties. Thus, these nanofibres have the potential to be used as thickness-reinforcing materials in composites. This paper investigates the effect of incorporating standalone electrospun nanofibre veils made of two different types of polyamide 6 (PA6) on the mechanical properties of carbon fibre/epoxy composites. The influence of positioning the electrospun veils at different interlaminar positions of the laminate has also been investigated.