Donor lymphocyte infusion after allogeneic haematopoietic cell transplantation for haematological malignancies: basic considerations and best practice recommendations from the EBMT.

Since the early description of three patients with relapsed leukaemia after allogeneic haematopoietic cell transplantation (HCT) who obtained complete remission after donor lymphocyte infusions (DLIs), the added value of this procedure to induce or maintain graft-versus-leukaemia immunity has been undisputed. For more than 30 years, DLIs have become common practice as prophylactic, pre-emptive, or therapeutic immunotherapy. However, as with many aspects of allogeneic HCT, centres have developed their own routines and practices, and many questions related to the optimal applications and toxicity, or to the immunobiology of DLI induced tumour-immunity, remain. As a part of the Practice Harmonization and Guidelines Committee and the Cellular Therapy and Immunobiology Working Party of the European Society for Blood and Marrow Transplantation effort, a panel of experts with clinical and translational knowledge in transplantation immunology and cellular therapy met during a 2-day workshop in September, 2023, in Lille, France, and developed a set of consensus-based recommendations for the application of unmanipulated DLI after allogeneic HCT for haematological malignancies. Given the absence of prospective data in the majority of publications, these recommendations are mostly based on retrospective studies and expert consensus.

Precision Medicine Approaches in Acute Myeloid Leukemia with Adverse Genetics.

The treatment of acute myeloid leukemia (AML) with adverse genetics remains unsatisfactory, with very low response rates to standard chemotherapy and shorter durations of remission commonly observed in these patients. The complex biology of AML with adverse genetics is continuously evolving. Herein, we discuss recent advances in the field focusing on the contribution of molecular drivers of leukemia biogenesis and evolution and on the alterations of the immune system that can be exploited with immune-based therapeutic strategies. We focus on the biological rationales for combining targeted therapy and immunotherapy, which are currently being investigated in ongoing trials, and could hopefully ameliorate the poor outcomes of patients affected by AML with adverse genetics.

Cellular Strategies for Separating GvHD from GvL in Haploidentical Transplantation.

GvHD still remains, despite the continuous improvement of transplantation platforms, a fearful complication of transplantation from allogeneic donors. Being able to separate GvHD from GvL represents the greatest challenge in the allogeneic transplant setting. This may be possible through continuous improvement of cell therapy techniques. In this review, current cell therapies are taken into consideration, which are based on the use of TCR alpha/beta depletion, CD45RA depletion, T regulatory cell enrichment, NK-cell-based immunotherapies, and suicide gene therapies in order to prevent GvHD and maximally amplify the GvL effect in the setting of haploidentical transplantation.

Matched unrelated donor transplantation versus haploidentical transplantation with post-transplant cyclophosphamide in children with acute myeloid leukemia: a PDWP-EBMT study.

In children with acute myeloid leukemia (AML) who lack a human leukocyte antigen (HLA) identical sibling, the donor can be replaced with an HLA-matched unrelated donor (MUD) or a haploidentical donor (haplo). We compared outcomes of patients <18 years with AML in first and second complete remission (CR1 and CR2) undergoing a hematopoietic stem cell transplantation (HCT) either with a MUD with anti-thymocyte globulin (ATG) (N=420) or a haplo HCT with post-transplant cyclophosphamide (PT-CY) (N=96) after a myeloablative conditioning regimen (MAC) between 2011 and 2021, reported to the European Society for Blood and Marrow Transplantation. A matched pair analysis was performed to adjust for differences among groups. The final analysis was performed on 253 MUD and 95 haplo-HCT. In the matched cohort, median age at HCT was 11.2 and 10 years and median year of HCT was 2017 and 2018, in MUD and haplo-HCT recipients, respectively. The risk of grade III-IV acute graft-versus-host disease (aGVHD) was significantly higher in the haplo group (hazard ratio [HR]=2.33, 95% confidence interval [CI]: 1.18-4.58; P=0.01). No significant differences were found in 2 years overall survival (OS; 78.4% vs. 71.5%; HR=1.39, 95% CI: 0.84-2.31; P=0.19), leukemia-free survival (LFS; 72.7% vs. 69.5%; HR=1.22, 95% CI: 0.76-1.95; P=0.41), CI of relapse (RI; 19.3% vs. 19.5%; HR=1.14, 95% CI: 0.62-2.08; P=0.68) non-relapse-mortality (NRM; 8% vs. 11%; HR=1.39, 95% CI: 0.66-2.93; P=0.39) and graft-versus-host free relapse-free survival (GRFS; 60.7% vs. 54.5%, HR=1.38, 95% CI: 0.95-2.02; P=0.09) after MUD and haplo-HCT respectively. Our study suggests that haplo-HCT with PT-CY is a suitable option to transplant children with AML lacking a matched related donor.

Donor lymphocyte infusions after haploidentical stem cell transplantation with PTCY: A study on behalf of the EBMT cellular therapy & immunobiology working party.

Donor lymphocyte infusion (DLI) is a treatment option to prevent or treat relapse after allogeneic hematopoietic cell transplantation (HCT). We here report data for 173 patients who received one or multiple DLIs after haploidentical-HCT with post-transplant cyclophosphamide (PTCY) at 47 EBMT centers from 2009 to 2018. Indication for DLI was: prophylactic for 59 (34.3%), preemptive for 20(11.6%), and therapeutic for 93(54.1%). For the prophylactic group, the median number of DLIs was 1 (IQR:1-2.5) with a median first dose of 0.1 × 106 CD3+ T cell/kg, for the preemptive 2 (IQR:1-3) with 0.5 × 106 CD3+ T cell/kg, for the therapeutic 1 (IQR:1-3) with 1 × 106CD3+ Tcell/kg, respectively. OS after first DLI was 61% (46-75%) for prophylactic, 40% (19-61%) for preemptive, and 22% (13-31%) for therapeutic. CI of II-IV aGVHD and cGVHD was 17% (7-27%) and 53% (40-67%) for the prophylactic, 20% (2-38%) and 21% (3-39%) for the preemptive, 17% (9-24%) and 24% (15-33%) for the therapeutic group, respectively. Our data show great variability in the indications and modalities of DLI across responding EBMT centers. Survival rates remain relatively low in patients with active disease. While the cumulative incidence of aGVHD appears acceptable, we showed a high incidence of cGVHD in the prophylactic group, compared with preemptive and therapeutic DLI. These data should be investigated further in prospective clinical trials.

Impact of conditioning intensity on outcomes of haploidentical stem cell transplantation for patients with acute myeloid leukemia 45 years of age and over.

BACKGROUND: T cell-replete haploidentical stem cell transplantation (haplo-SCT) is a valid therapeutic option for adult patients with high-risk acute myeloid leukemia (AML) lacking an HLA-matched sibling or unrelated donor. METHOD: We retrospectively analyzed the outcomes of 912 AML patients ≥45 years of age who had undergone haplo-SCT with either myeloablative conditioning (MAC; n = 373) or reduced intensity conditioning (RIC; n = 539) regimens. RESULTS: The median follow-up was 31.1 and 25.7 months for MAC and RIC, respectively. The incidence of relapse and nonrelapse mortality (NRM) were 25.1% versus 28.7% and 31.0% versus 30.3% for MAC and RIC, respectively; 2-year leukemia-free survival (LFS) was 43.9% for MAC versus 41.0% for RIC. In multivariate analysis, the use of MAC versus RIC was not associated with a difference in the outcomes. Results were confirmed in the propensity score-weighted analysis. Disease status and performance status at transplantation were associated with outcomes. Notably, the use of posttransplantation cyclophosphamide was associated with reduced acute graft-versus-host disease (aGVHD) stage III-IV, and NRM and increased overall survival, LFS, and GVHD-free, relapse-free survival. The use of mobilized peripheral blood stem cells was associated with an increased risk of stage II-IV aGVHD. CONCLUSION: No differences were found between MAC and RIC regimens for haplo-SCT in adults with AML who were ≥45 years of age. The type of GVHD prophylaxis, disease status, and performance status were the major predictors of transplantation outcome. These results may serve as the background for randomized study comparing RIC versus MAC for haplo-SCT in adults with AML.

Unmanipulated haploidentical in comparison with matched unrelated donor stem cell transplantation in patients 60 years and older with acute myeloid leukemia: a comparative study on behalf of the ALWP of the EBMT.

BACKGROUND: Acute myeloid leukemia (AML) is both more common and with more biologically aggressive phenotype in the elderly. Allogenic stem cell transplantation (allo-SCT) is the best treatment option in fit patients. Either HLA-matched unrelated donor (MUD) or haploidentical (Haplo) donor are possible alternative for patients in need. METHODS: We retrospectively compared non-T-cell-depleted Haplo (n = 250) to 10/10 MUD (n = 2589) in AML patients ≥ 60 years. RESULTS: Median follow-up was 23 months. Disease status at transplant differs significantly between the two groups (p < 10-4). Reduced intensity conditioning (RIC) was administrated to 73 and 77% of Haplo and MUD, respectively (p = 0.23). Stem cell source was the bone marrow (BM) in 52% of the Haplo and 6% of MUD (p < 10-4). Anti-thymocyte globulin (ATG) was most frequently used in MUD (p < 10-4) while post-Tx cyclophosphamide (PT-Cy) was given in 62% of Haplo. Engraftment was achieved in 90% of the Haplo vs 97% of MUD (p < 10-4). In multivariate analysis, no significant difference was found between Haplo and MUD for acute (a)graft versus host disease (GVHD) grade II-IV, relapse incidence (RI), non-relapse mortality (NRM), leukemia free survival (LFS), graft-versus-host-free-relapse free survival (GRFS), and overall survival (OS). Extensive chronic (c)GVHD was significantly higher for MUD as compared to Haplo (HR 2, p = 0.01, 95% CI 1.17-3.47). A propensity score analysis confirmed the higher risk of extensive cGVHD for MUD without differences for other outcomes. CONCLUSIONS: Allo-SCT from both Haplo and MUD are valid option for AML patients ≥ 60 years of age with similar results. Transplantation from MUD was associated with higher extensive cGVHD. Our findings suggest that Haplo is a suitable and attractive graft source for patients≥ 60 with AML in need of allo-SCT.

Unmanipulated haploidentical stem cell transplantation in adults with acute lymphoblastic leukemia: a study on behalf of the Acute Leukemia Working Party of the EBMT.

BACKGROUND: Allogenic hematopoietic stem cell transplantation (allo-SCT) is the most effective post-remission treatment for adults with high-risk acute lymphoblastic leukemia (ALL). The aim of the study was to analyze results of unmanipulated haploidentical allo-SCT (haplo-SCT) for adults with ALL and to identify prognostic factors. METHODS: We performed a retrospective analysis on 208 adults transplanted in EBMT centers from 2007 to 2014. RESULTS: Median age at haplo-SCT was 32 years and median follow-up, 31 months. Forty-four percent of the patients were in first complete remission (CR1). Stem cell source was the bone marrow (BM) for 43% and peripheral blood (PB) for 57% of patients. Myeloablative conditioning (MAC) was used for 66% and reduced intensity regimen (RIC) for 34% of patients. GVHD prophylaxis was based on post-transplant cyclophosphamide (PT-Cy) for 118 (57%) or on anti-thymocyte-globulin (ATG) for 90 (43%) plus standard prophylaxis. One hundred eighty-four (92%) patients achieved engraftment. Cumulative incidence (CI) of grade II-IV acute-graft-versus-host-disease (GVHD) was 31%, grade III-IV 11%, and chronic GVHD 29%. Non-relapse mortality (NRM) and relapse-incidence (RI) were 32 and 37%, respectively. Overall survival (OS), leukemia-free survival (LFS), and GVHD-free, relapse-free-survival (GRFS) at 3 years were 33, 31, and 26%. For patients in CR1, OS, LFS, and GRFS were 52, 47, and 40%, respectively. Disease status was the main factor associated with transplant outcomes. Use of BM was independently associated with improvement in NRM, acute GVHD, GRFS, LFS, and OS. CONCLUSIONS: Unmanipulated haplo-SCT may be considered a valid option for adult patients with high-risk ALL lacking HLA identical donor preferably in early disease status.

Enhanced lipid peroxidation and platelet activation as potential contributors to increased cardiovascular risk in the low-HDL phenotype.

BACKGROUND: Low high-density lipoprotein (HDL) levels are major predictors of cardiovascular (CV) events, even in patients on statin treatment with low-density lipoprotein (LDL) at target. In animal models HDLs protect LDL from oxidation and blunt platelet activation. Our study aimed to examine whether HDL levels are related to in vivo oxidative stress and platelet activation, as determinants of atherothrombosis. METHODS AND RESULTS: Urinary 8-iso-PGF2α and 11-dehydro-TXB2, in vivo markers of oxidative stress and platelet activation, respectively, were measured in 65 coronary heart disease (CHD) normocholesterolemic patients with HDL ≤35 mg/dL, and in 47 CHD patients with HDL >35 mg/dL. The 2 eicosanoids were also measured before and after an intensive exercise program in sedentary people (n=18) and before and after fenofibrate treatment in otherwise healthy subjects with low HDL (n=10). Patients with HDL ≤35 mg/dL showed significantly higher urinary 8-iso-PGF2α (median [25th to 75th percentiles]: 289 [189 to 380] versus 216 [171 to 321] pg/mg creatinine, P=0.019) and 11-dehydro-TXB2 (563 [421 to 767] versus 372 [249 to 465] pg/mg creatinine, P=0.0001) than patients with higher HDL. A direct correlation was found between urinary 8-iso-PGF2α and 11-dehydro-TXB2 in the entire group of patients (ρ=0.77, P<0.0001). HDL levels were inversely related to both 8-iso-PGF2α (ρ=-0.32, P=0.001) and 11-dehydro-TXB2 (ρ=-0.52, P<0.0001). On multiple regression, only 8-iso-PGF2α (ß=0.68, P<0.0001) and HDL level (ß=-0.29, P<0.0001) were associated with urinary 11-dehydro-TXB2 excretion, independent of sex, age, smoking, hypertension, diabetes, previous myocardial infarction, total cholesterol, LDL, and triglycerides. Both intensive exercise and fenofibrate treatment significantly reduced the 2 eicosanoids in healthy subjects, in parallel with an HDL increase. CONCLUSIONS: A low HDL phenotype, both in CHD patients and in healthy subjects, is associated with increased lipid peroxidation and platelet activation. These data provide novel insight into the mechanisms linking low HDL with increased CV risk.

Biomarkers of platelet activation in acute coronary syndromes.

The most convincing evidence for the participation of platelets in arterial thrombosis in humans comes from studies of platelet activation in patients with acute coronary syndromes (ACS) and from trials of antiplatelet drugs. Both strongly support the concept that repeated episodes of platelet activation over the thrombogenic surface of a vulnerable plaque may contribute to the risk of death from coronary causes. However, the relation of in vivo platelet activation and adverse clinical events to results of platelet function tests remains largely unknown. A valuable marker of in vivo platelet activation should be specific, unaltered by pre-analytical artefacts and reproducibly measured by easily performed methods. This article describes current biomarkers of platelet activation in ACS, reviews their advantages and disadvantages, discusses their potential pitfalls, and demonstrates emerging data supporting the positive clinical implications of monitoring in vivo platelet activation in the setting of ACS.