Nonmyeloablative blood stem cell transplantation as adoptive allogeneic immunotherapy for metastatic renal cell carcinoma

Allogeneic stem cell transplantation has emerged as a potentially curative form of immunotherapy for patients with hematological malignancies that are resistant to conventional chemo/radiotherapy. Donor T cell populations targeting allogeneic minor histocompatibility antigens expressed on the patient's malignant cells are felt to be the driving force of the graft-versus-leukemia reaction, although to date only a handful of these antigens have been fully characterized. Recent data from experimental animal models and limited clinical data in humans suggest that graft-versus-tumor effects, analogous to the graft-versus-leukemia reaction, may be generated against malignancies of epithelial origin. This article reviews the results of a pilot trial demonstrating graft-versus-renal cell carcinoma effects following nonmyeloablative stem cell transplantation, highlighting the potential of allogeneic immunotherapy for treating cancer.     

Adoptive immunotherapy with genetically modified lymphocytes in allogeneic stem cell transplantation

Hematopoietic stem cell transplantation from a healthy donor (allo-HSCT) represents the most potent form of cellular adoptive immunotherapy to treat malignancies. In allo-HSCT, donor T cells are double edge-swords: highly potent against residual tumor cells, but potentially highly toxic, and responsible for graft versus host disease (GVHD), a major clinical complication of transplantation. Gene transfer technologies coupled with current knowledge on cancer immunology have generated a wide range of approaches aimed at fostering the immunological response to cancer cells, while avoiding or controlling GVHD. In this review, we discuss cell and gene therapy approaches currently tested in preclinical models and in clinical trials.     

Adoptive immunotherapy to treat leukemic relapse following allogeneic hematopoietic stem cell transplantation

Acute leukemia patients who relapse after haematopoetic stem cell transplantation (HSCT) have poor prognosis with few therapeutic options. An immunotherapeutic approach that specifically targets the leukemia to treat and prevent these relapses could improve survival rates for these patients. Recently a number of potential antigenic targets for leukemia have been described. These include over-expressed normal antigens such as survivin, leukemia-specific targets resulting from translocations and mutations and hematopoietic-restricted minor histocompatibility antigens such as HA-1 and HA-2. Considerable experimental data indicates that cytotoxic T cells targeting these antigens can be generated in vitro. Further improvements in the efficacy of antigen presentation and T cell activation and expansion will facilitate the clinical application of these T cells as a therapeutic strategy for patients who are likely to relapse after HSCT.     

Natural history of metastatic renal cell carcinoma in patients who underwent consultation for allogeneic hematopoietic stem cell transplantation.

We characterized the natural history of metastatic renal cell carcinoma (RCC) and identified prognostic factors among patients who did or did not undergo allogeneic hematopoietic stem cell transplantation (HSCT). A total of 99 patients (23 who underwent HSCT and 76 who did not) were included in the study. Overall survival rates were comparable between the HSCT and no-HSCT groups (excluding patients with poor performance status or brain metastasis from the latter group) at a median 17.4 months of follow-up (P=.92). In univariate analyses, Fuhrman's nuclear grade 4 (P=.05), high serum calcium (P=.002), or low hemoglobin levels (P=.02), 3 or more metastatic sites (P=.02), and <12 months from diagnosis to initial recurrence (P=.04) were identified as poor prognostic factors. In multivariate analyses, 3 or more metastatic sites (P=.005) and low hemoglobin levels (P=.02) were poor prognostic factors. In the HSCT group, median survival times from consultation and from transplant were 25 and 19 months for those with 0 prognostic factors (n=7) and 11 and 7 months for those with 1 or more prognostic factors (n=16). In conclusion, previous concerns that HSCT would negatively affect long-term outcome of patients with metastatic RCC were not confirmed. Patients with any of these poor prognostic factors should not consider HSCT for metastatic RCC. The role of allogeneic HSCT for patients with no prognostic factors should be explored in clinical trials for patients with targeted therapy-resistant metastatic RCC.     

Preemptive cellular immunotherapy after T-cell-depleted allogeneic hematopoietic stem cell transplantation.

GVHD is a life-threatening complication of allogeneic hematopoietic stem cell transplantation (HSCT). GVHD is due to donor lymphocytes that are cotransplanted with donor stem cells. These donor lymphocytes are primed by histocompatibility differences between donors and recipients and activated by a cytokine storm caused by the conditioning regimen. The most efficient method for prevention of GVHD consists of T-cell depletion (TCD) of the graft. However, TCD usually leads to an increased risk of leukemia relapse because of the loss of the graft-versus-leukemia (GVL) effect. Several groups have studied the feasibility of preemptive donor lymphocyte infusion (DLI) to lessen the impact of TCD on leukemia relapse. Preemptive DLI is given several weeks to months after the transplantation, ie, after the cytokine storm and after the patient has recovered from conditioning-regimen-related toxicities. After briefly discussing various techniques of TCD of the graft and the efficacy of DLI, this article reviews the first clinical studies evaluating a strategy of TCD of the graft followed by preemptive DLI.     

转移性肾癌免疫治疗研究进展

转移性肾癌对传统放、化疗均不敏感,目前尚缺乏有效的治疗手段.IL-2和IFN-α是目前研究较多的细胞因子制剂,但单独应用于转移性肾癌患者的治疗时效率低.近年来,随着分子免疫机制的研究进展,疫苗、过继免疫治疗的研究发展迅速,特别是树突状细胞疫苗(DC vaccine)和自体细胞因子诱导的杀伤细胞(CIK)的研究取得了很大的进展.     

Bone density loss after allogeneic hematopoietic stem cell transplantation: a prospective study.

The incidence and course of bone density abnormalities following hematopoietic stem cell transplantation are poorly understood and complicated by the impact of multiple factors. Hip, spine, and wrist bone mineral densities (BMDs) were measured in 104 adults (54 women, 54 men; mean age, 40 years [range, 18-64 years]) at 3 and 12 months after allogeneic transplantation. Clinical and laboratory variables were evaluated using univariate and multivariate analyses to determine risk factors for osteoporosis, fracture, and avascular necrosis. At 3 months posttransplantation, combined (male and female) hip, spine, and wrist z scores were -0.35, -0.42, and +0.04 standard deviations, respectively. At 12 months both men and women experienced significant loss of hip BMD (4.2%, P < .0001); changes in the spine and wrist were minimal. The cumulative dose and number of days of glucocorticoid therapy and the number of days of cyclosporine or tacrolimus therapy showed significant associations with loss of BMD; age, total body irradiation, diagnosis, and donor type did not. Nontraumatic fractures occurred in 10.6% of patients and avascular necrosis in 9.6% within 3 years posttransplantation. The decrease in height between pretransplantation and 12 months posttransplantation was significant (P = .0001). Results indicate that loss of BMD after allogeneic stem cell transplantation is common and accelerated by the length of immunosuppressive therapy and cumulative dose of glucocorticoid. An increased incidence of fracture and avascular necrosis may adversely impact long-term quality of life. Prevention of bone demineralization appears warranted after stem cell transplantation.     

Interleukin-2 based immunotherapy in patients with metastatic renal cell carcinoma.

The present thesis consists of 8 published articles focusing on interleukin-2 based immunotherapy in metastatic renal cell carcinoma (mRCC). This disease represents a significant challenge, as the tumor is resistant to current chemotherapy, hormonal therapy and radiation therapy. However, IL-2 based immunotherapy may induce dramatic durable tumor regression by manipulating the immune system, however, only in a minority of patients. Two critical questions have driven the present thesis. First, which properties of the immune system are responsible for the dramatic tumor regression seen in some patients with mRCC following IL-2 administration? And second, can histamine increase the efficacy of IL-2 based immunotherapy by ending the immune suppression induced by phagocyte-generation of reactive oxygen species? 120 Danish patients, 41 UK patients and 20 Swedish patients were treated with low- or intermediate dose IL-2 based immunotherapy in an outpatient setting. As monitoring of the Danish patients, 443 serial blood samples and 225 serial tumor core biopsies were obtained. The regimen of outpatient low-dose subcutaneous IL-2 and IFN-alpha in mRCC is safe and active. In the Danish patients, an estimated 5-year survival rate of 16% was observed. From the blood and tumor analysis, an understanding emerged that IL-2 based immunotherapy is a "targeted therapy" requiring intratumoral immune cells (CD4+, CD8+, CD56+, CD57+ T- and NK cells) for treatment effect. In contrast, monocytes and neutrophils were harmful for the outcome of IL-2 based immunotherapy. In progressing patients, the leukocyte subsets in blood and tumor tissue remained unaffected by cytokine therapy. The fate of a patient with mRCC prior to IL-2 and IFN-alpha based immunotherapy cannot be determined by measuring baseline tumor features of FasL expression or Ki-67 (MIB-1) proliferation marker. We established a biological rationale for the potential use of histamine in conjunction with IL-2 in mRCC. A large confirmatory randomised phase III trial of IL-2 with and without histamine in mRCC appropriately stratified for monocytes and neutrophils in blood and tumor tissue is warranted. In a multivariate analysis, 5 clinical features (PS, bone metastases, lymph node metastases, low hemoglobin and high LDH) plus 3 supplemental immunological factors (intratumoral CD57+ NK cells <50 cells/mm(2), intratumoral neutrophils >0 and blood neutrophils >6.0) were independent prognostic factors of short survival in patients with mRCC receiving IL-2, identifying subgroups with estimated 5-year survival rates of 60%, 25% and 0%, respectively. These features may help to select patients more likely to benefit from IL-2 based immunotherapy.     

Conditioning therapy with intravenous busulfan and cyclophosphamide (IV BuCy2) for hematologic malignancies prior to allogeneic stem cell transplantation: a phase II study.

Busulfan (Bu) is commonly used as a component of conditioning regimens for hematopoietic stem cell transplantation. Precise delivery of the oral formulation is compromised by erratic gastrointestinal absorption. An IV Bu formulation was developed to provide dose assurance and complete bioavailability. In a phase I study, the plasma bioequivalence of IV Bu was established at approximately 80% of the oral dose. We now report the findings of the first phase II study, in which 61 adults with hematologic cancers were treated with a Bu-cyclophosphamide (BuCy) regimen consisting of IV Bu (0.8 mg/kg every 6 hours x 16) followed by Cy (60 mg/kg qd x 2) and transplantation of stem cells from an HLA-matched sibling donor. The median age of study participants was 37 years; 75% of patients had active disease; 48% were heavily pretreated, and 13% had undergone a prior transplantation. Median follow-up was 2.3 years; median time to engraftment (absolute neutrophil count, >0.5 x 10(9)/L) was 13 days; 100% of patients with cytogenetic and/or molecular markers had documented chimerism; and there were no engraftment failures. Two-year overall and disease-free survival were 67% and 42%, respectively. There were no unexpected toxic reactions. Fatal veno-occlusive disease occurred in 2 patients, 1 of whom had undergone a prior transplantation. Treatment-related mortality at 100 days was 9.8% (6/61). Bu pharmacokinetics after IV drug administration demonstrated high inter- and intrapatient consistency; 86% of patients maintained an area under the curve between 800 and 1500 microMol-min. In conclusion, the IV Bu in this regimen was very well tolerated and demonstrated excellent antitumor efficacy, most likely because of dose assurance with predictable pharmacokinetics.     

Interleukin-2 based immunotherapy in patients with metastatic renal cell carcinoma

The present thesis consists of 8 published articles focusing on interleukin-2 based immunotherapy in metastatic renal cell carcinoma (mRCC). This disease represents a significant challenge, as the tumor is resistant to current chemotherapy, hormonal therapy and radiation therapy. However, IL-2 based immunotherapy may induce dramatic durable tumor regression by manipulating the immune system, however, only in a minority of patients. Two critical questions have driven the present thesis. First, which properties of the immune system are responsible for the dramatic tumor regression seen in some patients with mRCC following IL-2 administration? And second, can histamine increase the efficacy of IL-2 based immunotherapy by ending the immune suppression induced by phagocyte-generation of reactive oxygen species? 120 Danish patients, 41 UK patients and 20 Swedish patients were treated with low- or intermediate dose IL-2 based immunotherapy in an outpatient setting. As monitoring of the Danish patients, 443 serial blood samples and 225 serial tumor core biopsies were obtained. The regimen of outpatient low-dose subcutaneous IL-2 and IFN-alpha in mRCC is safe and active. In the Danish patients, an estimated 5-year survival rate of 16% was observed. From the blood and tumor analysis, an understanding emerged that IL-2 based immunotherapy is a "targeted therapy" requiring intratumoral immune cells (CD4+, CD8+, CD56+, CD57+ T- and NK cells) for treatment effect. In contrast, monocytes and neutrophils were harmful for the outcome of IL-2 based immunotherapy. In progressing patients, the leukocyte subsets in blood and tumor tissue remained unaffected by cytokine therapy. The fate of a patient with mRCC prior to IL-2 and IFN-alpha based immunotherapy cannot be determined by measuring baseline tumor features of FasL expression or Ki-67 (MIB-1) proliferation marker. We established a biological rationale for the potential use of histamine in conjunction with IL-2 in mRCC. A large confirmatory randomised phase III trial of IL-2 with and without histamine in mRCC appropriately stratified for monocytes and neutrophils in blood and tumor tissue is warranted. In a multivariate analysis, 5 clinical features (PS, bone metastases, lymph node metastases, low hemoglobin and high LDH) plus 3 supplemental immunological factors (intratumoral CD57+ NK cells <50 cells/mm(2), intratumoral neutrophils >0 and blood neutrophils >6.0) were independent prognostic factors of short survival in patients with mRCC receiving IL-2, identifying subgroups with estimated 5-year survival rates of 60%, 25% and 0%, respectively. These features may help to select patients more likely to benefit from IL-2 based immunotherapy.     

Reduced-intensity allogeneic stem cell transplantation for patients whose prior autologous stem cell transplantation for hematologic malignancy failed.

Autologous hematopoietic stem cell transplantation (autoSCT) is an effective treatment for patients with various hematologic malignancies. Despite the significant improvement in the overall outcome, disease progression after transplantation remains the major cause of treatment failure. With longer follow-up, therapy-related myelodysplasia/acute myelogenous leukemia is becoming an important cause of treatment failure. The prognosis for these 2 groups of patients is very poor. Allogeneic hematopoietic stem cell transplantation (alloSCT) is a potential curative treatment for these patients. However, the outcome with conventional myeloablative alloSCT after failed autoSCT is typically poor because of high transplant-related mortality. In an attempt to reduce the treatment-related toxicity, we studied a reduced-intensity conditioning regimen followed by alloSCT for patients with progressive disease or therapy-related myelodysplasia/acute myelogenous leukemia after autoSCT. This report describes the outcomes of 28 patients with hematologic malignancies who received a reduced-intensity alloSCT after having treatment failure with a conventional autoSCT. Fourteen patients received a hematopoietic stem cell transplant from a related donor and 14 from an unrelated donor. The conditioning regimen consisted of low-dose (2 Gy) total body irradiation with or without fludarabine in 4 patients and the combination of melphalan (140 mg/m(2)) and fludarabine in 24. Cyclosporine and mycophenolate mofetil were used for posttransplantation immunosuppressive therapy, as well as graft-versus-host disease (GVHD) prophylaxis, in all patients. All patients engrafted and had >90% donor chimerism on day 100 after SCT. Currently, 13 patients (46%) are alive and disease free, 7 patients (25%) developed disease progression after alloSCT, and 8 (32%) died of nonrelapse causes. Day 100 mortality and nonrelapse mortality were 25% and 21%, respectively. With a median follow-up of 24 months for surviving patients, the 2-year probabilities of overall survival, event-free survival, and relapse rates were 56.5%, 41%, and 41.9%, respectively. Six patients (21%) developed grade III to IV acute GVHD. Among 21 evaluable patients, 15 (67%) developed chronic GVHD. We conclude that (1) reduced-intensity alloSCT is feasible and has an acceptable toxicity profile in patients who have previously received autoSCT and that (2) although follow-up was short, a durable remission may be achieved in some patients who would otherwise be expected to have a poor outcome.     

Phase I/II study of immunotherapy using autologous tumor lysate-pulsed dendritic cells in patients with metastatic renal cell carcinoma

This phase I/II study was conducted to evaluate the feasibility, safety and efficacy of immunotherapy using tumor lysate (TL)-pulsed dendritic cells (DC) in patients with metastatic renal cell carcinoma (RCC). DC were generated by culturing peripheral blood mononuclear cells in the presence of GM-CSF and IL-4 and were pulsed with autologous TL and keyhole limpet hemocyanin (KLH). Maturation of DC was induced by a combined treatment of CD40 ligand, IFN and monocyte-conditioned medium. The patients were administered two cycles of TL-pulsed DCs vaccination, each of which comprised of four doses injected subcutaneously at biweekly intervals. Nine patients were included. The immunotherapy was well tolerated without severe side effects. One patient achieved an objective partial response (PR). Five patients showed stable disease (SD), and the remaining three had progressive disease (PD). With a median follow-up of 17.5 months, the median time to progression was 5.2 months and the median overall survival was 29 months. In the antigen-specific lymphocyte proliferation assay, eight patients showed a proliferative response, which tended to be stronger in patients with SD or PR than in patients with PD. The ELISPOT assay was performed in two patients and indicated that one patient with PR showed a much stronger response than another with PD. Our results suggest that TL-pulsed DC immunotherapy in combination with nephrectomy affect the natural course of RCC and are associated with clinical benefits for patients with metastatic diseases.     

白消安在非亲缘异基因造血干细胞移植预处理中的应用

背景：口服白消安剂型胃肠道吸收不稳定,影响异基因造血干细胞疗效且毒性增加。静脉剂型白消安在国内最近几年用于临床,但在非亲缘异基因移植预处理中应用的相关报道甚少。 目的：探讨静脉剂型白消安在非亲缘异基因造血干细胞移植预处理中应用的疗效并观察其毒副作用。 方法：14例非亲缘异基因干细胞移植采用静脉剂型白消安联合环磷酰胺预处理方案,18例亲缘异基因干细胞移植采用口服白消安联合环磷酰胺预处理方案,观察两组造血重建、植入率等疗效指标及胃肠道反应、口腔黏膜炎、出血性膀胱炎、肝功能损害、移植物抗宿主病等相关毒性指标。 结果与结论：两组患者植入率均为100%。静脉剂型组肝脏毒性、口腔黏膜炎发生率明显低于口服剂型组(14% vs. 67%,7% vs. 55%),差异均有显著性意义(P < 0.01),而胃肠道反应、出血性膀胱炎、造血重建、急性移植物抗宿主病、局限性移植物抗宿主病等方面差异均无显著性意义(P > 0.05)。结果可见静脉剂型白消安应用于非亲缘异基因造血干细胞移植预处理可获得满意疗效,且毒副反应少。     

Phase II study of a moderate-intensity preparative regimen with allogeneic peripheral blood stem cell transplantation for hematologic diseases: the Texas Transplant Consortium experience.

Conventional preparative regimens for allogeneic stem cell transplantation are associated with excessive regimen-related toxicity (RRT) in some patients because of underlying comorbidities, advanced age, or prior treatment. We studied a preparative regimen designed to reduce RRT, yet allow for adequate engraftment and development of a graft-versus-malignancy effect. Thirty patients (median age, 57 years) were entered on study. Twenty-nine patientsreceived stem cells from HLA-identical siblings and 1 from a sibling mismatched for 1 antigen at the A locus. Sixteen patients had received previous stem cell transplants (6 allogeneic and 10 autologous). The preparative regimen consisted of fludarabine 30 mg/M2 per day IV on day -10 to day -5, busulfan 1 mg/kg per dose PO (n = 6) or 0.8 mg/kg per dose IV (n = 24) for 8 doses every 6 hours on day -6 to day -5, and horse-derived antithymocyte globulin 5 mg/kg per day IV (n = 12) or 15 mg/kg per day IV (n = 18) on day -4 to day -1. GVHD prophylaxis consisted of cyclosporine (CYA) 3 mg/kg BID PO starting on day -3 (n = 13) or CYA and methotrexate 15 mg/m2 IV on day +1 and 10 mg/m2 IV on day +3 and day +6 (n = 17). The median number of CD34 cells transplanted was 3.19 x 10(6)/kg. All patients demonstrated recovery of hematopoietic function. Twenty-six (89%) of 29 evaluable patients achieved greater than 90% donor cell chimerism before day 100. Three patients never achieved greater than 90% donor chimerism, and another 3 patients subsequently lost donor chimerism. All 6 of these patients had autologous reconstitution with progressive disease. RRT was minimal; 7 patients had greater than grade II nonhematologic toxicity and there were no toxic deaths attributable to the conditioning regimen. Transplantation-related mortality was 7% (95% confidence interval [CI], 6%-8%) at 3 months and 28% (95% CI, 23%-34%) at 12 months after transplantation. Non-relapse-related mortality was most often due to infection. Grade II or greater GVHD developed in 56% of evaluable patients, and all patients with disease response developed GVHD. Actuarial estimates of overall and disease-free survival at 12 months were 52% (95% CI, 43%-63%) and 30% (95% CI, 24%-37%), respectively. Although this preparative regimen allowed adequate engraftment with minimal RRT, GVHD and infectious complications caused significant morbidity and mortality. Further study to define appropriate patient populations for this regimen, while limiting GVHD and infection risks, is needed.     

Lung transplantation for bronchiolitis obliterans after allogeneic hematopoietic stem cell transplantation

Bronchiolitis obliterans (BO) is a late onset complication of allogeneic hematopoietic stem cell transplantation (HSCT), and treatment outcome is dismal if it does not respond to immunosuppressive therapy. A 21-year-old male diagnosed with acute myeloid leukemia received an allogeneic HSCT from human leukocyte antigen- identical sibling donor. Twenty one months after transplantation, he developed progressive dyspnea and was diagnosed BO. Despite standard immunosuppressive therapy, the patient rapidly progressed to respiratory failure and Novalung® interventional lung-assist membrane ventilator was applied in the intensive care unit. Three months after the diagnosis of BO, the patient underwent bilateral lung transplantation (LT) and was eventually able to wean from the ventilator and the Novalung®. Since the LT, the patient has been under a strict rehabilitation program in order to overcome a severe lower extremity weakness and muscle atrophy. Histologic findings of the explanted lungs confirmed the diagnosis of BO. Nine months after the LT, the patient showed no signs of rejection or infectious complications, but still required rehabilitation treatment. This is the first LT performed in a patient with BO after allogeneic HSCT in Korea. LT can be an effective therapy in terms of survival for patients with respiratory failure secondary to development of BO following HSCT.     

间充质干细胞改善移植肾功能的Meta分析

BACKGROUND:In recent years, with the use of new immunosuppressive agents, the survival rate of renal graft is greatly improved, but accompanied by lots of side effects and unchanged long-term graft survival. Mesenchymal stem cells (MSCs) have aroused people’s great interest, while their efficacy in kidney transplantation remains controversial. OBJECTIVE:To evaluate the efficacy of MSCs transplantation on post-transplant renal graft function with a systematic review. METHODS:PubMed, EMBASE, the Cochrane Library database, the Cochrane Central Register of Controlled Trials, Wanfang database and China National Knowledge Infrastructure (CNKI) were searched until November 2015. Revman 5.3 was used for statistical analysis. RESULTS AND CONCLUSION:A total of 6 randomized controlled trials were included, including 1 166 patients. Meta-analysis results showed that at 1, 2 weeks and 1 month after kidney transplantation, the posttransplantation estimated glomerular filtration rates in the MSC-treated group were significantly higher than those in the control group (P < 0.05). At 1, 3, 6, 12 months after kidney transplantation, the posttransplantation serum creatinine levels showed no significant difference between the MSC-treated group and the control group (P > 0.05). To conclude, MSC-based immunosuppression regimen is superior to current standard immunotherapy in improving renal graft function in the early stage after kidney transplantation, but the clinical efficacy is diminished in the later period. Therefore, further investigation using large-scale randomized controlled trials is warranted.     

Long-term outcome of myeloablative allogeneic stem cell transplantation for multiple myeloma.

Allogeneic stem cell transplantation (alloSCT) has been used in the hopes of harnessing the curative potential of the graft-versus-myeloma effect. This study examines the long-term outcomes of a large cohort of patients with myeloma who were treated with myeloablative alloSCT at a single center. Comparisons are made with those who were treated with autologous stem cell transplantation (ASCT). Between January 1989 and February 2002, 158 patients age10 years post myeloablative alloSCT, similarly there are long-term survivors post-ASCT. Myeloablative alloSCT should not be considered standard treatment, and should only be considered in the context of a clinical trial.     

The in vitro generation of multi-tumor antigen-specific cytotoxic T cell clones: Candidates for leukemia adoptive immunotherapy following allogeneic stem cell transplantation

Adoptive T-cell immunotherapy is a promising approach to manage and maintain relapse-free survival of leukemia patients, especially following allogeneic stem cell transplantation. Post-transplant adoptive immunotherapy using cytotoxic T lymphocytes (CTLs) of the donor origin provide graft-versus-tumor effects, with or without graft–versus-host disease. Myeloid leukemias express immunogenic leukemia associated antigens (LAAs); such as WT-1, PRAME, MAGE, h-TERT and others, most of them are able to induce specific T cell responses whenever associated with the proper co-stimulation. We investigated the ability of a LAA-expressing hybridoma cell line to induce CTL clones in PBMCs of HLA-matched healthy donors in vitro. The CTL clones were induced by repetitive co-culture with LAAs-expressing, HLA-A*0201⁺ hybrid cell line, generated by fusion of leukemia blasts to human immortalized APC (EBV-sensitized B-lymphoblastoid cell line; HMy2). The induced cytotoxic T cell clones were phenotypically and functionally characterized by pentamer analysis, IFN-γ release ELISPOT and cellular cytotoxicity assays. All T cell lines showed robust peptide recognition and functional activity when sensitized with HLA-A*0201-restricted WT-1_235–243, hTERT_615–624 or PRAME_100–108 peptides-pulsed T2 cells, in addition to partially HLA-matched leukemia blasts. This study demonstrates the feasibility of developing multi-tumor antigen-specific T cell lines in allogeneic PBMCs in vitro, using LAA-expressing tumor/HMy2 hybrid cell line model, for potential use in leukemia adoptive immunotherapy in partially matched donor-recipient setting.     

Early human herpesvirus type 6 reactivation after allogeneic stem cell transplantation: a large-scale clinical study

This study investigated the impact of human herpesvirus type 6 (HHV6) reactivation within 100 days of allogeneic stem cell transplantation (allo-SCT) on patient outcomes. HHV6 plasma loads were monitored weekly by quantitative PCR. Of 235 consecutive patients, 112 (48%) had an early positive HHV6 PCR test (group A) and 123 (52%) did not (group B). HHV6 reactivation was less frequent in patients who received reduced-intensity conditioning (P = .028). In group A, only 6 patients (5%) were asymptomatic; the most common clinical manifestations were fever (n = 60), skin rash (n = 57), diarrhea (n = 51), pulmonary complications (n = 19), and neurologic disorders (n = 12). Compared with the patients in group B, those in group A experienced delayed platelet engraftment (P = .003) and more frequent grade II-IV acute graft-versus-host disease (GVHD) (47% versus 30% in group B; P = .009). In multivariate analysis, the most important factors influencing the development of grade II-IV acute GVHD development were early HHV6 reactivation (P = .03) and unrelated donor status (P < .001). HHV6 reactivation adversely influenced 6-month survival (P = .04). Of?the 38 evaluable patients receiving antiviral treatment, 34 had a significantly decreased HHV6 load. Our findings indicate that HHV6 reactivation after allo-SCT is associated with delayed platelet engraftment, early posttransplantation mortality, and the development of acute GVHD. Careful monitoring of HHV6 by PCR is warranted during the early posttransplantation period.