Stephen Mackinnon

Adoptive cellular therapy for early cytomegalovirus infection after allogeneic stem-cell transplantation with virus-specific T-cell lines

Adoptive transfer of CMV-specific T cells offers the potential for reconstitution of viral immunity after allogeneic transplantation. However, the logistics of producing virus-specific T-cell clones has limited the application of cellular therapies. We treated 16 patients for CMV infection with polyclonal CMV-specific T-cell lines generated by short-term culture. Massive in-vivo expansions of CMV-specific cytotoxic T lymphocytes were observed, resulting in reconstitution of viral immunity. In eight cases antiviral drugs were not required, and subsequent episodes of reactivation occurred in only two patients. Our findings indicate that application of CMV-specific cell lines is both feasible and effective in a clinical environment.

Clinical evidence of a graft-versus-Hodgkin's-lymphoma effect after reduced-intensity allogeneic transplantation

BACKGROUND In patients with multiply relapsed Hodgkins lymphoma allogeneic stem-cell transplantation has been limited by prohibitive non-relapse-related mortality rates and by a lack of definitive evidence for a therapeutic graft-versus-tumour effect. Therefore, we aimed to assess the graft-versus-tumour effect of reduced-intensity allogeneic transplantation. METHODS We undertook reduced-intensity transplantation in 49 patients with multiply relapsed Hodgkins lymphoma, 44 (90%) of whom had progression of disease after previous autologous transplantation (median age 32 years [range 18-51], number of previous treatment courses was five [range 3-8], and time from diagnosis 4.8 years [range 0.6-4.8]). 31 patients had HLA matched donors who were related and 18 had donors who were unrelated. Median follow-up was 967 days (range 102-2232). The primary endpoints were engraftment, toxic effects, non-relapse-related mortality, incidence of graft-versus-host disease (GVHD), and the toxic effects of adjuvant donor-lymphocyte infusion. FINDINGS All patients engrafted. Eight of 49 (16%) had grade II-IV acute GVHD and seven (14%) had chronic GVHD before donor-lymphocyte infusion. 16 (33%) patients received donor-lymphocyte infusion from 3 months after transplantation for residual disease or progression. Six (38%) of the 16 developed grade II-IV acute GVHD and five developed chronic GVHD. Nine (56%) showed disease responses after infusion (eight complete, one partial). Non-relapse-related mortality was 16.3% at 730 days (7.2% for patients who had related donors vs 34.1% for those with unrelated donors, p=0.0206). Projected 4 year overall and progression-free survival were 55.7% and 39.0%, respectively (62.0% and 41.5% for related donors). INTERPRETATION These data show the potential for durable responses in patients who have previously had substantial treatment for Hodgkins lymphoma. The low non-relapse-related mortality suggests the procedure could be undertaken earlier in the course of the disease.

Allogeneic Stem-Cell Transplantation Using a Reduced-Intensity Conditioning Regimen Has the Capacity to Produce Durable Remissions and Long-Term Disease-Free Survival in Patients With High-Risk Acute Myeloid Leukemia and Myelodysplasia

PURPOSE The toxicity of allogeneic stem-cell transplantation can be substantially reduced using a reduced-intensity conditioning (RIC) regimen. This has increased the proportion of patients with myeloid malignancies eligible for allogeneic transplantation. However, the capacity of RIC allografts to produce durable remissions in patients with acute myeloid leukemia (AML) and myelodysplasia (MDS) has not yet been defined, and consequently, the role of RIC allografts in the management of these diseases remains conjectural. PATIENTS AND METHODS Seventy-six patients with high-risk AML or MDS received an allograft using a fludarabine/melphalan RIC regimen incorporating alemtuzumab. The median age of the cohort was 52 years (range, 18 to 71 years). RESULTS The 100-day transplantation-related mortality rate was 9%, and no patient developed greater than grade 2 graft-versus-host disease. With a median follow-up of 36 months (range, 13 to 70 months), 27 patients were alive and in remission, with 3-year actuarial overall survival (OS) and disease-free survival (DFS) rates of 41% and 37%, respectively. The 3-year OS and DFS rates of patients with AML in complete remission at the time of transplantation were 48% and 42%, respectively. Disease relapse was the most common cause of treatment failure and occurred at a median time of 6 months after transplantation. All but one patient destined to relapse did so within 24 months of transplantation. CONCLUSION The extended follow-up in this series identifies a high risk of early disease relapse but provides evidence that RIC allografts can produce sustained DFS in a significant number of patients with AML who would be ineligible for allogeneic transplantation with myeloablative conditioning.

Directly Selected Cytomegalovirus-Reactive Donor T Cells Confer Rapid and Safe Systemic Reconstitution of Virus-Specific Immunity Following Stem Cell Transplantation

BACKGROUND Adoptive transfer of virus-specific T cells may accelerate reconstitution of antigen-specific immunity and limit the morbidity and mortality of viral infections following allogeneic hematopoietic stem cell transplantation. The logistics of producing virus-specific T cells has, however, limited the application of cellular therapies, particularly following the introduction of more-recent regulatory stipulations. METHODS We investigated the ability of cytomegalovirus-specific T cells, directly isolated from donor leucapheresates on the basis of interferon γ secretion, to restore antiviral immunity in a group of 25 patients following related-donor transplantation in a single-arm phase I-II study. Selected cells were administered early following transplantation, either after the detection of cytomegalovirus DNA by polymerase chain reaction-based surveillance or prophylactically between day 40 and day 50. RESULTS Cell selection was successful in all cases, yielding a product biased towards CD4(+) over CD8(+) T cells. The target cell dose of 1 × 10(4) CD3(+) T cells/kg of recipient weight contained a median of 2840 cytomegalovirus-specific CD4(+) cells/kg and 630 cytomegalovirus-specific CD8(+) cells/kg, with a median purity of 43.9% interferon γ-secreting cells. Expansions of both CD4(+) and CD8(+) cytomegalovirus-specific T cells were observed in vivo within days of adoptive transfer. These cells were predominantly terminally differentiated effector-memory cells and showed the same T cell receptor variable β chain (TCRBV) -restriction as the infused cells. They offered protection from reinfection in the majority of patients. CONCLUSIONS These data indicate that application of cytomegalovirus-specific T cells generated by direct selection using γ-capture is both feasible and effective in a clinical environment. These simple in vitro methodologies should allow more widespread application of virus-specific T cell immunotherapies.

Favorable Long-Term Survival After Reduced-Intensity Allogeneic Transplantation for Multiple-Relapse Aggressive Non-Hodgkin's Lymphoma

PURPOSE The role of allogeneic transplantation with reduced-intensity conditioning in diffuse large B-cell lymphoma (DLBCL) is currently unclear, with relatively little published data. We report the outcome of reduced-intensity transplantation (RIT) in a cohort of 48 consecutive patients with relapsed/refractory DLBCL (30 patients with de novo disease and 18 patients with transformed follicular lymphoma) who underwent transplantation with an alemtuzumab-containing regimen, with a median follow-up of 52 months. PATIENTS AND METHODS Patients had experienced treatment failure with a median of five lines of prior therapy, including autologous transplantation in 69%, and 17% of patients were chemotherapy refractory at transplantation. Median age was 46 years, and 38% of patients had matched/mismatched unrelated donors. Conditioning was with alemtuzumab, fludarabine, and melphalan, and additional graft-versus-host disease (GVHD) prophylaxis was with cyclosporine. RESULTS All patients were successfully engrafted. Only 17% of patients developed grade 2 to 4 acute GVHD, with 13% experiencing extensive chronic GVHD. Four-year estimated nonrelapse mortality was 32%, and relapse risk was 33%. Twelve patients received donor lymphocyte infusions +/- chemoimmunotherapy for relapse, and five patients obtained durable remissions, giving current progression-free survival (PFS) and overall survival (OS) rates at 4 years of 48% and 47%, respectively. Patients who had chemotherapy-sensitive disease before RIT had current PFS and OS rates at 4 years of 55% and 54%, respectively. Chemotherapy-refractory patients had a poor outcome. CONCLUSION The encouraging survival rates with extended follow-up suggest a role for RIT in chemotherapy-sensitive relapsed DLBCL, even in patients who have previously experienced treatment failure with autologous transplantation. Future studies will be required to determine whether any subset of patients with relapsed DLBCL should be considered for RIT versus autologous transplantation.

Role of nonmyeloablative allogeneic stem-cell transplantation after failure of autologous transplantation in patients with lymphoproliferative malignancies

PURPOSE Conventional allogeneic stem-cell transplantation (SCT) after a prior failed autograft is associated with a transplant-related mortality rate of 50% to 80%. The aim of the current study was to evaluate the safety and efficacy of sibling, HLA-matched, nonmyeloablative allogeneic SCT with donor lymphocyte infusion (DLI) in patients with lymphoid malignancy after failure of autologous SCT. PATIENTS AND METHODS A total of 38 patients with refractory, progressive, or relapsed disease after autologous SCT were entered onto this study. The conditioning regimen consisted of the humanized monoclonal antibody CAMPATH-1H, fludarabine, and melphalan. Fifteen of 35 assessable patients received DLI after SCT. RESULTS Sustained neutrophil engraftment was achieved in 37 recipients, and platelet engraftment was achieved in 35 patients. The estimated transplant-related mortality was 7.9% at day 100 and 20% at 14 months, the median duration of follow-up. Eight patients experienced grade I/II acute graft-versus-host disease (GVHD) after transplantation, but no grade III/IV GVHD was observed in this setting. However, grade III/IV GVHD occurred in seven patients who received DLI. The actuarial overall survival at 14 months was 53%, with a progression-free survival of 50%. DLI produced a further response in three of 15 recipients. CONCLUSION Nonmyeloablative allogeneic SCT after CAMPATH-1H-containing conditioning is a relatively safe option compared with conventional allogeneic transplantation for patients who have failed previous autologous SCT. The low incidence of early GVHD enabled the subsequent administration of DLI to improve further clinical responses in this poor-risk group of lymphoma and myeloma patients.

T-Cell–Depleted Reduced-Intensity Transplantation Followed by Donor Leukocyte Infusions to Promote Graft-Versus-Lymphoma Activity Results in Excellent Long-Term Survival in Patients With Multiply Relapsed Follicular Lymphoma

PURPOSE Follicular lymphoma (FL) is an indolent disorder that is treatable but considered incurable with chemotherapy alone. The curative potential of allogeneic transplantation using conventional myeloablative conditioning has been demonstrated, but this approach is precluded in the majority of patients with FL because of excessive toxicity. Thus, reduced-intensity conditioning regimens are being explored. PATIENTS AND METHODS This study reports the outcome of 82 consecutive patients with FL who underwent transplantation using fludarabine, melphalan, and alemtuzumab for in vivo T-cell depletion. Patients were heavily pretreated, having received a median of four lines of prior therapy, and 26% had experienced treatment failure with previous autologous transplantation. Median patient age was 45 years, and 52% of patients received stem cells from unrelated donors. RESULTS With a median follow-up time of 43 months, the nonrelapse mortality was 15% at 4 years (8% for sibling and 22% for unrelated donor transplantations), acute grade 2 or 3 graft-versus-host disease (GVHD) occurred in 13%, and the incidence of extensive chronic GVHD was only 18%. Although relapse risk was 26%, this was significantly reduced where mixed chimerism had been converted to full donor chimerism by the use of donor lymphocyte infusion (DLI; P = .03). In addition, 10 (77%) of 13 patients given DLI for relapse after transplantation experienced remission, with nine of these responses being sustained. Current progression-free survival at 4 years was 76% for the whole cohort (90% for those with sibling donors and 64% for those with unrelated donors). CONCLUSION The excellent long-term survival with associated low rates of GVHD and the frequency and durability of DLI responses make this an extremely encouraging strategy for the treatment and potential cure of FL.

The fate of human Langerhans cells in hematopoietic stem cell transplantation.

Langerhans cells (LC) and other antigen-presenting cells are believed to be critical in initiating graft versus host responses that influence the outcome of allogeneic hematopoietic stem cell transplantation. However, their fate in humans is poorly understood. We have sought to define the effect of conditioning regimes and graft versus host disease (GVHD) on the survival of recipient LC and reconstitution of donor cells after transplant. Confocal microscopy of epidermal sheets shows that full intensity transplant (FIT) depletes LC more rapidly than reduced intensity transplant (RIT) at day 0, although the nadir is similar in both at 14–21 d. Recovery occurs rapidly within 40 d in the absence of acute GVHD, but is delayed beyond 100 d when GVHD is active. LC chimerism was determined in sex-mismatched transplants using a two-step Giemsa/fluorescence in situ hybridization assay on isolated cells. Acquisition of donor chimerism at 40 d is more rapid after FIT (97%) than RIT (36.5%), irrespective of blood myeloid engraftment. At 100 d, all transplants achieve at least 90% LC donor chimerism and over half achieve 100%. Complete donor chimerism is associated with prior acute cutaneous GVHD, suggesting a role for allogeneic T cells in promoting LC engraftment.

The role of Vδ2-negative γδ T cells during cytomegalovirus reactivation in recipients of allogeneic stem cell transplantation

Reactivation of cytomegalovirus (CMV) remains a serious complication after allogeneic stem cell transplantation, but the role of γδ T cells is undefined. We have studied the immune reconstitution of Vδ2negative (Vδ2neg) γδ T cells, including Vδ1 and Vδ3 subsets and Vδ2positive (Vδ2pos) γδ T cells in 40 patients during the first 24 months after stem cell transplantation. Significant long-term expansions of Vδ2neg but not Vδ2pos γδ T cells were observed during CMV reactivation early after transplantation, suggesting direct involvement of γδ T cells in anti-CMV immune responses. Similarly, significantly higher numbers of Vδ2neg γδ T cells were detected in CMV-seropositive healthy persons compared with seronegative donors; the absolute numbers of Vδ2pos cells were not significantly different. The expansion of Vδ2neg γδ T cells appeared to be CMV-related because it was absent in CMV-negative/Epstein-Barr virus-positive patients. T-cell receptor-δ chain determining region 3 spectratyping of Vδ2neg γδ T cells in healthy subjects and patients showed restricted clonality. Polyclonal Vδ2neg cell lines generated from CMV-seropositive healthy donors and from a recipient of a graft from a CMV-positive donor lysed CMV-infected targets in all cases. Our study shows new evidence for role of γδ T cells in the immune response to CMV reactivation in transplantation recipients.

Reduced-intensity conditioning for allogeneic haematopoietic stem cell transplantation in relapsed and refractory Hodgkin lymphoma: impact of alemtuzumab and donor lymphocyte infusions on long-term outcomes

The introduction of reduced‐intensity conditioning (RIC) has enabled the role of allogeneic transplantation to be re‐evaluated in Hodgkin lymphoma (HL). While T‐cell depletion reduces graft‐versus‐host disease (GvHD), it potentially abrogates graft‐versus‐tumour activity and increases infective complications. We compared the results in 67 sibling donor transplantations following RIC in multiply relapsed patients from two national phase II studies conditioned with fludarabine/melphalan. One used cyclosporine/alemtuzumab (MF‐A, n = 31), the other used cyclosporine/methotrexate (MF, n = 36) as GvHD prophylaxis. There was a small excess of chemorefractory cases in the MF cohort (P = NS). MF‐A resulted in significantly lower incidences of non‐relapse mortality, acute and chronic GvHD, but no significant excess of relapse/progression. Post donor lymphocyte infusion (DLI) disease responses occurred in 8/14 (57%) and 6/11 (55%) patients in the MF‐A and MF groups, respectively. Current progression‐free survival (CPFS) was superior with MF‐A (univariate analysis), with durable responses to DLI contributing to the favourable outcome (43% vs. 25%, P = 0·0356). Disease status at transplantation significantly influenced overall survival (P = 0·0038) and CPFS (P = 0·0014), retaining significance in multivariate analyses, which demonstrated a trend towards improved CPFS with T‐cell depletion (P = 0·0939). These data suggest that alemtuzumab significantly reduced GvHD without resulting in a deleterious impact on survival outcomes following RIC in HL, and that durable responses to DLI may be more common following the inclusion of alemtuzumab in the conditioning protocol.