A 14-year retrospective analysis of indications and outcomes of autologous haemopoietic stem cell transplantation in regional Queensland: a single-centre experience.

BACKGROUND: The Townsville Hospital is a tertiary hospital in North Queensland with one of the largest regional transplant centres in Australia, performing primarily autologous haemopoietic stem cell transplants (HSCT) for various haematological malignancies. AIMS: This single-centre, retrospective, observational study aims to describe the activity and outcomes of autologous HSCT at The Townsville Hospital between 2003 and 2017 to verify safety standards. METHODS: Patient-level data were collected, including demographics, frequency and indication for transplant, conditioning, current clinical status and cause of death. Key outcomes included overall survival, non-relapse mortality, incidence of therapy-related neoplasm and causes of death. Progression-free survival in the multiple myeloma (MM) subgroup was also assessed. RESULTS: There were 319 autologous HSCT in 286 patients, with a median age of 58 years (range 14-71 years); 62% of patients were male. Indications for transplantation were: MM 53.7%, non-Hodgkin lymphoma 29.4%, Hodgkin lymphoma 5.0% and other 11.9%. Causes of death were: disease progression/relapse (65.2%), second malignancy (17.0%), infection (9.8%) and other (8.0%). Non-relapse mortality was 1.2% (95% confidence interval 0.4-3.0) and 3.2% (1.7-5.7) at 100 days and 1 year, respectively, post-HSCT. Overall survival at 2 years was 81.0% (73.8-86.4) for MM and 69.6% (58.8-78.1) for non-Hodgkin lymphoma. The median progression-free survival in the MM cohort was 3.3 years. CONCLUSION: The Townsville Hospital transplant centre provides an important transplant service in regional Queensland, with outcomes comparable to national data. We reported a relatively high rate of second malignancy as a cause of death.

Soluble lymphotoxin is an important effector molecule in GVHD and GVL.

Tumor necrosis factor (TNF) is a key cytokine in the effector phase of graft-versus-host disease (GVHD) after bone marrow transplantation, and TNF inhibitors have shown efficacy in clinical and experimental GVHD. TNF signals through the TNF receptors (TNFR), which also bind soluble lymphotoxin (LTalpha3), a TNF family member with a previously unexamined role in GVHD pathogenesis. We have used preclinical models to investigate the role of LT in GVHD. We confirm that grafts deficient in LTalpha have an attenuated capacity to induce GVHD equal to that seen when grafts lack TNF. This is not associated with other defects in cytokine production or T-cell function, suggesting that LTalpha3 exerts its pathogenic activity directly via TNFR signaling. We confirm that donor-derived LTalpha is required for graft-versus-leukemia (GVL) effects, with equal impairment in leukemic clearance seen in recipients of LTalpha- and TNF-deficient grafts. Further impairment in tumor clearance was seen using Tnf/Lta(-/-) donors, suggesting that these molecules play nonredundant roles in GVL. Importantly, donor TNF/LTalpha were only required for GVL where the recipient leukemia was susceptible to apoptosis via p55 TNFR signaling. These data suggest that antagonists neutralizing both TNF and LTalpha3 may be effective for treatment of GVHD, particularly if residual leukemia lacks the p55 TNFR.

Invariant natural killer T cell-natural killer cell interactions dictate transplantation outcome after alpha-galactosylceramide administration.

Invariant natural killer T cells (iNKT cells) have pivotal roles in graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effects. iNKT cells are activated through their T-cell receptors by glycolipid moieties (typically the alpha-galactosylceramide [alpha-GalCer] derivative KRN7000) presented within CD1d. We investigated the ability of modified alpha-GalCer molecules to differentially modulate alloreactivity and GVL. KRN7000 and the N-acyl variant, C20:2, were administered in multiple well-established murine models of allogeneic stem cell transplantation. The highly potent and specific activation of all type I NKT cells with C20:2 failed to exacerbate and in most settings inhibited GVHD late after transplantation, whereas effects on GVL were variable. In contrast, the administration of KRN7000 induced hyperacute GVHD and early mortality in all models tested. Administration of KRN7000, but not C20:2, was found to result in downstream interleukin (IL)-12 and dendritic cell (DC)-dependent natural killer (NK)- and conventional T-cell activation. Specific depletion of host DCs, IL-12, or donor NK cells prevented this pathogenic response and the induction of hyperacute GVHD. These data demonstrate the ability of profound iNKT activation to modulate both the innate and adaptive immune response via the DC-NK-cell interaction and raise concern for the use of alpha-GalCer therapeutically to modulate GVHD and GVL effects.

Induction of natural killer T cell-dependent alloreactivity by administration of granulocyte colony-stimulating factor after bone marrow transplantation.

Granulocyte colony-stimulating factor (G-CSF) is often used to hasten neutrophil recovery after allogeneic bone marrow transplantation (BMT), but the clinical and immunological consequences evoked remain unclear. We examined the effect of G-CSF administration after transplantation in mouse models and found that exposure to either standard G-CSF or pegylated-G-CSF soon after BMT substantially increased graft-versus-host disease (GVHD). This effect was dependent on total body irradiation (TBI) rendering host dendritic cells (DCs) responsive to G-CSF by upregulating their expression of the G-CSF receptor. Stimulation of host DCs by G-CSF subsequently unleashed a cascade of events characterized by donor natural killer T cell (NKT cell) activation, interferon-gamma secretion and CD40-dependent amplification of donor cytotoxic T lymphocyte function during the effector phase of GVHD. Crucially, the detrimental effects of G-CSF were only present when it was administered after TBI conditioning and at a time when residual host antigen presenting cells were still present, perhaps explaining the conflicting and somewhat controversial clinical studies from the large European and North American BMT registries. These data have major implications for the use of G-CSF in disease states where NKT cell activation may have effects on outcome.

Donor treatment with a multipegylated G-CSF maximizes graft-versus-leukemia effects.

Donor treatment with granulocyle-colony stimulating factor (G-CSF) is known to modulate immune function, characterized by the generation of regulatory myelogenous and T cell populations and Th2 differentiation. Recently, these effects have been shown to be enhanced by pegylation of the G-CSF molecule, which also improves graft-versus-leukemia (GVL) via activation of invariant natural killer (iNK) T cells. We have compared G-CSF bound to a single PEG molecule (monopeg-G-CSF) as used clinically to a G-CSF molecule bound to multiple PEG molecules (multipeg-G-CSF) in major histocompatibility complex (MHC) disparate and matched models of graft-versus-host disease (GVHD) and GVL. We demonstrate that multipeg-G-CSF induces greater levels of progenitor cell, myelogenous, and iNKT cell expansion than monopeg-G-CSF, while inducing similar protection from GVHD. Despite this, multipeg-G-CSF enhanced CTL function in vivo and improved iNKT cell-dependent leukemia clearance. Thus, GVL and GVHD can be further separated after allogeneic stem cell transplantation by mobilization with a multiple-pegylated G-CSF molecule.

IFNgamma differentially controls the development of idiopathic pneumonia syndrome and GVHD of the gastrointestinal tract.

Although proinflammatory cytokines are key mediators of tissue damage during graft-versus-host disease (GVHD), IFNgamma has previously been attributed with both protective and pathogenic effects. We have resolved this paradox by using wild-type (wt), IFNgamma(-/-), and IFNgammaR(-/-) mice as donors or recipients in well-described models of allogeneic stem cell transplantation (SCT). We show that donor-derived IFNgamma augments acute GVHD via direct effects on (1) the donor T cell to promote T helper 1 (Th1) differentiation and (2) the gastrointestinal (GI) tract to augment inflammatory cytokine generation. However, these detrimental effects are overwhelmed by a protective role of IFNgamma in preventing the development of idiopathic pneumonia syndrome (IPS). This is the result of direct effects on pulmonary parenchyma to prevent donor cell migration and expansion within the lung. Thus, IFNgamma is the key cytokine differentially controlling the development of IPS and gastrointestinal GVHD after allogeneic SCT.

Effector and regulatory T-cell function is differentially regulated by RelB within antigen-presenting cells during GVHD.

Antigen-presenting cells (APCs) are critical for the initiation of graft-versus-host disease (GVHD), although the responsible APC subset and molecular mechanisms remain unclear. Because dendritic cells (DCs) are the most potent APCs and the NF-kB/Rel family member RelB is associated with DC maturation and potent APC function, we examined their role in GVHD. Within 4 hours of total body irradiation, RelB nuclear translocation was increased and restricted to CD11c(hi) DCs within the host APC compartment. Furthermore, the transient depletion of CD11c(hi) donor DCs that reconstitute in the second week after transplantation resulted in a transient decrease in GVHD severity. By using RelB(-/-) bone marrow chimeras as transplant recipients or RelB(-/-) donor bone marrow, we demonstrate that the induction and maintenance of GVHD is critically dependent on this transcription factor within both host and donor APCs. Critically, RelB within APCs was required for the expansion of donor helper T cell type 1 (Th1) effectors and subsequent alloreactivity, but not the peripheral expansion or function of donor FoxP3(+) regulatory T cells. These data suggest that the targeted inhibition of nuclear RelB translocation within APCs represents an attractive therapeutic strategy to dissociate effector and regulatory T-cell function in settings of Th1-mediated tissue injury.

Advances in the understanding of acute graft-versus-host disease.

Allogeneic stem cell transplantation (SCT) remains the definitive immunotherapy for malignancy. However, morbidity and mortality due to graft-vs.-host disease (GVHD) remains the major barrier to its advancement. Emerging experimental data highlights the immuno-modulatory roles of diverse cell populations in GVHD, including regulatory T cells, natural killer (NK) cells, NK T cells, gammadelta T cells, and antigen presenting cells (APC). Knowledge of the pathophysiology of GVHD has driven the investigation of new rational strategies to both prevent severe GVHD and treat steroid-refractory GVHD. Novel cytokine inhibitors, immune-suppressant agents known to preserve or even promote regulatory T-cell function and the depletion of specific alloreactive T-cell sub-populations all promise significant advances in the near future. As our knowledge and therapeutic options expand, the ability to limit GVHD whilst preserving anti-microbial and tumour responses becomes a realistic prospect.

Allogeneic stem cell transplantation with peripheral blood stem cells mobilized by pegylated G-CSF.

Mobilization of stem cells with pegylated granulocyte colony-stimulating factor (peg-G-CSF) modulates donor T- and natural killer T-cell (NKT-cell) functions, thus separating graft-versus-host from graft-versus-leukemia disease in animal models. We report a phase I/II study that analyzed the feasibility of mobilizing stem cells from normal donors with peg-G-CSF and the ability of these cells to restore hematopoiesis in allogeneic transplant recipients after myeloablative conditioning. Administration of 6 mg of peg-G-CSF resulted in suboptimal stem cell mobilization, with a peak peripheral blood CD34+ count of 29+/-5/microL. Apheresis 4 days after peg-G-CSF yielded 2.7+/-.4x10(6) CD34+ cells/kg recipient weight, and all donors required a second collection on day 5 to yield a total of 4.2+/-.5x10(6) CD34+ cells/kg recipient weight. After escalation of the dose to 12 mg, the peak CD34+ count was 99+/-11/microL and 12 of 13 donors collected sufficient stem cells for transplantation in a single apheresis (8.9+/-1.4x10(6) CD34+ cells/kg recipient weight). Late transient increases in serum hepatic transaminases were noted, but other side effects (predominantly bone pain) were otherwise similar to those seen in donors mobilized with standard G-CSF. Median neutrophil and platelet engraftments occurred on days 18 and 14, respectively, after transplantation and were identical to those seen with in recipients of grafts mobilized with standard G-CSF. With a median follow-up of 357 days, the incidence of grade II-IV acute graft-versus-host disease was 50% and there have been no relapses to date. Mobilization of stem cells with peg-G-CSF in normal donors is feasible and 12 mg results in mobilization characteristics similar to those of standard G-CSF.

Host B cells produce IL-10 following TBI and attenuate acute GVHD after allogeneic bone marrow transplantation.

Host antigen-presenting cells (APCs) are known to be critical for the induction of graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT), but the relative contribution of specific APC subsets remains unclear. We have studied the role of host B cells in GVHD by using B-cell-deficient microMT mice as BMT recipients in a model of CD4-dependent GVHD to major histocompatibility complex antigens. We demonstrate that acute GVHD is initially augmented in microMT recipients relative to wild-type recipients (mortality: 85% vs 44%, P < .01), and this is the result of an increase in donor T-cell proliferation, expansion, and inflammatory cytokine production early after BMT. Recipient B cells were depleted 28-fold at the time of BMT by total body irradiation (TBI) administered 24 hours earlier, and we demonstrate that TBI rapidly induces sustained interleukin-10 (IL-10) generation from B cells but not dendritic cells (DCs) or other cellular populations within the spleen. Finally, recipient mice in which B cells are unable to produce IL-10 due to homologous gene deletion develop more severe acute GVHD than recipient mice in which B cells are wild type. Thus, the induction of IL-10 in host B cells during conditioning attenuates experimental acute GVHD.

Tumor-derived interleukin-4 reduces tumor clearance and deviates the cytokine and granzyme profile of tumor-induced CD8+ T cells.

An interleukin (IL)-4-containing tumor environment is reported to be beneficial for immune clearance of tumor cells in vivo; however, the effect of IL-4 on the effector CD8+ T cells contributing to tumor clearance is not well defined. We have used the immunogenic HLA-CW3-expressing P815 (P.CW3) mastocytoma and investigated whether IL-4 expression by the tumor affects tumor clearance and, if so, whether it alters the tumor-induced Vbeta10+ CD8+ T-cell response. P.CW3 were stably transfected with IL-4 or the empty control vector, and independent cell lines were injected i.p. into syngeneic DBA/2 mice. After apparent clearance of primary tumors over 12 to 15 days, secondary tumors arose that lacked surface expression and H-2-restricted antigen presentation of CW3 in part due to the loss of the HLA-CW3 expression cassette. Surprisingly, mice that received IL-4-producing tumor cells showed delayed primary tumor clearance and were significantly more prone to develop secondary tumors compared with mice receiving control tumor cells. Tumor clearance was dependent on CD8+ T cells. The IL-4-secreting P.CW3 tumor cells led to markedly higher mRNA expression of IL-4 and granzyme A and B but no differences in IFN-gamma and IL-2 production, cell proliferation, or ex vivo CTL activity in primary Vbeta10+ CD8+ T cells when compared with the control tumor cells. We concluded that tumor-derived IL-4 selectively changed the quality of the tumor-induced CD8+ T-cell response and resulted in unexpected negative effects on tumor clearance. These data bring into question the delivery of IL-4 to the tumor environment for improving tumor immunotherapy.

Stem cell mobilization with G-CSF analogs: a rational approach to separate GVHD and GVL?

The separation of graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) remains the "holy grail" of allogeneic stem cell transplantation, and improvements are urgently needed to allow more effective therapy of malignant disease. The use of G-CSF-mobilized peripheral blood as a clinical stem cell source is associated with enhanced GVL effects without amplification of significant acute GVHD. Preclinical studies have demonstrated that G-CSF modulates donor T cell function before transplantation, promoting T(H)2 differentiation and regulatory T cell function. In addition, the expansion of immature antigen-presenting cells (APCs) and plasmacytoid dendritic cells (DCs) favors the maintenance of this pattern of T cell differentiation after transplantation. Although these patterns of T cell differentiation attenuate acute GVHD, they do not have an impact on the cytolytic pathways of the CD8(+) T cells that are critical for effective GVL. Recently, it has been demonstrated that modification of G-CSF, either by pegylation of the native cytokine or conjugation to Flt-3L, results in the expansion and activation of donor iNKT cells, which significantly augment CD8(+) T cell-mediated cytotoxicity and GVL effects after transplantation. Given that these cytokines also enhance the expansion of regulatory T cells and APCs, they further separate GVHD and GVL, offering potential clinical advantages for the transplant recipient.

NKT cell-dependent leukemia eradication following stem cell mobilization with potent G-CSF analogs.

NKT cells have pivotal roles in immune regulation and tumor immunosurveillance. We report that the G-CSF and FMS-like tyrosine kinase 3 ligand (Flt-3L) chimeric cytokine, progenipoietin-1, markedly expands the splenic and hepatic NKT cell population and enhances functional responses to alpha-galactosylceramide. In a murine model of allogeneic stem cell transplantation, donor NKT cells promoted host DC activation and enhanced perforin-restricted CD8+ T cell cytotoxicity against host-type antigens. Following leukemic challenge, donor treatment with progenipoietin-1 significantly improved overall survival when compared with G-CSF or control, attributable to reduced graft-versus-host disease mortality and paradoxical augmentation of graft-versus-leukemia (GVL) effects. Enhanced cellular cytotoxicity was dependent on donor NKT cells, and leukemia clearance was profoundly impaired in recipients of NKT cell-deficient grafts. Enhanced cytotoxicity and GVL effects were not associated with Flt-3L signaling or effects on DCs but were reproduced by prolonged G-CSF receptor engagement with pegylated G-CSF. Thus, modified G-CSF signaling during stem cell mobilization augments NKT cell-dependent CD8+ cytotoxicity, effectively separating graft-versus-host disease and GVL and greatly expanding the potential applicability of allogeneic stem cell transplantation for the therapy of malignant disease.

TGF-beta in allogeneic stem cell transplantation: friend or foe?

Donor treatment with granulocyte-colony-stimulating factor (G-CSF) attenuates the ability of donor T cells to induce acute graft-versus-host disease (aGVHD) but increases the severity of chronic GVHD (cGVHD). We investigated the role of the regulatory cytokine transforming growth factor beta (TGF-beta) in this paradox in well-established murine models of aGVHD and cGVHD wherein recipients undergo transplantation with splenocytes from donors treated with G-CSF. Neutralization of TGF-beta after stem-cell transplantation (SCT) significantly increased the severity of aGVHD, and the concurrent prevention of interleukin-10 (IL-10) production further exaggerated this effect. Early after SCT, donor T cells were the predominant source of TGF-beta and were able to attenuate aGVHD in a TGF-beta-dependent fashion. Although the neutralization of TGF-beta augmented the proliferation and expansion of donor T cells after SCT, it paradoxically impaired cellular cytotoxicity to host antigens and associated graft-versus-leukemia (GVL) effects. In cGVHD, neutralization of TGF-beta from day 14 after SCT attenuated histologic abnormalities, and CD11b+ mononuclear cells infiltrating sclerodermatous skin produced 50-fold more TGF-beta than corresponding T cells. Thus, though the production of TGF-beta by donor T cells early after transplantation attenuates aGVHD and is required for optimal GVL, the production of TGF-beta late after SCT is preferentially from mononuclear cells and mediates cGVHD. These data have important implications for the timing of therapeutic TGF-beta neutralization to prevent cGVHD after allogeneic SCT.

Chronic graft-versus-host disease after granulocyte colony-stimulating factor-mobilized allogeneic stem cell transplantation: the role of donor T-cell dose and differentiation.

The use of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood as a source of stem cells has resulted in a high incidence of severe chronic graft-versus-host disease (cGVHD), which compromises the outcome of clinical allogeneic stem cell transplantation. We have studied the effect of G-CSF on both immune complex and fibrotic cGVHD directed to major (DBA/2 --> B6D2F1) or minor (B10.D2 --> BALB/c) histocompatibility antigens. In both models, donor pretreatment with G-CSF reduced cGVHD mortality in association with type 2 differentiation. However, after escalation of the donor T-cell dose, scleroderma occurred in 90% of the recipients of grafts from G-CSF-treated donors. In contrast, only 11% of the recipients of control grafts developed scleroderma, and the severity of hepatic cGVHD was also reduced. Mixing studies confirmed that in the presence of high donor T-cell doses, the severity of scleroderma was determined by the non-T-cell fraction of grafts from G-CSF-treated donors. These data confirm that the induction of cGVHD after donor treatment with G-CSF is dependent on the transfer of large numbers of donor T cells in conjunction with a putatively expanded myeloid lineage, providing a further rationale for the limitation of cell dose in allogeneic stem cell transplantation.

Donor treatment with pegylated G-CSF augments the generation of IL-10-producing regulatory T cells and promotes transplantation tolerance.

We investigated whether the protection from graft-versus-host disease (GVHD) afforded by donor treatment with granulocyte colony-stimulating factor (G-CSF) could be enhanced by dose escalation. Donor treatment with human G-CSF prevented GVHD in the B6 --> B6D2F1 murine model in a dose-dependent fashion, and murine G-CSF provided equivalent protection from GVHD at 10-fold lower doses. Donor pretreatment with a single dose of pegylated G-CSF (peg-G-CSF) prevented GVHD to a significantly greater extent than standard G-CSF (survival, 75% versus 11%, P <.001). Donor T cells from peg-G-CSF-treated donors failed to proliferate to alloantigen and inhibited the responses of control T cells in an interleukin 10 (IL-10)-dependent fashion in vitro. T cells from peg-G-CSF-treated IL-10(-/-) donors induced lethal GVHD; T cells from peg-G-CSF-treated wild-type (wt) donors promoted long-term survival. Whereas T cells from peg-G-CSF wt donors were able to regulate GVHD induced by T cells from control-treated donors, T cells from G-CSF-treated wt donors and peg-G-CSF-treated IL-10(-/-) donors did not prevent mortality. Thus, peg-G-CSF is markedly superior to standard G-CSF for the prevention of GVHD following allogeneic stem cell transplantation (SCT), due to the generation of IL-10-producing regulatory T cells. These data support prospective clinical trials of peg-G-CSF-mobilized allogeneic blood SCT.