Blinatumomab in Children with MRD-Positive B-Cell Precursor Acute Lymphoblastic Leukemia: A Report of 11 Cases.

Background/Objectives: Relapsed B-cell acute lymphoblastic leukemia (B-ALL) remains an unresolved matter of concern regarding adverse outcomes. This case study aimed to evaluate the effectiveness of blinatumomab, with or without door lymphocyte infusion (DLI), in treating measurable residual disease (MRD)-positive B-ALL. Methods: All patients who received blinatumomab salvage therapy were included in this study. Eleven patients were included in the study. All patients were evaluated for MRD-negativity. Results: Before starting blinatumomab therapy, seven patients tested positive for MRD, three tested negative, and one had refractory disease. Hematopoietic cell transplantation (HCT) was reserved for five patients with persistent MRD. Six patients became MRD-negative and subsequent HCT was not performed. Only two patients relapsed; one patient died of relapse, and the other one received carfilzomib-based therapy and was MRD-negative thereafter. Nine patients were MRD-negative at a median follow-up of 28 months (15-52 months). Two of three MRD-positive post-transplant patients remained in complete molecular remission after preemptive DLI at the last follow-up date. In the first salvage, blinatumomab may achieve complete remission and bridging to HCT in pediatric patients with end-of-induction MRD-positive B-cell precursor ALL. Conclusions: The decision on how to treat post-transplant relapse continues to affect survival outcomes. Blinatumomab combined with DLI may extend the armamentarium of release options for high-risk pediatric patients. This approach is encouraging for high-risk ALL patients who are MRD-positive post-transplantation.

Donor Lymphocyte Infusion (DLI) post allogeneic stem cell transplant (allo-SCT) in Acute Myeloid Leukemia (AML) and High-Grade Myelodysplastic Syndrome (MDS). A longitudinal retrospective study using peripheral blood (PB) CD34+ and CD3+ donor chimerism (DC) monitoring.

INTRODUCTION: This longitudinal study was based on the outcomes of Donor Lymphocyte Infusion (DLI) for falling peripheral blood (PB) CD34+ and CD3+ donor chimerism (DC). METHODS: From 2012 to 2018, data was collected from the BMT database and electronic medical records (EMR). The primary objective was to compare the indication for DLI based on falling PB CD34+ or CD3+ DC in patients post allo-SCT for AML and MDS and their overall survival (OS). RESULTS: 18/70 patients met the inclusion criteria. Indications for DLI were i) falling PB CD34+ DC ≤ 80 % with morphological relapse, ii) falling PB CD34+ DC ≤ 80 % without morphological relapse and iii) falling PB CD3+ DC ≤ 80 % without falling PB CD34+ DC. Log rank analysis showed falling PB CD34+ DC and morphological relapse had significantly lower OS. Linear regression demonstrated better OS post DLI if there was PB CD34+ and CD3+ chimerism response at 30 days (p = 0.029), GVHD (p = 0.032) and tapering immunosuppression at the time of falling DC (p = 0.042). CONCLUSION: DLI for PB CD34+ DC values ≤ 80 % and morphological relapse had the lowest OS. In this study, full DC was achieved after DLI even with a PB CD3+DC value as low as 13 %, provided the PB CD34+ DC remained > 80 %. Further research is vital in CD34+ DC as a biomarker for disease relapse and loss of engraftment.

The graft versus leukemia effect: donor lymphocyte infusions and cellular therapy.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for many hematologic malignancies as well as non-malignant conditions. Part of the curative basis underlying HSCT for hematologic malignancies relies upon induction of the graft versus leukemia (GVL) effect in which donor immune cells recognize and eliminate residual malignant cells within the recipient, thereby maintaining remission. GVL is a clinically evident phenomenon; however, specific cell types responsible for inducing this effect and molecular mechanisms involved remain largely undefined. One of the best examples of GVL is observed after donor lymphocyte infusions (DLI), an established therapy for relapsed disease or incipient/anticipated relapse. DLI involves infusion of peripheral blood lymphocytes from the original HSCT donor into the recipient. Sustained remission can be observed in 20-80% of patients treated with DLI depending upon the underlying disease and the intrinsic burden of targeted cells. In this review, we will discuss current knowledge about mechanisms of GVL after DLI, experimental strategies for augmenting GVL by manipulation of DLI (e.g. neoantigen vaccination, specific cell type selection/depletion) and research outlook for improving DLI and cellular immunotherapies for hematologic malignancies through better molecular definition of the GVL effect.

Donor Lymphocyte Infusion in the Treatment of Post-Transplant Relapse of Acute Myeloid Leukemias and Myelodysplastic Syndromes Significantly Improves Overall Survival: A French-Italian Experience of 134 Patients.

BACKGROUND: Disease relapse after allogeneic stem cell transplantation (allo-SCT) is the main challenge for curing acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). We investigated the overall survival (OS) after allo-SCT relapse according to different therapeutic approaches. METHODS: We analyzed 134 patients who relapsed after allo-SCT performed between 2015 and 2021 at Saint-Antoine University Hospital, Paris and Spedali Civili di Brescia, Brescia. Of these, 103 (77%) were treated, comprising 69/103 (67%) who received therapy in overt relapse and 34/103 (33%) who were treated in a pre-emptive manner when molecular/cytogenetics recurrence or mixed chimerism occurred. The treatment was donor lymphocyte infusion (DLI)-based for 40/103 (39%) patients. RESULTS: The 1-, 2-, and 5-year OS of patients treated with DLI (n = 40) was 67%, 34%, and 34%, respectively, for those treated preventively (n = 20) and 43%, 20%, and 20%, respectively, for those treated in overt relapse (n = 20) (p < 0.01). The 1-, 2-, and 5-year OS of patients treated without DLI (n = 63) was 54%, 40%, and 26%, respectively, for those treated preventively (n = 14) and 17%, 5%, and 0%, respectively, for those treated in overt relapse (n = 49) (p < 0.01). CONCLUSIONS: Relapse treatment with a pre-emptive strategy was associated with improved outcomes, particularly when DLI was employed.

Successful Treatment With Venetoclax Plus Azacytidine Combined With Radiation Therapy and Donor Lymphocyte Infusion in a Patient With Extramedullary Relapse of Acute Myeloid Leukemia After Stem Cell Transplantation.

Extramedullary (EM) relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute myeloid leukemia (AML) is rare and causes systemic relapse. Consequently, the prognosis is very poor because limited treatment is feasible in post-transplant patients. The efficacy and safety of venetoclax (VEN), a newly developed oral inhibitor of B-cell leukemia/lymphoma-2, plus azacytidine (AZA) in patients newly diagnosed with AML who are ineligible for intensive chemotherapy have been reported. We report a case in which VEN + AZA salvage treatment following radiation therapy and donor lymphocyte infusion afforded promising results in a patient with AML who showed post-allo-HSCT EM relapse.

Risk factors for graft-versus-host-disease after donor lymphocyte infusion following T-cell depleted allogeneic stem cell transplantation.

Introduction: Unmodified donor lymphocyte infusions (DLI) after allogeneic stem cell transplantation (alloSCT) can boost the beneficial Graft-versus-Leukemia (GvL) effect but may also induce severe Graft-versus-Host-Disease (GvHD). To improve the balance between GvL and GvHD, it is crucial to identify factors that influence the alloreactivity of DLI. Methods: We investigated the effects of the presence of patient-derived antigen-presenting cells at time of DLI as estimated by the bone marrow (BM) chimerism status, lymphopenia as measured by the absolute lymphocyte count (ALC) at time of DLI, and the presence of a viral infection (de novo or reactivation) close to DLI on the risk of GvHD after DLI. The cohort consisted of patients with acute leukemia or myelodysplastic syndrome who prophylactically or pre-emptively received DLI as standard care after alemtuzumab-based alloSCT. In patients at high risk for relapse, DLI was administered at 3 months after alloSCT (n=88) with a dose of 0.3x106 or 0.15x106 T cells/kg in case of a related or unrelated donor, respectively. All other patients (n=76) received 3x106 or 1.5x106 T cells/kg, respectively, at 6 months after alloSCT. Results: For both DLIs, patients with reduced-intensity conditioning and an unrelated donor had the highest risk of GvHD. For DLI given at three months, viral infection within 1 week before and 2 weeks after DLI was an additional significant risk factor (hazard ratio (HR) 3.66 compared to no viral infection) for GvHD. At six months after alloSCT, viral infections were rare and not associated with GvHD. In contrast, mixed BM chimerism (HR 3.63 for ≥5% mixed chimerism compared to full donor) was an important risk factor for GvHD after DLI given at six months after alloSCT. ALC of <1000x106/l showed a trend for association with GvHD after this DLI (HR 2.05 compared to ≥1000x106/l, 95% confidence interval 0.94-4.45). Furthermore, the data suggested that the presence of a viral infection close to the DLI at three months or ≥5% mixed chimerism at time of the DLI at six months correlated with the severity of GvHD, thereby increasing their negative impact on the current GvHD-relapse-free survival. Conclusion: These data demonstrate that the risk factors for GvHD after DLI depend on the setting of the DLI.

Vitiligo and Alopecia Areata After Donor Lymphocyte Infusions in a Child With Relapsed Acute Myeloid Leukemia.

Rarely do patients with chronic graft-versus-host disease (cGVHD) experience vitiligo and alopecia areata. Nevertheless, the exact cause of vitiligo and alopecia areata is still not fully understood. The patient experienced a relapse of acute myeloid leukemia (AML) following a second complete remission after undergoing HLA-6/8 mismatched unrelated donor hematopoietic cell transplantation (HCT). Achieving full donor chimerism was successful during the initial stages of the transplant. Nevertheless, the molecular evidence of measurable residual disease remained, prompting the administration of donor lymphocyte infusions (DLI) following a dose-escalation protocol. After three cycles of DLI given at two-month intervals, the circulating blasts eventually vanished. After the third DLI dose, vitiligo developed despite achieving molecular remission. The dermatologist confirmed the presence of vitiligo and alopecia areata, along with cutaneous cGVHD. The outcome was the complete elimination of the molecular presence, and the patient experienced both clinical and molecular remission for a period of five years following DLI. Based on our observations, it was found that DLI could effectively eradicate molecular leukemia in cases of AML relapse after HCT. The development of vitiligo and alopecia areata was influenced by the destruction of melanocytes due to autoimmune reactions caused by cGVHD.

Donor Lymphocyte Infusion for Relapsed Acute Leukemia or Myelodysplastic Syndrome after Hematopoietic Stem Cell Transplantation: A Single-Institute Retrospective Analysis.

Objective The prognosis of the patients who relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poor, and therapeutic options are limited. In the present study, we investigated the efficacy and factors associated with the survival in patients with acute leukemia or myelodysplastic syndrome (MDS) who relapsed following allo-HSCT and were treated with donor lymphocyte infusion (DLI) in real-world practice. Patients Twenty-nine patients with acute myeloid leukemia21, acute lymphoid leukemia4 or MDS4 were enrolled. Eleven patients were diagnosed with hematological relapse, and 18 were diagnosed with molecular or cytogenetic relapse. Results The median injection number and median total number of infused CD3+ T cells were 2 and 5.0×107/kg, respectively. The cumulative incidence of acute graft-versus-host disease (aGVHD) of grade ≥II at 4 months after the initiation of DLI was 31.0%. Extensive chronic graft-versus-host disease (cGVHD) occurred in 3 (10.3%) patients. The overall response rate was 51.7%, including 3 cases of hematological complete remission (CR) and 12 cases of molecular/cytogenetic CR. Cumulative relapse rates at 24 and 60 months following DLI in patients who achieved CR were 21.4% and 30.0%, respectively. The overall survival rates at 1, 2 and 3 years after DLI were 41.4%, 37.9% and 30.3%, respectively. Molecular/cytogenetic relapse, a longer interval from HSCT to relapse, and concomitant chemotherapy with 5-azacytidine (Aza) were significantly associated with a relatively long survival following DLI. Conclusion These results indicated that DLI was beneficial for patients with acute leukemia or MDS who relapsed after allo-HSCT and suggested that DLI in combination with Aza for molecular or cytogenetic relapse might result in favorable outcomes.

Combination of Donor Lymphocyte Infusion and Blinatumomab for B-Cell Lymphoblastic Lymphoma Relapse after Allogeneic Stem-Cell Transplantation.

A woman in her forties with relapsed B-cell lymphoblastic lymphoma was treated with blinatumomab, but the drug proved ineffective. Salvage therapy with clofarabine induced a complete remission, and she received an allogeneic stem-cell transplantation (allo-SCT) from an HLA-matched sibling donor. However, her disease relapsed only 4 months after the allo-SCT. Three courses of combination therapy with donor lymphocyte infusion (DLI) and blinatumomab were administered, and the tumor progression was well controlled for 6 months, leading to a second allo-SCT from an HLA-haploidentical donor. The remission was persistent for approximately 1 year, but the disease relapsed in her central nervous system, and she eventually died. Our case demonstrated the efficacy and safety of concomitant use of DLI and blinatumomab. This combination presumably enhanced a graft-versus-lymphoma effect of allogeneic T-cells without provoking graft-versus-host disease.

Prophylactic donor lymphocyte infusion after haploidentical hematopoietic cell transplantation and post-transplant cyclophosphamide for treatment of high-risk myeloid neoplasms in children: A retrospective study.

BACKGROUND: Post-transplant cyclophosphamide (PTCy) has been recommended for prevention of graft-versus-host disease (GvHD) following haploidentical hematopoietic cell transplantation (haplo-HCT) for treatment of malignant blood diseases, but disease relapse remains a problem. Although donor lymphocyte infusion (DLI) is reported to be effective for treating post-transplantation relapse, the efficacy and safety of prophylactic-DLI (pro-DLI) post haplo-HCT, and PTCy in pediatric patients with hematological malignancies is unknown. METHODS: We retrospectively analyzed the outcomes of 54 pediatric patients with high-risk myeloid neoplasms who received a PTCy regimen for GvHD prophylaxis and pro-DLI after haploidentical peripheral blood stem cell transplantation. The high-risk myeloid neoplasms in this cohort included acute myeloid leukemia (n = 46) and myelodysplastic syndromes (n = 8). RESULTS: Median follow-up was for 19.7 (range: 3.4-46.6) months. The cumulative incidences of grade II-IV and III-IV acute GvHD were 37.0% (95% CI: 22.7%-48.7%) and 16.7% (95% CI: 6.1%-26.0%), respectively. There were no graft-failure events, and the 2-year rate of moderate/severe chronic GvHD was 8.1% (95% CI: 0%-16.7%). The 2-year non-relapse mortality, relapse, disease-free survival, GvHD-free relapse-free survival, and overall survival rates were 5.1% (95% CI: 0%-11.7%), 16.6% (95% CI: 5.3%-26.6%), 78.9% (95% CI: 68.0%-91.6%), 62.2% (95% CI: 49.4%-78.3%), and 87.3% (95% CI: 78.3%-97.4%), respectively. CONCLUSIONS: Prophylactic donor lymphocyte infusion in the setting of haploidentical hematopoietic cell transplantation with post-transplant cyclophosphamide appears to be effective and safe in pediatric patients with high-risk myeloid neoplasms.

Adoptive Immunotherapy via Donor Lymphocyte Infusions following Allogeneic Hematopoietic Stem Cell Transplantation for Myelofibrosis: A Real-World, Retrospective Multicenter Study.

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the sole curative option for myelofibrosis (MF). Relapse remains a significant problem, however, occurring in up to 20% to 30% of cases. Donor lymphocyte infusion (DLI) represents a potentially effective strategy for relapse prevention and management, but the optimal timing based on measurable residual disease/chimerism analyses and the choice of regimen remain undetermined. We performed a retrospective real-world analysis of a multicenter cohort of MF allo-HCT recipients from 8 European transplantation centers who received DLI between 2005 and 2022. Response was assessed using International Working Group-Myeloproliferative Neoplasms Research and Treatment-defined response criteria, and survival endpoints were estimated using the Kaplan-Meier estimator and log-rank test. The study included 28 patients with a median age of 58 years and a Karnofsky Performance Status of >80. The majority of patients had Dynamic International Prognostic Scoring System-plus intermediate-2 or high-risk disease at the time of allo-HCT. In vivo T cell depletion was used in 20 patients (71.2%), with 19 of the 20 receiving antithymocyte globulin. The indication for DLI was either "preemptive" (n = 15), due to a decrease in recipient chimerism (n = 13) or molecular relapse (n = 2), or "therapeutic" (n = 13) for clinician-defined hematologic/clinical relapse. No patient received DLI prophylactically. The median time of DLI administration was 23.4 months post allo-HCT. Of the 16 patients receiving multiple DLIs, 12 were part of a planned escalating dose regimen. The median follow-up from the time of first DLI was 55.4 months. The responses to DLI were complete response in 9 patients, partial response in 1 patient, and clinical improvement in 6 patients. Chimerism levels improved in 16 patients, and stable disease was reported in 5 patients. No response or progression was reported in 7 patients. DLI-induced acute graft-versus-host disease (aGVHD) was reported in 11 patients (39%), with grade III-IV aGVHD in 7 (25%). The median overall survival from the time of first DLI was 62.6 months, and the cumulative incidence of relapse/progression after first DLI was 30.8% at 6 months. This study highlights that good response rates can be achieved with DLI even after frank relapse in some patients in a cohort in which other treatment options are very limited. More prospective studies are warranted to identify the optimal DLI regimen and timing to improve patient outcomes.

Joint models quantify associations between immune cell kinetics and allo-immunological events after allogeneic stem cell transplantation and subsequent donor lymphocyte infusion.

Alloreactive donor-derived T-cells play a pivotal role in alloimmune responses after allogeneic hematopoietic stem cell transplantation (alloSCT); both in the relapse-preventing Graft-versus-Leukemia (GvL) effect and the potentially lethal complication Graft-versus-Host-Disease (GvHD). The balance between GvL and GvHD can be shifted by removing T-cells via T-cell depletion (TCD) to reduce the risk of GvHD, and by introducing additional donor T-cells (donor lymphocyte infusions [DLI]) to boost the GvL effect. However, the association between T-cell kinetics and the occurrence of allo-immunological events has not been clearly demonstrated yet. Therefore, we investigated the complex associations between the T-cell kinetics and alloimmune responses in a cohort of 166 acute leukemia patients receiving alemtuzumab-based TCD alloSCT. Of these patients, 62 with an anticipated high risk of relapse were scheduled to receive a prophylactic DLI at 3 months after transplant. In this setting, we applied joint modelling which allowed us to better capture the complex interplay between DLI, T-cell kinetics, GvHD and relapse than traditional statistical methods. We demonstrate that DLI can induce detectable T-cell expansion, leading to an increase in total, CD4+ and CD8+ T-cell counts starting at 3 months after alloSCT. CD4+ T-cells showed the strongest association with the development of alloimmune responses: higher CD4 counts increased the risk of GvHD (hazard ratio 2.44, 95% confidence interval 1.45-4.12) and decreased the risk of relapse (hazard ratio 0.65, 95% confidence interval 0.45-0.92). Similar models showed that natural killer cells recovered rapidly after alloSCT and were associated with a lower risk of relapse (HR 0.62, 95%-CI 0.41-0.93). The results of this study advocate the use of joint models to further study immune cell kinetics in different settings.

Magnesium enhances the graft-versus-tumor effect of donor lymphocytic infusion on hematologic malignancies.

Donor lymphocyte infusion (DLI) cures relapsed hematologic malignancies after allogeneic hematopoietic stem cell transplantation through the graft-versus-tumor (GVT) effect. Although the important role of magnesium in enhancing immunity has been mentioned in studies, limited clinical data have explored how magnesium affects the efficacy of DLI. Besides, although laboratory data demonstrate that magnesium can enhance CD8+ T cells effector function, whether magnesium regulates the tumor killing effect of peripheral blood mononuclear cells (PBMCs) remains to be explored. Here, for the retrospective study, we collected clinical data of relapsed patients receiving DLI and explored the relationship between different serum magnesium levels and patient outcomes. For in vitro studies, we investigated the effect of magnesium on the cytotoxicity of DLI cells which were PBMCs and preliminarily explored the mechanism. Eighty-one patients were enrolled in this study. It was found that the high post-DLI magnesium level was significantly associated with a higher incidence of complete remission (CR) or partial remission (CR/PR) and a higher possibility of survival. The magnesium level after DLI was an independent risk factor of overall survival. In vitro studies proved that increased magnesium enhanced the cytotoxic function of PBMCs on hematologic malignancies. Besides, magnesium modulated LFA-1 headpiece opening. When blocking the integrin-ligand interaction between LFA-1 and ICAM-1, the regulation effect of magnesium on PBMCs was weakened. Therefore, it was possible that magnesium regulated PBMCs effector function by stimulating LFA-1. These results show that serum magnesium levels affect immunological responses mediated by donor lymphocytes in hematologic malignancies.

The graft-versus-leukemia effect of prophylactic donor lymphocyte infusions after allogeneic stem cell transplantation is equally effective in relapse prevention but safer compared to spontaneous graft-versus-host disease.

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.

Donor-derived CAR-T therapy improves the survival of relapsed B-ALL after allogeneic transplantation compared with donor lymphocyte infusion.

Chimeric antigen receptor (CAR)-T cell therapy revolutionized treatment for various hematologic malignances. However, limited studies were reported to compare the efficacy and safety of CAR-T and donor lymphocyte infusion (DLI) for patients with relapsed B-cell acute lymphoblastic leukemia (B-ALL) after hematopoietic stem cell transplantation (HSCT) comprehensively. We conducted a single-center, retrospective comparative study that consisted of 12 patients who were treated with DLI (control group) and 12 patients treated with donor-derived CD19 CAR-T cells (experimental group, 6 patients also received CD22 or CD123 CAR-T cells sequentially) with 3 overlaps. The event-free survival (EFS) of patients in experimental group was superior to that of the control group: 516 days versus 98 days (p = 0.0415). Compared with 7 of 12 patients treated with DLI suffered grades III-IV acute graft versus host disease (aGVHD), one grade III aGVHD developed in patients treated with CAR-T therapy. No significant difference in the incidence of infection was identified between these two groups. Most patients in the experimental group had only mild cytokine release syndrome and none developed neurotoxicity. The univariate analysis of patients in the experiment group revealed that earlier CAR-T therapy for post-transplantation relapse was associated with better EFS. There was no significant difference in EFS between patients treated with dual-target CAR-T with those with single CD19 CAR-T. In this study, our data supported that donor-derived CAR-T therapy is a safe and potentially effective treatment for relapsed B-ALL after HSCT and may be superior to DLI.

Donor-derived CD19 CAR-T Cells versus Chemotherapy Plus Donor Lymphocyte Infusion for Treatment of Recurrent CD19-positive B-ALL After Allogeneic Hematopoietic Stem Cell Transplantation.

OBJECTIVE: This study aimed to compare the efficacy of anti-CD19 chimeric antigen receptor T cells (CAR-T cells) versus chemotherapy plus donor lymphocyte infusion (chemo-DLI) for treating relapsed CD19-positive B-cell acute lymphoblastic leukemia (B-ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Clinical data of 43 patients with B-ALL who relapsed after allo-HSCT were retrospectively analyzed. Twenty-two patients were treated with CAR-T cells (CAR-T group), and 21 with chemotherapy plus DLI (chemo-DLI group). The complete remission (CR) and minimal residual disease (MRD)-negative CR rates, leukemia-free survival (LFS) rate, overall survival (OS) rate, and incidence of acute graft-versus-host disease (aGVHD), cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were compared between the two groups. RESULTS: The CR and MRD-negative CR rates in the CAR-T group (77.3% and 61.5%) were significantly higher than those in the chemo-DLI group (38.1% and 23.8%) (P=0.008 and P=0.003). The 1- and 2-year LFS rates in the CAR-T group were superior to those in the chemo-DLI group: 54.5% and 50.0% vs. 9.5% and 4.8% (P=0.0001 and P=0.00004). The 1- and 2-year OS rates in the CAR-T versus chemo-DLI group were 59.1% and 54.5% vs. 19% and 9.5% (P=0.011 and P=0.003). Six patients (28.6%) with grade 2-4 aGVHD were identified in the chemo-DLI group. Two patients (9.1%) in the CAR-T group developed grade 1-2 aGVHD. Nineteen patients (86.4%) developed CRS in the CAR-T group, comprising grade 1-2 CRS in 13 patients (59.1%) and grade 3 CRS in 6 patients (27.3%). Two patients (9.1%) developed grade 1-2 ICANS. CONCLUSION: Donor-derived anti-CD19 CAR-T-cell therapy may be better, safer, and more effective than chemo-DLI for B-ALL patients who relapse after allo-HSCT.

Pre-emptive and prophylactic donor lymphocyte infusion following allogeneic stem cell transplantation.

Donor lymphocyte infusion (DLI) is an allogenic immunotherapy used after allogeneic hematopoietic stem cell transplantation. DLI takes advantage of the graft-versus-tumor effect induced by the infused CD3 + T cells, but may induce graft-versus-host disease. To date, DLI has been attempted to prevent hematological relapse after allogeneic hematopoietic stem cell transplantation in patients with mixed chimerism and molecular relapse (pre-emptive DLI), and as maintenance therapy in patients with high-risk hematological malignancies (prophylactic DLI). DLI response and efficacy depend on patient, disease, and DLI factors. This review discusses the efficacy and risks of DLI, with a focus on pre-emptive and prophylactic use.

Donor Hematopoietic Stem Cell/Lymphocyte Maintenance Treatment After CAR T-Cell Therapy in Patients With B-Cell Acute Lymphoblastic Leukemia Relapse Following Stem Cell Transplant.

Maintaining the efficacy of anti-CD19 chimeric antigen receptor modified (CAR) T-cell therapy in patients with B-cell acute lymphoblastic leukemia (B-ALL) relapse after allogeneic hematopoietic stem cell transplant (allo-HSCT) is an urgent problem. In this study, we aimed to compare the efficacy of donor hematopoietic stem cell infusion (DSI) therapy and donor lymphocyte infusion (DLI) therapy as a maintenance therapy after R/R B-ALL patients achieved CR in anti-CD19-CAR T-cell therapy but relapsed after allo-HSCT. In total, 22 B-ALL patients who relapsed after allo-HSCT received anti-CD19-CAR T-cell therapy. Patients who responded to CAR T-cell therapy received DSI or DLI as maintenance therapy. We compared the clinical responses, acute graft versus host disease (aGVHD), expansion of CAR-T-cells, and adverse events between the two groups. In our study, 19 patients received DSI/DLI as maintenance therapy. After DSI/DLI therapy, progression-free survival and overall survival were higher in the DSI group than in the DLI group at 365 days. The grades I and II of aGVHD was observed in four patients (36.4%) in the DSI group. Only one patient developed grade II aGVHD in the DLI group. The peaks of CAR T-cells in the DSI group were higher than those in the DLI group. IL-6 and TNF-α levels increased again in nine of 11 patients after DSI but not in the DLI group. Our findings indicate that for B-ALL patients who relapse after allo-HSCT, DSI is a feasible maintenance therapy if CR is obtained with CAR-T-cell therapy.

Case report: HLA-haploidentical HSCT rescued with donor lymphocytes infusions in a patient with X-linked chronic granulomatous disease.

Chronic granulomatous disease is an inborn error of immunity due to disrupted function of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. This results in impaired respiratory burst of phagocytes and insufficient killing of bacteria and fungi. Patients with chronic granulomatous disease are at increased risk for infections, autoinflammation and autoimmunity. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only widely available curative therapy. While HSCT from human leukocyte antigen (HLA) matched siblings or unrelated donors are standard of care, transplantation from HLA-haploidentical donors or gene therapy are considered alternative options. We describe a 14-month-old male with X-linked chronic granulomatous disease who underwent a paternal HLA-haploidentical HSCT using T-cell receptor (TCR) alpha/beta+/CD19+ depleted peripheral blood stem cells followed by mycophenolate graft versus host disease prophylaxis. Decreasing donor fraction of CD3+ T cells was overcome by repeated infusions of donor lymphocytes from the paternal HLA-haploidentical donor. The patient achieved normalized respiratory burst and full donor chimerism. He remained disease-free off any antibiotic prophylaxis for more than three years after HLA-haploidentical HSCT. In patients with x-linked chronic granulomatous disease without a matched donor paternal HLA-haploidentical HSCT is a treatment option worth to consider. Administration of donor lymphocytes can prevent imminent graft failure.