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γδ T cells support the immunological control of viral infections, in particular during cytomegalovirus (CMV) reactivation in immunocompromised patients after allogeneic hematopoietic stem cell transplantation. It is unclear how γδ T cells sense CMV-infection and whether this involves specific T cell receptor (TCR)-ligand interaction. Here we summarize recent findings that revealed an adaptive-like anti-CMV immune response of γδ T cells, characterized by acquisition of effector functions and long-lasting clonal expansion. We propose that rather CMV-induced self-antigen than viral antigens trigger γδ TCRs during CMV reactivation. Given that the TCRs of CMV-activated γδ T cells are often cross-reactive to tumor cells, these findings pinpoint γδ T cells and their γδ TCRs as attractive multipurpose tools for antiviral and antitumor therapy. [ABSTRACT FROM AUTHOR]

Background: Post-transplant lymphoproliferative disorder (PTLD) adversely affects patients' long-term outcome. Methods: The paired t test and McNemar's test were applied in a retrospective 1:1 matched-pair analysis including 36 patients with PTLD and 36 patients without PTLD after kidney or liver transplantation. Matching criteria were age, gender, indication, type of transplantation, and duration of follow-up. All investigated PTLD specimen were histologically positive for EBV. Risk-adjusted multivariable regression analysis was used to identify independence of risk factors for PTLD detected in matched-pair analysis. The resultant prognostic model was assessed with ROC-curve analysis. Results: Patients suffering with PTLD had shorter mean survival (p = 0.004), more episodes of CMV infections or reactivations (p = 0.042), and fewer recipient HLA A2 haplotypes (p = 0.007), a tacrolimus-based immunosuppressive regimen (p = 0.052) and higher dosages of tacrolimus at hospital discharge (Tac dosage) (p = 0.052). Significant independent risk factors for PTLD were recipient HLA A2 (OR = 0.07, 95 % CI = 0.01-0.55, = 0.011), higher Tac dosages (OR = 1.29, 95 % CI = 1.01-1.64, p = 0.040), and higher numbers of graft rejection episodes (OR = 0.38, 95 % CI = 0.17-0.87, p = 0.023). The following prognostic model for the prediction of PTLD demonstrated good model fit and a large area under the ROC curve (0.823): PTLD probability in % = Exp(y)/(1 + Exp(y)) with y =0.671 - 1.096 x HLA A2-positive recipient + 0.151 x Tac dosage - 0.805 x number of graft rejection episodes. Conclusions: This study suggests prognostic relevance for recipient HLA A2, CMV, and EBV infections or reactivations and strong initial tacrolimus-based immunosuppression. Patients with risk factors may benefit from intensified screening for PTLD. [ABSTRACT FROM AUTHOR]

It is emerging that CD4+Foxp3+ regulatory T (Treg) cells can produce the proinflammatory cytokine IFN-&ggr; when stimulated in a Thl cytokine environment. In this study, we report that Foxp3+ Treg cells readily produced IFN-&ggr; in vivo in a highly inflammatory model of graft-versus-host disease (GVHD) and during a Thl-dominated immune response to intracellular bacteria. Moreover, stimulation in vitro via TCR in the presence of IL-12 alone was sufficient to induce IFN-&ggr; production by Treg cells in a dose-dependent manner. Transfer of donor Treg cells can prevent lethal GVHD; therefore, we used this model as a robust readout for in vivo Treg function. Interestingly, >50% of allogeneic donor, but not residual recipient Foxp3+ Treg cells produced IFN-&ggr; after transplantation, suggesting that this cytokine production was alloantigen specific. These IFN-&ggr; producers were stable Foxp3+ Treg cells because methylation analysis of the Foxp3 gene locus of transferred and reisolated Treg cells during GVHD showed a fully demethylated Treg-specific-demethylated region. Next, we addressed whether IFN-&ggr; production was supporting or rather impairing the immunosuppressive function of Treg cells during GVHD. Blocking of IFN-&ggr; with specific mAb completely abolished the beneficial effect of donor Treg cells. We could further show that only wild-type Treg cells, but not Treg cells from IFN-&ggr;-deficient donor mice, prevented GVHD. This indicated that Treg cell-intrinsic IFN-&ggr; production was required for their protective function. In conclusion, our data show that IFN-&ggr; produced by Foxp3+ Treg cells has essential immune-regulatory functions that are required for prevention of expérimentai GVHD. [ABSTRACT FROM AUTHOR]

Gut-homing of donor T cells is causative for the development of intestinal GvHD in recipients of allogeneic hematopoietic stem cell transplantation (HSCT). Expression of the gut-specific homing receptors integrin-α4β7 and chemokine receptor CCR9 on T cells is imprinted in gut-associated lymphoid tissues (GALT) under the influence of the vitamin A metabolite retinoic acid. Here we addressed the role of vitamin A deficiency in HSCT-recipients for donor T cell migration in the course of experimental GvHD. Vitamin A-deficient (VAD) mice were prepared by feeding them a vitamin A-depleted diet. Experiments were performed in a C57BL/6 into BALB/c model of acute GvHD. We found that expression of integrin-α4β7 and CCR9 in GALT was reduced in VAD recipients after HSCT. Competitive in vivo homing assays showed that allogeneic T cells primed in VAD mice did not home as efficiently to the intestine as T cells primed in mice fed with standard diet (STD). The course of GvHD was ameliorated in VAD HSCT-recipients and, consequently, their survival was prolonged compared to recipients receiving STD. However, VAD-recipients were not protected and died of clinical GvHD. We found reduced numbers of donor T cells in the intestine but increased cell counts and tissue damage in other organs of VAD-recipients. Furthermore, we observed high IFN-γ+CD4+ and low FoxP3+CD4+ frequencies of total donor CD4+ T cells in VAD as compared to STD recipients. Taken together, these results indicate that dietary vitamin A deficiency in HSCT-recipients changed target organ tropism in GvHD but also resulted in fatal inflammation after HSCT. [ABSTRACT FROM AUTHOR]

Angiogenesis plays an important role in the growth and viability of hematologic malignancies. Emerging data suggest a crucial involvement of the endothelial-specific Tie2 receptor and its antagonistic ligand Angiopoietin-2 (Ang-2) in this process. The purpose of this study was to elucidate whether the soluble domain of the Tie2 receptor (sTie2) predicts outcome in patients with acute myeloid leukemia (AML) undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Serum levels of sTie2 and Ang-2 were measured by ELISA in 181 AML patients before conditioning for HSCT. The median follow-up time was 22 months after HSCT. Pre-HSCT sTie2 levels were significantly higher in patients (median 2.2 (range 1.8–3.0) ng/mL) compared to healthy controls (1.3 (0.9–1.6); p < 0.0001). Elevated sTie2 levels were independently associated with active AML but did not relate to cytogenetics/mutational status before transplantation. Logistic regression analysis identified elevated sTie2 (odds ratio (OR) 3.07 (95% confidence interval (CI; 1.56–6.04), p = 0.001) as a strong predictor for disease relapse and poor overall survival after HSCT. In a multimarker approach the highest risk for relapse was observed in patients with both elevated sTie2 and elevated Ang-2 (OR 4.07, (95% CI 1.79–9.25) p < 0.0001), as well as patients with both elevated Ang-2 and elevated bone marrow blast count (OR 4.16, (95% CI 1.88–7.36) p < 0.0001). Elevated serum sTie2 levels were related to active leukemia, correlated with the percentage of leukemic blasts in the bone marrow, and independently predicted relapse in AML patients after allogeneic HSCT. Furthermore, our data indicate that Tie2 shedding and Ang-2 release seem to reflect overlapping, but nevertheless distinctive features in leukemia-associated neoangiogenesis. [ABSTRACT FROM AUTHOR]

Whereas sarcoidosis is characterized by an excessive inflammatory immune response mainly at the pulmonary site, circulating T lymphocytes poorly respond to antigen challenge. It has been suggested, that the extensive local inflammation might be triggered by bacterial pathogens. Recently, it has been shown that this paradoxically immunological situation likely results from a disequilibrium between effector and regulatory T lymphocytes (Treg). Here, we apply a DNA microarray approach in order to analyze circulating T cells for specific dysregulatory events, which should provide detailed insights in the impairment of cell-mediated immunity. Gene expression profiles were performed from peripheral blood T lymphocytes of untreated patients with pulmonary sarcoidosis (stage I) (n = 3) and a control group consisting of healthy donors (n = 3). Circulating T lymphocytes in sarcoidosis exhibit a specific gene expression pattern of molecules that are primarily involved in immune responses and lymphocyte signalling. Compared to controls patients with sarcoidosis display also alterations in gene expression of molecules with bacteriolytic and chemotactic function. Among others, array analysis resulted in increased transcript levels of Th2 immune response, whereas genes coding for molecules involved in Th1 differentiation are down-regulated. Furthermore, genes encoding proteins representing primordial antimicrobial peptides which may mobilise immunocompetent T cells and other inflammatory cells are up-regulated. This observation supports recent reports suggesting that bacterial antigens play a role in the pathogenesis of sarcoidosis. However, the results of our study indicate an unbalanced immune response towards Th2 in the peripheral blood of patients with sarcoidosis. [ABSTRACT FROM AUTHOR]

: ObjectiveNatural killer (NK) cells kill allogeneic cells that lack a class I MHC ligand for clonally distributed killer inhibitory receptors (KIR). Following HLA-mismatched hematopoietic cell transplantation (HCT), donor NK cells might mediate graft-vs-host (GVH) reactions that promote donor chimerism and mediate anti-tumor effects. Additionally, recipient NK cells might mediate donor marrow rejection. We have developed a nonmyeloablative approach to haploidentical HCT involving recipient treatment with a T cell–depleting mAb, Medi-507, that can achieve donor engraftment and mixed hematopoietic chimerism without graft-vs-host disease (GVHD). Donor lymphocyte infusions (DLI) are later administered in an effort to achieve graft-vs-leukemia/lymphoma (GVL) effects without GVHD. It is unknown whether NK cell “tolerance” develops in human mixed chimeras.: MethodsWe have addressed these issues in 12 patients receiving Medi-507-based nonmyeloablative haploidentical HCT.: ResultsNK cells recovered relatively early, despite the presence of circulating anti-CD2 mAb, but the majority of initially recovering cells lacked CD2 expression. These NK cells showed a reduced capacity, compared to those from normal donors, to kill class I–deficient targets. No association was detected between KIR mismatches in the host-vs-graft (HVG) or GVH direction and graft or tumor outcomes in this small series. NK cell chimerism did not correlate with chimerism in other lineages in mixed chimeras. NK cell tolerance to the host was not observed in a patient with full donor chimerism. One patient developed NK cell reactivity against donor-derived lymphoblast targets after loss of chimerism, despite the absence of an HVG KIR mismatch.: ConclusionOur results do not show an impact of NK cells on the outcome of nonmyeloablative, even T cell–depleted, HCT across haplotype barriers using an anti-CD2 mAb. Our data also raise questions about the applicability of observations made with NK cell clones to the bulk NK cell repertoire in humans. [Copyright &y& Elsevier]

Simple Summary: CD19+ Chimeric antigen receptor (CAR) T-cells are used against CD19+ hematologic malignancies, such as high-grade B-cell lymphoma and acute lymphoblastic leukemia. Since this is a relatively new treatment approach, not all potential side effects are well described, and the underlying pathobiology is often not well defined. Here, we summarize current data on the incidence and the current management of CD19+ CAR T-cell complications. We discuss frequently occurring toxicities and we highlight evidence for the occurrence of rarer side effects affecting different organ systems. In addition, we highlight new findings that shed light on the pathophysiology of CAR T-cell-related complications. Clinical trials demonstrated that CD19+ chimeric antigen receptor (CAR) T-cells can be highly effective against a number of malignancies. However, the complete risk profile of CAR T-cells could not be defined in the initial trials. Currently, there is emerging evidence derived from post approval studies in CD19+ CAR T-cells demonstrating both short-term and medium-term effects, which were unknown at the time of regulatory approval. Here, we review the incidence and the current management of CD19+ CAR T-cell complications. We highlight frequently occurring events, such as cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, cardiotoxicity, pulmonary toxicity, metabolic complications, secondary macrophage-activation syndrome, and prolonged cytopenia. Furthermore, we present evidence supporting the hypothesis that CAR T-cell-mediated toxicities can involve any other organ system and we discuss the potential risk of long-term complications. Finally, we discuss recent pre-clinical and clinical data shedding new light on the pathophysiology of CAR T-cell-related complications. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Belantamab mafodotin (belamaf) has shown promising antimyeloma activity in relapsed or refractory multiple myeloma (RRMM) as a single agent. It was hypothesized that its multimodal activity may be enhanced by programmed cell death protein 1 pathway inhibition and activation of T cell–mediated antitumor responses. This study investigated the efficacy and safety of belamaf with pembrolizumab in patients with RRMM.DREAMM‐4 (NCT03848845) was an open‐label, single‐arm, phase 1/2 study divided into dose‐escalation (part 1) and dose‐expansion (part 2) phases. Patients were ≥18 years old with ≥3 prior lines of therapy including a proteasome inhibitor, an immunomodulatory drug, and an anti‐CD38 agent. Patients received belamaf (2.5 or 3.4 mg/kg, part 1; 2.5 mg/kg, part 2) and 200 mg pembrolizumab for ≤35 cycles.Of 41 enrolled patients, 34 (n = 6 part 1, n = 28 part 2) who received 2.5 mg/kg belamaf plus pembrolizumab were included in this final analysis. Sixteen patients (47%) achieved an overall response. Minimal residual disease negativity was achieved in three of 10 patients who had very good partial response or better. Five of eight patients who had prior anti–B‐cell maturation antigen therapy achieved partial response or better, including two who had B‐cell maturation antigen–refractory disease. Common grade ≥3 adverse events were keratopathy (38%) and thrombocytopenia (29%). Despite belamaf‐related ocular events, quality‐of‐life measures remained stable over time. No new safety signals were observed.The results of DREAMM‐4 demonstrated clinical activity and a favorable safety profile of belamaf plus pembrolizumab in patients with RRMM. This trial is registered at www.ClinicalTrials.gov as NCT03848845. [ABSTRACT FROM AUTHOR]

Objectives: Treatment intensification (including consolidative high‐dose chemotherapy with autologous stem cell transplantation [HDT‐ASCT]) significantly improved outcome in primary central nervous system lymphoma (PCNSL) patients. Methods: We conducted a multicenter, retrospective analysis of newly diagnosed PCNSL patients, treated with intensified treatment regimens. The following scores were evaluated in terms of overall survival (OS) and progression‐free survival (PFS): Memorial Sloan‐Kettering Cancer Center (MSKCC), International Extranodal Lymphoma Study Group (IELSG), and three‐factor (3F) prognostic score. Further, all scores were comparatively investigated for model quality and concordance. Results: Altogether, 174 PCNSL patients were included. One hundred and five patients (60.3%) underwent HDT‐ASCT. Two‐year OS and 2‐year PFS for the entire population were 73.3% and 48.5%, respectively. The MSKCC (p =.003) and 3F score (p <.001), but not the IELSG score (p =.06), had the discriminatory power to identify different risk groups for OS. In regard to concordance, the 3F score (C‐index [0.71]) outperformed both the MSKCC (C‐index [0.64]) and IELSG (C‐index [0.53]) score. Moreover, the superiority of the 3F score was shown for PFS, successfully stratifying patients in three risk groups, which also resulted in the highest C‐index (0.66). Conclusion: The comparative analysis of established PCNSL risk scores affirm the clinical utility of the 3F score stratifying the widest prognostic spectrum among PCNSL patients treated with intensified treatment approaches. [ABSTRACT FROM AUTHOR]

Introduction: Chimeric antigen receptor positive T cell (CAR-T cell) treatment became standard therapy for relapsed or refractory hematologic malignancies, such as non-Hodgkin's lymphoma and multiple myeloma. Owing to the rapidly progressing field of CAR-T cell therapy and the lack of generally accepted treatment guidelines, we hypothesized significant differences between centers in the prevention, diagnosis, and management of short- and long-term complications. Methods: To capture the current CAR-T cell management among German centers to determine the medical need and specific areas for future clinical research, the DAG-HSZT (Deutsche Arbeitsgemeinschaft für Hämatopoetische Stammzelltransplantation und Zelluläre Therapie; German Working Group for Hematopoietic Stem Cell Transplantation and Cellular Therapy) performed a survey among 26 German CAR-T cell centers. Results: We received answers from 17 centers (65%). The survey documents the relevance of evidence in the CAR-T cell field with a homogeneity of practice in areas with existing clinical evidence. In contrast, in areas with no – or low quality – clinical evidence, we identified significant variety in management in between the centers: management of cytokine release syndrome, immune effector cell-related neurotoxicity syndrome, IgG substitution, autologous stem cell backups, anti-infective prophylaxis, and vaccinations. Conclusion: The results indicate the urgent need for better harmonization of supportive care in CAR-T cell therapies including clinical research to improve clinical outcome. [ABSTRACT FROM AUTHOR]

Therapeutic donor lymphocyte infusions (tDLI) are used to reinforce the graft-versus-leukemia (GvL) effect in relapse after allogeneic stem cell transplantation (alloSCT). In contrast, the role of prophylactic DLI (proDLI) in preventing leukemia relapse has been less clearly established, although supported by retrospective, case-control, and registry analyses. We report a prospective, monocentric, ten year cohort of patients with high risk acute leukemias (AL) or myelodysplasia (MDS) in whom proDLI were applied beyond day +120 post alloSCT to compensate for lack of GvL. 272 consecutive allotransplanted AL or MDS patients in complete remission and off immunosuppression at day +120 were stratified according to the prior appearance of relevant GvHD (acute GvHD °II-IV or extensive chronic GvHD) as a clinical indicator for GvL. Escalating doses of unmodified proDLI were applied to 72/272 patients without prior relevant GvHD. Conversely, 157/272 patients with prior spontaneous GvHD did not receive proDLI, nor did 43/272 patients with contraindications (uncontrolled infections, patient refusal, DLI unavailability). By day 160-landmark analysis (median day of first DLI application), proDLI recipients had significantly higher five-year overall (OS) and disease free survival (DFS) (77% and 67%) than patients with spontaneous GvHD (54% and 53%) or with contraindications (46% and 45%) (p=0.003). Relapse incidence for patients with proDLI (30%) or spontaneous GvHD (29%) was significantly lower than in patients with contraindications (39%; p=0.021). With similar GvHD incidence beyond day +160, non-relapse mortality (NRM) was less with proDLI (5%) than without proDLI (18%; p=0.036). In conclusion, proDLI may be able to compensate for lack of GvL in alloSCT recipients with high risk AL or MDS. [ABSTRACT FROM AUTHOR]

Simple Summary: Donor lymphocyte infusions (DLIs) are immune cells of the donor. They can potentially directly target leukemic cells. Thus, DLIs can be given to acute myeloid leukemia (AML) patients after allogeneic hematopoietic cell transplantation (alloHCT) in order to prevent or treat relapse. Measurable residual disease (MRD) describes very low levels of disease. Currently, it is still not well described how we can use MRD assessment for predicting response and outcome after DLI. This is a retrospective study looking at 76 AML patients receiving DLI treatment. MRD was evaluated prior to DLI treatment as well as 30 and 90 days after DLI. It was observed that within 90 days after DLI treatment, 73% of MRD+ patients converted to MRD−. Furthermore, MRD and remission status at the time of DLI were highly prognostic for the outcome (both for the relapse rate and also for relapse-free survival). Donor lymphocyte infusions (DLIs) can directly target leukemic cells through a graft-versus-leukemia effect and play a key role in the prevention and management of relapse after allogeneic hematopoietic cell transplantation (alloHCT). Predictors of response to DLIs are not well established. We evaluated measurable residual disease (MRD) before, 30 and 90 days after DLI treatment as biomarkers of response. MRD was assessed by next-generation sequencing in 76 DLI-treated acute myeloid leukemia patients. MRD status before DLI treatment was independently prognostic for event-free survival (EFS, p < 0.001) and overall survival (OS, p < 0.001). Within 90 days of DLI treatment, 73% of MRD+ patients converted to MRD− and 32% of patients without remission achieved remission. MRD status 90 days after DLI treatment was independently prognostic for the cumulative incidence of relapse (CIR, p = 0.011) and relapse-free survival (RFS, p = 0.001), but not for OS. To evaluate the role of DLI treatment in MRD− patients, 23 MRD− patients who received DLIs were compared with a control cohort of 68 MRD− patients not receiving DLIs. RFS (p = 0.23) and OS (p = 0.48) were similar between the two cohorts. In conclusion, MRD is prognostic before (EFS, OS) and after (CIR, RFS) DLI treatment and may help in the selection of patients who benefit most from DLIs. [ABSTRACT FROM AUTHOR]

Purpose: Intensive care unit (ICU) admission of allogeneic hematopoietic stem cell transplant (HSCT) recipients is associated with relatively poor outcome. Since longitudinal data on this topic remains scarce, we analyzed reasons for ICU admission as well as short- and long-term outcome of critically ill HSCT recipients.Methods: A total of 942 consecutive adult patients were transplanted at Hannover Medical School from 2000 to 2013. Of those, 330 patients were at least admitted once to the ICU and included in this retrospective study. To analyze time-dependent improvements, we separately compared patient characteristics as well as reasons and outcome of ICU admission for the periods 2000-2006 and 2007-2013.Results: The main reasons for ICU admission were acute respiratory failure (ARF) in 35%, severe sepsis/septic shock in 23%, and cardiac problems in 18%. ICU admission was clearly associated with shortened survival (p < 0.001), but survival of ICU patients after hospital discharge reached 44% up to 5 years and was comparable to that of non-ICU HSCT patients. When ICU admission periods were compared, patients were older (48 vs. 52 years; p < 0.005) and the percentage of ARF as leading cause for ICU admission decreased from 43% in the first to 30% in the second period. Over time ICU and hospital survival improved from 44 to 60% (p < 0.01) and from 26 to 43% (p < 0.01), respectively. The 1- and 3-year survival rate after ICU admission increased significantly from 14 to 32% and from 11 to 23% (p < 0.01).Conclusions: Besides ARF and septic shock, cardiac events were especially a major reason for ICU admission. Both short- and long-term survival of critically ill HSCT patients has improved significantly in recent years, and survival of HSCT recipients discharged from hospital is not significantly affected by a former ICU stay. [ABSTRACT FROM AUTHOR]

To evaluate the outcomes of salvage third autologous stem cell transplantation (ASCT) in patients with relapsed multiple myeloma. We analyzed 570 patients who had undergone a third ASCT between 1997 and 2010 (European Society for Blood and Marrow Transplantation data), of whom 482 patients underwent tandem ASCT and a third ASCT at first relapse (AARA group) and 88 patients underwent an upfront ASCT with second and third transplantations after subsequent relapses (ARARA group). With a median follow-up after salvage third ASCT of 61 months in the AARA group and 48 months in the ARARA group, the day +100 nonrelapse mortality in the 2 groups was 4% and 7%, the incidence of second primary malignancy was 6% and 7%, the median progression-free survival was 13 and 8 months, and median overall survival (OS) was 33 and 15 months. In the AARA group, according to the relapse-free interval (RFI) from the second ASCT, the median OS after the third ASCT was 17 months if the RFI was <18 months, 37 months if the RFI was between 18 and 36 months, and 64 months if the RFI was ≥36 months ( P  < .001). In the ARARA group, the median OS after the third ASCT was 7 months if the RFI was <6 months, 13 months if the RFI was between 6 and 18 months, and 27 months if the RFI was ≥18 months ( P  < .001). In a multivariate analysis of the AARA group, the favorable prognostic factor was an RFI after second ASCT of ≥18 months. Progressive disease and a Karnofsky Performance Status score of <70 at third ASCT were unfavorable factors. A salvage third ASCT is of value for patients with relapsed myeloma, particularly for those with a long duration of response and chemosensitive disease at the time of transplantation. [ABSTRACT FROM AUTHOR]

Donor lymphocyte infusion (DLI) can (re-)induce durable remission in relapsing patients after allogeneic hematopoietic stem-cell transplantation (alloHSCT). However, DLI harbors the risk of increased non-relapse mortality due to the co-occurrence of graft-versus-host disease (GVHD). GVHD onset may be caused or accompanied by changes in the clonal T-cell receptor (TCR) repertoire. To investigate this, we analyzed T cells in a cohort of 21 patients receiving DLI after alloHSCT. We performed deep T-cell receptor β (TRB) sequencing of sorted CD4+CD25+CD127low regulatory T cells (Treg cells) and CD4+ conventional T cells (Tcon cells) in order to track longitudinal changes in the TCR repertoire. GVHD following DLI was associated with less diverse but clonally expanded CD4+CD25+CD127low Treg and CD4+ Tcon TCR repertoires, while patients without GVHD exhibited healthy-like repertoire properties. Moreover, the diversification of the repertoires upon GVHD treatment was linked to steroid-sensitive GVHD, whereas decreased diversity was observed in steroid-refractory GVHD. Finally, the unbiased sample analysis revealed that the healthy-like attributes of the CD4+CD25+CD127low Treg TCR repertoire were associated with reduced GVHD incidence. In conclusion, CD4+CD25+CD127low Treg and CD4+ Tcon TRB repertoire dynamics may provide a helpful real-time tool to improve the diagnosis and monitoring of treatment in GVHD following DLI. [ABSTRACT FROM AUTHOR]

In patients with relapse of classical Hodgkin lymphoma (cHL) after autologous stem cell transplant, brentuximab vedotin and anti-PD1 treatment, the outcome is poor. To assess the efficacy of the bispecific anti-CD30/CD16A, NK-cell engaging antibody AFM13 and to select the optimal treatment schedule (arm A–C), we initiated a randomized two-stage phase II trial (NCT02321592). Due to slow recruitment, the trial was terminated after treatment of 25 patients. Treatment with AFM13 was well tolerated: only two treatment-associated serious adverse events (SAEs) were reported; all SAEs resolved completely. With an objective response rate (ORR) of 16.7% (1/5 in arm A, 1/11 in arm B, and 2/8 in arm C) and a 12-month progression-free survival (PFS) of 12.6% (95% CI 3.2–28.9), treatment efficacy of AFM13 monotherapy in all evaluable patients was modest. The continuous application schedule (arm C) might be more effective, but the visit schedule should be better aligned with patients' daily life. [ABSTRACT FROM AUTHOR]

Background: Respiratory syncytial virus (RSV) causes community-acquired respiratory tract infections during winter. However, outbreaks in hospitals also occur repeatedly. In particular, patients with hematologic malignancies are at an increased risk for a severe and potentially fatal course of RSV infection. Here we present the investigation of an RSV outbreak in a hematology ward for adults following the ORION statement. Methods: An epidemiologic and molecular outbreak analysis was performed. We developed and employed a minimal oligonucleotide probe set in target capture probe sequencing that allows cost-effective RSV-A or -B capturing to reconstruct RSV genomes from clinical samples. Results: Four adult patients were involved in the outbreak caused by RSV-B in March 2019. The enforcement of the pre-existing infection control measures by effective training of hospital staff contributed to a successful containment. PCR-based RSV screening on the ward enabled early detection of new cases and rapid isolation measures. The molecular analysis demonstrated that the outbreak sequences were highly related and distinct to other RSV-B strains circulating at the same time. Conclusions: A multimodal infection control concept is essential for the timely detection and control of RSV outbreaks in patients with hematological disease. Among other measures, preventive screening for respiratory viruses is recommended. Furthermore, the integration of conventional and molecular epidemiology, such as whole-genome sequencing and variant calling, significantly contributes to the understanding of transmission pathways. Based on this, appropriate conclusions can be drawn for targeted prevention measures that have prepared us for the COVID-19 pandemic beyond the RSV approach described here. [ABSTRACT FROM AUTHOR]

BACKGROUND: Delayed donor red blood cell chimerism (DRCC), pure red blood cell aplasia (PRCA), and autoimmune hemolytic anemia (AIHA) are poorly documented complications after hematopoietic cell transplantation (HCT). The clinical variable “prolonged isolated red blood cell transfusion requirement” (PRTR) was evaluated as a trigger for an extended diagnostic workup. STUDY DESIGN AND METHODS: PRTR was defined as the need for red blood cell (RBC) transfusions beyond Day 60 after HCT. We analyzed 487 patients transplanted between 2000 and 2006. Median age was 37 years (range, 0-70 years). Peripheral blood stem cells (n = 344), marrow (n = 138), and cord blood (n = 5) from 278 unrelated and 209 family donors were used. RESULTS: Univariate analysis identified age (incidence of 18.3% among elderly patients, 10.5% in adults, and 2.0% among children [p = 0.002]), ABO incompatibility (16.4% after major incompatible, 2.9% after minor incompatible, and 9.4% after ABO-compatible transplantations [p = 0.003]), conditioning (15.2% after reduced-intensity regimens vs. 7.3% after myeloablative conditioning; p = 0.006), donor type (13.2% after HLA-matched unrelated, 13.6% after mismatched unrelated, 5.7% after matched related, and 0.0% after mismatched related grafts; p = 0.026), and acute graft-versus-host disease (aGVHD; 7.1% with aGVHD vs. 12.5% without aGVHD; p = 0.046) as predisposing factors. In multivariate analysis minor ABO incompatibility (odds ratio [OR] = 0.2, p = 0.01), younger age (OR = 0.1, p = 0.02), and matched related HCT (OR = 0.4, p = 0.02) remained independent protective factors. CONCLUSIONS: PRTR could serve as a trigger for a standardized screening for DRCC, PRCA, and AIHA after HCT. [ABSTRACT FROM AUTHOR]

Despite the prophylactic use of uricostatic agents, TLS is of potential concern in venetoclax-treated AML patients, and only limited data on its clinical relevance in relapsed/refractory patients are available. Curves for patients with and without TLS are separated for better legibility of the error bars The median follow-up for patients with TLS was 13.8 months and for patients without TLS 13.5 months. In our study, venetoclax treatment in combination with LDAC or HMA without dose ramp-up induced LTLS in 12% of patients, while clinical TLS was formally observed in one dialysis patient only (2%). [Extracted from the article]

IL-17A and IL-17F cytokines are important regulators of acute graft-versus-host-disease (GVHD). However, contrary effects of these cytokines in inflammatory diseases have been reported. To investigate the effects of donor-derived IL-17A and IL-17F on GVHD, we made use of single (Il17a-/- or Il17f-/-) and double deficient (Il17af-/-) allogeneic donor CD4+ T cells. We could demonstrate that transplantation of Il17af-/- CD4+ donor T cells led to aggravated GVHD. However, this phenotype was not observed after transplantation of single, Il17a-/- or Il17f-/-, deficient CD4+ T cells, suggesting redundant effects of IL-17A and IL-17F. Moreover, Il17af-/- cell recipients showed an increase of systemic IFNγ, indicating a heightened pro-inflammatory state, as well as infiltration of IFNγ-secreting CD4+ T cells in the recipients' intestinal tract. These recipients exhibited significant gut leakage, and markedly macrophage infiltration in the gastrointestinal epithelial layer. Moreover, we saw evidence of impaired recovery of gut epithelial cells in recipients of Il17af-/- CD4+ T cells. In this study, we show that IL-17A/F double deficiency of donor CD4+ T cells leads to accelerated GVHD and therefore highlight the importance of these cytokines. Together, IL-17 cytokines might serve as a brake to an intensified Th1 response, leading to the exacerbated gut damage in acute GVHD. [ABSTRACT FROM AUTHOR]

FLA-IDA salvage chemotherapy combined with a seven-day course of venetoclax (FLAVIDA) in patients with relapsed/refractory acute leukaemia Eighty-one patients were identified that fulfilled the selection criteria of the FLAVIDA patients and were compared to the FLAVIDA patients included in this analysis (detailed information about the dosing scheme are provided in the Supplementary materials). Cumulative incidence of blood count recovery amongst responding patients in the FLAVIDA cohort (red line) and patients in the FLA-IDA control cohort (blue line). (C) Relapse-free survival of the nine patients in the FLAVIDA cohort and of the 32 patients in the FLA-IDA control cohort who achieved CR/CRi after one cycle of chemotherapy. [Extracted from the article]

Microbial invasion into the intestinal mucosa after allogeneic hematopoietic cell transplantation (allo-HCT) triggers neutrophil activation and requires antibiotic interventions to prevent sepsis. However, antibiotics lead to a loss of microbiota diversity, which is connected to a higher incidence of acute graft-versus-host disease (aGVHD). Antimicrobial therapies that eliminate invading bacteria and reduce neutrophil-mediated damage without reducing the diversity of the microbiota are therefore highly desirable. A potential solution would be the use of antimicrobial antibodies that target invading pathogens, ultimately leading to their elimination by innate immune cells. In a mouse model of aGVHD, we investigated the potency of active and passive immunization against the conserved microbial surface polysaccharide poly-N-acetylglucosamine (PNAG) that is expressed on numerous pathogens. Treatment with monoclonal or polyclonal antibodies to PNAG (anti-PNAG) or vaccination against PNAG reduced aGVHD-related mortality. Anti-PNAG treatment did not change the intestinal microbial diversity as determined by 16S ribosomal DNA sequencing. Anti-PNAG treatment reduced myeloperoxidase activation and proliferation of neutrophil granulocytes (neutrophils) in the ileum of mice developing GVHD. In vitro, anti-PNAG treatment showed high antimicrobial activity. The functional role of neutrophils was confirmed by using neutrophil-deficient LysMcre Mcl1fl/fl mice that had no survival advantage under anti-PNAG treatment. In summary, the control of invading bacteria by anti-PNAG treatment could be a novel approach to reduce the uncontrolled neutrophil activation that promotes early GVHD and opens a new avenue to interfere with aGVHD without affecting commensal intestinal microbial diversity. [ABSTRACT FROM AUTHOR]

Summary: Myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN) and chronic myelomonocytic leukaemia (CMML) can progress to secondary acute myeloid leukaemia (sAML). We compared the outcome of 4214 sAML patients who received allogeneic haematopoietic stem cell transplantation (allo‐HSCT) from an unrelated (62%) or human leucocyte antigen (HLA)‐identical sibling donor (38%) according the underlying disease: MDS (n = 3541), CMML (n = 251) or MPN (n = 422). After a median follow up of 46·5 months, the estimated 3‐year progression‐free (PFS) and overall survival (OS) for the entire group was 36% (34–37%) and 41% (40–43%), respectively. The cumulative incidence of relapse and non‐relapse mortality (NRM) was 37% (35–39%) and 27% (26–29%), respectively. In a multivariable analysis for OS, besides age (P < 0·001), unrelated donor (P = 0·011), cytomegalovirus ± constellation (P = 0·007), Karnofsky index ≤ 80 (P < 0·001), remission status (P < 0·001), peripheral blood as stem cell source (P = 0·009), sAML from MPN (P = 0·003) remained a significant factor in comparison to sAML from MDS, while worse outcome of sAML from CMML did not reach statistical significance (P = 0·06). This large registry study demonstrates a major impact of the underlying disease on outcome of sAML after allo‐HSCT. [ABSTRACT FROM AUTHOR]

Molecular measurable residual disease (MRD) assessment is not established in approximately 60% of acute myeloid leukemia (AML) patients because of the lack of suitable markers for quantitative real-time polymerase chain reaction. To overcome this limitation, we established an error-corrected next-generation sequencing (NGS) MRD approach that can be applied to any somatic gene mutation. The clinical significance of this approach was evaluated in 116 AML patients undergoing allogeneic hematopoietic cell transplantation (alloHCT) in complete morphologic remission (CR). Targeted resequencing at the time of diagnosis identified a suitable mutation in 93% of the patients, covering 24 different genes. MRD was measured in CR samples from peripheral blood or bone marrow before alloHCT and identified 12 patients with persistence of an ancestral clone (variant allele frequency [VAF] >5%). The remaining 96 patients formed the final cohort of which 45% were MRD+ (median VAF, 0.33%; range, 0.016%-4.91%). In competing risk analysis, cumulative incidence of relapse (CIR) was higher in MRD+ than in MRD- patients (hazard ratio [HR], 5.58; P < .001; 5-year CIR, 66% vs 17%), whereas nonrelapse mortality was not significantly different (HR, 0.60; P = .47). In multivariate analysis, MRD positivity was an independent negative predictor of CIR (HR, 5.68; P < .001), in addition to FLT3-ITD and NPM1 mutation status at the time of diagnosis, and of overall survival (HR, 3.0; P = .004), in addition to conditioning regimen and TP53 and KRAS mutation status. In conclusion, NGS-based MRD is widely applicable to AML patients, is highly predictive of relapse and survival, and may help refine transplantation and posttransplantation management in AML patients. [ABSTRACT FROM AUTHOR]

CMV reactivation is a major complication after allogeneic stem cell transplantation (SCT). Immune reconstitution of CMV-specific CTLs (CMV-CTLs) is essential for virus control. During CMV-CTL monitoring using mutated HLA/CMV tetramers selectively detecting high-avidity T cells, we observed coappearance of CMV-CTLs with low (CMV tetlow CTLs) and high tetramer binding (CMV tethigh CTLs) in 53/115 CMV IgG+ patients stem cell transplanted from CMV IgG+ donors. However, the relevance of these coappearing differentially tetramer binding ("dual") CMV-CTLs was unclear. In this study, we investigated the kinetics, properties, and clinical impact of coappearing CMV tetlow and tethigh CTLs after allogeneic SCT. Patients with dual CMV-CTLs had more CMV tethigh than tetlow CTLs. Chimerism analysis of isolated CMV tetlow and tethigh CTLs revealed their exclusive donor origin. CMV tetlow and tethigh CTLs had an identical effector memory CD45RA-CCR7- and CD45RA+CCR7- T cell distribution, equal differentiation, senescence, and exhaustion marker expression and were negative for regulatory CD8+ T cell markers. Isolated CMV tetlow and tethigh CTLs were equally sensitive to CMV peptides in IFN-γ release and cytotoxicity assays. However, CMV tethigh CTLs proliferated more in response to low CMV peptide concentrations than tetlow CTLs. TCR repertoire analysis revealed that CMV tetlow and tethigh CTLs use different TCRs. Finally, dual CMV-CTLs were not associated with CMV antigenemia. In conclusion, these data show for the first time, to our knowledge, that both CMV tetlow and tethigh CTLs are functional effector T cells differing by proliferation, numbers in peripheral blood, and probably by their precursors without increasing the CMV reactivation risk after allogeneic SCT. [ABSTRACT FROM AUTHOR]

Molecular genetics may influence outcome for patients with myelofibrosis. To determine the impact of molecular genetics on outcome after allogeneic stem cell transplantation, we screened 169 patients with primary myelofibrosis (n = 110), post-essential thrombocythemia/polycythemia vera myelofibrosis (n = 46), and myelofibrosis in transformation (n = 13) for mutations in 16 frequently mutated genes. The most frequent mutation was JAK2V617F (n = 101), followed by ASXL1 (n = 49), calreticulin (n = 34), SRSF2 (n = 16), TET2 (n = 10), U2AF1 (n = 11), EZH2 (n = 7), MPL (n = 6), IDH2 (n = 5), IDH1 (n = 4), and CBL (n = 1). The cumulative incidence of nonrelapse mortality (NRM) at 1 year was 21% and of relapse at 5 years 25%. The 5-year rates progression-free (PFS) and overall survival (OS) were and 56%, respectively. In a multivariate analysis CALR mutation was an independent factor for lower NRM (HR, .415; P  = .05), improved PFS (HR, .393; P  = .01), and OS (HR, .448; P  = .03). ASXL1 and IDH2 mutations were independent risk factors for lower PFS (HR, 1.53 [ P  = .008], and HR, 5.451 [ P  = .002], respectively), whereas no impact was observed for “triple negative” patients. Molecular genetics, especially CALR , IDH2 , and ASXL1 mutations, may thus be useful to predict outcome independently from known clinical risk factors after allogeneic stem cell transplantation for myelofibrosis. [ABSTRACT FROM AUTHOR]

After allogeneic hematopoietic stem cell transplantation (HSCT), recovery of humoral immunity is essential to protect from life-threatening infections. However, monitoring the humoral immune system after transplantation with standard techniques in the clinical routine is imprecise. Here, we performed sequencing of mononuclear bone marrow cells to characterize the VH1-repertoire of switched B cells of healthy volunteers and patients undergoing HSCT. Analysis of healthy bone marrow donors and patients showed virtually no clonally related sequences between individuals. Interestingly, clonally related sequences were present in pre- and post-transplantation bone marrow of patients undergoing HSCT for acute myeloid leukemia treatment. We consistently observed such related B cell clones, irrespective of conditioning regimen, donor source or time post transplantation. In general, repertoire diversity was lower in post-HSCT as compared to pre-HSCT samples. However, post-HSCT repertoires retained highly mutated sequences, despite immunosuppressive therapy and presence of T cell deficiency after HSCT. These observations identify key properties of the recovering B cell compartment and provide a conceptual framework for the surveillance of humoral immunity after allogeneic transplantation. [ABSTRACT FROM AUTHOR]

Because miR-181a has been described to alter T cell activation, we hypothesized that manipulation of miR-181a expression in donor T cells may alter acute graft-versus-host disease (aGvHD) after allogeneic bone marrow transplantation (BMT). We therefore analyzed the impact of enhanced and reduced miR-181a expression in donor T cells on aGvHD induction by lentiviral gene transfer into primary T cells and using miR-181a/b-1-/- T cells, respectively. BMT-recipient mice receiving donor T cells with enhanced miR-181a expression showed no signs of aGvHD and survived for the time of follow-up, whereas T cells lacking miR-181a/b-1 accelerated aGvHD. In line with these data, analysis of donor T cells in blood, secondary lymphoid organs, and target organs of aGvHD after BMT showed significantly reduced numbers of miR-181a-transduced T cells, as compared with controls. In addition, expansion of activated T cells with enhanced miR-181a expression was reduced in vitro and in vivo. We further show that anti-apoptotic BCL-2 protein expression is reduced in murine and human T cells upon overexpression of miR-181a, suggesting that regulation of BCL-2-expression by miR-181a may contribute to altered alloreactivity of T cells in aGvHD. These data indicate that proteins regulated by miR-181a may be therapeutic targets for aGvHD prevention. [ABSTRACT FROM AUTHOR]

Homing of allogeneic donor T cells to recipient tissue is imperative for the development of acute graft-versus-host disease (GVHD) after bone marrow transplantation (BMT). In this study we show that alteration of T cell homing due to integrin-β7 deficiency on T cells or its ligand MAdCAM-1 in BMT recipients contributes to the pathophysiology of experimental GVHD. In contrast, lack of CC chemokine receptor 9 on donor T cells alters tissue homing but does not impact GVHD survival. We further demonstrate that MAdCAM-1 is aberrantly expressed in hepatic murine GVHD as well as in patients with active liver GVHD. However, infiltration of donor T cells in gut but not liver was dependent of MAdCAM-1 expression, indicating, that homing and/or retention of donor T cells rests on divergent molecular pathways depending on the GVHD target tissue. [ABSTRACT FROM AUTHOR]

Hematopoietic stem cell transplantation (HSCT) remains the only curative treatment in patients with higher risk myelodysplastic syndrome (MDS), but the choice of the optimal alternative stem cell source is still a subject of debate in patients lacking an HLA-matched sibling donor. Here, we report on a large series of patients with MDS (N = 631) transplanted either with mobilized peripheral stem cells (PBs) from unrelated donors (n = 502) or with umbilical cord blood transplant (UCB, n = 129) as alternative grafts after reduced-intensity conditioning. Neutrophil engraftment was higher after PB (98% versus 78%, P < .0001). Acute graft-versus-host disease (GVHD) was similar after PB (31%) and UCB (29%), and chronic GVHD incidence was higher after PB (41% versus 23%). Two-year nonrelapse mortality was lower after PB (31% versus 42% P = .03). There was a better overall survival (OS) and disease-free survival (DFS) after PB (49% ± 2% versus 30% ± 4%, P < .0001 and 44% ± 2% versus 28% ± 4%, P < .0001). Multivariate analysis confirmed the advantage of PB for treatment-related mortality, OS, and DFS, whereas relative risk of chronic GVHD was similar. A multivariate analysis comparing PB from a 10/10 HLA-matched donor, PB from a 9/10 HLA-matched donor, and UCB showed an advantage on treatment-related mortality, DFS, and OS only in 10/10 PB. We conclude that in MDS patients lacking an HLA-matched sibling donor, PB from a 10/10 HLA-matched unrelated donor is the preferred source of hematopoietic stem cells. HLA-mismatched unrelated donor or cord blood seem to give similar inferior results except for neutrophil engraftment, which is delayed after UCB. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Endothelial activation leading to vascular barrier breakdown plays an essential role in the pathophysiology of multiple-organ dysfunction syndrome (MODS) in sepsis. Increasing evidence suggests that the function of the vessel-protective factor Angiopoietin-1 (Ang-1), a ligand of the endothelial-specific Tie2 receptor, is inhibited by its antagonist Angiopoietin-2 (Ang-2) during sepsis. In order to reverse the effects of the sepsis-induced suppression of Ang-1 and elevation of Ang-2 we aimed to investigate whether an intravenous injection of recombinant human (rh) Ang-1 protects against MODS in murine sepsis. Methods: Polymicrobiological abdominal sepsis was induced by cecal ligation and puncture (CLP). Mice were treated with either 1μg of intravenous rhAng-1 or control buffer immediately after CLP induction and every 8h thereafter. Sham-operated animals served as time-matched controls. Results: Compared to buffer-treated controls, rhAng-1 treated septic mice showed significant improvements in several hematologic and biochemical indicators of MODS. Moreover, rhAng-1 stabilized endothelial barrier function, as evidenced by inhibition of protein leakage from lung capillaries into the alveolar compartment. Histological analysis revealed that rhAng-1 treatment attenuated leukocyte infiltration in lungs and kidneys of septic mice, probably due to reduced endothelial adhesion molecule expression in rhAng-1 treated mice. Finally, the protective effects of rhAng-1 treatment were reflected by an improved survival time in a lethal CLP model. Conclusions: In a clinically relevant murine sepsis model, intravenous rhAng-1 treatment alone is sufficient to significantly improve a variety of sepsis-associated organ dysfunctions and survival time, most likely by preserving endothelial barrier function. Further studies are needed to pave the road for clinical application of this therapy concept. [Copyright &y& Elsevier]