Lymphocyte Infusion Research Articles

Formononetin reverses Treg/Th17 imbalance in immune-mediated bone marrow failure mice by regulating the PI3K/Akt signaling pathway

BackgroundSevere aplastic anemia (SAA) is a syndrome of bone marrow failure which is life-threatening. Recent studies have demonstrated that CD4 + T cell subsets, including T regulatory (Treg) and T helper 17 (Th17) cells, play a pivotal role in the pathogenesis of SAA. Formononetin (FMN) is a natural compound extracted from the traditional Chinese medicine Huangqi, which has the ability to regulate the imbalance of Treg/Th17 cells in some inflammatory diseases. Nevertheless, the therapeutic effect of FMN in SAA has yet to be definitively established. Therefore, the objective of this research was to investigate the effect of FMN on SAA and elucidate its underlying mechanism.MethodsIn vivo experiments, the mice were divided into the following five groups: control, model, low-dose FMN, high-dose FMN, and positive control cyclosporine A group. The immune-mediated bone marrow failure (BMF) mouse model was established by the total body X-ray radiation and lymphocyte infusion. After 10 days of continuous administration of FMN, the numbers of Treg/Th17 cells in the bone marrow and spleen were assessed by flow cytometry. The protein expressions of PI3K/Akt pathway in the bone marrow and spleen was assessed by immunohistochemistry and western blotting. In vitro, the impact of FMN on the differentiation of naive CD4 + T cells into Treg cells was investigated by flow cytometry and ELISA.ResultsIn comparison with the control group, the model group showed a reduction in bone marrow nucleated cells, a significant decrease in peripheral blood cells, and an altered CD8 + /CD4 + T cell ratio. These findings indicate the successful establishment of a mouse model of immune-mediated BMF. After FMN treatment, there were the increased levels of red blood cells and hemoglobin. In addition, FMN mitigated the bone marrow destruction and restored the CD8 + /CD4 + T cell ratio. Furthermore, in comparison with the control group, the model group showed the decreased levels of Treg cells and the increased levels of Th17 cells. After FMN treatment, there was a significantly increased number of Treg cells and a decreased number of Th17 cells. Additionally, FMN remarkably down-regulated the expression levels of PI3K and Akt proteins in immune-mediated BMF mice.ConclusionsFMN alleviates immune-mediated BMF by modulating the balance of Treg/Th17 cells through the PI3K/Akt signaling pathway.

Harnessing Immune Response in Acute Myeloid Leukemia.

Despite the results achieved with the evolution of conventional chemotherapy and the inclusion of targeted therapies in the treatment of acute myeloid leukemia (AML), survival is still not satisfying, in particular in the setting of relapsed/refractory (R/R) disease or elderly/unfit patients. Among the most innovative therapeutic options, cellular therapy has shown great results in different hematological malignancies such as acute lymphoblastic leukemia and lymphomas, with several products already approved for clinical use. However, despite the great interest in also expanding the application of these new treatments to R/R AML, no product has been approved yet for clinical application. Furthermore, cellular therapy could indeed represent a powerful tool and an appealing alternative to allogeneic hematopoietic stem cell transplantation for ineligible patients. In this review, we aim to provide an overview of the most recent clinical research exploring the effectiveness of cellular therapy in AML, moving from consolidated approaches such as post- transplant donor's lymphocytes infusion, to modern adoptive immunotherapies such as alloreactive NK cell infusions, engineered T and NK cells (CAR-T, CAR-NK) and novel platforms of T and NK cells engaging (i.e., BiTEs, DARTs and ANKETTM).

The role of blinatumomab in the treatment of B-cell relapses of acute lymphoblastic leukemia in children: own experience

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. Despite remarkable improvements in the treatment of pediatric acute lymphoblastic leukemia over last years, relapse still carries a poor prognosis with considerable morbidity and mortality. New immunotherapeutic approaches will change the way we treated our patients and the results we had. Blinatumomab is a bispecific T-cell-engaging antibody indicated for the treatment of relapsed/refractory B-cell lymphoblastic leukemia. The use of Blinatumomab in relapsed B-cell ALL has shown promising effects, especially as a bridging tool to hematopoietic stem cell transplantation. The therapy results for patients in the high risk group remain far from optimal due to refractoriness to chemotherapy, death from infectious complications, as well as acute chemotherapy toxicity. This article demonstrates the results of our experience of using Blinatumomab in children with the high-risk group relapsed B-cell ALL treated according to the ALL-REZ 2016 protocol. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The efficacy and toxicity of innovational blocks with the use of fludarabine and clofarabine with subsequent Blinatumomab infusion are shown. And we present the efficacy of autologous CD3+ lymphocytes infusion once a week during the continuous blinatumomab therapy. Also we demonstrate the results of using Blinatumomab for the treatment of patients with refractory to the first line therapy relapsed B-lymphoblastic leukemia and patients with a second relapse of B-cell ALL. The first line therapy in these patients was carried out according to the ALL-REZ 2014 protocol. Our results show an improved reduction in minimal residual disease in patients with refractory relapsed B-cell ALL as well as an increased event free survival in children with the high-risk group relapsed B-cell ALL.

Myeloid-Derived Suppressor Cells in Immune-Related Bone Marrow Failure: Novel Therapeutic Implication

Immune-related bone marrow failure (IBMF) is characterized by pancytopenia and bone marrow (BM) hypoplasia. Abnormally activated CD8+ T cells are important in its pathogenesis and majority of the patients having this abnormity are diagnosed as aplastic anemia (AA). The exploration of intra-BM immune network will help to conduct novel treatments to this disease.BM mesenchymal stromal cells (MSCs), regulatory T cells (Tregs), natural killer (NK) cells, myeloid-derived suppressor cells (MDSCs) are all immune-regulators within BM microenvironment. Among them, lymphocytes including CD8+ T cells, Tregs, NKs were indicated relating to IBMF pathogenesis with either stimulating or suppressive function. However, the relationship within BM between activated CD8+ T cells and other immune-regulating component remains largely unknown. In this study, we investigated MDSCs' characterization in IBMF models and AA patients to look into the intra-BM immune response during IBMF occurrence and progression.IBMF mice models were produced by lymphocyte infusion as previously described (Chen J, et al. Blood. 2004). To determine the major T cell population responsible for attacking BM environment, we injected H2 b/b -CD3+CD4+ T cells or H2 b/b -CD3+CD8+ T cells in sublethally irradiated hybrid F1 recipients of H2 b/b and H2 d/d mice. The recipients infused with CD3+CD8+ T cells were manifested BMF as pancytopenia, promoted BM-MSC adipogenesis and shorter life span. To further clarify why BM is the major targeted organ of CD8+ T cell in IBMF models, we detected homing receptors and proliferative potential of CD8+ T cells in BM, spleen and lymph nodes. CXCR4, CXCR6, CD49d, TRAIL as well as CD25, EDU were increasingly expressed on intra-BM CD8+ T cells, suggesting that CD8+ T cells reside more sufficiently in BM than in other lymph organs.MDSCs, subgrouped as mMDSCs and gMDSCs by a panel of surface markers, are a heterogeneous population of immature myeloid cells with immunoregulatory function (Gabrilovich DI, et al. Nat Rev Immunol. 2009). The numbers of either circulating MDSCs (CD11b+CD33+HLA-DR-/low) in AA patients or intra-BM MDSCs (CD11b+Gr1+) in IBMF models were decreased compared to normal controls (p=0.0016 and 0.03, respectively), indicating that MDSCs are impacted in the presence of over-activated CD8+ T cells. In vitro co-cultivation of MDSC subpopulation with T cells showed that it was not gMDSCs (CD11b+Ly6G+Ly6Clow, p=0.112) but mMDSCs (CD11b+Ly6G-/lowLy6Chi, p=0.017) capable of reducing anti-CD3/CD28-stimulated T cell proliferation. A nitric oxide synthase (NOS) inhibitor, L-NG-Nitroarginine Methyl Ester (L-NAME), significantly reversed mMDSC-induced T cell hypoproliferation (38.7%±17.5% vs 72.3%±3.5%, p=0.031), suggesting that inducible NOS pathway is an important modulator in the interaction of mMDSC and activated CD8+ T cells.To further investigate whether mMDSCs exert immune regulating function in vivo, freshly sorted H2 b/b -mMDSCs were transfused in sublethally irradiated H2 b/d with CD3+ T cells or lately in IBMF models every three days. The earlier mMDSCs transfusion was able to reduce the severity of pancytopenia and intra-BM infiltration of CD8+ T cells. The overall survival (OS) of repeatedly transfusion group was significantly longer than that of non-mMDSCs transfusion controls (26 days vs 17days, p=0.025).Taking these together, mMDSCs serve as an important regulator with other immune suppressive parts on one side of the teeter-totter, the other side of which the overactivated CD8+ T cells are the major counterpart attacking hematopoietic components in IBMF. In BM microenvironment, immune balance together with orderly multi-differentiation of MSCs and hematopoietic stem cells are all essential to orchestrate normal hematopoiesis. DisclosuresNo relevant conflicts of interest to declare.

The safety and effctiveness of donor memory T lymphocyte infusions after hematopoietic stem cell transplantation with ab T cell depletion platform in children with acute leukemia

T-cell ab depletion prevents “graft-versus-host” disease (GVHD), does not impair engraftment, and improves the outcomes of hematopoietic stem cell transplantation (HSCT) from a haploidentical donor. Memory T lymphocyte infusions (CD45RA-depleted) can transfer functional immunity to common pathogens to recipients. In a randomized study, we explored the safety and effctiveness of donor memory T lymphocyte infusions (DLI) in children with leukemia after HSCT with ab T cell depletion platform. The study was approved by the Independent Ethics Committee and the Scientifi Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of the Ministry of Healthcare of the Russian Federation. A total of 149 patients were enrolled in the study; 76 patients were randomly assigned to the DLI group and 73 patients were allocated to the control group. Donors were haploidentical related in 91% of cases. The myeloablative conditioning regimen included treosulfan and total body irradiation. Anti-thymocyte globulin (ATG) was excluded from the conditioning regimen, instead, we used a combination of abatacept and tocilizumab. Graft processing involved TCRab-/CD19-depletion. The main parameters of assessment included the cumulative risk of detection of cytomegalovirus (CMV) DNA and the cumulative risk of grade II–IV GVHD. The additional parameters of assessment were the cumulative risk of transplant-related mortality, the cumulative risk of relapse, the overall and event-free survival rates, and the parameters of immune recovery. A historical control group was used to compare the primary outcomes of HSCT with ATG and an alternative immunomodulatory regimen (abatacept and tocilizumab). The cumulative risk of grade II–IV GVHD was 14% in the experimental group and 12% in the control group (p = 0.8). The cumulative risk of CMV viremia was 45% and 55% in the experimental and control groups, respectively (p = 0.4). In the prospective cohort, the rates of transplant-related mortality, the cumulative risk of relapse, and the overall survival were 2%, 25%, and 80%, respectively, without statistical diffrence between the arms. In the experimental group, we noticed a tendency toward an increase in the proportion of patients who developed an immune response to CMV in the early post-HSCT period. The substitution of ATG with tocilizumab and abatacept was not accompanied by a higher incidence of GVHD or graft failure; it was associated with signifiantly lower transplant-related mortality rates (2% vs 13%, p = 0.002) and improved immune recovery in the early post-HSCT period. Prophylactic infusions of donor memory lymphocytes are safe and may be used for further improvement in. the results of HSCT with ab T cell depletion platform.

Defining the Role of Donor Lymphocyte Infusion in High-Risk Hematologic Malignancies.

The infusion of lymphocytes from the original donor (DLI) to a recipient of an allogeneic stem cell transplantation (SCT) has been the case of cellular immunotherapy. Following its introduction in the late 1980's, unmodified donor cells have been used within the treatment of post-transplant relapse in various hematological malignancies. Later on, preemptive and prophylactic strategies were introduced. Over time, clinical experience identified both the therapeutic potential and the limits of this strategy, prompting numbers of different approaches to improve efficacy and safety of unmodified DLI. Among these were activation of cell subsets by cytokines or growth factors, selection and expansion of specific T-cell subsets, and infusion of NK-cells. Later on, genetical T-cells engineering, including suicide gene technology, T-cell receptor gene transfer and most recently the CAR T-cells, entered the field to increase the allogeneic Graft-versus-Malignancy effect while reducing the risk of complications such as Graft-versus-Host disease. Similarly, synergistic effects of DLI with pharmacological approaches were discovered, leading to combined strategies. Nevertheless, standardization of the "drug" DLI and its clinical use is still challenging, and many sophisticated modifications of DLI still have to prove their suitability for a broader use. Further, increasing knowledge on escape mechanism from an allogeneic immune reaction need to be considered for the clinical application of DLI. Hence, further research requires intelligent strategies and international cooperation to fully exploit the potential of adoptive cellular immunotherapy in the context of allogeneic SCT.

Maintenance therapy following CD19 CAR-T treatment for relapsed B-cell acute lymphoblastic leukemia after allogeneic hematopoietic stem cell transplantation

目的探讨异基因造血干细胞移植后复发急性B淋巴细胞白血病（B-ALL）CD19 CAR-T细胞治疗缓解后的维持治疗，观察单独输注供者造血干细胞和供者T淋巴细胞对CD19 CAR-T细胞扩增的影响。方法1例难治B-ALL患者，CD19 CAR-T（鼠源，克隆号：FMC63）细胞治疗后桥接同胞全相合异基因造血干细胞移植，后再次复发。接受CD19 CAR-T（可变区人源化的FMC63）细胞治疗再次缓解，缓解后先后接受单独输注供者造血干细胞、供者T淋巴细胞的维持治疗，期间监测患者细胞因子水平、CD19 CAR-T细胞比例、CD19 CAR的DNA表达变化，观察骨髓白血病细胞比例及供者嵌合情况。另外，通过制备小鼠CD19 CAR-T（FMC63）细胞，并将CAR-T细胞注射至同窝小鼠体内，14 d后，再次注射同窝小鼠的B淋巴细胞，在此过程中观察CAR-T细胞、B淋巴细胞比例以及CD19 CAR的DNA表达，以此来模拟临床治疗过程。结果①患者输注人源化CD19 CAR-T细胞后第14天，疗效评估达完全缓解（CR），供者嵌合率为99.76%，细胞因子释放综合征1级。②人源化CD19 CAR-T细胞治疗缓解后，单独输注供者造血干细胞维持治疗，输注后第24天出现移植物抗宿主病（GVHD），患者GVHD期间伴有外周血CD19 CAR-T细胞比例及CD19 CAR DNA水平的升高，并随GVHD缓解下降。过程中患者维持CR且供者嵌合率为99.69%。③随后单独输注供者T淋巴细胞维持治疗，回输后第12天患者出现GVHD，而患者外周血CD19 CAR-T细胞比例及CD19 CAR的DNA水平并未出现再次升高。过程中患者维持CR且供者嵌合率为99.87%。④C57小鼠体内试验证实，CAR-T细胞输注后小鼠体内CAR-T细胞扩增及DNA表达上调，同时CD19+ B淋巴细胞耗竭。之后输注CD19+ B淋巴细胞，CD19 CAR-T细胞扩增和CD19 CAR的DNA表达再度上调。结论供者造血干细胞、供者T淋巴细胞的单独输注，可作为异基因造血干细胞移植后复发B-ALL接受CD19 CAR-T治疗缓解后的维持治疗手段，且输注供者造血干细胞诱发GVHD同时出现CD19 CAR-T细胞和CD19 CAR的DNA表达上调，有可能进一步清除残留灶。

Effects of Shikonin on the Functions of Myeloid Dendritic Cells in a Mouse Model of Severe Aplastic Anemia.

This study is aimed at investigating the effects of shikonin, a pyruvate kinase M2 (PKM2) inhibitor, on the functions of myeloid dendritic cells (mDCs) in a mouse model of severe aplastic anemia (AA) generated by total body irradiation and lymphocyte infusion. Flow cytometry and qPCR were used to determine the proportions of PKM2+ mDCs and other immune indicators in the AA mice. Glucose consumption level, pyruvate generation level, and ATP content were used to determine the level of glycolytic metabolism in the mDCs. The survival rates of AA mice were evaluated after the administration of shikonin or the immunosuppressive agent cyclosporin A. The AA mice displayed pancytopenia, decreased CD4+/CD8+ cell ratio, increased perforin and granzyme levels in CD8+ cells, increased costimulatory CD80 and CD86 expressions, and inadequate regulatory T cell number. In vivo animal experiments showed that the shikonin-mediated inhibition of the PKM2 expression in mice was associated with high survival rates. In addition, the administration of cyclosporin A or shikonin decreased the expression of cytotoxic molecules and costimulatory CD80 and CD86 on CD8+ cells. Taken together, the results of this study indicated that shikonin could inhibit the activation and proliferation of mDCs as well as the activation of downstream cytotoxic T cells by reducing the PKM2 level in mDCs.

Exploiting an Anti-CD3/CD33 Bispecific Antibody to Redirect Donor T Cells Against HLA Loss Leukemia Relapses

Background Genomic loss of mismatched HLAs ("HLA loss") represents a frequent modality by which acute myeloid leukemia (AML) evades immune recognition from donor T cells after partially HLA-incompatible allogeneic hematopoietic cell transplantation (allo-HCT). One important consequence of this post-transplantation relapse mechanism is that infusions of lymphocytes from the original donor become ineffectual, prompting the search for alternative therapeutic options. Here, to circumvent the loss of physiological T cell receptor-HLA interactions in these patients, we tested the ability of an anti-CD3/CD33 bispecific antibody (BsAb) to re-target donor T cells towards HLA loss relapses. Methods For short-term in vitro experiments, T cells were co-cultured with the MOLM-13 AML cell line or with primary patient blasts for 96 hours in presence or absence of an anti-CD3/CD33 BsAb. As readouts, we measured T cell activation (as surface expression of CD25 and CD69) and the absolute counts and relative proportion of effectors and targets. For long-term in vitro experiments, we established mixed lymphocyte cultures (MLCs) of T cells purified from two patients after haploidentical HCT and primary AML blasts obtained from the same patients at the time of diagnosis. After sequential stimulations, the co-cultures were tested against targets of interest, with or without addition of the BsAb. Functional readouts were T cell degranulation (measured as CD107a expression), antigen-specific activation (as CD137/41-BB expression) and target-specific cytotoxicity (measured by time-lapse live cell imaging over a 48 hour time span). For in vivo experiments, human leukemic cells were infused intravenously into non-irradiated NSG mice, followed by intraperitoneal infusion of T cells and daily administration of the BiTE compound. Results First, we retrospectively analyzed immunophenotypic data of 36 AML patients who experienced HLA loss relapses at our Institution, documenting robust expression of CD33 on the surface of the relapsed leukemia in 35 of them (97%; Figure 1A). By short-term co-culture experiments we titrated the BsAb concentration to be used for subsequent in vitro assays to 100 ng/ml, and the most informative effector:target ratio to 1:3. Then, we established MLCs by stimulating T cells collected from two patients after partially HLA-incompatible allo-HCT with AML blasts collected from the same patients at the time of diagnosis. In both cases, donor-derived T cells robustly responded against the patient blasts both in term of degranulation (Figure 1B) and of antigen-specific activation (Figure 1C). As expected, when we tested the same T cells against the patient leukemia at time of HLA loss relapse, we detected no T cell-mediated responses. Noticeably, when the BsAb was added, in both cases we detected a strong response not only against the diagnosis but also against the HLA loss variants, indicating that T cells were effectively re-targeted towards leukemic cells. Similar results were obtained also by live cell imaging, measuring target cell apoptosis over 48 hours of recording: also in this assay, in fact, donor T cells recognized and killed leukemia at diagnosis (45% of detection area positive for apoptosis dye) and failed to recognize its HLA loss relapse counterpart (32% of area positive for apoptosis dye). Addition of the BsAb to the co-cultures had a minor effect on recognition of the original disease (45% of area positive for apoptosis dye) but drove dramatic cell death of HLA loss blasts (80% of area positive for apoptosis dye), demonstrating that the BsAb induced not only T cell activation but also and most importantly target cell killing (Figure 1D). Finally, we modeled the BsAb activity in vivo, showing that, whereas the sole infusion of human T cells is not able to prevent the outgrowth of leukemia in the bone marrow of NSG mice, addition of the bispecific antibody leads to effective disease clearance (Figure 1E). Conclusions Our results demonstrate that anti-CD3/CD33 BsAbs can effectively redirect donor T cells against HLA loss leukemia variants, resulting in their rapid and effective killing. Taken together, these promising findings strongly support translation of this approach to ad hoc designed early-phase clinical trials, to provide a rational therapy for this increasingly recognized but still treatment-orphan modality of post-transplantation relapse. Figure 1 Disclosures Subklewe: Janssen: Consultancy; Miltenyi: Research Funding; Pfizer: Consultancy, Honoraria; Oxford Biotherapeutics: Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Morphosys: Research Funding; Roche: Consultancy, Research Funding; AMGEN: Consultancy, Honoraria, Research Funding. Vago:Moderna Therapeutics: Research Funding; GenDx: Research Funding.

The Effect of Pyruvate Kinase M2: Inhibitor(shikonin) on the Function of Mdc in Severe Aplastic Anemia Mouse Model

Severe aplastic anemia (SAA) is a rare disease characterized by severe pancytopenia and bone marrow failure. Over-activated myeloid dendritic cells (mDCs) play an important role in the pathogenesis of SAA. In recent years, the role of pyruvate kinase M2 (PKM2) in DC function and autoimmune response has been gradually recognized. In this study, an immune attack-mediated AA mouse model was constructed by total body irradiation and lymphocyte infusion. The AA model mice showed pancytopenia, decreased ratio of CD4+/CD8+ cells, increased expression of cytotoxic molecules perforin and granzyme in CD8+ cells, increased levels of co-stimulatory molecules CD80 and CD86 in DCs and inadequate Treg number. In-vitro animal experiments confirmed the activation of PKM2 in mDCs, which promoted glycolytic metabolism. High levels of PKM2 in mice contributed to the poor survival rate. Additionally, intervention treatment with shikonin or cyclosporin A in the AA mouse model reduced the expression not only of co-stimulatory molecules CD80 and CD86 in mDCs but also of cytotoxic molecules in CD8+ cells. In conclusion, we confirmed the activation of PKM2 in mDCs in AA mouse models. PKM2 is involved in mDC activation and proliferation, which might contribute to activating the downstream cytotoxic T cells (CTLs). PKM2 is a possible novel target in SAA treatment. Disclosures No relevant conflicts of interest to declare.

Abstract 3204: Pre-immunization of donor lymphocytes with GITR agonistic antibody enhances antitumor immunity in autologous hematopoietic stem cell transplantation

Abstract Lymphopenia-induced homeostatic proliferation (HP) of T cells following autologous hematopoietic stem cell transplantation (HSCT) skews the T-cell repertoire by engaging tumor-associated antigens, and induces an antitumor immunity. However, the cure by autologous HSCT alone is difficult in case of solid cancers. Glucocorticoid-induced tumor necrosis factor receptor (GITR) is well-known immune-checkpoint molecules. GITR-GITR ligand interaction can provide a co-stimulatory signal to both CD4+ and CD8+ naïve T cells, enhancing proliferation and effector function. Since the tumor-reactive lymphocytes preferentially proliferate during the condition of HP, due to the synergic effect with encountering their cognate antigens in tumor-bearing host, we hypothesize that administration of GITR agonistic antibody (Ab) could increase tumor-responsive T cells in the graft and induce a strong antitumor immunity in HSCT recipients. First, we confirmed that the intraperitoneal administration of GITR Ab into CT26 subcutaneous tumor model mice significantly increased the number of IFN-γ+ lymphocytes in response to CT26 cells in the spleens and regional lymph nodes. Second, to examine the antitumor effect of HSCT, the bone marrow cells and lymphocytes were harvested from CT26 tumor-bearing mice as donor cells, and infused into the lethally-irradiated recipient mice with CT26 inoculation (autologous HSCT model). In the HSCT recipients infused with primed lymphocytes by GITR Ab, the CT26 tumor growth was markedly suppressed compared with the recipients infused with non-primed lymphocytes, and tumors disappeared in all recipient mice infused with primed lymphocytes. An ELISpot assay showed that the number of IFN-γ+ spots in response to CT26 cells was significantly increased in HSCT recipient mice infused with GITR Ab-primed and non-primed donor lymphocytes as compared to wild type mice until 4 weeks after HSCT; while the frequency in recipients with primed lymphocytes was markedly elevated compared with that in mice with non-primed lymphocytes at 2 weeks after HSCT. At present, autologous HSCT is clinically practiced after intensive chemotherapy in patients with lymphomas and solid cancers such as neuroblastoma and sarcoma, the infusion of hematopoietic stem cells and pre-immunized lymphocytes after high dose chemotherapy is an attractive and feasible clinical introduction of HSCT-mediated immunotherapy. Although the subcutaneous tumors of NHOS murine osteosarcoma cells were resistant for HSCT, the infusion of GITR Ab-primed lymphocytes significantly induced stronger antitumor effect than the non-primed lymphocytes did. In conclusion, the combination of HSCT with pre-immunization by GITR Ab can induce a strong antitumor immunity. This therapeutic strategy deserves an evaluation in future clinical trial for solid cancers. Citation Format: Kenta Narumi, Marina Henmi, Chihiro Shibasaki, Aya Hirata, Yukihiro Mizoguchi, Kazunori Aoki. Pre-immunization of donor lymphocytes with GITR agonistic antibody enhances antitumor immunity in autologous hematopoietic stem cell transplantation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3204.

Preemptive Infusion of Donor Lymphocytes Depleted of TCR + T Cells + CD19+ B Cells Following ASCT

Preemptive Infusion of Donor Lymphocytes Depleted of TCR + T Cells + CD19+ B Cells Following ASCT

Treatment Patterns for Patients with Post-Transplant Lymphoproliferative Disorder Who Fail Rituximab after Allogeneic Hematopoietic Stem Cell Transplantation: Findings from a Systematic Literature Review

Introduction: Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized disease after allogeneic hematopoietic stem cell transplantation (HCT) and is one of the most common post-transplant malignancies. In most cases, PTLD is associated with Epstein-Barr Virus (EBV) infection. The management of PTLD remains a challenge, with no approved treatments for patients. Clinical practice treatment guidelines recommend rituximab as first-line therapy for PTLD post-allogeneic HCT; however, treatment options for PTLD patients who fail rituximab are not clearly defined. We conducted a systematic literature review of the published literature to better understand treatment patterns for patients with PTLD who fail rituximab post-allogeneic HCT in a real-world setting.Methods: The systematic literature review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with the scope defined in terms of Population, Intervention Comparators, Outcomes, and Study design (PICOS) criteria. Using extensive search terms for the indication and study designs, studies were identified using key biomedical literature databases: EMBASE, MEDLINE, and Cochrane. The literature search was conducted on July 19, 2018 and included studies published between database inception in January 1, 1959 and July 19, 2018. Relevant congress abstracts published between January 2015 and June 2018 were also identified. The PICOS-based inclusion and exclusion criteria were used to review identified citations. No treatment limitations were imposed to ensure inclusion of all relevant evidence; the study designs were limited to prospective and retrospective observational studies. Case reports were included regardless of sample size. Two independent reviewers screened all citations and full-text articles; any discrepancies were resolved by a third independent reviewer. Data from included studies were extracted into a pre-defined template, and results were summarized using the PRISMA flow diagram.Results: A total of 69 studies were identified that described patients with PTLD post-allogeneic HCT. The majority (61 studies) were retrospective chart reviews, of which 54 studies were single-center studies. Forty-eight studies reported data on treatment of patients with PTLD. Among these, 5 studies included data prior to 2000, 33 studies included data from 2000-2010, and 26 studies included data from 2010-2016. The sample size for PTLD patients was between 1 and 144 patients, with only one study of > 100 patients. First-line therapy in PTLD included rituximab (41 studies), various chemotherapy regimens (15 studies), and lymphocyte infusion (10 studies). Nine studies reported treatment for patients who failed first-line rituximab (13-67% of PTLD patients); the number of patients with second-line treatments ranged from 2-10 across studies. Second-line treatments varied greatly across studies and included cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP, n=1); rituximab plus CHOP (R-CHOP, n=1-2); cyclophosphamide, etoposide/cytarabine (VP16/ARA-C, n=1); rituximab plus cyclophosphamide (n=1); rituximab plus high-dose cytarabine (n=1); chemotherapy unspecified (n=2-4), and lymphocyte infusion (n=3-5). Only 2 studies reported treatment outcomes in rituximab-refractory patients. One study (N=62, second-line n=10, median age 49 years) reported no complete or partial remission in the chemotherapy group; 60% had complete remission in the lymphocyte infusion group. The second study (N=12, second-line n=3, mean age 5 years) reported complete remission in 1 patient with lymphocyte infusion as second-line treatment.Conclusions: This systematic literature review demonstrates that data on treatment patterns for PTLD patients who failed rituximab post-allogeneic HCT are limited (9 studies with a sample size ≤ 10). Published data suggest that the percentage of patients who fail rituximab vary greatly (13-67%), there is no consistent standard of care for PTLD patients who fail rituximab, and outcomes are poor. There continues to be a significant unmet need among PTLD patients who fail rituximab, and further studies are needed to better understand rituximab response rates in the real-world setting. DisclosuresXu:Atara Biotherapeutics, Inc: Employment, Equity Ownership. Watson:Atara Biotherapeutics, Inc: Employment, Equity Ownership. Forsythe:Novartis: Consultancy. Barlev:Atara Biotherapeutics, Inc: Employment, Equity Ownership.

Abstract 2626: Combination of chemotherapy and cytokine facilitates adoptive transferred effector T cells homing to the core of metastatic tumors

Abstract Metastatic disease accounts for most cases of cancer mortality, due to its systemic nature and resistance to existing therapeutics for primary tumors. Immune therapy has become a viable alternative for treating drug-resistant tumors. In fact, increased immune density in metastasis lesions is associated with beneficial clinical outcomes. Notably, tumor infiltrating lymphocyte (TIL) infusions extended the overall survival of refractory melanoma patients. However, whether or not T cell therapy could be used to successfully limit the metastatic progression largely depends on the complexity of T cell penetration and tumor-immune cell interaction in distant sites. During the past years, our group has identified a simple combination of an immune stimulatory signal (interleukin-12) and chemotherapy (doxorubicin) that persistently induces NKG2D ligand on tumor cells in vivo across tumor types and developed a novel CD28 stimulation based approach for fast induction of NKG2D receptor on CD8+ T cells. We found in breast carcinoma model (4T-1) and pediatric osteosarcoma models (K7M3 and LM8), adoptive transfer of NKG2D+CD8+ T cells after the combination of IL-12 plus doxorubicin treatment dramatically reduced the numbers and sizes of metastatic nodules, leading to significantly prolonged survival time. Mechanically, the treatment of IL-12 plus doxorubicin widely upregulated the expression of NKG2D ligands exclusively on tumor cells in metastatic lesions, and allowed high density of NKG2D+CD8+ T cell accumulation at both the core and invasive margin areas of metastatic tumors. Furthermore, this combination therapeutic led to reduced regulatory T cell infiltration, resulting in increased CD8+ T cell to regulatory T cell ratios in metastatic tumors. Collectively, here we reported that a simple combination treatment of IL-12 plus doxorubicin with subsequent NKG2D+ CD8+T cell adoptive transfer may transform the metastatic tumor microenvironment to enable the influx of NKG2D+CD8+ T cells which effectively kill tumor cells via NKG2D-NKG2D ligand interaction. This promising therapeutic approach greatly improved the effectiveness and potential of adoptive T cell therapy in treating cancer patients with metastatic diseases. Citation Format: Jiemiao Hu, Qingnan Zhao, Xueqing Xia, Richard Gorlick, Shulin Li. Combination of chemotherapy and cytokine facilitates adoptive transferred effector T cells homing to the core of metastatic tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2626.

Immunotherapy for EBV-Associated Nasopharyngeal Carcinoma

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies in southern China and Southeast Asia. Unfortunately, 70% of NPC patients have locally advanced disease at the first diagnosis. Radiotherapy alone and concurrent chemoradiotherapy are important treatment approaches for NPC, but they have a limited effect on patients with locally advanced or distantly metastatic disease. 1-5 Nevertheless, the unique immune environment of the EBV-associated NPC provides rational targets for immunotherapy. Diverse types of immunotherapies are actively being studied, including adoptive immunotherapy, therapeutic vaccines, immune checkpoint inhibitors, lytic-induction therapy, and viral immunotherapy. Specifically, adoptive immunotherapy with lymphocyte infusion was well tolerated and effective in 71.4% of patients combined with first-line chemotherapy. Several therapeutic vaccines and PD-1/PD-L1 pathway checkpoint inhibitors have shown promising clinic outcomes at phase I/II clinical trials. Moreover, EBV-lytic inducing therapy and viral immunotherapy for NPC are also being investigated. In this review, we summarized the current status, advantages, and disadvantages of each immunotherapy for EBV-associated NPC, which may shed light on developing safer and more effective treatment modalities in the future.

Применение инфузий T-клеток памяти с целью профилактики вирусных инфекций у пациентов с гемобластозами, перенесших аллогенную трансплантацию гемопоэтических стволовых клеток с деплецией α/β-Т-лимфоцитов

Viral infections are frequent complications in the recipients of the HSCT with TCRαβ and CD19-graft depletion. Adoptive transfer of memory T cells may improve immune response to common pathogens. The work reflects the retrospective safety analysis of using the infusions of CD45RA-depleted donor lymphocytes. Data from 80 patients were analyzed. Up to 3 doses of donor lymphocytes were administered at monthly intervals, escalating to 100 × 103/kg in haploidentical transplants and 300 × 103/kg in MUD transplants. Median follow-up for alive patients was 18 (8–44) months. We did not observe any allergic reactions, septic complications after infusion of donor lymphocytes (DLI). The cumulative incidence of a de novo acute GVHD after DLI was 5% (95% CI: 2–13). In 64% patients (n = 51) was detected CMV in the blood. There were no cases of resistant CMV disease on the background of drug therapy. In patients who received DLI, 70% (n = 56) had documented appearance of virus-specific lymphocytes in peripheral blood (Elispot assay). Thus, the introduction of memory T cells at a dose of 25–100 × 103/kg body weight of the recipient for CD3+ in the case of HSCT from a haploidentical donor and 100–300 × 103/kg for an unrelated HSCT. Infusions of low dose memory T-lymphocytes after transplant engraftment are safe, potentially effective and constitute a simple measure to prevent infections in the setting of alpha/beta T-cell-depleted transplantation.

Suspected chromosomally integrated human herpes virus 6 in hematopoietic stem cell transplantation

Background and aims: We report a case of a 27-year-old male affected by acute myeloid leukaemia <em>MLL-PTD</em> positive. After autologous stem cell transplantation, he was monitored based on cytomegalovirus, Epstein-Barr virus and human herpes virus 6 (HHV-6) DNA quantification in blood. Relapse occurred one year after transplantation; then the patient underwent to allogenic bone marrow transplantation using genotypically HLA-identical donor (sister). HHV-6 DNAemia was positive and persistently elevated, either after autologous either after allogenic transplant suggesting the occurrence of HHV-6 chromosomally integration. The work aim is to prove the occurrence of chromosomally integrated-HHV-6 (ci-HHV-6). <br />Materials and Methods: HHV-6 DNA extraction was performed by automated extractor and DNA was amplified-quantified by Real Time polymerase chain reaction. Species identification was performed by sequencing HHV6-U100 glycoprotein using automated sequencer and sequencing products were analysed using the Blast program. <br />Results: After autologous transplantation HHV6-DNAemia was 5.4 log copies/mL setting to 3.9 log copies/mL for a long period post allogenic transplantation. The patient’s hair follicles were tested for HHV- 6 DNA having positive results. Sequences of both strains of HHV6 extracts from blood and hair follicles resulted species B. HHV6 viral load decreased significantly after Lymphocyte Infusion by ci-HHV6 negative donor (sister), having steady viral load during the following six months of monitoring. One year later, patient is in complete haematological remission. <br />Conclusions: Detection of HHV-6 in hair follicles and HHV-6 DNAemia persistently elevated before allogenic transplant, confirm the occurrence of ci-HHV-6. The observed important decreasing viral load is potentially due to the successful engraftment of ci-HHV-6-negative donor marrow after allogeneic transplant.

Concurrent Use of Blinatumomab and Donor Lymphocyte Infusion (DLI) for Treatment of Relapsed Precursor B Cell Acute Lymphoblastic Leukemia (pre B ALL) after Allogeneic Hematopoietic Cell Transplant (HCT)

Adults with relapsed pre B ALL after allogeneic HCT historically have poor prognosis, but new therapies may improve outcomes. Blinatumomab is a bispecific engager anti-CD19/CD3 antibody that simultaneously binds cytotoxic T cells and CD19+ normal and malignant B cells. Each cycle consists of a 4-week continuous infusion. Blinatumomab engages endogenous T cells and is usually used as a bridge to HCT; however in the post-HCT setting donor T cells are engaged. DLI used for treatment of ALL relapse after transplant exerts modest effect, and we hypothesized that co-administration of blinatumomab and DLI may have synergistic anti-leukemic activity. We report 2 cases of relapsed Philadelphia chromosome (Ph) negative pre B ALL after HCT treated concurrently with blinatumomab and DLI. Case 1: A 35 year-old woman with pre B ALL received a matched related donor peripheral blood HCT in first remission using clofarabine and busulfan preparative regimen. Marrow relapse occurred 136 days after HCT with 24% donor chimerism. She received salvage chemotherapy with 2 DLI (5 x 107 CD3 cells/kg each) but had persistent disease (7% marrow blasts and 99% donor chimerism). Blinatumomab was subsequently started. After 2 cycles marrow showed complete hematologic remission, 98% donor chimerism and persistent cytogenetic abnormality. Third and fourth DLI were given on day 15 of the third and fourth cycles of blinatumomab. No adverse effects were noted during lymphocyte infusion. There was no exacerbation of the mild chronic skin GVHD present prior to the third cycle of blinatumomab. Extramedullary relapse in a CD19+ sacral mass was discovered 1 month after cycle 4 of blinatumomab, successfully treated with radiation. Patient currently has second extramedullary ALL relapse with a CD19- lung mass (16 months after HCT and 11 months after first relapse) with no ALL in the marrow and 100% donor chimerism. Case 2: A 71 year-old woman with Ph-negative pre B ALL received reduced intensity conditioning matched unrelated donor peripheral blood HCT in second remission using fludarabine, 2 Gy TBI and ATG as preparative regimen. She developed flow cytometry and cytogenetic relapse 106 days after HCT with 97% donor chimerism. Blinatumomab was started and DLI (1 x 107 CD3 cells/kg) was given on day 2 of cycle 3 of blinatumomab without adverse events. She developed grade 3 late onset acute skin and gut GVHD 15 days after completion of cycle 3 of blinatumomab which was successfully treated with corticosteroids. No further cycles of blinatumomab or DLI were given and she remains in complete remission for 6 months. Co-administration of DLI and blinatumomab appears to be safe with no acute adverse effects observed in 2 patients. Dual therapy resulted in anti-leukemia effect in both cases of pre B ALL relapsed after HCT. A larger series is needed for further investigation of the safety and efficacy of this approach.

Rapamycin Is Highly Effective in a Mouse Model of Immune-Mediated Bone Marrow Failure By Mechanisms Distinct from Cyclosporine

Acquired aplastic anemia (AA) is bone marrow (BM) failure characterized by pancytopenia and marrow hypocellularity, in most patients due to immune attack by T cells that target hematopoietic stem and progenitor cells. Most patients respond to immunosuppressive therapy, but relapse, especially on withdrawal of cyclosporine A (CsA), occurs frequently (Scheinberg P, Am J Hematol., 2014). Rapamycin has been successful in some human autoimmune diseases and in mouse models of autoimmunity; rapamycin also appears to induce tolerance, as for example in the organ transplant setting. We have developed murine models of BM failure; animals can be salvaged by biologics and drugs that are effective in humans with AA. One purpose of these models is to test potential new therapies. We have compared rapamycin with customary immunosuppression by CsA. Infusion of lymph node cells from C57BL6 (B6) donor mice into CByB6F1 (F1) recipient mice (MHC-mismatched) induced massive BM destruction by activated T cells. Treatment with rapamycin (2 mg/kg/day, starting 1 hour post lymphocyte injection and continued for 2 weeks, n=9) effectively ameliorated pancytopenia and improved BM cellularity, better than did maximal dosing with CsA (50 mg/kg/day, starting 1 hour post lymphocyte injection, continued for 5 days, n=8) (Fig 1A). Rapamycin eliminated most BM-infiltrating CD8+ T cells, while CsA had less effect on CD8+ T cells than did rapamycin. Elimination of BM infiltrated T cells and restoration of megakaryocytes by rapamycin was visualized by confocal microscopy using whole-mounts of sternum, for which donor B6 lymph node cells were replaced with B6-DsRed lymph node cells. Plasma cytokines were measured by Luminex: IFNg, TNFa, IL-2, MIP1b, RANTES, sCD137 (all p < 0.001) were increased in BM failure mice compared with the control animals, indicating an inflammatory environment in AA. Rapamycin reduced these cytokines (p < 0.001) but increased Th2 cytokines such as IL-4 and IL-10 (p < 0.001) levels. CsA only decreased sCD137, reversely it even increased IFNg levels. Transcriptome analysis using pooled FACS-sorted CD4+ and CD8+ T cells from BM focusing on genes related to T cell functions revealed that rapamycin suppressed expression of Icam1, and Tnfsf14 in CD8+ T cells, and Cd27, Lgals3, Il10ra, Itga1, Tbx21, Gzmb, Tnfsf14 and Cd70 in CD4+ T cells, but increased Il-4, Il-2ra, and Tnfrsf8 expression in CD4+ T cells compared with AA mice. CsA suppressed Lgals3 in CD8+ T cells and Cd70 in CD4+ T cells, suggesting differential mechanisms of action by these two immunosuppressive drugs. All untreated AA mice (n=6) died within 3 weeks post lymphocyte infusion, while all mice treated with rapamycin for 2 weeks (n=8) survived until study termination at 7 weeks; similar results were obtained when we tested delayed treatment with rapamycin (starting 3 days post lymphocyte injection and continued for 10 days, n=8) in BM failure mice; but brief exposure to rapamycin, for only 5 days from 1 hour post lymphocyte infusion (n=8), could not rescue mice, suggesting a requirement for sustained administration. In contrast, all animals treated with CsA (n=6) died within 5 weeks (Fig 1B). We also tested the effect of rapamycin on antigen-specific T cells in another BM failure model induced by infusion of lymphocytes from B6 donor mice into C.B10-H2b /LilMcd recipient mice (MHC-matched but minor antigen-mismatched, n=10), in which BM destruction is mediated by H60-specific cytotoxic T cells (CTL) (Chen J, JI, 2007). Similar results were observed. Flow cytometry revealed massive expansion of H60-specific CTL in BM of untreated AA mice, rapamycin eliminated BM CD8+ T cell infiltration. CsA decreased BM CD8+ T cells, but had much weaker effect on H60 CTLs (Fig 1C). In summary, rapamycin is effective in treatment of AA murine models, which holds implications in the application in immune-mediated pathophysiologies in the laboratory and in the clinic. Compared with CsA, rapamycin suppressed expression of T cell activation genes more broadly, increased Th2 cytokines, eliminated antigen-specific T cells, and had better survival rate in animal BM failure model, supporting a clinical trial of rapamycin to prevent relapse and induce tolerance in patients with AA, many of whom are dependent on CsA administration for support of blood counts but at risk of CsA nephrotoxicity. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Allogeneic T-Cells Expressing an Anti-CD19 Chimeric Antigen Receptor Cause Remissions of B-Cell Malignancies after Allogeneic Hematopoietic Stem Cell Transplantation without Causing Graft-Versus-Host Disease

Introduction Progressive malignancy is the leading cause of death after allogeneic hematopoietic stem cell transplantation (alloHSCT). After alloHSCT, B-cell malignancies are often treated with infusions of unmanipulated donor lymphocytes (DLIs) from the transplant donor. DLIs are frequently not effective at eradicating malignancy, and DLIs often cause graft-versus-host disease (GVHD), which is a potentially lethal allogeneic immune response against normal recipient tissues. Methods We conducted a clinical trial of allogeneic T cells that were genetically engineered to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. The CAR was encoded by a gamma-retroviral vector and included a CD28 costimulatory domain. Patients with B-cell malignancies after alloHSCT received a single infusion of CAR T cells. No chemotherapy or other therapies were administered. The T cells were obtained from each recipient's alloHSCT donor. Findings Eight of 20 treated patients obtained remissions, including 6 complete remissions (CR) and 2 partial remissions. The response rate was highest for acute lymphoblastic leukemia with 4/5 patients obtaining minimal-residual-disease-negative CRs, but responses also occurred in chronic lymphocytic leukemia (CLL) and lymphoma. The longest ongoing CR is 30+ months in a patient with CLL. No patient developed new-onset acute GVHD after CAR T-cells were infused. Toxicities included fever, tachycardia, and hypotension. Median peak blood CAR T-cell levels were higher in patients who obtained remissions (39 CAR+ cells/mL) than in patients who did not obtain remissions (2 CAR+ cells/mL, P=0.001). Presence of endogenous normal or malignant blood B lymphocytes before CAR T-cell infusion was associated with higher post-infusion median blood CAR T-cell levels (P=0.04). Compared to patients who did not obtain a remission of their malignancies, patients obtaining remissions had a higher CD8:CD4 ratio of blood CAR+ T cells at the time of peak CAR T-cell levels (P=0.007). The mean percentage of CAR+CD8+ T cells expressing the programmed cell death-1 (PD-1) protein increased from 12% at the time of infusion to 82% at the time of peak blood CAR T-cell levels (P&lt;0.0001). The mean percentage of CAR+CD4+ T cells expressing PD-1 increased from 32% at the time of infusion to 91% at the time of peak blood CAR T-cell levels (P&lt;0.0001). Interpretation Infusion of allogeneic anti-CD19 CAR T cells is a promising approach for treating B-cell malignancies after alloHSCT. Our findings point toward a future in which antigen-specific T-cell therapies will be an important part of the field of allogeneic hematopoietic stem cell transplantation. Table. PatientNumber Malignancy Transplant type Total T cellsinfused/kg Anti-CD19CAR-expressingT cells infused/kg Malignancyresponseat last follow-up(interval from infusion to last follow-up in months) 1 CLL URD 10/10 HLA match 1x106 0.4x106 SD (3) 2 DLBCL Sibling 2x106 0.7x106 SD (1) 3 CLL Sibling 4x106 2.4x106 PD 4 DLBCL Sibling 4x106 2.2x106 SD (31+) 5 CLL URD 10/10 HLA match 1.5x106 1.0x106 CR (30+) 6 MCL Sibling 7x106 4.6x106 SD (3) 7 CLL URD 10/10 HLA match 1x106 0.7x106 PD 8 MCL Sibling 7x106 3.9x106 SD (24+) 9 MCL URD 10/10 HLA match 4x106 2.2x106 PR (3) 10 MCL Sibling 10x106 7.8x106 SD (2) 11 CLL URD 9/10 HLA match 5x106 3.1x106 PR (12+) 12 ALL Ph+ Sibling 7x106 5.2x106 MRD-negative CR (15+) 13 MCL Sibling 10x106 7.1x106 SD (9) 14 ALL Ph-neg Sibling 10x106 7.0x106 MRD-negative CR (5) 15 ALL Ph-neg Sibling 10x106 6.9x106 MRD-negative CR (3) 16 ALL Ph-neg Sibling 7x106 5.6x106 PD 17 DLBCL Sibling 10x106 8.2x106 CR (6+) 18 DLBCL Sibling 10x106 3.1x106 SD (2) 19 FL transformed to DLBCL URD 10/10 HLA match 5x106 4.3x106 PD 20 ALL Ph-neg URD 9/10 HLA match 5x106 4.2x106 MRD-negative CR (3+)^ CLL, chronic lymphocytic leukemia; ALL Ph+, Philadelphia chromosome positive acute lymphoblastic leukemia; ALL Ph-neg, Philadelphia chromosome negative acute lymphoblastic leukemia; MCL, mantle cell lymphoma; DLBCL, diffuse large B-cell lymphoma; FL, follicular lymphoma; Sibling, human leukocyte antigen-matched sibling donor; URD, unrelated donor; HLA, human leukocyte antigen; PD, progressive disease; SD, stable disease; PR, partial remission; CR, complete remission; MRD-negative, minimal residual disease negative. ^Patient 20 underwent a second alloHSCT 3.5 months after anti-CD19 CAR T-cell infusion while in MRD-negative CR. Disclosures Goy: Celgene: Consultancy, Research Funding, Speakers Bureau; Allos, Biogen Idec, Celgene, Genentech, and Millennium. Gilead: Speakers Bureau. Rosenberg:Kite Pharma: Other: CRADA between Surgery Branch-NCI and Kite Pharma.