Search

Graft-versus-host disease (GvHD) remains one of the major complications following allogeneic haematopoietic stem cell transplantation (allo-HSCT). GvHD can occur in almost every tissue, with the skin, liver, and intestines being the mainly affected organs. T cells are implicated in initiating GvHD. T cells identify a broad range of antigens and mediate the immune response through receptors on their surfaces (T cell receptors, TCRs). The composition of TCRs within a T cell population defines the TCR repertoire of an individual, and this repertoire represents exposure to self and non-self proteins. Monitoring the changes in the TCR repertoire using TCR sequencing can provide an indication of the dynamics of a T cell population. Monitoring the frequency and specificities of specific TCR clonotypes longitudinally in different conditions and specimens (peripheral blood, GvHD-affected tissue samples) can provide insights into factors modulating immune reactions following allogeneic transplantation and will help to understand the underlying mechanisms mediating GvHD. This review provides insights into current studies of the TCR repertoire in GvHD and potential future clinical implications of TCR sequencing.

ZusammenfassungDer Nachweis klonaler Hämatopoese (CH) bei Patient*innen mit hämatologischen Neoplasien, die mit einer zellulären Therapie behandelt werden, ist häufig. Zu den gängigen, in der klinischen Routine verwendeten zellulären Therapieverfahren zählen die autologe und allogene Stammzelltransplantation (SZT) und seit Kurzem die CAR-T-Zell-Therapie (CAR chimärer Antigenrezeptor). Alle drei Verfahren unterscheiden sich fundamental im Hinblick auf Gewinnung, Verarbeitung und Einsatz des jeweiligen Zellprodukts. Deshalb ist die Bedeutung der CH in Bezug auf das jeweilige Therapieverfahren grundsätzlich unterschiedlich zu bewerten und einzuordnen. Bei der autologen SZT trägt das Ausmaß der zytotoxischen Vortherapie maßgeblich zur hohen CH-Prävalenz bei. Der klinisch bedeutsamste Aspekt ist hier die Entwicklung von Sekundärneoplasien aus einer präexistenten CH sowie das potenziell erhöhte Risiko kardiovaskulärer Nebenwirkungen. Bei der allogenen SZT bestimmt die Auswahl der Spender*innen im Hinblick auf das Alter die Wahrscheinlichkeit für das Vorliegen einer CH. Die Entwicklung von Sekundärmalignomen spielt verglichen mit der autologen SZT nur eine untergeordnete Rolle. Vielmehr scheinen die Induktion eines Graft-versus-Host(GvH)- bzw. eines Graft-versus-Leukemia(GvL)-Effekts und deren Einfluss auf Rezidivfreiheit und Überleben von möglicher klinischer Relevanz. Die CAR-T-Zell-Therapie ist in ihrer Wirkungsweise und in Bezug auf das Nebenwirkungsprofil eng verknüpft mit Inflammationsreaktionen. Auch hier besteht ein potenzieller Zusammenhang zwischen CH sowie Wirkung und Nebenwirkung einer CAR-T-Zell-Therapie. Erste Daten berichten über eine hohe Prävalenz von CH bei Patient*innen vor CAR-T-Zell-Therapie und deuten auf eine erhöhte Rate an inflammatorischen Nebenwirkungen hin, wenngleich sich bisher kein negativer Effekt auf das Überleben zeigt.

Plain language summaryThere are various ways in which clinicians can predict the risk of disease progression in patients with leukemia, helping them to treat the patients accordingly. However, these approaches are usually designed by human experts and might not fully capture the complexity of a patient's disease. Here, with a large cohort of patients with acute myeloid leukemia, we design an unsupervised machine learning model - a type of computer model that learns from patterns in data without human input-to separate these patients into subgroups according to risk. We identify four distinct groups which differ with regards to patient genetics, laboratory values, and clinical characteristics. These groups have differences in response to treatment and patient survival, and we validate our findings in another dataset. Our approach might help clinicians to better predict outcomes in patients with leukemia and make decisions on treatment. Eckardt et al. identify four distinct risk clusters of patients with acute myeloid leukemia using unsupervised metaclustering, which is agnostic to current risk stratification models, in a large multicenter cohort. Clusters differ in terms of response to induction therapy and long-term survival, and are externally validated. BackgroundIncreasingly large and complex biomedical data sets challenge conventional hypothesis-driven analytical approaches, however, data-driven unsupervised learning can detect inherent patterns in such data sets.MethodsWhile unsupervised analysis in the medical literature commonly only utilizes a single clustering algorithm for a given data set, we developed a large-scale model with 605 different combinations of target dimensionalities as well as transformation and clustering algorithms and subsequent meta-clustering of individual results. With this model, we investigated a large cohort of 1383 patients from 59 centers in Germany with newly diagnosed acute myeloid leukemia for whom 212 clinical, laboratory, cytogenetic and molecular genetic parameters were available.ResultsUnsupervised learning identifies four distinct patient clusters, and statistical analysis shows significant differences in rate of complete remissions, event-free, relapse-free and overall survival between the four clusters. In comparison to the standard-of-care hypothesis-driven European Leukemia Net (ELN2017) risk stratification model, we find all three ELN2017 risk categories being represented in all four clusters in varying proportions indicating unappreciated complexity of AML biology in current established risk stratification models. Further, by using assigned clusters as labels we subsequently train a supervised model to validate cluster assignments on a large external multicenter cohort of 664 intensively treated AML patients.ConclusionsDynamic data-driven models are likely more suitable for risk stratification in the context of increasingly complex medical data than rigid hypothesis-driven models to allow for a more personalized treatment allocation and gain novel insights into disease biology. CA Eckardt

Allogeneic transplantation (allo-HCT) is a curative treatment in CLL whose efficacy including the most severe forms had led to the 2006 EBMT recommendations. The advent after 2014 of targeted therapies has revolutionized CLL management, allowing prolonged control to patients who have failed immunochemotherapy and/or have TP53 alterations. We analysed the pre COVID pandemic 2009–2019 EBMT registry. The yearly number of allo-HCT raised to 458 in 2011 yet dropped from 2013 onwards to an apparent plateau above 100. Within the 10 countries who were under the EMA for drug approval and performed 83.5% of those procedures, large initial differences were found but the annual number converged to 2–3 per 10 million inhabitants during the 3 most recent years suggesting that allo-HCT remains applied in selected patients. Long-term follow-up on targeted therapies shows that most patients relapse, some early, with risk factors and resistance mechanisms being described. The treatment of patients exposed to both BCL2 and BTK inhibitors and especially those with double refractory disease will become a challenge in which allo-HCT remains a solid option in competition with emerging therapies that have yet to demonstrate their long-term effectiveness.

Purpose Patients undergoing allogeneic hematopoietic cell transplantation (alloHCT) spend many weeks of treatment in an isolated environment with little room for exercise. Feasibility of a daily-performed, unassisted fascia-training program and its effects on back and foot pain, back flexibility, and quality of life were investigated. Methods Eighteen patients receiving alloHCT were randomized to an intervention (IG: n = 9; 60.7 ± 9.2 years) or control group (CG: n = 9; 54.0 ± 15.5 years) and assessed from 1 week before to 3 weeks after transplantation (t0–t3). CG received standard care physical therapy, IG performed additionally fascia training for the back and feet twice daily. Back and foot pain, back flexibility, muscle tone, and quality of life were assessed for both IG and CG at baseline and three timepoints after alloHCT. Results Fascia-training program was well accepted. No increase in hematoma formation was observed. IG reported a trend towards reduction in back pain from pre- to post-intervention (p = .074), whereas CG showed a slight increase in back pain at t3 (p = .257). IG also improved back flexibility (− 1.79 ± 5.5 cm; p = .397) while CG declined (+ 2.71 ± 5.6 cm; p = .167). No differences between groups were found for muscle tone and no significant improvements in quality of life were reported at t3. Conclusion Unassisted fascia training is feasible and safe for patients undergoing alloHCT. This pilot study suggests that fascia training has the potential to improve back flexibility and reduce back pain, and might be a valuable component for physical therapy in patients receiving alloHCT.

The evaluation of bone marrow morphology by experienced hematopathologists is essential in the diagnosis of acute myeloid leukemia (AML); however, it suffers from a lack of standardization and inter-observer variability. Deep learning (DL) can process medical image data and provides data-driven class predictions. Here, we apply a multi-step DL approach to automatically segment cells from bone marrow images, distinguish between AML samples and healthy controls with an area under the receiver operating characteristic (AUROC) of 0.9699, and predict the mutation status of Nucleophosmin 1 (NPM1)—one of the most common mutations in AML—with an AUROC of 0.92 using only image data from bone marrow smears. Utilizing occlusion sensitivity maps, we observed so far unreported morphologic cell features such as a pattern of condensed chromatin and perinuclear lightening zones in myeloblasts of NPM1-mutated AML and prominent nucleoli in wild-type NPM1 AML enabling the DL model to provide accurate class predictions.

Acute graft-versus-host disease (aGvHD) contributes to about 50% of transplant-related mortality (non-relapse mortality) after allogeneic hematopoietic stem cell transplantation (HSCT). Here the predictive value of a urinary proteomic profile (aGvHD_MS17) was tested together with preemptive prednisolone therapy. Two-hundred and fifty-nine of 267 patients were eligible for analysis. Ninety-two patients were randomized upon aGvHD_MS17 classification factor above 0.1 to receive either prednisolone (2–2.5 mg/kg, N = 44) or placebo (N = 47; N = 1 randomization failure) for 5 days followed by tapering. The remaining 167 patients formed the observation group. The primary endpoint of the randomized trial was incidence of aGvHD grade II between randomization and day +100 post HSCT. Analysis of the short-term preemptive prednisolone therapy in the randomized patients showed no significant difference in incidence or severity of acute GvHD (HR: 1.69, 95% CI: 0.66–4.32, P = 0.27). Prednisolone as preemptive treatment did not lead to an increase in relapse (20.2% in the placebo and 14.0% in the prednisolone group (P = 0.46)). The frequency of adverse events was slightly higher in the placebo group (64.4% versus 50%, respectively). Taken together, the results of the Pre-GvHD trial demonstrated the feasibility and safety of preemptive prednisolone treatment in the randomized patients.

The fusion genes CBFB/MYH11 and RUNX1/RUNX1T1 block differentiation through disruption of the core binding factor (CBF) complex and are found in 10–15% of adult de novo acute myeloid leukemia (AML) cases. This AML subtype is associated with a favorable prognosis; however, nearly half of CBF-rearranged patients cannot be cured with chemotherapy. This divergent outcome might be due to additional mutations, whose spectrum and prognostic relevance remains hardly defined. Here, we identify nonsilent mutations, which may collaborate with CBF-rearrangements during leukemogenesis by targeted sequencing of 129 genes in 292 adult CBF leukemia patients, and thus provide a comprehensive overview of the mutational spectrum (‘mutatome’) in CBF leukemia. Thereby, we detected fundamental differences between CBFB/MYH11- and RUNX1/RUNX1T1-rearranged patients with ASXL2, JAK2, JAK3, RAD21, TET2, and ZBTB7A being strongly correlated with the latter subgroup. We found prognostic relevance of mutations in genes previously known to be AML-associated such as KIT, SMC1A, and DHX15 and identified novel, recurrent mutations in NFE2 (3%), MN1 (4%), HERC1 (3%), and ZFHX4 (5%). Furthermore, age >60 years, nonprimary AML and loss of the Y-chromosomes are important predictors of survival. These findings are important for refinement of treatment stratification and development of targeted therapy approaches in CBF leukemia.

Background Acute promyelocytic leukemia (APL) is considered a hematologic emergency due to high risk of bleeding and fatal hemorrhages being a major cause of death. Despite lower death rates reported from clinical trials, patient registry data suggest an early death rate of 20%, especially for elderly and frail patients. Therefore, reliable diagnosis is required as treatment with differentiation-inducing agents leads to cure in the majority of patients. However, diagnosis commonly relies on cytomorphology and genetic confirmation of the pathognomonic t(15;17). Yet, the latter is more time consuming and in some regions unavailable. Methods In recent years, deep learning (DL) has been evaluated for medical image recognition showing outstanding capabilities in analyzing large amounts of image data and provides reliable classification results. We developed a multi-stage DL platform that automatically reads images of bone marrow smears, accurately segments cells, and subsequently predicts APL using image data only. We retrospectively identified 51 APL patients from previous multicenter trials and compared them to 1048 non-APL acute myeloid leukemia (AML) patients and 236 healthy bone marrow donor samples, respectively. Results Our DL platform segments bone marrow cells with a mean average precision and a mean average recall of both 0.97. Further, it achieves high accuracy in detecting APL by distinguishing between APL and non-APL AML as well as APL and healthy donors with an area under the receiver operating characteristic of 0.8575 and 0.9585, respectively, using visual image data only. Conclusions Our study underlines not only the feasibility of DL to detect distinct morphologies that accompany a cytogenetic aberration like t(15;17) in APL, but also shows the capability of DL to abstract information from a small medical data set, i. e. 51 APL patients, and infer correct predictions. This demonstrates the suitability of DL to assist in the diagnosis of rare cancer entities. As our DL platform predicts APL from bone marrow smear images alone, this may be used to diagnose APL in regions were molecular or cytogenetic subtyping is not routinely available and raise attention to suspected cases of APL for expert evaluation.

Clostridium difficile (CD) infection is the main cause of nosocomial enterocolitis in western countries and in patients undergoing allogeneic hematopoietic stem cell transplantation (alloHCT). Recipients of alloHCT are at high risk for CD infection but large studies in this population are rare and conflicting results have been reported. We analyzed 727 patients with AML or MDS undergoing alloHCT in our center from 2004 to 2015. Ninety-six patients (13%) had CD infection and 103 patients (14%) were identified as asymptomatic carriers by screening at admission and once a week during aplasia. Patients with CD infection had a shorter median overall survival of 8 months (95% CI, 6-36 months) compared with 25 months (95% CI, 17-35 months) for patients without CD infection, (HR 1.4, p = 0.04). CD positive patients were less likely to develop acute graft-versus-host disease (aGvHD; HR 0.6, p = 0.004) compared with CD-negative patients, but did not show differences in gastrointestinal aGvHD (HR 0.9, p = 0.5). Symptomatic patients developed gastrointestinal aGvHD (HR 2.5, p = 0.02) more often compared with asymptomatic CD positive patients. This analysis demonstrates a high prevalence for CD infection in patients undergoing alloHCT. A significant lower overall survival for patients with CD infection could be demonstrated.

The COVID-19 pandemic has serious implications also for patients with other diseases. Here, we describe the effects of the pandemic on unrelated hematopoietic stem cell donation and transplantation from the perspective of DKMS, a large international donor registry. Especially, we cover the development of PBSC and bone marrow collection figures, donor management including Health and Availability Check (HAC), transport and cryopreservation of stem cell products, donor recruitment and business continuity measures. The total number of stem cell products provided declined by around 15% during the crisis with a particularly strong decrease in bone marrow products. We modified donor management processes to ensure donor and product safety. HAC instead of confirmatory typing was helpful especially in countries with strict lockdowns. New transport modes were developed so that stem cell products could be safely delivered despite COVID-19-related travel restrictions. Cryopreservation of stem cell products became the new temporary standard during the pandemic to minimize risks related to transport logistics and donor availability. However, many products from unrelated donors will never be transfused. DKMS discontinued public offline donor recruitment, leading to a 40% decline in new donors during the crisis. Most DKMS employees worked from home to ensure business continuity during the crisis.

Donor T-cells transferred after allogeneic stem cell transplantation (alloSCT) can result in long-term disease control in myeloma by the graft-versus-myeloma (GvM) effect. However, T-cell therapy may show differential effectiveness against bone marrow (BM) infiltration and focal myeloma lesions resulting in different control and progression patterns. Outcomes of 43 myeloma patients who underwent T-cell-depleted alloSCT with scheduled donor lymphocyte infusion (DLI) were analyzed with respect to diffuse BM infiltration and focal progression. For comparison, 12 patients for whom a donor search was started but no alloSCT was performed, were analyzed. After DLI, complete disappearance of myeloma cells in BM occurred in 86% of evaluable patients. The probabilities of BM progression-free survival (PFS) at 2 years after start of donor search, alloSCT and DLI, were 17% (95% confidence interval 0-38%), 51% (36-66%), and 62% (44-80%) respectively. In contrast, the probabilities of focal PFS at 2 years after start of donor search, alloSCT and DLI, were 17% (0-38%), 30% (17-44%) and 28% (11-44%), respectively. Donor-derived T-cell responses effectively reduce BM infiltration, but not focal progression in myeloma, illustrating potent immunological responses in BM with only limited effect of T-cells on focal lesions.

Donor cell leukemia: evidence for multiple preleukemic clones and parallel long term clonal evolution in donor and recipient

The optimal timing of allogeneic hematopoietic stem cell transplantation (HCT) in acute myeloid leukemia (AML) is controversial. We report on 1179 patients with a median age of 48 years who were randomized upfront. In the control arm, sibling HCT was scheduled in the first complete remission for intermediate-risk or high-risk AML and matched unrelated HCT in complex karyotype AML. In the experimental arm, matched unrelated HCT in first remission was offered also to patients with an FLT3-ITD (FMS-like tyrosine kinase 3-internal tandem duplication) allelic ratio >0.8, poor day +15 marrow blast clearance and adverse karyotypes. Further, allogeneic HCT was recommended in high-risk AML to be performed in aplasia after induction chemotherapy. In the intent-to-treat (ITT) analysis, superiority of the experimental transplant strategy could not be shown with respect to overall survival (OS) or event-free survival. As-treated analyses suggest a profound effect of allogeneic HCT on OS (HR 0.73; P=0.002) and event-free survival (HR 0.67; P

Early intervention with allogeneic hematopoietic cell transplantation during chemotherapy-induced aplasia in patients with high-risk acute myeloid leukemia

The aim of this project was to identify situations where allogeneic stem cell transplantation (allo-SCT) might be considered as a preferred treatment option for patients with B-cell chronic lymphocytic leukemia (CLL). Based on a MEDLINE search and additional sources, a consented proposal was drafted, refined and approved upon final discussion by an international expert panel. Key elements of the consensus are (1) allo-SCT is a procedure with evidence-based efficacy in poor-risk CLL; (2) although definition of 'poor-risk CLL' requires further investigation, allo-SCT is a reasonable treatment option for younger patients with (i) non-response or early relapse (within 12 months) after purine analogues, (ii) relapse within 24 months after having achieved a response with purine-analogue-based combination therapy or autologous transplantation, and (iii) patients with p53 abnormalities requiring treatment; and (3) optimum transplant strategies may vary according to distinct clinical situations and should be defined in prospective trials. This is the first attempt to define standard indications for allo-SCT in CLL. Nevertheless, whenever possible, allo-SCT should be performed within disease-specific prospective clinical protocols in order to continuously refine transplant indications according to new developments in risk assessment and treatment of CLL.

Allogeneic hematopoietic stem cell transplantation represents the only curative approach for many hematological malignancies. During the last years the impact of the conditioning regimen has been re-assessed. With the advent of reduced-intensity conditioning the paradigm has changed from cytoreduction executed by high-dose radio-chemotherapy to immunological surveillance of leukemia by donor cells. Distinct subsets of T cells and NK cells contribute to graft-versus-leukemia reactions. So far, cytotoxic T lymphocytes are the mainstay of allogeneic immunotherapy. Here, we summarise the current knowledge of T cell-mediated graft-versus-leukemia reactions and present results from pre-clinical and clinical studies of T cell-based adoptive immunotherapy. We address the issues of feasibility and specificity of adoptive immunotransfer from a clinical point of view and discuss the prerequisites for successful clinical applications. Finally, the prospects for immunological research that have evolved with the increasing use of reduced-intensity conditioning and allogeneic stem cell transplantation are highlighted.

Since the incidence of cytomegalovirus (CMV) infections after hematopoietic stem cell transplantation (HSCT) may depend on the intensity of the pretreatment, we studied the incidence of CMV infections after reduced-intensity compared to myeloablative conditioning. A total of 82 patients with matched related or unrelated donors were prospectively monitored for CMV infections after HSCT by CMV-PCR techniques, CMV-antigenemia and clinical observation. A total of 45 patients received reduced-intensity conditioning consisting of fludarabine, busulfan and ATG and 37 patients received myeloablative conditioning. Leukocyte engraftment occurred after a median of 15 vs 18 days (P=0.012) and platelet engraftment after 12 days vs 20 days (P=0.001), respectively. Acute graft-versus-host disease (GVHD) grade II-IV was observed in 58 vs 54% patients (P=0.737), respectively. The onset and peak values of CMV-antigenemia and DNAemia and the incidence of CMV infections did not differ statistically significantly between the two treatment groups. Multivariate analysis confirmed CMV seropositivity of the recipient (P=0.035), acute GVHD II-IV (P=0.001) but not the type of conditioning as significant risk factors for CMV-antigenemia. In conclusion, the kinetics of CMV-antigenemia and DNAemia and the incidence of CMV infections were not statistically different in patients who received HSCT after reduced-intensity conditioning with fludarabine, busulfan and ATG compared to myeloablative conditioning.

Antiviral treatment of Influenza A (H1N1-09) guided by molecular resistance testing in aplasia after allo-SCT

We investigated the feasibility and efficacy of a fludarabine-based dose-reduced conditioning regimen followed by stem cell transplantation from related (n = 5) or unrelated HLA-matched donors (n = 7) in 12 patients with high risk MDS, who were not eligible for a standard myeloablative conditioning regimen. The conditioning regimen consisted of fludarabine 30 mg/m(2) daily for 6 days, busulfan 4 mg/kg daily for 2 days and anti-thymocyte globulin (ATG, rabbit) 10 mg/kg daily for 4 days in 11 patients, while one patient received fludarabine, ATG, cyclophosphamide and thiotepa. Graft-versus-host disease prophylaxis consisted of cyclosporine and a short course of methotrexate. The median age of the patients was 53 years (range 37-59). The median percentage of blasts in bone marrow aspirate at transplantation was 15% (range

Infusion of bcr/abl peptide-reactive donor T cells to achieve molecular remission of chronic myeloid leukemia after CD34 + selected allogeneic hematopoietic cell transplantation