Donor CD4 T cells are critical in allogeneic stem cell transplantation against murine solid tumor

Immunotherapy for neuroblastoma by hematopoietic cell transplantation and post-transplant immunomodulation

Neuroblastoma represents a relatively common childhood tumor that imposes therapeutic difficulties. High risk neuroblastoma patients have poor prognosis, display limited response to radiochemotherapy and may be treated by hematopoietic cell transplantation. Allogeneic and haploidentical transplants have the distinct advantage of reinstitution of immune surveillance, reinforced by antigenic barriers. The key factors favorable to ignition of potent anti-tumor reactions are transition to adaptive immunity, recovery from lymphopenia and removal of inhibitory signals that inactivate immune cells at the local and systemic levels. Post-transplant immunomodulation may further foster anti-tumor reactivity, with positive but transient impact of infusions of lymphocytes and natural killer cells both from the donor, the recipient or third party. The most promising approaches include introduction of antigen-presenting cells in early post-transplant stages and neutralization of inhibitory signals. Further studies will likely shed light on the nature and actions of suppressor factors within tumor stroma and at the systemic level.

Human leukocyte antigen disparities reduce relapse after hematopoietic stem cell transplantation in children with juvenile myelomonocytic leukemia: A single-center retrospective study from China

BACKGROUND

HSCT is the only proven curative therapy for JMML. Matching donor and recipient HLA alleles is considered optimal to reduce the risk of GVHD after HSCT but is not always possible. Only a limited number of studies have compared the influence of HLA disparities on HSCT outcomes for patients with JMML.

METHODS

We conducted a retrospective study among 47 children with JMML who received related or unrelated unmanipulated HSCT (March 2010-October 2018). Among our participants, 27 (57.4%) donor-recipient pairs had 0-1 HLA disparities (Group 1: HLA-matched or ≤1 allele/antigen mismatch donor) and 20 (42.6%) had ≥2 HLA disparities (Group 2: 2-3 mismatched/haploidentical donors).

RESULTS

The median follow-up period was 26.0 months (range: 1-105 months), and the 5-year probabilities of DFS and RI for the whole cohort were 54.6 ± 7.7% and 34.8 ± 15.0%, respectively. Compared to Group 1, Group 2 patients had a significantly lower RI (5.3 ± 10.5% vs 55.5 ± 20.9%, P ˂ .001), though similar rates of grade II-IV acute GVHD (60.0 ± 22.4% vs 33.3 ± 18.2%, P = .08), grade III-IV acute GVHD (25.0 ± 19.5% vs 7.4 ± 10.1%, P = .08), chronic GVHD (30.0 ± 20.9% vs 34.9 ± 18.8%, P = .85), NRM (20.0 ± 18.0% vs 3.9 ± 7.7%, P = .07), and DFS (74.4 ± 9.9% vs 41.3 ± 10.0%, P = .08).

CONCLUSIONS

Disease relapse remains the major cause of treatment failure in JMML patients, especially in patients receiving HLA-matched and limited HLA-mismatched HSCT. Our findings suggest that donor-recipient HLA disparities may improve the outcome of HSCT in children with JMML.

Combination of anti-CD4 antibody treatment and donor lymphocyte infusion ameliorates graft-versus-host disease while preserving graft-versus-tumor effects in murine allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is not only a well‐established immunotherapy for hematologic malignancies, but is potentially useful for treating solid tumors refractory to available therapies. However, application of allo‐HSCT to solid tumors is limited, despite the beneficial antitumor effects, by the risk of graft‐versus‐host disease (GVHD). CD4⁺ T cells have been implicated in several aspects of GVHD, and suppress antitumor CD8⁺ T‐cell responses. In the present study, we investigated clinically applicable allo‐HSCT protocols designed to maximize antitumor effects while reducing the risk of GVHD. We used a mouse model of allo‐HSCT with s.c. tumors. We found that myeloablative conditioning was associated with better inhibition of tumor growth but with severe acute GVHD. Early treatment with anti‐CD4 mAb substantially ameliorated GVHD while preserving antitumor effects, leading to improved survival in myeloablative allo‐HSCT. Late treatment with anti‐CD4 mAb also ameliorated GVHD to some extent. Donor lymphocyte infusion in GVHD mice treated with anti‐CD4 mAb further suppressed tumor growth without exacerbating GVHD. Collectively, our results suggest that myeloablative allo‐HSCT followed by anti‐CD4 mAb treatment and donor lymphocyte infusion could be a potent and safe immunotherapy for patients with cancers refractory to available therapies.

IFN-γ mediates graft-versus-breast cancer effects via enhancing cytotoxic T lymphocyte activity

Previous studies have demonstrated the beneficial effect of graft-versus-tumor (GVT) following hematopoietic stem cell transplantation (HSCT) on the incidence of leukemia relapse and the overall survival rate of patients with leukemia; however, detailed mechanisms underlying the effects GVT exhibits on solid tumors following allogeneic HSCT are yet to be elucidated. The aim of the present study was to investigate the immune mechanism underlying the effect of interferon (IFN)-γ on GVT following allogeneic HSCT in breast cancer therapy. An in situ breast cancer mouse model was established by injecting 5×10⁴ 4T1 cells into the mammary fat pads of BALB/c mice. The 4T1 cells were transfected with the firefly luciferase reporter gene in order to monitor the tumor progression in real time. An allogeneic HSCT model was then established by transplanting bone marrow mononuclear cells from C57BL/6 mice to the BALB/c mice. To investigate the influence of T lymphocyte proliferation following allogeneic bone marrow transplantation, the levels of CD3⁺CD8⁺ cytotoxic T lymphocytes (CTLs) and CD4⁺CD25⁺ regulatory T cells were determined. In addition, IFN-γ and granzyme B expression levels in splenic lymphocytes were analyzed using flow cytometry. Allogeneic HSCT was found to significantly promote the proliferation and cytotoxicity of CTLs and suppress the growth of breast cancer. Furthermore, the secretory levels of IFN-γ and granzyme B by T cells were elevated following allogeneic HSCT. These results indicated that alloreactive T cells increased the secretion of IFN-γ, which promoted the alloresponse of donor CTLs. In addition, the CTLs produced granzyme B, which exerted a tumor suppressive effect.

Gr-1 Ab administered after bone marrow transplantation plus thymus transplantation suppresses tumor growth by depleting granulocytic myeloid-derived suppressor cells

It has been shown that allogeneic intra-bone marrow–bone marrow transplantation (IBM-BMT) plus thymus transplantation (TT) is effective in treating recipients with malignant tumors. Although TT increases the percentage of T cells in the early term after BMT, the myeloid-derived suppressor cells (MDSCs) are still the dominant population. We used the Gr-1 Ab to deplete the granulocytic MDSCs (G-MDSCs) in tumor-bearing mice that had received BMT+TT. Two weeks after the BMT, the mice injected with Gr-1 Ab showed smaller tumors than those in the control group. In addition, Gr-1 Ab significantly increased the percentages and numbers of CD4⁺ and CD8⁺ T cells, and decreased the percentages and numbers of MDSCs and G-MDSCs. No side effects of the Gr-1 Ab on recipient or donor thymus were observed. These findings indicate that Gr-1 Ab administered after BMT+TT may enhance the effectiveness of tumor suppression.

Donor lymphocyte infusion following allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (SCT) is the treatment of choice for many malignant hematological disorders. Following recent improvements in non-relapse-related mortality rates, relapse has become the commonest cause of treatment failure. Infusion of donor lymphocytes can potentially enhance immune-mediated antitumor activity and offers a salvage option for some patients. This paper reviews the current literature on the efficacy of this therapeutic strategy.

AREAS COVERED

The biology of adoptive cellular therapy with allogeneic immune cells to treat relapse across a spectrum of diseases in both the full intensity and reduced intensity hematopoietic SCT settings is explored. The review discusses the current limitations of the approach and reviews several new experimental strategies which aim to segregate the desired graft-versus-tumor effect from the deleterious effects of more widespread graft-versus-host reactivity.

EXPERT OPINION

Durable responses to DLI have been noted in chronic myeloid leukemia and responses have also been described in acute leukemia, multiple myeloma and chronic lymphoproliferative disorders. The new challenge in transplantation is to optimize DLI therapy in order to further improve patient outcomes.

Eradication of medullary multiple myeloma by CD4+ cytotoxic human T lymphocytes directed at a single minor histocompatibility antigen

PURPOSE

The essential role of CD4(+) T cells as helpers of anticancer immunity is indisputable. Little is known, however, about their capacity to serve as effector cells in cancer treatment. Therefore, we explored the efficacy of immunotherapy with sole CD4(+) cytotoxic human T cells directed at a hematopoietic-restricted minor histocompatibility antigen (mHag).

EXPERIMENTAL DESIGN

In macrophage-depleted Rag2(-/-)γc(-/-) mice, which were also devoid of T, B, and natural killer cells, mHag-specific native T cells or tetanus toxoid (TT)-specific T cells transduced with the mHag-specific T-cell receptor (TCR) were injected to treat full-blown mHag(+) human multiple myeloma tumors.

RESULTS

mHag-specific antitumor responses were achieved after injection of native or mHag-TCR-transduced T cells. Although the therapy completely eradicated the primary tumors in the bone marrow, it failed to control extramedullary relapses, even after repeated T-cell injections. Detailed analyses ruled out mHag or MHC downregulation as mechanisms of extramedullary tumor escape. Impaired T-cell survival in vivo or defective homing to the tumor site were also ruled out as mechanisms behind extramedullary relapses, because injections of TT-loaded antigen presenting cells could facilitate homing of long-term surviving T cells to s.c. tumor sites. Moreover, intratumoral treatment of extramedullary tumors with 3AB11 was also ineffective.

CONCLUSIONS

Taken together, these results for the first time show the feasibility of immunotherapy of primary bone marrow tumors with sole CD4(+) human T cells directed to a tumor-associated mHag. Extramedullary relapses, probably due to microenvironment-dependent inhibitory mechanisms, remain a challenging issue towards effective cellular immunotherapy of hematologic malignancies.

Immunomodulation with dendritic cells and donor lymphocyte infusion converge to induce graft vs neuroblastoma reactions without GVHD after allogeneic bone marrow transplantation

BACKGROUND

Mounting evidence points to the efficacy of donor lymphocyte infusion (DLI) and immunisation with tumour-pulsed dendritic cells (DC) in generating graft vs leukaemia reactions after allogeneic bone marrow transplantation (BMT). We assessed the efficacy of DLI and DC in generating potent graft vs neuroblastoma tumour (GVT) reactions following allogeneic BMT.

METHODS

Mice bearing congenic (H2K(a)) Neuro-2a tumours were grafted with allogeneic (H2K(b)) T-cell-depleted bone marrow cells. Tumour-pulsed donor DC (DC(Neuro2a)) were inoculated (on day +7) in conjunction with donor (H2K(b)) and haploidentical (H2K(a/b)) lymphocytes.

RESULTS

Murine Neuro-2a cells elicit immune reactions as efficient as B lymphoma in major histocompatibility complex antigen-disparate mice. Lymphopenia induced by conditioning facilitates GVT, and transition to adaptive immunity is enhanced by simultaneous infusion of and DC(Neuro2a) and lymphocytes devoid of graft vs host (GVH) activity (H2K(a/b)). In variance, the efficacy of DC-mediated immunomodulation was diminished by severe graft vs host disease (GVHD), showing mechanistic dissociation and antagonising potential to GVT.

CONCLUSIONS

The GVHD is not a prerequisite to induce GVT reactivity after allogeneic BMT, but is rather detrimental to induction of anti-tumour immunity by DC-mediated immunomodulation. Simultaneous inoculation of tumour-pulsed donor DC and DLI synergise in stimulation of potent GVT reactions to the extent of eradication of established NB tumours.

Autologous and allogeneic cellular therapies for high-risk pediatric solid tumors

Since the 1950s, the overall survival of children with cancer has gone from almost zero to approaching 80%. Although there have been notable successes in treating solid tumors such as Wilms tumor, some childhood solid tumors have continued to elude effective therapy. With the use of megatherapy techniques such as tandem transplantation, dose escalation has been pushed to the edge of dose-limiting toxicities, and any further improvements in event-free survival will have to be achieved through novel therapeutic approaches. This article reviews the status of autologous and allogeneic hematopoietic stem cell transplantation (HSCT) for many pediatric solid tumor types. Most of the clinical experience in transplant for pediatric solid tumors is in the autologous setting, so some general principles of autologous HSCT are reviewed. The article then examines HSCT for diseases such as Hodgkin disease, Ewing sarcoma, and neuroblastoma, and the future of cell-based therapies by considering some experimental approaches to cell therapies.

Nonmyeloablative HLA-haploidentical bone marrow transplantation with high-dose posttransplantation cyclophosphamide: effect of HLA disparity on outcome

Although some reports have found an association between increasing HLA disparity between donor and recipient and fewer relapses after allogeneic blood or marrow transplantation (BMT), this potential benefit has been offset by more graft-versus-host disease (GVHD) and nonrelapse mortality (NRM). However, the type of GVHD prophylaxis might influence the balance between GVHD toxicity and relapse. The present study analyzed the impact of greater HLA disparity on outcomes of a specific platform for nonmyeloablative (NMA), HLA-haploidentical transplantation. A retrospective analysis was performed of 185 patients with hematologic malignancies enrolled in 3 similar trials of NMA, related donor, haploidentical BMT incorporating high-dose posttransplantation cyclophosphamide for GVHD prophylaxis. No significant association was found between the number of HLA mismatches (HLA-A, -B, -Cw, and -DRB1 combined) and risk of acute grade II-IV GVHD (hazard ratio [HR] = 0.89; P = .68 for 3-4 vs fewer antigen mismatches). More mismatching also had no detrimental effect on event-free survival (on multivariate analysis, HR = 0.60, P = .03 for 3-4 vs fewer antigen mismatches and HR = 0.55, P = .03 for 3-4 vs fewer allele mismatches). Thus, greater HLA disparity does not appear to worsen overall outcome after NMA haploidentical BMT with high-dose posttransplantation cyclophosphamide.