Recent Metabolic Advances for Preventing and Treating Acute and Chronic Graft Versus Host Disease

The therapeutic efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is limited by the development of graft-versus-host disease (GVHD). In GVHD, rigorous pre-conditioning regimen resets the immune landscape and inflammatory milieu causing immune dysregulation, characterized by an expansion of alloreactive cells and a reduction in immune regulatory cells. In acute GVHD (aGVHD), the release of damage- and pathogen- associated molecular patterns from damaged tissue caused by the conditioning regimen sets the stage for T cell priming, activation and expansion further exacerbating tissue injury and organ damage, particularly in the gastrointestinal tract. Studies have shown that donor T cells utilize multiple energetic and biosynthetic pathways to mediate GVHD that can be distinct from the pathways used by regulatory T cells for their suppressive function. In chronic GVHD (cGVHD), donor T cells may differentiate into IL-21 producing T follicular helper cells or tissue resident T helper cells that cooperate with germinal center B cells or memory B cells, respectively, to produce allo- and auto-reactive antibodies with subsequent tissue fibrosis. Alternatively, donor T cells can become IFN- γ/IL-17 cytokine expressing T cells that mediate sclerodermatous skin injury. Patients refractory to the first line standard regimens for GVHD treatment have a poor prognosis indicating an urgent need for new therapies to restore the balance between effector and regulatory immune cells while preserving the beneficial graft-versus-tumor effect. Emerging data points toward a role for metabolism in regulating these allo- and auto-immune responses. Here, we will discuss the preclinical and clinical data available on the distinct metabolic demands of acute and chronic GVHD and recent efforts in identifying therapeutic targets using metabolomics. Another dimension of this review will examine the changing microbiome after allo-HSCT and the role of microbial metabolites such as short chain fatty acids and long chain fatty acids on regulating immune responses. Lastly, we will examine the metabolic implications of coinhibitory pathway blockade and cellular therapies in allo-HSCT. In conclusion, greater understanding of metabolic pathways involved in immune cell dysregulation during allo-HSCT may pave the way to provide novel therapies to prevent and treat GVHD.

Combining Immunocytokine and Ex Vivo Activated NK Cells as a Platform for Enhancing Graft-Versus-Tumor Effects Against GD2+ Murine Neuroblastoma

Management for high-risk neuroblastoma (NBL) has included autologous hematopoietic stem cell transplant (HSCT) and anti-GD2 immunotherapy, but survival remains around 50%. The aim of this study was to determine if allogeneic HSCT could serve as a platform for inducing a graft-versus-tumor (GVT) effect against NBL with combination immunocytokine and NK cells in a murine model. Lethally irradiated C57BL/6 (B6) x A/J recipients were transplanted with B6 bone marrow on Day +0. On day +10, allogeneic HSCT recipients were challenged with NXS2, a GD2+ NBL. On days +14-16, mice were treated with the anti-GD2 immunocytokine hu14.18-IL2. In select groups, hu14.18-IL2 was combined with infusions of B6 NK cells activated with IL-15/IL-15Rα and CD137L ex vivo. Allogeneic HSCT alone was insufficient to control NXS2 tumor growth, but the addition of hu14.18-IL2 controlled tumor growth and improved survival. Adoptive transfer of ex vivo CD137L/IL-15/IL-15Rα activated NK cells with or without hu14.18-IL2 exacerbated lethality. CD137L/IL-15/IL-15Rα activated NK cells showed enhanced cytotoxicity and produced high levels of TNF-α in vitro, but induced cytokine release syndrome (CRS) in vivo. Infusing Perforin-/- CD137L/IL-15/IL-15Rα activated NK cells had no impact on GVT, whereas TNF-α-/- CD137L/IL-15/IL-15Rα activated NK cells improved GVT by decreasing peripheral effector cell subsets while preserving tumor-infiltrating lymphocytes. Depletion of Ly49H+ NK cells also improved GVT. Using allogeneic HSCT for NBL is a viable platform for immunocytokines and ex vivo activated NK cell infusions, but must be balanced with induction of CRS. Regulation of TNFα or activating NK subsets may be needed to improve GVT effects.

MyD88 Costimulation in Donor CD8+ T Cells Enhances the Graft-versus-Tumor Effect in Murine Hematopoietic Cell Transplantation

Donor-derived lymphocytes from allogeneic hematopoietic cell transplantation (allo-HCT) or donor lymphocyte infusion can mediate eradication of host tumor cells in a process labeled the graft-versus-tumor (GVT) effect. Unfortunately, these treatments have produced limited results in various types of leukemia because of an insufficient GVT effect. In this context, molecular engineering of donor lymphocytes to increase the GVT effect may benefit cancer patients. Activating MyD88 signaling in CD8+ T cells via TLR enhances T cell activation and cytotoxicity. However, systemic administration of TLR ligands to stimulate MyD88 could induce hyperinflammation or elicit protumor effects. To circumvent this problem, we devised a synthetic molecule consisting of MyD88 linked to the ectopic domain of CD8a (CD8α:MyD88). We used this construct to test the hypothesis that MyD88 costimulation in donor CD8+ T cells increases tumor control following allo-HCT in mice by increasing T cell activation, function, and direct tumor cytotoxicity. Indeed, an increase in both in vitro and in vivo tumor control was observed with CD8α:MyD88 T cells. This increase in the GVT response was associated with increased T cell expansion, increased functional capacity, and an increase in direct cytotoxic killing of the tumor cells. However, MyD88 costimulation in donor CD8+ T cells was linked to increased yet nonlethal graft-versus-host disease in mice treated with these engineered CD8+ T cells. Given these observations, synthetic CD8α:MyD88 donor T cells may represent a unique and versatile approach to enhance the GVT response that merits further refinement to improve the effectiveness of allo-HCT.

Autologous graft versus myeloma: it's not a myth

Graft-versus-tumor (GVT) effects have been thought to mostly result from allogeneic transplants; however, there is a growing body of research that supports a possible autologous GVT effect. In early clinical studies, a positive correlation between lymphocyte count recovery after autologous transplantation and overall survival has been observed. However, mechanistic studies to identify the mediators of autologous GVT responses have been lacking. In this issue of the JCI, Vuckovic et al. observed a T cell-dependent autologous GVT effect in the Vk*MYC myeloma model. Moreover, the authors showed that CD8+ T cells mediate myeloma control through IFN-γ secretion, which could be further augmented with a CD137 agonist, suggesting a therapeutic approach for enhancing autologous GVT.

Incorporation of high-dose 131 I-metaiodobenzylguanidine treatment into killer immunoglobulin-like receptor/HLA-ligand mismatched haploidentical stem cell transplantation for children with neuroblastoma who failed tandem autologous stem cell transplantation

BACKGROUND

We performed a pilot study (NCT 00793351) to evaluate the effectiveness and feasibility of a strategy incorporating high-dose ¹³¹ I-metaiodobenzylguanidine (HD-MIBG) treatment into killer immunoglobulin-like receptor (KIR)/HLA-ligand mismatched haploidentical stem cell transplantation (haplo-SCT) in improving the survival of children with neuroblastoma who failed previous tandem autologous SCT.

PROCEDURE

If the patient remained progression free with salvage treatment, HD-MIBG treatment (18 mCi/kg) was given prior to reduced-intensity conditioning (cyclophosphamide + fludarabine + antithymocyte globulin). Grafts from KIR/HLA-ligand mismatched, preferably BX haplotype, haploidentical donors were transplanted to enhance the graft-versus-tumor (GVT) effect.

RESULTS

A total of seven patients were enrolled and three donors had a BX haplotype. Toxicities during HD-MIBG treatment and reduced-intensity conditioning were mild. Neutrophil recovery and complete or near complete donor chimerism were rapidly achieved. Six patients experienced acute graft-versus-host disease (GVHD; grade I in five and grade III in one), and four of six evaluable patients experienced chronic GVHD (two mild and two severe). Four patients died from tumor progression, one died from sepsis without progression, and the other two remained alive in complete response during 34 and 48 months posttransplant. All three patients remained progression free after BX haplotype SCT, whereas the other four experienced progression after AA haplotype SCT.

CONCLUSIONS

Our results suggest that the incorporation of HD-MIBG treatment in haplo-SCT and the use of BX haplotype donors might improve outcome, but this approach is currently limited by unacceptable GVHD. Further work focused on enhancement of GVT effects in relapsed neuroblastoma should be coupled with efforts to reduce GVHD.

Development of a Minor Histocompatibility Antigen Vaccine Regimen in the Canine Model of Hematopoietic Cell Transplantation

BACKGROUND

Minor histocompatibility antigen (miHA) vaccines have the potential to augment graft-versus-tumor effects without graft-versus-host disease (GVHD). We used mixed hematopoietic chimerism in the canine model of major histocompatibility complex-matched allogeneic hematopoietic cell transplantation as a platform to develop a miHA vaccination regimen.

METHODS

We engineered DNA plasmids and replication-deficient human adenovirus type 5 constructs encoding large sections of canine SMCY and the entire canine SRY gene.

RESULTS

Priming with replication-deficient human adenovirus type 5 constructs and boosting with ex vivo plasmid-transfected dendritic cells and cutaneous delivery of plasmids with a particle-mediated epidermal delivery device (PMED) in 2 female dogs induced antigen-specific T-cell responses. Similar responses were observed after a prime-boost vaccine regimen in three female hematopoietic cell transplantation donors. Subsequent donor lymphocyte infusion resulted in a significant change of chimerism in 1 of 3 male recipients without any signs of graft-versus-host disease. The change in chimerism in the recipient occurred in association with the development of CD4+ and CD8+ T-cell responses to the same peptide pools detected in the donor.

CONCLUSIONS

These studies describe the first in vivo response to miHA vaccination in a large, outbred animal model without using recipient cells to sensitize the donor. This model provides a platform for ongoing experiments designed to define optimal miHA targets and develop protocols to directly vaccinate the recipient.

The role of allogeneic stem cell transplantation in Hodgkin's lymphoma

OPINION STATEMENT

The treatment of patients with classical Hodgkin's lymphoma relapsing after autologous stem cell transplantation represents a clear unmet need. Overall long-term outcome is not the same in these patients and therapeutic options in this setting are very heterogeneous and include salvage CT and/or RT followed or not by a second stem cell transplantation, palliative care, new drugs, or biological agents. Despite the absence of prospective, randomized, clinical trials, allogeneic stem cell transplantation either from a HLA identical sibling or a matched, unrelated donor represents an attractive option for those young patients with chemosensitive disease after being treated with a salvage protocol. The use of reduced intensity conditioning regimens has been able to drastically decrease nonrelapse mortality, although relapse rate remains a significant issue in this setting. More intense conditioning protocols could eventually decrease the relapse rate after the allogeneic procedure and, as indicated by a recent retrospective analysis of the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation, nonrelapse mortality does not represent a major problem nowadays for patients with multiply relapsed Hodgkin's lymphoma. Brentuximab vedotin is an antibody-drug conjugate that selectively delivers monomethyl auristatin E, an antimicrotubule agent, into CD30-expressing cells. Its use has been approved recently for patients with Hodgkin's lymphoma relapsing after autologous stem cell transplantation. As a single dose, brentuximab vedotin is able to achieve an objective response rate of 75 % with 34 % of the patients achieving a complete remission. Its widespread use will most certainly change the treatment paradigm of this subgroup of patients, either avoiding the allogeneic procedure in some patients or by increasing the group of potential candidates to an allogeneic transplant being used as a "bridge to allo." Additional information on long-term outcome of patients being treated with this drug or the development of prospective clinical trials in this setting will most probably give some light to this question we have nowadays.

Strategies for the identification of T cell-recognized tumor antigens in hematological malignancies for improved graft-versus-tumor responses after allogeneic blood and marrow transplantation

Allogeneic blood and marrow transplantation (allo-BMT) is an effective immunotherapeutic treatment that can provide partial or complete remission for patients with hematological malignancies. Mature donor T cells in the donor inoculum play a central role in mediating graft-versus-tumor (GVT) responses by destroying residual tumor cells that persist after conditioning regimens. Alloreactivity towards minor histocompatibility antigens (miHA), which are varied tissue-related self-peptides presented in the context of major histocompatibility complex (MHC) molecules on recipient cells, some of which may be shared on tumor cells, is a dominant factor for the development of GVT. Potentially, GVT can also be directed to tumor-associated antigens or tumor-specific antigens that are more specific to the tumor cells themselves. The full exploitation of allo-BMT, however, is greatly limited by the development of graft-versus-host disease (GVHD), which is mediated by the donor T cell response against the miHA expressed in the recipient's cells of the intestine, skin, and liver. Because of the significance of GVT and GVHD responses in determining the clinical outcome of patients, miHA and tumor antigens have been intensively studied, and one active immunotherapeutic approach to separate these two responses has been cancer vaccination after allo-BMT. The combination of these two strategies has an advantage over vaccination of the patient without allo-BMT because his or her immune system has already been exposed and rendered unresponsive to the tumor antigens. The conditioning for allo-BMT eliminates the patient's existing immune system, including regulatory elements, and provides a more permissive environment for the newly developing donor immune compartment to selectively target the malignant cells. Utilizing recent technological advances, the identities of many human miHA and tumor antigenic peptides have been defined and are currently being evaluated in clinical and basic immunological studies for their ability to produce effective T cell responses. The first step towards this goal is the identification of targetable tumor antigens. In this review, we will highlight some of the technologies currently used to identify tumor antigens and anti-tumor T cell clones in hematological malignancies.

Transplantation tolerance: from theory to clinic

Tolerance induction and alloreactivity can be applied to the clinic for the transplantation of solid organs and in the treatment of human cancers respectively. Hematopoietic chimerism, the stable coexistence of host and donor blood cells, guarantees that a solid organ from the same donor will be tolerated without a requirement for maintenance immunosuppression, and it also serves as a platform for the adoptive immunotherapy of hematologic malignancies using donor lymphocyte infusions. This review focuses on clinically relevant methods for inducing hematopoietic chimerism and transplantation tolerance, with a special emphasis on reduced intensity transplantation conditioning and high dose, post-transplantation cyclophosphamide to prevent graft rejection and graft-versus-host disease (GVHD). Reduced intensity transplantation regimens permit a transient cooperation between donor and host immune systems to eradicate malignancy without producing GVHD. Their favorable toxicity profile also enables the application of allogeneic stem cell transplantation to treat non-malignant disorders of hematopoiesis and to induce tolerance for solid organ transplantation.

Role of allogeneic stem cell transplantation in multiple myeloma

Multiple myeloma is currently incurable using standard treatment regimens. While the introduction of high-dose chemotherapy with autologous stem cell rescue has been shown to increase overall survival when compared with chemotherapy alone, this strategy is palliative. Allogeneic stem cell transplantation provides the potential for long-term disease-free survival in a small proportion of patients, although its application has been limited by procedure-related mortality, reflecting the intensive myeloablative conditioning given. Recently, reduced intensity conditioning regimens have been developed in an attempt to reduce toxicity whilst preserving the allogeneic graft-versus-myeloma effect, therefore maintaining the potential for disease eradication. This review aims to examine the current position of allogeneic transplantation in the management of myeloma.

Treatment of Lymphoid Malignancies with Non-myeloablative Stem Cell Transplantation

The traditional approach to allogeneic hematopoietic stem cell transplantation involves the administration of myeloablative preparative regimens. This form of conditioning is associated with a relatively high incidence of regimen-related toxicity. As a result, candidates for allogeneic stem cell transplantation may be excluded owing to advanced age or co-morbid medical illness. Recently, so-called "non-myeloablative" regimens have been introduced, where less intense conditioning therapy is used in an attempt to reduce regimen-related toxicity. In addition, non-myeloablative transplantation takes advantage of the graft-versus-tumour effect that is characteristic of allogeneic stem cell transplantation. We review the background, available clinical data, and future directions in non-myeloablative stem cell transplantation, and focus on its potential use in the treatment of lymphoid malignancies.

Graft-versus-host disease and graft-versus-tumor effects after allogeneic hematopoietic cell transplantation

PURPOSE

We designed a minimal-intensity conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) in patients with advanced hematologic malignancies unable to tolerate high-intensity regimens because of age, serious comorbidities, or previous high-dose HCT. The regimen allows the purest assessment of graft-versus-tumor (GVT) effects apart from conditioning and graft-versus-host disease (GVHD) not augmented by regimen-related toxicities.

PATIENTS AND METHODS

Patients received low-dose total-body irradiation ± fludarabine before HCT from HLA-matched related (n = 611) or unrelated (n = 481) donors, followed by mycophenolate mofetil and a calcineurin inhibitor to aid engraftment and control GVHD. Median patient age was 56 years (range, 7 to 75 years). Forty-five percent of patients had comorbidity scores of ≥ 3. Median follow-up time was 5 years (range, 0.6 to 12.7 years).

RESULTS

Depending on disease risk, comorbidities, and GVHD, lasting remissions were seen in 45% to 75% of patients, and 5-year survival ranged from 25% to 60%. At 5 years, the nonrelapse mortality (NRM) rate was 24%, and the relapse mortality rate was 34.5%. Most NRM was a result of GVHD. The most significant factors associated with GVHD-associated NRM were serious comorbidities and grafts from unrelated donors. Most relapses occurred early while the immune system was compromised. GVT effects were comparable after unrelated and related grafts. Chronic GVHD, but not acute GVHD, further increased GVT effects. The potential benefit associated with chronic GVHD was outweighed by increased NRM.

CONCLUSION

Allogeneic HCT relying on GVT effects is feasible and results in cures of an appreciable number of malignancies. Improved results could come from methods that control progression of malignancy early after HCT and effectively prevent GVHD.

Reduced-intensity allogeneic stem cell transplantation for children with neuroblastoma who failed tandem autologous stem cell transplantation

BACKGROUND

To date, no effective curative option is available for children with neuroblastoma (NB) who failed tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT). The present study evaluated the feasibility and efficacy of reduced-intensity allogeneic stem cell transplantation (RI alloSCT) in six children with NB who failed tandem HDCT/autoSCT.

PROCEDURE

A cyclophosphamide/fludarabine regimen was used as a conditioning for HLA-matched SCT, and ATG was added for haploidentical SCT. Peripheral blood stem cells from four HLA-matched donors and two haploidentical donors were transplanted. Immune suppression was rapidly tapered if graft-versus-host disease (GVHD) was absent.

RESULTS

Regimen-related short-term toxicity was manageable, and complete donor chimerism was achieved in the early period after transplant. Grade I/II acute GVHD developed or was induced in all patients. Tumor response, attributed to a graft-versus-tumor (GVT) effect, was observed in two of six patients after induction of acute GVHD. The other four patients with significant tumor burden prior to transplant had tumor progression despite presence of GVHD. However, it was difficult to effectively reduce the tumor burden prior to transplant through the use of conventional treatment modalities.

CONCLUSION

Although regimen-related short-term toxicity was manageable in intensively pretreated patients with NB, GVT effect was not sufficiently strong to control tumor progression in patients who had a significant tumor burden at transplant. Therefore, new treatment modalities to effectively reduce tumor burden prior to transplant in concert with post-transplant adjuvant treatment to enhance the GVT effect are needed to improve the outcome after RI alloSCT.

Allogeneic stem cell transplantation in follicular lymphoma

Myeloablative allogeneic transplantation in follicular lymphoma has been found to be particularly effective in patients with relapsed disease and an inadequate bone marrow reserve or massive bone marrow involvement. Allogeneic transplantation carries the promise of long-term disease control by graft-versus-lymphoma immunity but is associated with a 30%-40% risk of transplant-related mortality. Nonmyeloablative stem cell transplantation exploits the graft-versus-lymphoma effect without the attendant toxicity of myeloablative conditioning. The results of several recent reports suggest that it has a high likelihood of resulting in long-term disease-free survival in patients up to 70 years of age with a good performance status, chemotherapy-sensitive disease, and HLA-matched sibling donors. At The University of Texas MD Anderson Cancer Center, the standard NST conditioning regimen for patients with follicular lymphoma is fludarabine, cyclophosphamide, and rituximab. This regimen results in a transplantation-related mortality rate of 10%, and 85% of patients are alive without disease at 8 years. In this article, we discuss the current issues in NST for follicular lymphoma, including chemosensitivity, conditioning intensity, graft-versus-host disease, donor lymphocyte infusion's role, and ongoing strategies to treat refractory disease.

[Bortezomib plus dexamethasone treatment followed by reduced-intensity allogeneic stem cell transplantation for multiple myeloma refractory to high-dose chemotherapy with autologous transplantation]

We present two long-term survivors after allogeneic transplantation with reduced-intensity conditioning regimen following relapse after autologous stem cell transplantation (ASCT) for multiple myeloma (MM). The first case was a 47-year-old male with IgG MM treated with 2 courses of high-dose melphalan along with ASCT and thalidomide, resulting in a minimal response. He then received 2 courses of bortezomib plus dexamethasone (BD) regimen, which was discontinued due to peripheral neuropathy. Allogeneic peripheral stem cell transplantation (PBSCT) from a sibling donor was performed after pretreatment with fludarabin (125 mg/m(2)) and melphalan (100 mg/m(2)). Engraftment was observed on day 11 and monoclonal IgG had disappeared 5 months after transplantation. The patient has been in complete remission for more than two and a half years with moderate chronic graft-versus-host disease (GVHD). The second case was a 51-year-old male who relapsed after ASCT for IgA MM. After 3 courses of BD treatment, irradiation to lumbar plasmacytoma, and thalidomide therapy, he received allogeneic PBSCT from a related donor after the same reduced intensity conditioning as performed in case 1. A complete response was observed 6 months after PBSCT. The patient has remained relapse-free for two years without GVHD. BD treatment followed by allogeneic stem cell transplantation with reduced intensity conditioning is supposed to be one of the most powerful strategies for patients showing relapse after ASCT.

Engraftment of unrelated cord blood after reduced-intensity conditioning regimen in children with refractory neuroblastoma: a feasibility trial

Relapsed or refractory neuroblastoma is uniformly fatal. We hypothesized that allogeneic response could provide a platform for immunotherapy in neuroblastoma. We therefore undertook a pilot trial of unrelated cord blood transplantation after reduced intensity conditioning regimen (RIC) in children with relapsed neuroblastoma to assess engraftment and tolerability in this heavily pretreated population. The RIC included CY (50 mg/kg, day -6), fludarabine (40 mg/m(2), days -6 to -2), total body irradiation (200 cGy, day -1), and rabbit anti-thymocyte globulin (2.5 mg/kg, days -3 to -1). Six patients were enrolled: four were in partial responsive relapse, one with a mixed response and one in refractory relapse. All patients tolerated the regimen well and had donor engraftment with full neutrophil and plt recovery (median time 12 and 35 days, respectively). One patient never experienced neutropenia and another did not need plt transfusions. All patients progressed after transplant (median time 55 days, 26-180 days). Natural killer (NK) cell counts were normal within 2 months, whereas T-cell recovery was slower. In conclusion, unrelated cord blood engrafts after RIC in children with refractory neuroblastoma. Future research should be aimed at transplanting patients with minimal residual disease, using less intensive immunosuppression and adding NK-cell based post transplant immunotherapy.

Reduced-intensity conditioning followed by related allografts in hematologic malignancies: long-term outcomes most successful in indolent and aggressive non-Hodgkin lymphomas

Reduced-intensity conditioning (RIC) extends the curative potential of allogeneic hematopoietic cell transplantation (HCT) to patients with hematologic malignancies unable to withstand myeloablative conditioning. We prospectively analyzed the outcomes of 123 patients (median age, 57 years; range, 23-70 years) with hematologic malignancies treated with a uniform RIC regimen of cyclophosphamide, fludarabine, and total-body irradiation (200 cGy) with or without antithymocyte globulin followed by related donor allogeneic HCT at the University of Minnesota between 2002 and 2008. The cohort included 45 patients with acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS), 27 with aggressive non-Hodgkin lymphoma (NHL), 8 with indolent NHL, 10 with Hodgkin lymphoma (HL), 10 with myeloma, and 23 with acute lymphocytic leukemia, chronic myelogenous leukemia, other leukemias, or myeloproliferative disorders. The probability of 4-year overall survival was 73% for patients with indolent NHL, 58% for those with aggressive NHL, 67% for those with HL, 30% for those with AML/MDS, and only 10% for those with myeloma. Corresponding outcomes for relapse in these patients were 0%, 32%, 50%, 33%, and 38%, and those for progression-free survival were 73%, 45%, 27%, 27%, and 10%. The incidence of treatment-related mortality was 14% at day +100 and 22% at 1 year. The incidence of grade II-IV acute graft-versus-host disease was 38% at day +100, and that of chronic graft-versus-host disease was 50% at 2 years. Multivariate analysis revealed superior overall survival and progression-free survival in patients with both indolent and aggressive NHL compared with those with AML/MDS, HL, or myeloma. Worse 1-year treatment-related mortality was observed in patients with a Hematopoietic Cell Transplantation Comorbidity Index score ≥ 3 and in cytomegalovirus-seropositive recipients. These results suggest that (1) RIC conditioning was well tolerated by an older, heavily pretreated population; (2) patients with indolent and aggressive NHL respond well to RIC conditioning, highlighting the importance of the graft-versus-lymphoma effect; and (3) additional peri-transplantation manipulations are needed to improve outcomes for patients with AML/MDS or myeloma receiving RIC conditioning before HCT.

Nonmyeloablative allogeneic stem cell transplantation for nasopharyngeal carcinoma

We present a case of a patient with metastatic nasopharyngeal carcinoma who failed two lines of palliative combination chemotherapy and was treated with allogeneic nonmyeloablative stem cell transplantation (NST). This patient achieved a durable tumor response, dramatic relief of his symptoms, and elimination of tumor in his bone marrow-an effect likely achieved via a graft-versus-tumor response. Although NST has been explored previously in solid tumors, such as renal cell carcinoma and breast cancer, it has not been widely explored in nasopharyngeal carcinoma. We also present data from a flow cytometric immune analysis and cytokine enzyme-linked immunosorbent assay analysis in the pre- and post-NST period.

NCI first International Workshop on the biology, prevention, and treatment of relapse after allogeneic hematopoietic stem cell transplantation: report from the committee on the biological considerations of hematological relapse following allogeneic stem cell transplantation unrelated to graft-versus-tumor effects: state of the science

Hematopoietic malignant relapse still remains the major cause of death following allogeneic hematopoietic stem cell transplantation (HSCT). Although there has been a large focus on the immunologic mechanisms responsible for the graft-versus-tumor (GVT) effect or lack thereof, there has been little attention paid to investigating the biologic basis of hematologic malignant disease relapse following allogeneic HSCT. There are a large number of factors that are responsible for the biologic resistance of hematopoietic tumors following allogeneic HSCT. We have focused on 5 major areas including clonal evolution of cancer drug resistance, cancer radiation resistance, genomic basis of leukemia resistance, cancer epigenetics, and resistant leukemia stem cells. We recommend increased funding to pursue 3 broad areas that will significantly enhance our understanding of the biologic basis of malignant relapse after allogeneic HSCT, including: (1) genomic and epigenetic alterations, (2) cancer stem cell biology, and (3) clonal cancer drug and radiation resistance.

The graft-versus-tumor effect in pediatric malignancy

Because severe forms of the graft-versus-host reaction directed against normal tissues (also termed graft-versus-host disease [GVHD]) also contribute to morbidity and mortality following allogeneic hematopoietic stem cell transplantation, major efforts have focused on strategies to separate GVHD from the potentially beneficial immune reactivity against tumor (also called the graft-versus-tumor [GVT] effect). This article focuses on the data supporting the contribution of the GVT effect to cure of malignancy, what is known about the biology of the GVT reaction, and, finally, strategies to manipulate the GVT effect to increase the potency of HSCT.

Immunotherapy by allogeneic stem cell transplantation

During the past three decades, allogeneic stem cell transplantation (ASCT) has developed from being an experimental therapy in patients with endstage leukemia into a well-established therapy in patients with a range of disorders of the immunohematopoietic system. Graft-versus-host disease (GVHD), acute or chronic, attacking host tissue is a major threat. However, donor immunocompetent T cells have a potent graft-versus-leukemia effect. A combination of calcineurin inhibitors and methotrexate is the standard therapy to prevent GVHD. Modulation of the immunosuppressive regimen may induce mild acute and mild chronic GVHD, reduce the risk of relapse, and improve long-term survival. Natural killer cells also play a role in this context. Killer cell immunoglobulin-like receptor incompatibility between recipient and donor may reduce the risk of relapse in patients with myeloid leukemia. Relapse of leukemia is a major cause of death after ASCT. Minimal residual disease and recipient leukemia lineage-specific chimerism are sensitive techniques for early detection of leukemic relapse. Donor lymphocyte infusions can enhance the antitumor effect, especially for patients with molecular relapse. The allogeneic graft-versus-cancer effect has been demonstrated in patients with metastatic breast, renal, colorectal, ovarian, prostatic, and pancreatic carcinoma. Mesenchymal stem cells have immunomodulatory properties and may be used for immunomodulation of GVHD and tissue repair. All things considered, the future looks promising for ASCT.

Autologous-allogeneic tandem stem cell transplantation in patients with multiple myeloma

The decrease in treatment-related mortality by using reduced intensity conditioning and the well-proven immunological effect of the graft to multiple myeloma cells has increased the interest in using allogeneic stem cell transplantation in patients with multiple myeloma. The concept of a cytoreductive autograft followed by a dose-reduced allogeneic stem cell transplantation appears to be the most promising approach. Preliminary reports of several groups observed a treatment-related mortality at 1 year ranged from 0-17%. The rate of acute graft-vs.-host disease (GvHD) grade II-IV ranged from 32-44% and of chronic GvHD from 28-64%. The overall response rates for all studies ranged from 68-83%, including a high rate of complete remissions of 52-83%. The overall survival at 2 or 3 years was between 62% and 78%, and the progression-free survival between 54% and 56%. Despite the high rate of complete remissions after autologous-allogeneic tandem transplantation observed in nearly all trials, the relapse rate is quite considerable and exceeded nearly 40% at 2 years. Therefore, the reduced allogeneic treatment approach in patients with multiple myeloma has still to be improved and further preclinical and clinical research is focused on two major issues: (i) to further reduce treatment-related mortality and (ii) to enhance the remission status after transplantation, via adoptive immunotherapy inducing molecular remission and enhancing the cure rate of this approach.

[Multiple myeloma relapsed or progressed as plasmacytoma after allogeneic reduced-intensity stem cell transplantation: report of three cases]

Autologous peripheral blood stem cell transplantation (auto-PBSCT) is considered the standard therapy for younger patients with multiple myeloma, however, survival curve doesn't reach plateau. On the other hand, allogeneic reduced-intensity stem cell transplantation (RIST) with graft-versus-myeloma (GVM) effects is expected to be the curable therapy. We had three cases received RIST (one case as a salvage therapy for relapse after tandem auto-PBSCT, and two cases as an intentional RIST after achieving partial response by auto-PBSCT). All of three cases relapsing or progressing after RIST showed disease type of plasmacytoma without plasma cells in the bone marrow. That may be because conditioning regimen doesn't include total body irradiation, or GVM is ineffective in plasmacytoma, but effective in bone marrow. Here, we report clinical course of these three cases with some consideration.

[Physiopathology and possible clinical use of hematopoietic stem cells. Recent advances]

Studies carried out during these last years have lead to a considerable improvement in the understanding of the biology of hematopoietic stem cells. The development of hematopoietic stem cell transplantation had a considerable impact on the therapy of leukemias. The improvement in transplantation protocols allowed the development of allogenic transplantations in which the graft versus tumor contributes to the anti-tumor effects. In parallel many growth factors acting on hematopoietic cells have been isolated and used in clinic to stimulate hematopoietic recovery and stem cell mobilization. Finally, malignant stem cells have been isolated and characterized in acute and chronic leukemias: these cells are responsible for the development and maintenance of the leukemic process and must be eradicated to obtain an effective treatment of leukemias.

Immunotherapy in mantle cell lymphoma: anti-CD20-based therapy and beyond

Mantle cell lymphoma (MCL), an aggressive non-Hodgkin's lymphoma characterized by t(11; 14)(q13; q32) chromosomal translocation and overexpression of cyclin D1, has the worst prognosis among all lymphomas. Recent advances in biology, genetics, and immunology have supported the development of immunotherapy in MCL. Rituximab monotherapy in MCL has limited activity. It is more effective when used in combination with chemotherapy such as R-CHOP, R-hyperCVAD/MTX-Ara-C, or R-FCM as front-line or salvage therapy for mantle cell lymphoma. Maintenance with Rituximab was shown to prolong response duration. Although most results have suggested that combining autologous stem cell transplantation with Rituximab may lead to durable remission, the sample size was not sufficient to declare survival benefit. Anti-CD20 radioimmunoconjugates (RICs) (90)Yttrium-ibritumomab tiuxetan and (131)Iodine-tositumomab have been used in mantle cell lymphoma even when patients are relatively resistant to Rituximab-based therapy. Allogeneic stem cell transplantation is a treatment modality in advanced or relapsed MCL, particularly using reduced-intensity conditioning. MCL may have high response rates and sustained remissions after donor lymphocyte infusion. Dendritic cells (DCs) fused with MCL cells for immunostimulation have preliminarily shown anti-lymphoma effects as well. Idiotype vaccination in MCL patients following Rituximab-containing chemotherapy induced tumor-specific T-cell immunity in the absence of B cells. Other immunotherapy, such as the combination of thalidomide with Rituximab, has shown substantial antitumor activity. A Phase I/II study is ongoing to determine the maximum tolerated dose (MTD) and the efficacy of lenalidomide in combination with Rituximab for relapsed/refractory MCL. This review summarizes the latest and exciting advances in MCL.

Durable remission of Sézary syndrome after unrelated bone marrow transplantation by reduced-intensity conditioning

A 22-year-old Japanese man was diagnosed with Sézary syndrome with large cell transformation. His skin lesions persisted after treatment with 7 cycles of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone), psoralen and ultraviolet light A, and total skin electron beam irradiation. He subsequently underwent allogeneic bone marrow transplantation by reduced-intensity conditioning from a human leukocyte antigen-identical unrelated donor. He developed grade II of acute graft-versus-host disease and extensive-type chronic graft-versus-host disease. He has no signs of disease 36 months after the transplantation. The prognosis of patients with advanced stage of mycosis fungoides or Sézary syndrome is very poor. Allogeneic hematopoietic stem cell transplantation, especially by reduced-intensity conditioning, is expected to become a curative treatment option, and graft-versus-tumor effect might play a critical role for sustained remission.

Development of natural killer cells from hematopoietic stem cells

Natural killer (NK) cells play a crucial role in innate immune system and tumor surveillance. NK cells are derived from CD34+hematopoietic stem cells and undergo differentiation via precursor NK cells in bone marrow (BM) through sequential acquisition of functional surface receptors. During differentiation of NK cells, many factors are involved including cytokines, membrane factors and transcription factors as well as microenvironment of BM. NK cells express their own repertoire of receptors including activating and inhibitory receptors that bind to major histocompatibility complex (MHC) class I or class I-related molecules. The balance between activating and inhibitory receptors determines the function of NK cells to kill targets. Binding of NK cell inhibitory receptors to their MHC class I-ligand renders the target cells to be protected from NK cell-mediated cytotoxicity. Thus, NK cells are able to discriminate self from non-self through MHC class I-binding inhibitory receptor. Using intrinsic properties of NK cells, NK cells are emerging to apply as therapeutic agents against many types of cancers. Recently, NK cell alloactivity has also been exploited in killer cell immunoglobulin-like receptor mismatched haploidentical stem cell transplantation to reduce the rate of relapse and graft versus host disease. In this review, we discuss the basic mechanisms of NK cell differentiation, diversity of NK cell receptors, and clinical applications of NK cells for anti-cancer immunotherapy.

Induction of autologous graft-versus-host disease: results of a randomized prospective clinical trial in patients with poor risk lymphoma

The results of blood or marrow transplantation in patients with chemorefractory aggressive lymphoma, that is, those not responding to conventional-dose chemotherapy at the time of transplant, have been poor. The relapse rate has been high after autologous bone marrow transplant, whereas allogeneic transplantation has been associated with excessive transplant-related toxicity. Administration of cyclosporine after autologous transplantation can induce an autoreactive syndrome that resembles graft-versus-host disease (GVHD). This syndrome, named autologous graft-versus-host disease, has clear antitumor activity in animal models that can be enhanced by the addition of cytokines such as gamma-interferon and interleukin-2. A randomized, prospective study was conducted to evaluate the antitumor effect of autologous graft-versus-host disease induced with cyclosporine, and augmented by the administration of gamma-interferon and interleukin-2 in patients with chemorefractory Hodgkin and aggressive non-Hodgkin lymphomas. Fifty-one patients were randomized, 24 to the autologous GVHD induction arm, and 27 to the noninduction arm after autologous transplant using mobilized peripheral blood stem cell (PBSC) grafts. There were no differences in treatment-related mortality, overall and event-free survival (OS, EFS) between both groups; however, in the induction arm, GVHD developed only in 4 patients. The administration of oral cyclosporine followed by interleukin-2 and gamma-interferon is generally not well tolerated, and does not appear to be an effective method to induce autologous GVHD in patients receiving autologous PBSC grafts.

Minor histocompatibility antigens as targets for immunotherapy using allogeneic immune reactions

Minor histocompatibility antigens (mHag) were originally identified as antigens causing graft rejection or graft-versus-host disease in human leukocyte antigen (HLA)-matched allogeneic transplantation. Molecular identification has revealed most to be major histocompatibility complex (MHC)-bound short peptide fragments encoded by genes which are polymorphic due to single nucleotide polymorphisms (SNP). Genotypic disparity of SNP between transplantation donors and recipients gives rise to mHag as non-self antigens for both the donor and the recipient. Subsequently, mHag have been explored as immunotherapeutic antigens for use against recurring hematological malignancies after allogeneic hematopoietic cell transplantation (HCT), because mHag expressed only on hematopoietic cells are considered to augment graft-versus-leukemia/lymphoma (GVL) effects without increasing the risk of life-threatening graft-versus-host disease (GVHD). Accumulating evidence suggests that T-cell responses to mHag aberrantly expressed on solid tumor cells are also involved in the eradication of sensitive tumors such as renal cell carcinomas following HCT. Over the past decade, the number of putative GVL-directed mHag has increased to a level that covers more than 30% of the Japanese patient population, so that clinical trials may now be executed in the setting of either vaccination or adoptive immunotherapy. As it is expected that immune responses to alloantigens are more powerful than to tumor antigens mostly derived from overexpressed self-proteins, mHag-based immunotherapy may lead to a new treatment modality for high-risk malignancies following allogeneic HCT.

Evidence of graft-versus-Waldenstrom's macroglobulinaemia effect after allogeneic stem cell transplantation: a single centre experience

The role of allogeneic stem cell transplantation (SCT) in Waldenstrom's macroglobulinaemia (WM) is not yet clear, as published data on allogeneic SCT in WM are limited. We present a retrospective study of allogeneic SCT in five patients with WM. Median age was 56 years (range 40-60 years). All patients were heavily pretreated. Conditioning therapy with busulphan and cyclophosphamide was used for all patients and all were given cyclosporine and methotrexate for graft-versus-host disease prophylaxis. With a median follow-up of 32 months (range 2-43), all except one are alive and disease free. Progressive, delayed decline in serum IgM levels were noted in all the patients, suggesting an active graft-versus-Waldenstrom's effect. With the limited available data, it appears that allogeneic SCT is a useful treatment option for advanced WM.

Mini-Midi-Maxi? How to harness the graft-versus-myeloma effect and target molecular remission after allogeneic stem cell transplantation

Allogeneic stem cell transplantation in multiple myeloma after standard myeloablative conditioning induces a high rate of complete remissions, but long-term freedom from disease is achieved in 30-40% of the cases only. The therapeutic effect of allogeneic stem cell transplantation is due to cytotoxicity of high-dose chemotherapy and immune-mediated graft-versus-myeloma effect by donor T cells. Retrospective studies clearly suggest that both (a) reducing the intensity of high-dose chemotherapy by using reduced-intensity or non-myeloablative conditioning regimen or (b) reducing the immunotherapy of donor T cells by using T-cell depletion result in lower treatment-related morbidity and mortality, but also in higher rate of relapse. Therefore, this review will focus on potential strategies of how treatment-related morbidity and mortality might be kept low without an increased risk of relapse and how remission status after transplantation can be enhanced by using the newly established donor immunosystems after allografting as a platform for post-transplant treatment strategies with new drugs (thalidomide, lenalidomide, bortezomib) or immunotherapy (donor lymphocyte infusion, vaccination, tumor-specific T cells) in order to achieve remission on a molecular level, which seems to be a 'conditio sine qua non' to cure myeloma patients.

The Beneficial Effect of Chronic Graft-versus-Host Disease on the Clinical Outcome of Transplantation with Fludarabine/Busulfan-Based Reduced-Intensity Conditioning for Patients with De Novo Myelodysplastic Syndrome

Allogeneic hematopoietic stem cell transplantation following reduced-intensity stem cell transplantation (RIST) has enabled the treatment of older or medically infirm patients with myeloid malignancies; however, determining the value of RIST outcomes for myelodysplastic syndrome (MDS) is difficult because of the heterogeneity of the diseases included in most trials. To define the role of RIST in MDS, we performed RIST for 22 consecutive patients who had de novo MDS as classified by World Health Organization (WHO) criteria and who received an allograft with fludarabine/busulfan (Busulfex) or fludarabine/Busulfex/antithymocyte globulin (ATG) conditioning. Nineteen patients (86.4%) achieved engraftment. At a median follow-up of 18.9 months (range, 13.1-24.8 months), the estimated 2-year rates of overall survival, event-free survival (EFS), transplantation-related mortality, and relapse were 78.7%, 67.7%, 12.6%, and 22.5%, respectively. Acute graft-versus-host disease (GVHD) greater than grade II developed in 3 patients (15.8%). Chronic GVHD developed in 10 patients (55.6%), none of whom received ATG as a conditioning regimen. Variables influencing EFS were chronic GVHD, marrow blasts before transplantation, and the WHO criteria. The present study clarifies the benefits of the fludarabine/Busulfex-based conditioning regimen for de novo MDS diagnosed according to the WHO criteria and shows that chronic GVHD appears to have a beneficial effect on survival rates, which are strongly associated with graft-versus-tumor effects.

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 age<or=55 years underwent SCT for myeloma. Seventy-two patients underwent myeloablative alloSCT (58 related; 14 unrelated), whereas 86 patients underwent ASCT. Most patients received single-agent high dose dexamethasone or VAD (vincristine, adriamycin, dexamethasone) therapy pre-SCT. Conditioning regimens were melphalan-based for all ASCT patients, whereas the alloSCT patients received melphalan-based (70%), total-body irradiation (TBI)-based (18%), or other (13%). Patients who underwent alloSCT were younger, had a higher Durie-Salmon stage disease, and a shorter median time from diagnosis to transplant. Myeloma subtypes were similar between groups. Other pre-SCT (BMT) characteristics were similar except that ASCT patients had a higher proportion of cases that received palliative radiotherapy pre-SCT. Disease response pre-SCT was similar. At last follow-up, 61 of 158 patients are alive with a median follow-up of 88.4 months (range: 35.5-208.5). The overall survival (OS) of the alloSCT cohort was 48.1% at 5 years and 39.9% at 10 years compared to 46.2% at 5 years and 30.8% at 10 years for the ASCT cohort (P=.94). The event-free survival of the alloSCT cohort was 33.3% at 5 years and 31.4% at 10 years compared to 32.9% and 15.2%for the ASCT cohort (P=.64). Treatment-related mortality (TRM) at 1 year was 22% for the alloSCT cohort and 14% in the ASCT cohort (P=.21). Cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 72% and the cumulative incidence of chronic GVHD (cGVHD) was 68% at 2 years. Neither aGVHD nor cGVHD had an influence on OS or event-free survival, although 5 of 14 patients who have received donor lymphocyte infusions (DLI) have had disease response. The risk of relapse was reduced in those who developed aGVHD (P=.02) but not cGVHD (P=.23). In conclusion, although there are patient who are alive without disease>10 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.

Immune reconstitution after allogeneic stem cell transplantation with reduced-intensity conditioning regimens

Reduced-intensity conditioning (RIC) regimens have been increasingly used as an alternative to conventional myeloablative conditioning (MAC) regimens for elderly patients, for patients medically infirm to qualify for conventional allogeneic stem cell transplantation (SCT), and for disorders in which traditional MAC-SCT are associated with high rates of non-relapse mortality. One of the theoretical advantages of RIC-SCT is that it might lend to better immune reconstitution after transplantation due to less damage of the thymus, allowing regeneration of naive T cells derived from prethymic donor stem cells, and due to the proliferation of immunologically competent host T cells that survive the conditioning regimen. Although limited, studies comparing immune recovery following RIC and MAC-SCT have been insightful. One of the main difficulties of these studies is the current spectrum of RIC protocols, which vary considerably in myeloablative and immunosuppressive potential, resulting in apparently contradictory findings. In spite of this, most reports have shown significant quantitative and/or qualitative differences in T- and B-cell reconstitution after RIC-SCT in comparison with conventional SCT. This paper will review current knowledge of immune reconstitution following RIC-SCT.

Mycosis fongoïde transformé chez un enfant : traitement par transplantation médullaire allogénique avec effet « graft-versus-lymphoma »

BACKGROUND

Mycosis fungoides is the most frequent cutaneous T-cell lymphoma but has been rarely reported in children and teenagers. Although transformation into large-cell T-cell lymphoma has been described in 10% of adult cases, it is seen very rarely in children. We report here the clinical case of mycosis fungoides in a child with an unusual transformed form at presentation and treated by bone marrow allograft.

CASE-REPORT

A 13 year-old boy, presenting guttate parapsoriasis for 5 years was referred to our Dermatology Department with a 2-month history of infiltrated plaques throughout the body and face. Large erythematous-squamous plaques on the trunk and face as well as a nodular lesion of the arm were also noted. On histology, typical features of mycosis fungoides were observed, in addition to transformed cells which were CD30-negative. Local treatment comprising caryolysin and dermal corticosteroids allowed initial regression of the lesions. However, a few months later, nodular lesions reappeared as well as axillary lymph nodes. Repeated histology confirmed the diagnosis of transformed mycosis fungoides with large CD30-positive cells. Despite chemotherapy, cutaneous and lymph node disease recurred, and bone marrow allograft was performed, resulting in rapid disease regression. Following the recurrence of skin lesions 2 years later, donor lymphocytes were administered in addition to treatment with interferon alpha, aiming at stimulating a graft-versus-lymphoma reaction. One year post-lymphocyte injection, the patient is in full remission.

DISCUSSION

This is a new case report of juvenile mycosis fungoides with unusual clinical features such as rapid course and transformed form at presentation. Juvenile mycosis fungoides represents 2.5 to 5% of cases of mycosis fungoides and transformation to large cell lymphoma is exceptional. Our case illustrates the aggressive pattern observed in some teenage patients as well as the efficacy of bone marrow allograft, most likely thanks chiefly to its graft-versus-lymphoma effect.