Potential allogeneic graft-versus-tumor effect in a patient with ovarian cancer

m6A RNA methylation regulators were associated with the malignancy and prognosis of ovarian cancer

N6-methyladenosine (m6A) RNA methylation regulators play a regulatory role in tumor pathogenesis and development. However, the role of m6A regulator genes in ovarian cancer (OC) has not been fully elucidated. This study aims to investigate the mRNA expressions, clinicopathological features, and prognostic values of m6A regulators in OC. Here, we demonstrate that the 17 m6A RNA methylation regulators are differentially expressed in ovarian cancer and normal tissues. By using consensus clustering, all ovarian cancer patients can be divided into two subgroups (cluster 1 and 2) based on the expression of 17 m6A RNA methylation regulators. Using Gene Set Enrichment Analysis, we identified that cluster 1 was most connected to oxidative phosphorylation pathways. Regression models identified that prognosis is associated with HNRNPA2B1, KIAA1429, and WTAP. qRT-PCR result show that the expression trends of HNRNPA2B1 and KIAA1429 are consistent with the predicted results. Multivariate Cox regression analysis results show that the risk score was an independent predictive factor in OV. The overall survival of high-risk patients was significantly shorter than that of low-risk patients. ROC curve analysis showed that the prognostic signature precisely predicted the 5-year survival of OV patients. A nomogram was developed to predict each patient's survival probability and well calibrated and showed a satisfactory discrimination. Dendritic fraction, macrophage fraction, and neutrophil fraction showed higher fraction in high-risk patients. In conclusion, m6A RNA methylation regulators are vital participants in ovarian cancer pathology, and three-gene mRNA levels are valuable factors for prognosis predictions.

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-1235-243, hTERT615-624 or PRAME100-108 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.

Nonmyeloablative stem cell transplantation as immunotherapy for kidney cancer and other metastatic solid tumors

Over the past few decades, great strides have been made to advance the field of allogeneic hematopoietic stem cell transplantation. The donor immune mediated graft-vs-tumor effect that follows the procedure is now widely accepted as the most effective form cancer immunotherapy available for patients with a variety of advanced hematological malignancies. Recognition that a transplanted immune system could cure patients with treatment refractory leukemia led to the development of ;low-intensity' conditioning regimens, which have improved the safety of the procedure and broadened the application of allogeneic immunotherapy to a growing list of neoplastic diseases. Here we discuss the investigational use of allogeneic transplantation as immunotherapy for patients with metastatic, treatment-refractory solid tumors.

Rapid expansion of tumor-reactive cells from HLA-matched siblings for adoptive immunotherapy of melanoma

BACKGROUND

Administration of expanded tumor-infiltrating lymphocytes in association with lymphodepleting chemotherapy is effective in some patients with advanced malignant melanoma. However, obtaining lymphocytes and subsequent expansion is labor intensive, making it impractical for broad clinical application. Allogeneic transplantation may have anti-melanoma efficacy because of a graft vs. tumor effect. The disappointing tumor control observed post-transplant suggests that adoptive immunotherapy using melanoma-reactive cells will be essential for sustained responses.

METHODS

Melanoma cell lines were grown from two patients with advanced disease. High-level CD80 and CD86 expression was obtained in the tumor lines using a retroviral vector for gene transfer. Transduced melanoma and controls were cultured with mononuclear cells from HLA-identical sibling donors.

RESULTS

Expression of CD80 and CD86, particularly the former, promoted marked expansion of lymphocytes from HLA-matched sibling donors. Proliferation of up to 300-fold after 4 weeks of culture was observed. Lymphocytes from cultures stimulated with CD80 demonstrated cytotoxicity against recipient-untransfected melanoma (45-75% specific lysis at an E:T ratio of 50:1). Although expanded lymphocytes were predominantly CD4(+), cytotoxicity was greatest in the numerically smaller CD8(+) subpopulation. Both CD4(+) and CD8(+) cells secreted IFN-gamma (but not IL-4) on exposure to untransduced stimulator melanoma cells.

DISCUSSION

Our strategy generates a large number of melanoma-reactive lymphocytes from HLA-identical siblings using a 4-week culture strategy. Lymphocytes expanded in this way offer an alternative to tumor-infiltrating lymphocytes for allogeneic cellular immunotherapy after stem cell transplantation in young patients.

Generation of tumour-specific cytotoxic T-cell clones from histocompatibility leucocyte antigen-identical siblings of patients with melanoma

Lymphodepletion and infusion of autologous expanded tumour-infiltrating lymphocytes is effective therapy for patients with malignant melanoma. Antitumour responses are likely to be mediated by HLA class I- and II-restricted immune responses directed at tumour antigens. We assessed whether the peripheral blood of normal HLA-matched siblings of patients with melanoma could be used to generate lymphocytes with antimelanoma activity for adoptive immunotherapy after allogeneic blood or marrow transplantation. Melanoma cell lines were derived from two donors and were used to stimulate the mononuclear cells of three HLA-identical siblings. CD4(+) clones dominated cultures. Of these, approximately half were directly cytotoxic towards recipient melanoma cells and secreted interferon-gamma in response to tumour stimulation. More than half of the noncytotoxic clones also secreted interferon-gamma after melanoma stimulation. No CD4(+) clones responded to stimulation with recipient haemopoietic cells. The majority of CD8(+) clones directly lysed recipient melanoma, but did not persist in long-term culture in vitro. No crossreactivity with recipient haemopoietic cells was observed. The antigenic target of one CD4(+) clone was determined to be an HLA-DR11-restricted MAGE-3 epitope. Antigenic targets of the remaining clones were not elucidated, but appeared to be restricted through a non-HLA-DR class II molecule. We conclude that the blood of allogeneic HLA-matched sibling donors contains melanoma-reactive lymphocyte precursors directed at tumour-associated antigens. Adoptive immunotherapy with unselected or ex vivo-stimulated donor lymphocytes after allogeneic stem cell transplantation has a rational basis for the treatment of malignant melanoma.

Cellular immune therapy for refractory cancers: novel therapeutic strategies

OBJECTIVE

Allogeneic stem cell transplantation is curative for certain cancers, but the high doses of chemotherapy and radiotherapy may lead to toxicity. This review summarizes the field of cellular immune therapy using very-low-dose conditioning for refractory cancers.

METHODS

In our initial study, we treated 25 patients with refractory cancers with 100 cGy total body irradiation followed by allogeneic, nonmobilized peripheral blood cells. Eighteen patients received sibling and seven patients received unrelated cord blood stem cells.

RESULTS

None of the 13 patients with solid tumors achieved donor chimerism or had a sustained response. Twelve patients with hematologic malignancies were treated, 1 received a cord blood transplant and 11 received sibling donor cells. Nine of these 11 patients achieved donor chimerism, ranging from 5% to 100%. Four patients had sustained complete remission of their cancers. The patients who received cord blood transplants did not respond. Development of chimerism correlated with total previous myelotoxic chemotherapy (p < 0.001). We review additional studies in this area, including data in the haploidentical and unrelated donor setting. The data presented comprises studies performed at the four institutions represented by the authors, and a review of other pertinent studies in this area.

CONCLUSIONS

Cellular immune therapy is an emerging application of transplantation therapy, which may be appropriate for refractory cancers. New studies in solid tumors, and with alternative donors, will expand the application of this new and promising treatment.

Low dose total body irradiation followed by allogeneic lymphocyte infusion for refractory hematologic malignancy--an updated review

Allogeneic stem cell transplantation is curative for certain cancers, but the high doses of chemotherapy and radiotherapy used in conventional myeloablative conditioning regimens may lead to severe toxicity. In our initial study, we treated 25 patients with refractory cancers with 100 cGy total body irradiation (TBI) followed by allogeneic, non mobilized peripheral blood cells. Eighteen patients received sibling and 7 patients received unrelated cord blood stem cells. None of the 13 patients with solid tumors achieved donor chimerism or had a sustained response. Twelve patients with hematologic malignancies were treated, 1 received a cord blood transplant and 11 received sibling donor cells. Nine of these 11 patients achieved donor chimerism, ranging from 5% to 100%. Four patients had sustained complete remission of their cancers, and 2 are long-term survivors. The development of chimerism correlated with total previous myelotoxic chemotherapy (p < 0.001). This technique is now being extended into the haploidentical setting.

Allogeneic stem cell transplantation for the treatment of advanced solid tumors

Allogeneic stem cell transplantation has emerged as a potentially curative treatment modality for patients with hematological malignancies. The graft-versus-leukemia effect, an immune mechanism mediated by the donor immune system, is an important component of the therapeutic effect of allogeneic transplantation. Recent data from experimental animal models and from preliminary clinical experience suggest that a graft-versus-tumor effect, analogous to the graft-versus-leukemia effect, may be generated against solid tumors such as renal cell cancer, breast cancer, and other malignancies. The use of non-myeloablative, immunosuppressive conditioning regimens offers the opportunity to achieve a full-donor engraftment with reduced transplant-related complications and mortality, enabling also patients of advanced age and with co-morbidities to receive an allografting. Advanced renal cell cancer, an essentially incurable disease, has emerged from pilot studies as a disease susceptible to the graft-versus-tumor effect. Future studies will demonstrate if the tumor responses observed after allografting will translate into a clinically meaningful survival advantage. Other tumors in which tumor responses have been observed are: breast cancer, ovarian cancer, colorectal cancer, soft-tissue sarcoma, and others. Advanced melanoma may not be amenable to graft-versus-tumor effect. Future studies will point to the identification, isolation and cloning of target antigen(s) of graft-versus-tumor effect, to further reduce toxicities and to achieve a selective cell-mediated immunotherapy.

Minor histocompatibility antigens: allo target molecules for tumor-specific immunotherapy

Minor histocompatibility antigens have to be considered as key molecules in the stem cell-based immunotherapy of malignancies. Allogeneic stem cell transplantation (SCT) is a well-established and effective therapy for advanced hematologic malignancies. The apparent powerful graft-versus-leukemia effect of SCT led clinicians to apply SCT for the treatment of metastatic solid tumors. The SCT-based graft-versus-tumor reaction in the allogeneic human leukocyte antigen-matched SCT setting is mediated by allo-immune effectorcells directed against tumor-related target antigens. The target molecules involved in the allo-immune graft-versus-tumor reaction are tumor-specific antigens, tumor-associated antigens, and tissue- and cell-specific minor histocompatibility antigens. The power of the minor histocompatibility antigens in the human leukocyte antigen-identical, stem cell-based immunotherapy for malignancies is their "allo-ness." As opposed to tumor-associated self antigens, the complexes of MHC and allo-target peptide are likely to be more immunogeneic than the major histocompatibility complex and self-target peptide complexes. Moreover, minor histocompatibility allo-antigens are not subject to self tolerance. Earlier minor histocompatibility antigens were seen as alien entities, disturbing the success of the so ideally matched organ and SCT donor-recipient combinations. To date, minor histocompatibility antigens can be set in the favorable light of useful tools for immunotherapy for cancer. The first clinical application of the hematopoietic minor histocompatibility antigens HA-1 and HA-2 is currently being explored in a stem cell-based setting for hematologic malignancies. Because HA-1 is also expressed on carcinoma cells, a stem cell-based vaccination trial for patients with metastatic breast or renal cancer is about to start as well. The immunotherapeutic potential of minor histocompatibility antigens demands serious searches for new minor histocompatibility antigens and analyses of their phenotype frequency, tissue distribution, and functional membrane expression. The minor histocompatibility antigens meeting the prerequisites for specific immunotherapy for malignancies, such as membrane expression and tissue and/or cell specificity, may offer the curative tools for stem cell-based immunotherapy for various hematologic and nonhematologic malignancies.

Nonmyeloablative allogeneic immunotherapy for solid tumors

Over the past decade, considerable advances have been made in the field of allogeneic hematopoietic stem cell transplantation. Recognition that transplanted donor immune cells can cure patients with leukemia has led to the development of nonmyeloablative or "low-intensity" conditioning regimens, which have expanded the application of allogeneic transplantation to a growing number of hematological malignancies. The improved safety and preliminary success of this transplant approach have justified applying allogeneic immunotherapy to patients with treatment-refractory solid tumors.

Allogeneic stem cell transplantation as immunotherapy for nonhematological cancers

Over the past two decades biologic therapy has played an increasing role in the treatment of cancer. While this field is still early in its development, there now exists compelling evidence that the immune system is capable of detecting and eliminating cancer cells. Although the majority of immunotherapy approaches for metastatic cancer involve strategies designed to enhance autologous immunity, most would agree that the graft-versus-leukemia reaction induced following allogeneic stem cell transplantation represents modern day's most potent form of cancer immunotherapy. While allogeneic stem cell transplantation has gained recognition as a potentially curative "immunotherapy" for a growing number of different hematological malignancies, its efficacy in inducing antimalignancy effects against nonhematological cancers has only recently begun to be investigated. The historical basis, development, and preliminary clinical results of allogeneic stem cell transplantation as a form of immunotherapy for treatment refractory solid tumors are reviewed.

Possible allogeneic graft-versus-tumor effect in childhood melanoma

Patients with metastatic melanoma have a very poor prognosis despite contemporary biochemotherapy. A 14-year-old girl with stage IV melanoma and brain metastasis received a nonmyeloablative conditioning and a hematopoietic graft from an HLA-identical sibling. She had progression of disease in the first 2 months after transplantation. After withdrawal of immunosuppressant and establishment of a full donor chimeric status, peripheral disease response was documented by regression of metastatic disease and lack of tumor progression until 1 year after transplantation. She died of progressive disease 21 months after diagnosis and 17 months after transplantation. Her clinical course suggested the possible existence of an allogeneic graft-versus-melanoma response that prolonged her survival.

Reduced-intensity allogeneic hematopoietic cell transplantation: Graft versus tumor effects with decreased toxicity

The potentially curative role of allogeneic hematopoietic cell transplantation (HCT) in neoplastic and non-neoplastic diseases is offset by the substantial risks of morbidity and mortality from complications of the intensive myeloablative and immunosuppressive preparative regimen. These regimen-related toxicities have restricted allogeneic HCT to young, otherwise healthy individuals without comorbid diseases. Pediatric patients undergoing conventional allogeneic HCT have lower procedure-related mortality but are at risk for non-fatal late effects of the high-dose pretransplant chemoradiotherapy, such as growth retardation, sterility and other endocrine dysfunction. Evaluation of reduced-intensity preparative regimens is the major focus of current clinical research in allogeneic HCT. Reduced-intensity HCT (RI-HCT) relies on the use of immunosuppressive but non-myeloablative agents that allow engraftment of donor cells, which provide adoptive allogeneic cellular immunotherapy and graft versus tumor (GVT) effects, with decreased regimen-related toxicities. Although the experience with RI-HCT in pediatric patients is very limited at this time, results in adults indicate that attenuated-dose preparative regimens allow older patients and those with organ dysfunction to undergo successful allogeneic HCT with acceptable morbidity and mortality. In adults, the potency of the allogeneic GVT effect varies among neoplastic diseases, with better results observed in patients with indolent hematological malignancies or renal cell carcinoma. The effectiveness of RI-HCT as treatment for children with hemoglobinopathies, chronic granulomatous disease and cellular immunodeficiencies is encouraging, and the role of reduced-intensity preparative regimens for allogeneic HCT in pediatric malignancies is under investigation.

Generation of melanoma-specific cytotoxic T lymphocytes for allogeneic immunotherapy

To exploit alloreactive T-cell responses known as the graft-versus-tumor effect, allogeneic hematopoietic stem cell transplantation is being explored as experimental therapy in selected solid tumors, including metastatic melanoma. However, donor T-cell responses are often delayed and associated with severe graft-versus-host disease. Posttransplant adoptive immunotherapy using tumor-specific cytotoxic T lymphocytes (CTL) of donor origin might provide immediate graft-versus-tumor effects but not graft-versus-host disease. Therefore, the aim of the current study was to define in vitro conditions for the expansion of allogeneic major histocompatibility complex-matched CTLs targeting melanoma-associated antigens (MAA). The CTLs were generated from peripheral blood mononuclear cells (PBMCs) of HLA-A*0201+ healthy donors by repetitive stimulations with HLA-A*0201-restricted MAA-derived peptides. Melanoma reactivity, as determined by lysis of peptide-pulsed T2 cells and HLA-A2+/Ag+ melanoma cells, was detected using in vitro expanded CTL targeting MAA peptides AAGIGILTV(MT(27-35)), IMDQVPFSV(G(209-2M)), and YMDGTMSQV(T(368-376)). In contrast, FLWGPRALV(MAGE3(271)-(279)) and VLPDVFIRCV(GnT-V(nt38-67)) induced peptide-specific recognition of T2 target cells only, whereas ITDQVPFSV(G(209-217)), KTWGQYWQV(G9(154)), MLLAVLYCL(T(1-9)), and tumor lysate could not induce specific CTLs. Specific cytolytic activity was accompanied by interferon-gamma secretion. Peptide-pulsed dendritic cells were required only for the initial stimulation of CTLs and could be substituted by PBMCs during restimulations. The median expansion rate of CTL was five to six times, regardless of whether dendritic cells or PBMCs were used after the initial stimulation. The results delineate the conditions for effective ex vivo expansion of melanoma-specific CTLs from PBMCs of healthy donors to be used as an adjunct in allogeneic cell therapy of metastatic melanoma.

Hematopoietic Cell Transplantation for Benign Hematological Disorders and Solid Tumors

Allogeneic hematopoietic cell transplantation (HCT) has been successfully used as replacement therapy for patients with aplastic anemia and hemoglobinopathies. Both autologous and allogeneic HCT following high-dose chemotherapy can correct manifestations of autoimmune diseases. The impressive allogeneic graft-versus-tumor effects seen in patients given HCT for hematological malignancies have stimulated trials of allogeneic immunotherapy in patients with otherwise refractory metastatic solid tumors. This session will update the status of HCT in the treatment of benign hematological diseases and solid tumors.

In Section I, Dr. Rainer Storb reviews the development of nonmyeloablative conditioning for patients with severe aplastic anemia who have HLA-matched family members. He also describes the results in patients with aplastic anemia given HCT from unrelated donors after failure of responding to immunosuppressive therapy. The importance of leuko-poor and in vitro irradiated blood product transfusions for avoiding graft rejection will be discussed.

In Section II, Dr. Guido Lucarelli reviews the status of marrow transplantation for thalassemia major and updates results obtained in children with class I and class II severity of thalassemia. He also describes results of new protocols for class III patients and efforts to extend HCT to thalassemic patients without HLA-matched family members.

In Section III, Dr. Peter McSweeney reviews the current status of HCT for severe autoimmune diseases. He summarizes the results of autologous HCT for systemic sclerosis, multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus, and reviews the status of planned Phase III studies for autologous HCT for these diseases in North America and Europe. He also discusses a possible role of allogeneic HCT in the treatment of these diseases.

In Section IV, Dr. Richard Childs discusses the development and application of nonmyeloablative HCT as allogeneic immunotherapy for treatment-refractory solid tumors. He reviews the results of pilot clinical trials demonstrating graft-versus-solid tumor effects in a variety of metastatic cancers and describes efforts to characterize the immune cell populations mediating these effects, as well as newer methods to target the donor immune system to the tumor.

Minitransplants: allogeneic stem cell transplantation with reduced toxicity

Allogeneic hematopoietic stem cell transplantation (HSCT) is used for the treatment of selected hematological malignancies. Its curative potential is based on two very different mechanisms, involving the conditioning regimen and the graft-versus-host reactions, respectively. The high-dose chemo-radiotherapy conditioning regimen is aimed at destroying tumor cells, ablating the host immune system (to prevent rejection) and eliminating the host bone marrow (to "make space" for donor stem cells). However, the definitive eradication of tumor cells is also largely mediated by an immune-mediated destruction of malignant cells by donor lymphocytes termed graft-versus-leukemia (GVL) or graft-versus-tumor (GVT) effect. However, because of its toxicity, conventional allogeneic HSCT is restricted to younger (< 55 years) and fitter patients. These observations led several groups to set up new (less toxic) transplant protocols based on a two step approach: first the use of immunosuppressive (but nonmyeloablative) conditioning regimens providing sufficient immunosuppression to achieve engraftment of allogeneic hematopoietic stem cells and, in a second step, destruction of malignant cells by the GVL effect. These transplants are called nonmyeloablative HSCT or reduced-conditioning HSCT or minitransplants. Preliminary results show that minitransplants are feasible with a relatively low transplant-related mortality (TRM) even in patients up to 70 years. In addition, strong anti-tumor responses are observed in several hematological malignancies as well as in some patients with renal cell carcinoma. As the benefits of minitransplants over alternative forms of treatment remain to be demonstrated, this strategy should be restricted to patients included in clinical trials.

Hematopoietic Cell Transplantation for Benign Hematological Disorders and Solid Tumors

Allogeneic hematopoietic cell transplantation (HCT) has been successfully used as replacement therapy for patients with aplastic anemia and hemoglobinopathies. Both autologous and allogeneic HCT following high-dose chemotherapy can correct manifestations of autoimmune diseases. The impressive allogeneic graft-versus-tumor effects seen in patients given HCT for hematological malignancies have stimulated trials of allogeneic immunotherapy in patients with otherwise refractory metastatic solid tumors. This session will update the status of HCT in the treatment of benign hematological diseases and solid tumors.

In Section I, Dr. Rainer Storb reviews the development of nonmyeloablative conditioning for patients with severe aplastic anemia who have HLA-matched family members. He also describes the results in patients with aplastic anemia given HCT from unrelated donors after failure of responding to immunosuppressive therapy. The importance of leuko-poor and in vitro irradiated blood product transfusions for avoiding graft rejection will be discussed.

In Section II, Dr. Guido Lucarelli reviews the status of marrow transplantation for thalassemia major and updates results obtained in children with class I and class II severity of thalassemia. He also describes results of new protocols for class III patients and efforts to extend HCT to thalassemic patients without HLA-matched family members.

In Section III, Dr. Peter McSweeney reviews the current status of HCT for severe autoimmune diseases. He summarizes the results of autologous HCT for systemic sclerosis, multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus, and reviews the status of planned Phase III studies for autologous HCT for these diseases in North America and Europe. He also discusses a possible role of allogeneic HCT in the treatment of these diseases.

In Section IV, Dr. Richard Childs discusses the development and application of nonmyeloablative HCT as allogeneic immunotherapy for treatment-refractory solid tumors. He reviews the results of pilot clinical trials demonstrating graft-versus-solid tumor effects in a variety of metastatic cancers and describes efforts to characterize the immune cell populations mediating these effects, as well as newer methods to target the donor immune system to the tumor.

Administration of low-dose interleukin-2 plus G-CSF/EPO early after autologous PBSC transplantation: effects on immune recovery and NK activity in a prospective study in women with breast and ovarian cancer

This study evaluated the effects of low-dose IL-2 plus G-CSF/EPO on post-PBSC transplantation (PBSCT) immune-hematopoietic reconstitution and NK activity in patients with breast (BrCa) and ovarian cancer (OvCa). To this end, two consecutive series of patients were prospectively assigned to distinct post-PBSCT cytokine regimens (from day +1 to day +12) which consisted of G-CSF (5 microg/kg/day) plus EPO (150 IU/kg/every other day) in 17 patients (13 BrCa and 4 OvCa) or G-CSF/EPO plus IL-2 (2 x 10(5) IU/m(2)/day) in 15 patients (10 BrCa and 5 OvCa). Hematopoietic recovery and post-transplantation clinical courses were comparable in G-CSF/EPO- and in G-CSF/EPO plus IL-2-treated patients, without significant side-effects attributable to IL-2 administration. In the early and late post-transplant period a significantly higher PMN count was observed in G-CSF/EPO plus IL-2-treated patients (P = 0.034 and P = 0.040 on day +20 and +100, respectively). No significant differences were found between the two groups of patients in the kinetics of most lymphocyte subsets except naive CD45RA(+) T cells which had a delayed recovery in G-CSF/EPO plus IL-2 patients (P = 0.021 on day +100). No significant difference was observed between NK activity in the two different groups, albeit a significantly higher NK count was observed in G-CSF/EPO plus IL-2 series on day +20 (P = 0.020). These results demonstrate that low-dose IL-2 can be safely administered in combination with G-CSF/EPO early after PBSCT and that it exerts favorable effects on post-PBSCT myeloid reconstitution, but not on immune recovery.

The hematopoietic system-specific minor histocompatibility antigen HA-1 shows aberrant expression in epithelial cancer cells

Allogeneic stem cell transplantation (SCT) can induce curative graft-versus-tumor reactions in patients with hematological malignancies and solid tumors. The graft-versus-tumor reaction after human histocompatibility leukocyte antigen (HLA)-identical SCT is mediated by alloimmune donor T cells specific for polymorphic minor histocompatibility antigens (mHags). Among these, the mHag HA-1 was found to be restricted to the hematopoietic system. Here, we report on the HA-1 ribonucleic acid expression by microdissected carcinoma tissues and by single disseminated tumor cells isolated from patients with various epithelial tumors. The HA-1 peptide is molecularly defined, as it forms an immunogenic peptide ligand with HLA-A2 on the cell membrane of carcinoma cell lines. HA-1-specific cytotoxic T cells lyse epithelial tumor cell lines in vitro, whereas normal epithelial cells are not recognized. Thus, HA-1-specific immunotherapy combined with HLA-identical allogeneic SCT may now be feasible for patients with HA-1(+) carcinomas.

Allogeneic hematopoietic stem cell transplantation in ovarian carcinoma: results of five patients

Allogeneic hematopoietic stem cell transplantation is often used to treat hematologic malignancies. The efficacy of this procedure is due to both myeloablative conditioning and graft-versus-leukemia (GVL). However, the disadvantages of allogeneic transplantation include graft-versus-host disease (GVHD), relapse from the original tumor, and patient susceptibility to opportunistic infections. Lately, allogeneic transplantation has been developed to treat solid tumors, with the expectation that graft-versus-tumor (GVT), like GVL, will have a significant anti-tumor effect. This effect has been demonstrated in renal carcinomas, and with less evidence in breast cancers. Five patients with malignant ovarian tumors resistant to chemotherapy underwent allogeneic transplantation, four from bone marrow, and one from peripheral blood stem cells. All donors were HLA-identical siblings. One patient received a myeloablative conditioning regimen, while the other four received a non-myeloablative regimen. Two patients received donor lymphocyte infusions (DLI). Four of the patients presented with acute or chronic GVHD associated with tumor regression of at least 50%. These tumor regressions were measured by CA-125 levels and CT scans. The fifth patient died of rapid progression just after transplantation. Of the four transplantation survivors, three received a non-myeloablative regimen which did not seem to reduce treatment effectiveness. While it did reduce toxicity, one of these patients died of GVHD after 127 days. DLI was administered to two patients. These infusions seemed to promote GVHD which was able to control disease progression for one patient and had no apparent effect on the other. Allograft of hematopoietic stem cells might be of interest in ovarian cancer. The results in one patient also suggest that DLI may be an effective immunotherapy, although doses and timing need to be determined. The number of cases presented is small, however, and clinical experience on a larger scale will be required to determine the real clinical efficacy of graft versus cancerous ovarian cells.

Nonmyeloablative conditioning followed by hematopoietic cell allografting and donor lymphocyte infusions for patients with metastatic renal and breast cancer

The feasibility and toxicity of allogeneic stem cell transplantation after nonmyeloablative conditioning including thiotepa, fludarabine, and cyclophosphamide have been investigated in 6 patients with breast cancer and 7 patients with renal cell cancer. The program included the use of escalating doses of donor lymphocyte infusions (DLI) and/or interferon alpha (IFNalpha) for patients showing no tumor response and no graft-versus-host disease (GVHD). Patients were at high risk of transplant-related mortality (TRM) because of age, advanced stage, and previous treatments. We observed a partial remission in 4 renal cancer and in 2 breast cancer patients (one at the molecular level in the bone marrow), occurring after cyclosporine withdrawal or after DLI and/or IFNalpha. All the responses were accompanied by the occurrence of acute GVHD. We conclude that reduced-intensity allogeneic stem cell transplantation is a feasible procedure in renal and breast cancer, and that the exploitation of graft-versus-tumor effect after DLI is a promising finding.

Allogeneic blood stem cell transplantation after a reduced-intensity, preparative regimen: a pilot study in patients with refractory malignancies

BACKGROUND

The immune-mediated graft-versus-tumor (GVT) effect plays a therapeutic role in the treatment of patients with hematologic malignancies who undergo allogeneic hematopoietic stem cell transplantation (HSCT). More recently, it was reported that a GVT effect also occurred in patients who underwent transplantation for metastatic renal carcinoma. The authors carried out a pilot trial of allogeneic transplantation after a reduced-intensity, preparative regimen in patients with refractory malignancies, including solid tumors. The objectives of the current study were to evaluate the feasibility of this approach in terms of toxicity and engraftment and to document evidence of GVT effects.

METHODS

Seventeen patients with Stage IV malignancies (7 patients with renal cell carcinoma, 3 patients with sarcoma, 2 patients with breast carcinoma, 2 patients with Hodgkin disease, 1 patient with ovarian carcinoma, 1 patient with melanoma, and 1 patient with both melanoma and renal cell carcinoma) that were not amenable to further conventional treatment were enrolled. The median patient age was 43 years (range, 10-60 years). The Eastern Cooperative Oncology Group performance status (PS) was 0-1 in 11 patients and 2-3 in 6 patients. Preparative treatment consisted of reduced-intensity chemotherapy with fludarabine (30 mg/m(2) per day for 4 consecutive days) and cyclophosphamide (30 mg/Kg per day for 2 consecutive days) prior to allogeneic HSCT from a human leukocyte antigen-identical sibling. The median number of CD34+ cells infused was 6.06 x 10(6)/kg (range, 1.5-14.0 x 10(6)/kg). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporin-A and short-term methotrexate.

RESULTS

Patients who had a PS of 2-3 prior to undergoing HSCT experienced Grade 4 hematologic toxicities and Grade > or = 3 organ toxicities and died of either treatment-related complications or disease progression within 100 days from transplantation. By contrast, 10 of 11 patients who had a PS of 0-1 prior to undergoing HSCT experienced only short-lasting, Grade < or = 3 neutropenia and thrombocytopenia and no organ toxicity; 1 of 10 patients died of graft failure on Day +29 after undergoing HSCT. By Day +90, 100% donor chimerism was documented in all patients with a past history of heavy chemotherapy, whereas mixed donor chimerism was observed in the 4 patients with a past history of only 1 line of chemotherapy and/or immunotherapy prior to entering the HSCT program. Grade 2-3 acute GVHD occurred in 5 patients. Among patients with a follow-up > 100 days, 2 complete responses and 3 transitory partial responses were recorded.

CONCLUSIONS

With this conditioning regimen, full donor chimerism was achieved rapidly only in patients who had received previous intensive chemotherapy. In a proportion of patients with refractory malignancies, allogeneic transplantation resulted in tumor regression. This novel therapeutic strategy may provide little benefit in patients with poor PS and rapidly progressing disease.

Nonmyeloablative allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is the most effective treatment for selected hematological malignancies. Its curative potential is largely mediated by an immune-mediated destruction of malignant cells by donor lymphocytes termed graft-versus-leukemia (GVL) effect. However, because of its toxicity, conventional allogeneic HSCT is restricted to younger and fitter patients. These observations led several groups to set up new (less toxic) transplant protocols (nonmyeloablative stem cell transplantation or NMSCT) based on a two-step approach: first, the use of immunosuppressive (but nonmyeloablative) preparative regimens providing sufficient immunosuppression to achieve engraftment of allogeneic hematopoietic stem cells and, in a second step, destruction of malignant cells by the GVL effect. Preliminary results showed that NMSCT were feasible with a relatively low transplant-related mortality (TRM), even in patients older than 65 years. In addition, strong antitumor responses were observed in several hematological malignancies as well as in some patients with renal cell carcinoma. After discussing the mechanisms and efficacy of the GVL effect as well as the rationale for NMSCT strategies, this article reviews the first results of ongoing clinical trials. Innovative modalities that may permit amplification of the GVL effect while minimizing the risk of GVHD are discussed. Because the benefits of NMSCT over alternative forms of treatment remain to be demonstrated, this strategy should be restricted to patients included in clinical trials.

Advances in allogeneic stem cell transplantation: directing graft-versus-leukemia at solid tumors

Allogeneic stem cell transplantation was originally developed as a method to rescue hematopoietic function following high dose "myeloablative" therapy in the treatment of hematological malignancies. In the first two decades of its use, dose-intensive chemotherapy alone was credited with curing those patients who achieved sustained remission following this procedure. However, more recently investigators have come to recognize that antineoplastic effects mediated by immunocompetent donor T-cells transplanted with the stem cell allograft can be induced against hematological malignancies. Indeed, this graft-vs-leukemia (GVL) or graft-vs-tumor (GVT) effect is now felt to represent the principal modality required to sustain durable remissions of hematological malignancies following this approach. The powerful and potentially curative nature of the GVT effect in hematological cancers has recently lured oncologists into exploring the therapeutic potential of allogeneic stem cell transplantation as an investigational approach for treatment-refractory solid tumors. We review here the development and early clinical results of allogeneic stem cell transplantation as potential immunotherapy for solid tumors.

Nonmyeloablative stem cell transplantation for solid tumors: expanding the application of allogeneic immunotherapy

In the arena of tumor immunology, there is a growing perception that the graft-versus-leukemia (GVL) reaction that follows allogeneic stem cell transplantation represents the most potent form of cancer immunotherapy currently in clinical use. While allogeneic stem cell transplantation has become an accepted form of "immunotherapy" for the treatment of hematological malignancies, its efficacy in inducing antitumor effects against nonhematological cancers has, until recently, been largely unexplored. The investigational application of nonmyeloablative allogeneic stem cell transplantation (NST) in solid tumors represents the logical consequence of almost 50 years of experimental and clinical research into the immunological basis for the cure of hematological malignancies following allogeneic bone marrow transplant (BMT). Here we review the historical background, development, and preliminary clinical results of allogeneic stem cell transplantation as immunotherapy for solid tumors.

Blood stem cell transplantation for breast cancer: new approaches using pre- peri- post-transplant immunotherapy

Autologous peripheral blood stem cell transplantation (auto-PBSCT) after high dose chemotherapy is usually offered to breast cancer patients carrying a high risk of relapse or having chemosensitive metastatic disease. Whether progression free and overall survival of such patients is improved after auto-PBSCT compared to conventional chemotherapy is a matter of debate. Currently available results of randomised trials could not uniformly prove or disprove auto-PBSCT being advantageous. Yet such studies have not employed any manipulation of the stem cell graft or any post-transplant immunomodulation exploiting the unique immunological environment for tumour eradication which exists only after auto-PBSCT. Preliminary data have discussed the ex vivo and in vivo generation of cytotoxic effector cells employing IL-2 and/or IFN-alpha/gamma in the auto-PBSCT setting. Other cytokines such as IL-12, IL-15 and prolactin have likewise been considered. Several anticancer vaccine protocols after auto-PBSCT are ongoing using monovalent vaccines or anti-idiotypic antibodies. Polyvalent anticancer vaccines, cytokine secreting tumour cells, tumour pulsed or hybridised dendritic cells (DC) enhanced with cytokines are studied. Monoclonal antibodies (mAb) could assist: unlabelled for pretransplant exvivo purging, post-transplant for enhancing antibody-dependent cell mediated cytotoxicity (ADCC) or radioimmunoconjugated as an additive cytotoxic part of the conditioning regimen. Autologous graft versus host induction and allogeneic stem cell transplantation (probably with non-myeloablative conditioning followed by donor lymphocyte infusions) are other approaches. Evaluation of successful combinations, optimal dosages and appropriate timing schedules is the subject of future investigations. Since breast cancer patients belong to countless subgroups, a large number of protocols need to be addressed in order to avoid over treatment and prevent relapse.