Hematopoietic cell transplantation in older patients with hematologic malignancies: replacing high-dose cytotoxic therapy with graft-versus-tumor effects

Reduced-intensity allogeneic hematopoietic cell transplantation using fludarabine-melphalan conditioning for treatment of mature T-cell lymphomas

Among non-Hodgkin's lymphoma subtypes, T-cell phenotype confers a poor clinical prognosis. For more aggressive histologies, patients frequently present with advanced disease that is inherently chemoresistant. For cutaneous histologies, disease progresses less rapidly, but is debilitating and often incurable in the long term. Here we report the retrospective analysis of data from 27 patients with mature T-cell lymphoma treated with salvage allogeneic haematopoietic cell transplantation at the City of Hope, Duarte, CA, USA, using a reduced-intensity fludarabine/melphalan conditioning regimen between the years 2001 and 2008. Eleven of the twenty-seven patients had cutaneous T-cell lymphoma (CTCL). The majority of patients had advanced disease at the time of transplant (17/27 or 63%). Median follow-up was 36 months. We observed a 2-year OS of 55%, a PFS of 47% and a cumulative incidence of relapse/progression and non-relapse mortality (NRM) of 30 and 22%, respectively. For CTCL, patients had a 2-year PFS of 45% and NRM of 27% compared with patients with other histologies, who had a PFS of 62% and NRM of 19%. Overall, our results suggest that meaningful long-term survival rates and disease control can be achieved with acceptable non-relapse mortality in patients with mature T-cell lymphomas, including CTCL using reduced-intensity conditioning with melphalan and fludarabine.

What is the role of transplantation for indolent lymphoma?

Despite advances in chemoimmunotherapy, indolent B-cell non-Hodgkin lymphomas (B-NHLs) are generally not considered curable with this approach. Much attention has been paid to the prospect of hematopoietic cell transplantation (HCT) as a way to improve long-term outcomes for this group of diseases. Autologous (auto) HCT provides intensive conditioning therapy followed by rescue of hematopoiesis, and this has been shown in randomized studies to prolong survival compared with more standard chemotherapy, albeit with increased short-term toxicity and the potential for higher rates of secondary malignancies. Allogeneic (allo) HCT can provide anticancer effects beyond the conditioning therapy through the immune-mediated graft-versus-lymphoma (GVL) effect. It can be administered following myeloablative (MA) conditioning or reduced-intensity (RI) regimens aimed at sufficiently suppressing the patient's immune system to allow engraftment of donor hematopoiesis. However, this same potentially curative alloreactivity of the engrafted immune system can lead to graft-versus-host disease (GVHD), a significant cause of morbidity and mortality following allo HCT. This article will discuss the current role of both auto HCT and allo HCT in the management of indolent lymphoma as well as the relative risks and benefits of each approach such that the reader can place this in context of the multitude of options available for patients with indolent B-NHL.

Treatment, risk factors, and outcome of adults with relapsed AML after reduced intensity conditioning for allogeneic stem cell transplantation

Because information on management and outcome of AML relapse after allogeneic hematopoietic stem cell transplantation (HSCT) with reduced intensity conditioning (RIC) is scarce, a retrospective registry study was performed by the Acute Leukemia Working Party of EBMT. Among 2815 RIC transplants performed for AML in complete remission (CR) between 1999 and 2008, cumulative incidence of relapse was 32% ± 1%. Relapsed patients (263) were included into a detailed analysis of risk factors for overall survival (OS) and building of a prognostic score. CR was reinduced in 32%; remission duration after transplantation was the only prognostic factor for response (P = .003). Estimated 2-year OS from relapse was 14%, thereby resembling results of AML relapse after standard conditioning. Among variables available at the time of relapse, remission after HSCT > 5 months (hazard ratio [HR] = 0.50, 95% confidence interval [CI], 0.37-0.67, P < .001), bone marrow blasts less than 27% (HR = 0.53, 95% CI, 0.40-0.72, P < .001), and absence of acute GVHD after HSCT (HR = 0.67, 95% CI, 0.49-0.93, P = .017) were associated with better OS. Based on these factors, 3 prognostic groups could be discriminated, showing OS of 32% ± 7%, 19% ± 4%, and 4% ± 2% at 2 years (P < .0001). Long-term survival was achieved almost exclusively after successful induction of CR by cytoreductive therapy, followed either by donor lymphocyte infusion or second HSCT for consolidation.

Frequency and prognostic value of D alloantibodies after D-mismatched allogeneic hematopoietic stem cell transplantation after reduced-intensity conditioning

BACKGROUND

Due to the fact that the ABO and D system is inherited independently from the HLA system, approximately 40% of allogeneic hematopoietic stem cell transplants (HSCT) are performed across the blood group barrier. Reports on the development of de novo anti-D in patients undergoing reduced-intensity conditioning (RIC) followed by D-mismatched allogeneic HSCT are rare. The objective of this study was to evaluate the frequency of anti-D alloimmunization after D-mismatched HSCT following RIC and its prognostic impact on transplant outcome.

STUDY DESIGN AND METHODS

Forty patients with hematologic diseases who underwent D-mismatched HSCT were retrospectively analyzed: 19 D- patients with a D+ donor and 21 D+ patients with a D- donor. Routine serologic testing for blood group typing and antibody screening was performed by a column agglutination method every time when transfusion of red blood cell units was requested and in the posttransplantation course to demonstrate establishment of donor ABO type and to detect alloimmunization.

RESULTS

After a median serologic follow-up of 21 (range, 0 to 73) months after HSCT, anti-D was identified in 2 of 21 (10%) D+ patients receiving a D- transplant, 23 and 34 months after HSCT. None of the 19 D- patients with a D+ donor developed an anti-D.

CONCLUSION

We observed an infrequent de novo anti-D formation that is more likely in D+ recipients of D- grafts. However, the development of anti-D does not normally impair the transplant outcome and is not of clinical relevance in the posttransplant course.

Allogeneic stem cell transplantation for chronic myeloid leukemia resistant to tyrosine kinase inhibitors

Allogeneic hematopoietic stem cell transplantation (HSCT) is well-established as a potentially curative treatment for patients who have chronic myeloid leukemia. The success of imatinib and other tyrosine kinase inhibitors (TKI) as initial therapy has changed the treatment paradigm for this disease. Allogeneic hematopoietic transplants are now reserved for patients whose disease does not respond optimally to TKI treatment. Patients whose disease does not have an optimal response to imatinib may respond to a second-generation TKI, dasatinib or nilotinib, and many achieve major or complete molecular and cytogenetic responses. The indication for allogeneic HSCT versus continued second-line therapy is not well-defined and is the subject of ongoing study. There has been continued progress in reducing the toxicity and risks of HSCT with development of reduced-intensity regimens; transplants can be routinely performed in patients up to the age of 75 years who are in fair general medical condition. Transplantation results from unrelated donors have improved, with survival rates similar that achieved with matched siblings. Results with haploidentical and cord blood transplants have markedly improved, and should be considered for patients lacking a matched donor. Allogeneic hematopoietic transplants have the best chance to be curative in patients with chronic phase that is under hematologic control with 80% disease-free survival; patients progressing to the accelerated phase or blast crisis have a much poorer prognosis. Thus, HSCT should be considered for patients with imatinib failure. Patients receiving second-line TKI therapy must be closely monitored and referred for transplantation if a complete cytogenetic response and major molecular response is not achieved. HSCT should be performed if feasible in patients without a continued response to TKI treatment.

Long-term outcomes among older patients following nonmyeloablative conditioning and allogeneic hematopoietic cell transplantation for advanced hematologic malignancies

CONTEXT

A minimally toxic nonmyeloablative regimen was developed for allogeneic hematopoietic cell transplantation (HCT) to treat patients with advanced hematologic malignancies who are older or have comorbid conditions.

OBJECTIVE

To describe outcomes of patients 60 years or older after receiving minimally toxic nonmyeloablative allogeneic HCT.

DESIGN, SETTING, AND PARTICIPANTS

From 1998 to 2008, 372 patients aged 60 to 75 years were enrolled in prospective clinical HCT trials at 18 collaborating institutions using conditioning with low-dose total body irradiation alone or combined with fludarabine, 90 mg/m(2), before related (n = 184) or unrelated (n = 188) donor transplants. Postgrafting immunosuppression included mycophenolate mofetil and a calcineurin inhibitor.

MAIN OUTCOME MEASURES

Overall and progression-free survival were estimated by Kaplan-Meier method. Cumulative incidence estimates were calculated for acute and chronic graft-vs-host disease, toxicities, achievement of full donor chimerism, complete remission, relapse, and nonrelapse mortality. Hazard ratios (HRs) were estimated from Cox regression models.

RESULTS

Overall, 5-year cumulative incidences of nonrelapse mortality and relapse were 27% (95% CI, 22%-32%) and 41% (95% CI, 36%-46%), respectively, leading to 5-year overall and progression-free survival of 35% (95% CI, 30%-40%) and 32% (95% CI, 27%-37%), respectively. These outcomes were not statistically significantly different when stratified by age groups. Furthermore, increasing age was not associated with increases in acute or chronic graft-vs-host disease or organ toxicities. In multivariate models, HCT-specific comorbidity index scores of 1 to 2 (HR, 1.58 [95% CI, 1.08-2.31]) and 3 or greater (HR, 1.97 [95% CI, 1.38-2.80]) were associated with worse survival compared with an HCT-specific comorbidity index score of 0 (P = .003 overall). Similarly, standard relapse risk (HR, 1.67 [95% CI, 1.10-2.54]) and high relapse risk (HR, 2.22 [95% CI, 1.43-3.43]) were associated with worse survival compared with low relapse risk (P < .001 overall).

CONCLUSION

Among patients aged 60 to 75 years treated with nonmyeloablative allogeneic HCT, 5-year overall and progression-free survivals were 35% and 32%, respectively.

Decreased serum albumin as a biomarker for severe acute graft-versus-host disease after reduced-intensity allogeneic hematopoietic cell transplantation

Biomarkers capable of predicting the onset and severity of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplantation (HCT) would enable preemptive and risk-stratified therapy. Severe aGVHD leads to gastrointestinal protein loss, resulting in hypoalbuminemia. We hypothesized that decreases in serum albumin at onset of aGVHD would predict the risk of progression to severe aGVHD. We identified 401 patients who developed aGVHD grades II-IV after reduced-intensity allogeneic HCT and reviewed all available serum albumin values from 30 days before HCT to 45 days after initiation of treatment for aGVHD. A ≥0.5 g/dL decrease in serum albumin concentration from pretransplantation baseline to the onset of treatment for aGVHD predicted the subsequent development of grade III/IV aGVHD (versus grade II aGVHD) with a sensitivity of 69% and a specificity of 73%. Overall mortality at 6 months after initiation of aGVHD treatment was 36% versus 17% for patients with and without ≥0.5 g/dL decreases in serum albumin, respectively (P = .0009). We conclude that change in serum albumin concentration from baseline to initiation of aGVHD treatment is an inexpensive, readily available, and predictive biomarker of GVHD severity and mortality after reduced-intensity allogeneic HCT.

Extracorporeal photopheresis in addition to pentostatin in conditioning for canine hematopoietic cell transplantation: role in engraftment

Extracorporeal photopheresis (ECP) and the purine analog pentostatin exert potent immunomodulatory effects, but have not been evaluated for their ability to enhance engraftment of hematopoietic stem cells. We evaluated, in a canine model of dog leukocyte antigen (DLA)-identical hematopoietic cell transplantation (HCT), whether ECP in combination with pentostatin could enhance engraftment using a nonmyeloablative regimen consisting of 100 cGy TBI and postgrafting immunosuppression with mycophenolate mofetil and CYA. We have shown previously that with 100 cGy TBI alone as conditioning, all of the six dogs rejected their grafts 2-12 weeks after HCT. With the addition of pentostatin to 100 cGy TBI, 6 of 10 dogs rejected their graft. We now tested the additional use of ECP alone (n=2) or ECP and 3-6 doses of pentostatin (n=7) before 100 cGy TBI and HCT. Eight out of nine dogs rejected their grafts within 6-11 weeks after HCT. Compared with data without ECP, we failed to demonstrate a positive impact of the use of either ECP or pentostatin for prevention of rejection.

Hematopoietic stem cell transplantation in the Department of Hematology, Fukushima Medical University

From 1996 to the end of 2009, a total of 114 cases of hematopoietic stem cell transplantation were performed in the Department of Hematology, Fukushima Medical University. We report here a general overview of our results. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) was performed in 37 cases of acute leukemia, 10 of myelodysplastic syndrome, 5 of aplastic anemia, and 5 others. The 5-year survival rate with allo-HSCT was 51.1%. Autologous hematopoietic stem cell transplantation (auto-HSCT) was performed in 34 cases of malignant lymphoma, 15 of multiple myeloma, and 8 others. The 5-year patient survival rate was 75.2% with malignant lymphoma and 46.7% with multiple myeloma. These results are comparable to those from a nationwide survey in Japan, confirming that our hospital has attained a creditable level as a transplantation center.

Selective resistance of CD44hi T cells to p53-dependent cell death results in persistence of immunologic memory after total body irradiation

Our previous studies showed that treatment of mice with total body irradiation (TBI) or total lymphoid tissue irradiation markedly changes the balance of residual T cell subsets to favor CD4(+)CD44(hi) NKT cells because of the differential resistance of the latter subset to cell death. The object of the current study was to further elucidate the changed balance and mechanisms of differential radioresistance of T cell subsets after graded doses of TBI. The experimental results showed that CD4(+) T cells were markedly more resistant than CD8(+) T cells, and CD44(hi) T cells, including NKT cells and memory T cells, were markedly more resistant than CD44(lo) (naive) T cells. The memory T cells immunized to alloantigens persisted even after myeloablative (1000 cGy) TBI and were able to prevent engraftment of bone marrow transplants. Although T cell death after 1000 cGy was prevented in p53(-/-) mice, there was progressive T cell death in p53(-/-) mice at higher doses. Although p53-dependent T cell death changed the balance of subsets, p53-independent T cell death did not. In conclusion, resistance of CD44(hi) T cells to p53-dependent cell death results in the persistence of immunological memory after TBI and can explain the immune-mediated rejection of marrow transplants in sensitized recipients.

Usefulness of the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) in predicting outcomes for adolescents and young adults with hematologic malignancies undergoing allogeneic stem cell transplant

BACKGROUND

The HCT-CI helps to predict non-relapse mortality (NRM) and overall survival (OS) in allogeneic hematopoietic cell transplantation (HCT) recipients. The usefulness of this index in a younger, adolescent and young adult (AYA) population is unclear.

PROCEDURE

We tested the validity of the HCT-CI as a predictor of mortality in a retrospective cohort of 56 AYA recipients between the ages of 16 and 39, using chart abstraction followed by univariable and multivariate analysis.

RESULTS

Only pulmonary dysfunction (46%), hepatic dysfunction (27%), infection (20%), and psychiatric disturbance (11%) had frequencies greater than 5% in this population. HCT-CI scores of 0-2 were present in 54%, and scores of >3 in 46%. The cumulative incidence of NRM at 2 years was 32%, with an OS of 46%; the NRM and OS for patients with an HCT-CI of 0-2 were 24% and 62%, whereas the NRM and OS for patients with an HCT-CI >3 were 38% and 28%. Patients with pulmonary dysfunction prior to transplant had a 29% OS at 2 years, compared to a 61% OS among patients without (P = 0.001). There was no statistically significant difference for patients and a worse NRM (P = 0.08). In multivariable analysis, both an HCT-CI score of >3 and any pulmonary dysfunction remained associated with OS (P = 0.01, P = 0.03), but neither with NRM.

CONCLUSIONS

The HCT-CI appears useful in predicting OS in AYAs, though higher scores may reflect prior treatment, with pulmonary dysfunction particularly prevalent. Prospective studies to further validate and explain these findings are warranted.

Cytopenias after day 28 in allogeneic hematopoietic cell transplantation: impact of recipient/donor factors, transplant conditions and myelotoxic drugs

BACKGROUND

Secondary cytopenias are serious complications following hematopoietic cell transplantation. Etiologies include myelotoxic agents, viral infections, and possibly transplant-related factors such as the intensity of the conditioning regimen and the source of stem cells.

DESIGN AND METHODS

We retrospectively analyzed data from 2162 hematopoietic cell transplant recipients to examine the effect of these factors on overall cytopenias occurring after 28 days in hematopoietic cell transplantation.

RESULTS

Advanced age of the patient, recipient cytomegalovirus seropositivity, unrelated donor status, human leukocyte antigen mismatch and lower doses of transplanted CD34(+) cells (≤ 6.4×10(6)/kg) significantly increased the risk of cytopenias after day 28. Non-myeloablative hematopoietic cell transplantation had protective effects on anemia and thrombocytopenia after day 28 (adjusted odds ratio 0.76, probability value of 0.05 and adjusted odds ratio 0.31, probability value of <0.0001, respectively) but not on overall or ganciclovir-related neutropenia. This lack of protection appeared to be due to the use of mycophenolate mofetil in the majority of recipients of non-myeloablative hematopoietic cell transplants. Peripheral blood stem cells did not confer protection from cytopenias when compared to bone marrow.

CONCLUSIONS

Elderly patients appear to be more prone to cumulative toxicities of post-transplant drug regimens, but non-myeloablative conditioning, optimized human leukocyte antigen matching, and higher doses of CD34(+) cell infusions may reduce the risk of cytopenia after day 28.

A comparison of immune reconstitution and graft-versus-host disease following myeloablative conditioning versus reduced toxicity conditioning and umbilical cord blood transplantation in paediatric recipients

Immune reconstitution appears to be delayed following myeloablative conditioning (MAC) and umbilical cord blood transplantation (UCBT) in paediatric recipients. Although reduced toxicity conditioning (RTC) versus MAC prior to allogeneic stem cell transplantation is associated with decreased transplant-related mortality, the effects of RTC versus MAC prior to UCBT on immune reconstitution and risk of graft-versus-host disease (GVHD) are unknown. In 88 consecutive paediatric recipients of UCBT, we assessed immune cell recovery and immunoglobulin reconstitution at days +100, 180 and 365 and analysed risk factors associated with acute and chronic GVHD. Immune cell subset recovery, immunoglobulin reconstitution, and the incidence of opportunistic infections did not differ significantly between MAC versus RTC groups. In a Cox model, MAC versus RTC recipients had significantly higher risk of grade II-IV acute GVHD [Hazard Ratio (HR) 6·1, P = 0·002] as did recipients of 4/6 vs. 5-6/6 HLA-matched UCBT (HR 3·1, P = 0·03), who also had significantly increased risk of chronic GVHD (HR 18·5, P = 0·04). In multivariate analyses, MAC versus RTC was furthermore associated with significantly increased transplant-related (Odds Ratio 26·8, P = 0·008) and overall mortality (HR = 4·1, P = 0·0001). The use of adoptive cellular immunotherapy to accelerate immune reconstitution and prevent and treat opportunistic infections and malignant relapse following UCBT warrants further investigation.

[Allogeneic hematopoietic stem cell transplantation in elderly]

Most of patients with hematological malignancies are elderly (more than 60  years). Allogeneic stem cell transplantation is an important and effective treatment for most of these diseases. However, the toxicity and the supposed frailty of elderly patients, have limited the applicability of allogeneic transplantation for these patients. Elderly patients are at high risk to develop life-threatening complications, if allogeneic transplantation is performed with myeloablative conditioning regimens and using bone marrow stem source. Since more than 10 years, reduced intensity conditioning regimen have been developed, allowing to overcome the age as contra-indication for allogeneic transplantation. On the other hand, it is the presence of comorbidities which identify frail patients. For these subjects, allogeneic transplantation should be not indicated. Furthermore, advances in the supportive care and the development of new molecules could allow to reduce the toxicity of myeloablative conditioning regimens and thus to offer more intensive regimens before transplantation also in elderly population.

Pharmacological immunosuppression reduces but does not eliminate the need for total-body irradiation in nonmyeloablative conditioning regimens for hematopoietic cell transplantation

In the dog leukocyte antigen (DLA)-identical hematopoietic cell transplantation (HCT) model, stable marrow engraftment can be achieved with total-body irradiation (TBI) of 200 cGy when used in combination with postgrafting immunosuppression. The TBI dose can be reduced to 100 cGy without compromising engraftment rates if granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (G-PBMC) are infused with the marrow. T cell-depleting the G-PBMC product abrogates this effect. These results were interpreted to suggest that the additional T cells provided with G-PBMC facilitated engraftment by overcoming host resistance. We therefore hypothesized that the TBI dose may be further reduced to 50 cGy by augmenting immunosupression either by (1) tolerizing or killing recipient T cells, or (2) enhancing the graft-versus-host (GVH) activity of donor T cells. To test the first hypothesis, recipient T cells were activated before HCT by repetitive donor-specific PBMC infusions followed by administration of methotrexate (MTX) (n = 5), CTLA4-Ig (n = 4), denileukin diftitox (Ontak; n = 4), CTLA4-Ig + MTX (n = 8), or 5c8 antibody (anti-CD154) + MTX (n = 3). To test the second hypothesis, recipient dendritic cells were expanded in vivo by infusion of Flt3 ligand given either pre-HCT (n = 4) or pre- and post-HCT (n = 5) to augment GVH reactions. Although all dogs showed initial allogeneic engraftment, sustained engraftment was seen in only 6 of 42 dogs (14% of all dogs treated in 9 experimental groups). Hence, unless more innovative pharmacotherapy can be developed that more forcefully shifts the immunologic balance in favor of the donor, noncytotoxic immunosuppressive drug therapy as the sole component of HCT preparative regimens may not suffice to ensure sustained engraftment.

Use of matched unrelated donors compared with matched related donors is associated with lower relapse and superior progression-free survival after reduced-intensity conditioning hematopoietic stem cell transplantation

As success of reduced-intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT) relies primarily on graft-versus-leukemia (GVL) activity, increased minor HLA disparity in unrelated compared to related donors could have a significant impact on transplant outcomes. To assess whether use of unrelated donors (URD) engenders more potent GVL in RIC HSCT compared to matched related donors (MRD), we retrospectively studied 433 consecutive T-replete 6/6 HLA matched URD (n = 246) and MRD (n = 187) RIC HSCT for hematologic malignancies at our institution. Diseases included: acute myelogenous leukemia (AML) (127), non-Hodgkin lymphoma (NHL) (71), chronic lymphocytic leukemia (CLL) (68), myelodysplastic syndrome (MDS) (64), Hodgkin disease (HD) (40), chronic myeloid leukemia (CML) (25), multiple myeloma (MM) (23), myeloproliferative disorder (MPD) (12), acute lymphoblastic leukemia (ALL) (7), and other leukemia (1). All received uniform fludarabine and intravenous busulfan conditioning, and GVHD prophylaxis with tacrolimus/mini-methroxate (mini-MTX) or tacrolimus/sirolimus ± mini-MTX. Unrelated donors were younger compared to MRD (median donor age: 33 years versus 52 years, P < .0001), and provided larger CD34(+) products (median CD34(+) cells infused: 8.7 × 10(6)/kg versus 7.5 × 10(6)/kg, P = .002). Distribution of diseases, disease risk, prior transplant, and cytomegalovirus (CMV) status was similar in both cohorts. Cumulative incidence of grade II-IV acute GVHD (at day +180), 2-year chronic GVHD, and 2-year nonrelapse mortality (NRM) were 20% versus 16%, 55% versus 50%, and 8% versus 6% in URD and MRD, respectively (P = NS). Cumulative incidence of relapse at 2 years was lower in URD, 52% versus 65% (P = .005). With median follow-up of 26.5 and 35.8 months, 2-year progression-free survival (PFS) was significantly better in unrelated donor transplants, 39.5% for URD, and 29% for MRD (P = .01). Overall survival (OS) at 2 years were 56% for URD versus 50% for MRD (P = .53). In multivariable analysis, URD was associated with a lower risk of relapse (hazard ratio [HR] 0.67, P = .002) and superior PFS (HR 0.69, P = .002). These results suggest that URD is associated with greater GVL activity than MRD, and could have practice changing impact on future donor selection in RIC HSCT.

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

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

Local gene delivery and methods to control immune responses in muscles of normal and dystrophic dogs

Adeno-associated viral vector (AAV)-mediated gene transfer represents a promising gene replacement strategy for treating Duchenne muscular dystrophy (DMD). However, recent studies demonstrated cellular immunity specific to AAV capsid proteins in animal models, which resulted in liver toxicity and elimination of transgene expression in a human trial of hemophilia B. We have recently developed immunosuppressive strategies to prevent such immunity for successful long-term transgene expression in dog muscle. Here, we describe in detail the immunosuppressive regimens employed in both normal and DMD dogs and provide methods for evaluating the efficiency of the regimens following intramuscular injection of AAV in dogs.

Cancer immunotherapy

Cancer immunotherapy consists of approaches that modify the host immune system, and/or the utilization of components of the immune system, as cancer treatment. During the past 25 years, 17 immunologic products have received regulatory approval based on anticancer activity as single agents and/or in combination with chemotherapy. These include the nonspecific immune stimulants BCG and levamisole; the cytokines interferon-α and interleukin-2; the monoclonal antibodies rituximab, ofatumumab, alemtuzumab, trastuzumab, bevacizumab, cetuximab, and panitumumab; the radiolabeled antibodies Y-90 ibritumomab tiuxetan and I-131 tositumomab; the immunotoxins denileukin diftitox and gemtuzumab ozogamicin; nonmyeloablative allogeneic transplants with donor lymphocyte infusions; and the anti-prostate cancer cell-based therapy sipuleucel-T. All but two of these products are still regularly used to treat various B- and T-cell malignancies, and numerous solid tumors, including breast, lung, colorectal, prostate, melanoma, kidney, glioblastoma, bladder, and head and neck. Positive randomized trials have recently been reported for idiotype vaccines in lymphoma and a peptide vaccine in melanoma. The anti-CTLA-4 monoclonal antibody ipilumumab, which blocks regulatory T-cells, is expected to receive regulatory approval in the near future, based on a randomized trial in melanoma. As the fourth modality of cancer treatment, biotherapy/immunotherapy is an increasingly important component of the anticancer armamentarium.

Reduced-intensity allogeneic hematopoietic stem cell transplantation for multiple myeloma: a concise review

Reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (HSCT) can result in reliable donor engraftment, relatively low treatment-related mortality, and sustained remissions in the treatment of multiple myeloma. However, substantial cytoreduction pre-allografting is often necessary because of a variable graft-versus-myeloma effect. The use of RIC allogeneic HSCT immediately after autologous HSCT provides a temporal separation between tumor reduction by high-dose chemotherapy and the graft-versus-myeloma effect. There are currently a number of prospective trials attempting to address the issue of whether this strategy leads to decreases in relapse and/or improvement in overall survival as compared with double autologous transplants. Unfortunately, similar to autografting, relapse remains the major cause of treatment failure after RIC allogeneic HSCT. To improve treatment results with allografting, consideration should be given to incorporating immunomodulatory drugs and targeted treatments to enhance pretransplantation remission status, as posttransplantation maintenance therapy, or in combination with donor lymphocyte infusions for refractory or relapsed disease. Studies exploring these strategies are ongoing.

Non-myeloablative conditioning with allogeneic hematopoietic cell transplantation for the treatment of high-risk acute lymphoblastic leukemia

BACKGROUND

Allogeneic hematopoietic cell transplantation is a potentially curative treatment for patients with acute lymphoblastic leukemia. However, the majority of older adults with acute lymphoblastic leukemia are not candidates for myeloablative conditioning regimens. A non-myeloablative preparative regimen is a reasonable treatment option for this group. We sought to determine the outcome of non-myeloablative conditioning and allogeneic transplantation in patients with high-risk acute lymphoblastic leukemia.

DESIGN AND METHODS

Fifty-one patients (median age 56 years) underwent allogeneic hematopoietic cell transplantation from sibling or unrelated donors after fludarabine and 2 Gray total body irradiation. Twenty-five patients had Philadelphia chromosome-positive acute lymphoblastic leukemia. Eighteen of these patients received post-grafting imatinib.

RESULTS

With a median follow-up of 43 months, the 3-year overall survival was 34%. The 3-year relapse/progression and non-relapse mortality rates were 40% and 28%, respectively. The cumulative incidences of grades II and III-IV acute graft-versus-host disease were 53% and 6%, respectively. The cumulative incidence of chronic graft-versus-host disease was 44%. Hematopoietic cell transplantation in first complete remission and post-grafting imatinib were associated with improved survival (P=0.005 and P=0.03, respectively). Three-year overall survival rates for patients with Philadelphia-negative acute lymphoblastic leukemia in first remission and beyond first remission were 52% and 8%, respectively. For patients with Philadelphia chromosome-positive acute lymphoblastic leukemia in first remission who received post-grafting imatinib, the 3-year overall survival rate was 62%; for the subgroup without evidence of minimal residual disease at transplantation, the overall survival was 73%.

CONCLUSIONS

For patients with high-risk acute lymphoblastic leukemia in first complete remission, non-myeloablative conditioning and allogeneic hematopoietic cell transplantation, with post-grafting imatinib for Philadelphia chromosome-positive disease, can result in favorable long-term survival.

Long-term follow-up of a comparison of nonmyeloablative allografting with autografting for newly diagnosed myeloma

Before the introduction of new drugs, we designed a trial where treatment of newly diagnosed myeloma patients was based on the presence or absence of HLA-identical siblings. First-line treatments included a cytoreductive autograft followed by a nonmyeloablative allograft or a second melphalan-based autograft. Here, we report long-term clinical outcomes and discuss them in the light of the recent remarkable advancements in the treatment of myeloma. After a median follow-up of 7 years, median overall survival (OS) was not reached (P = .001) and event-free survival (EFS) was 2.8 years (P = .005) for 80 patients with HLA-identical siblings and 4.25 and 2.4 years for 82 without, respectively. Median OS was not reached (P = .02) and EFS was 39 months (P = .02) in the 58 patients who received a nonmyeloablative allograft whereas OS was 5.3 years and EFS 33 months in the 46 who received 2 high-dose melphalan autografts. Among patients who reached complete remission in these 2 cohorts, 53% and 19% are in continuous complete remission. Among relapsed patients rescued with "new drugs," median OS from the start of salvage therapy was not reached and was 1.7 (P = .01) years, respectively. Allografting conferred a long-term survival and disease-free advantage over standard autografting in this comparative study.

Treatment of Fanconi anemia patients using fludarabine and low-dose TBI, followed by unrelated donor hematopoietic cell transplantation

A nonmyeloablative conditioning regimen consisting of fludarabine (FLU) and 2 Gy TBI has been used extensively and with substantial engraftment success without promoting excessive nonrelapse mortality in medically infirm patients requiring hematopoietic cell transplantation. In this paper, we studied this same low-toxicity regimen as a means of promoting engraftment of unrelated donor hematopoietic cell transplantation in patients with Fanconi anemia (FA). All patients tolerated the regimen well with no mucositis or other severe toxicities. Of six patients transplanted, five achieved stable mixed or full donor chimerism. Acute and chronic GVHD occurred in four and three patients, respectively. Three patients are alive and well at a median of 45.9 (range, 20.9-68.1) months after transplant. In summary, this FLU-based regimen facilitates stable engraftment of unrelated PBSCs, but is associated with significant chronic GVHD.

Reduced-intensity conditioning regimen combined with low-dose total body irradiation in the treatment of myelodysplastic syndrome

Although reduced-intensity conditioning (RIC) has been increasingly used in patients with myelodysplastic syndrome (MDS) to reduce transplant-related mortality, a high relapse rate in RIC remains an unresolved problem. Considering the additive antileukemic effect of low-dose total body irradiation (TBI), we evaluated the feasibility of combining RIC regimens with low-dose TBI in de novo MDS. The RIC regimen combined with low-dose TBI in this study consisted of fludarabine (150 mg/m(2)), intravenous busulfan (6.4 mg/kg), and TBI (400 cGy). Antithymocyte globulin was used to overcome HLA mismatching. A total of 31 subjects were recruited with a median age of 39 years (range 19-63). The patients received transplants from siblings (n = 20) or unrelated donors (n = 11). All patients rapidly achieved full-donor chimerism. At a median follow-up for survivors of 35 months (range 6.0-54.9), the 3-year overall survival, event-free survival, transplantation-related mortality, and relapse rates were 67.6, 63.2, 20.5 and 11.4%, respectively. The 3-year cumulative incidence of acute (grades II-IV) and chronic extensive graft-versus-host disease in patients who survived at least 100 days was 39.2 and 44.6%, respectively. These results suggest that an RIC combined with low-dose TBI may be a feasible therapeutic approach for treating de novo MDS.

Allogeneic immunotherapy to optimize the graft-versus-tumor effect: concepts and controversies

This article focuses on the recent evolution of novel conditioning regimens in combination with adoptive cellular therapy in the allogeneic transplant setting for hematologic malignancies. Building on data from animal models, the field of allogeneic transplantation is undergoing a paradigm shift toward immunosuppressive regimens with less toxicity that allow donor hematopoietic engraftment in order to provide a graft-versus-tumor effect as the primary goal of transplantation, rather than chemoablation. In addition, the strategies described in this article, including the use of T-cell subsets as adoptive therapy, will apply to a much broader pool of patients than traditional transplant approaches, thereby allowing more patients with life-limiting illnesses, previously deemed ineligible, to pursue therapy with curative intent.

Lineage-specific chimerism analysis in nucleated cells, T cells and natural killer cells after myeloablative allogeneic hematopoietic stem cell transplantation

Background

Chimerism analysis is an important tool for assessing the origin of hematopoietic cells after allogeneic stem cell transplantation (allo-SCT) and can be used to detect impending graft rejection and the recurrence of underlying malignant or nonmalignant diseases.

Methods

This study included 24 patients who underwent myeloablative allo-SCT. DNA was extracted from nucleated cells (NCs), T cells, and natural killer (NK) cells, and the chimerism status of these cell fractions was determined by STR-PCR performed using an automated fluorescent DNA analyzer.

Results

Twenty-three out of the 24 patients achieved engraftment. Mixed chimerism (MC) in NCs, but not in T cells and NK cells, was significantly correlated with disease relapse. MC in all cell fractions was correlated with mortality. Ten patients (41.6%) developed extensive chronic GVHD. Six patients had MC in T cells, and 3 of them had chronic GVHD. Four patients with MC and relapse received donor lymphocyte infusion (DLI), and among them, 3 had secondary relapse. Further, the chimerism status differed among different cell lineages in 6 patients with myeloid malignancies.

Conclusion

The implications of MC in lymphocyte subsets are an important area for future research. Chimerism analysis in lineage-specific cells permits detection of relapse and facilitates the monitoring of therapeutic interventions. These results can provide the basic data for chimerism analysis after myeloablative SCT.

Features of Epstein-Barr Virus (EBV) reactivation after reduced intensity conditioning allogeneic hematopoietic stem cell transplantation

This single centre study assessed the incidence, kinetics and predictive factors of Epstein-Barr Virus (EBV) reactivation and EBV-related lymphoproliferative diseases (LPDs) in 175 consecutive patients who received a reduced-intensity conditioning (RIC) before allogeneic hematopoietic stem cell transplantation (allo-HSCT). The cumulative incidence of EBV reactivation at 6 months after allo-HSCT defined as an EBV PCR load above 1000 copies of EBV DNA/10(5) cells was 15%, and none of these patients experienced any sign or symptom of LPD. A total of 17 patients, who had EBV DNA levels exceeding 1000 copies/10(5) cells on two or more occasions, were pre-emptively treated with rituximab. With a median follow-up of 655 (range, 92-1542) days post allo-HSCT, there was no statistically significant difference in term of outcome between those patients who experienced an EBV reactivation and those who did not. In multivariate analysis, the use of antithymocyte globulin as part of the RIC regimen was the only independent risk factor associated with EBV reactivation (relative risk=4.9; 95% confidence interval, 1.1-21.0; P=0.03). We conclude that patients undergoing RIC allo-HSCT using anti-thymocyte globulin as part of the preparative regimen are at higher risk for EBV reactivation. However, this did not impact on outcome, as quantitative monitoring of EBV viral load by PCR and preemptive rituximab therapy allowed for significantly reducing the risk of EBV-related LPD.

High-dose cyclophosphamide for graft-versus-host disease prevention

PURPOSE OF REVIEW

Administration of high-dose cyclophosphamide after transplantation inhibits both graft rejection and graft-versus-host disease (GvHD) in mouse models of allogeneic blood or marrow transplantation (alloBMT). This strategy has recently been adapted to human transplantation.

RECENT FINDINGS

The safety and efficacy of high-dose posttransplantation cyclophosphamide, when given in combination with tacrolimus and mycophenolate mofetil, was first demonstrated after nonmyeloablative conditioning and allografting using human leukocyte antigen (HLA)-mismatched related donors. Further analysis shows that increasing HLA disparity does not worsen overall outcome. High-dose posttransplantation cyclophosphamide was also found to be effective as sole prophylaxis of acute and chronic GvHD after HLA-matched alloBMT.

SUMMARY

Taking advantage of the differential susceptibility of proliferating, alloreactive T cells over nonproliferating, nonalloreactive T cells to high-dose cyclophosphamide, and owing to the drug's stem cell sparing effects, this novel strategy provides a unique opportunity to optimize GvHD prophylaxis after HLA-matched alloBMT and increase the use of HLA-mismatched related donors. Well tolerated and effective mismatched related alloBMT provides access to essentially everyone, such as patients with sickle cell anemia, in need of the procedure.

Allogeneic stem-cell transplantation as salvage therapy for patients with diffuse large B-cell non-Hodgkin's lymphoma relapsing after an autologous stem-cell transplantation: an analysis of the European Group for Blood and Marrow Transplantation Registry

PURPOSE

To analyze the outcome, including nonrelapse mortality (NRM), relapse rate (RR), progression-free survival (PFS), and overall survival (OS), of patients with diffuse large B-cell non-Hodgkin's lymphoma (DLBCL) relapsed after an autologous stem-cell transplantation (ASCT) and treated with an allogeneic stem-cell transplantation (allo-SCT).

PATIENTS AND METHODS

The European Group for Blood and Marrow Transplantation database was scanned for a first allo-SCT in relapsed DLBCL after a previous ASCT between 1997 and 2006. Other inclusion criteria were age at allo-SCT ≥ 18 years and availability of an HLA-identical sibling or a matched unrelated donor. A total of 101 patients (57 males; median age, 46 years) were included. Median follow-up for survivors was 36 months.

RESULTS

Myeloablative conditioning regimen was used in 37 patients and reduced intensity conditioning (RIC) was used in 64 patients. Three-year NRM was 28.2% (95% CI, 20% to 39%), RR was 30.1% (95% CI, 22% to 41%), PFS was 41.7% (95% CI, 32% to 52%), and OS was 53.8% (95% CI, 44% to 64%). NRM was significantly increased in patients ≥ 45 years (P = .01) and in those with an early relapse (< 12 months) after ASCT (P = .01). RR was significantly higher in refractory patients (P = .03). A time interval to relapse after ASCT of < 12 months was associated with lower PFS (P = .03). The use of RIC regimens was followed by a trend to a lower NRM (P = .1) and a trend to a higher RR (P = .1), with no differences in PFS and OS. No differences were seen between HLA-identical siblings and matched unrelated donors.

CONCLUSION

Allo-SCT in relapsed DLBCL after ASCT is a promising therapeutic modality. Patients with a long remission after ASCT and with sensitive disease at allo-SCT are the best candidates for this approach.

A prospective dose-finding trial using a modified continual reassessment method for optimization of fludarabine plus melphalan conditioning for marrow transplantation from unrelated donors in patients with hematopoietic malignancies

BACKGROUND

Because of the less graft-facilitating effect by bone marrow (BM), we need to assess a dosage of conditioning more accurately particularly in combination with reduced-intensity conditioning. Thus we examined that modified continual reassessment method (mCRM) is applicable for deciding appropriate conditioning of allogeneic BM transplantation.

PATIENTS AND METHODS

The conditioning regimen consisted of i.v. fludarabine (125 mg/m2) plus an examination dose of i.v. melphalan. The primary endpoint was a donor-type T-cell chimerism at day 28 with successful engraftment defined as >90% donor cells. Five patients per dose level were planned to be accrued and chimerism data were used to determine the next dose.

RESULTS

Seventeen patients were enrolled at doses between 130 and 160 mg/m2. The dose was changed from 160 to 130 mg/m(2) (second level) after five full-donor chimerisms. With one patient of 0% chimera in the second level, the dose was increased to 135 mg/m2 (third level). Following five full-donor chimerisms in the third level, the study was complete as projected.

CONCLUSIONS

mCRM was shown to be a relevant method for dose-finding of conditioning regimen. The melphalan dose of 135 mg/m2 was determined as the recommended phase II dose to induce initial full-donor chimerism.

Comparison of reduced intensity and myeloablative conditioning regimens for stem cell transplantation in patients with malignancies: a meta-analysis

OBJECTIVE

The reduced intensity conditioning (RIC) stem cell transplantation is widely employed for the treatment of many hematologic malignancies, but the survival effectiveness is still unclear. This study conducted an updated meta-analysis to determine whether any significant difference could be found by using RIC vs. myeloablative conditioning (MAC) regimen for transplantation in patients with malignancies.

METHODS

We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and relevant articles (1987.01-2009.12). Comparative studies were carried out on clinical therapeutic effect of RIC and MAC on the survival outcomes and the transplantation-related complications.

RESULTS

We obtained 1776 records, and 29 studies totaling 6235 patients have been assessed. Compared with MAC regimen, the RIC regimen had a higher overall survival (OS) at one-yr and no difference at two-yr later after transplantation. RIC regimen had significantly lower rates of disease-free survival (DFS) after two-yr follow-up, lower incidences of ≥ II degree acute graft-versus-host disease (aGVHD), and lower TRM [OR, 0.61, 95% CI (0.53, 0.69)], but with a higher relapse rate [OR, 1.88(1.41, 2.51)]. No significant difference was found in rates of cytomegalovirus (CMV) infection and chronic GVHD between the regimens.

CONCLUSIONS

This meta-analysis confirmed that compared with MAC condition regimen, the RIC regimen had a consistently equivalent or even better rate in OS, but with lower DFS at longer follow-up.

Targeting of B and T lymphocyte associated (BTLA) prevents graft-versus-host disease without global immunosuppression

One-time treatment with an antibody against BTLA provides long-term protection against graft-versus-host disease without affecting effector T cell responses to tumors or pathogens.

Graft-versus-host disease (GVHD) causes significant morbidity and mortality in allogeneic hematopoietic stem cell transplantation (aHSCT), preventing its broader application to non–life-threatening diseases. We show that a single administration of a nondepleting monoclonal antibody specific for the coinhibitory immunoglobulin receptor, B and T lymphocyte associated (BTLA), permanently prevented GVHD when administered at the time of aHSCT. Once GVHD was established, anti-BTLA treatment was unable to reverse disease, suggesting that its mechanism occurs early after aHSCT. Anti-BTLA treatment prevented GVHD independently of its ligand, the costimulatory tumor necrosis factor receptor herpesvirus entry mediator (HVEM), and required BTLA expression by donor-derived T cells. Furthermore, anti-BTLA treatment led to the relative inhibition of CD4⁺ forkhead box P3⁻ (Foxp3⁻) effector T cell (T eff cell) expansion compared with precommitted naturally occurring donor-derived CD4⁺ Foxp3⁺ regulatory T cell (T reg cell) and allowed for graft-versus-tumor (GVT) effects as well as robust responses to pathogens. These results suggest that BTLA agonism rebalances T cell expansion in lymphopenic hosts after aHSCT, thereby preventing GVHD without global immunosuppression. Thus, targeting BTLA with a monoclonal antibody at the initiation of aHSCT therapy might reduce limitations imposed by histocompatibility and allow broader application to treatment of non–life-threatening diseases.

Intravenous apoptotic cell infusion as a cell-based therapy toward improving hematopoietic cell transplantation outcome

Allogeneic hematopoietic cell transplantation (AHCT) is an efficient therapy for different malignant and nonmalignant hematological diseases. However, the use of this therapeutic approach is still limited by some severe toxic side effects, mainly graft-versus-host disease (GvHD). Today, the risk of fatal GvHD restrains the wider application of AHCT to many patients in need of an effective therapy for their high-risk hematologic malignancies. Thus, new strategies, including cell-based therapy approaches, are required. We propose to use intravenous donor apoptotic leukocyte infusion to improve AHCT outcome. In experimental AHCT models, we demonstrated that intravenous apoptotic leukocyte infusion, simultaneously with allogeneic bone marrow grafts, favors hematopoietic engraftment, prevents allo-immunization, and delays acute GvHD onset. Here, we review the different mechanisms and the potential beneficial effects associated with the immunomodulatory properties of apoptotic cells in the AHCT setting.

International Myeloma Working Group Consensus Statement Regarding the Current Status of Allogeneic Stem-Cell Transplantation for Multiple Myeloma

Purpose

To define consensus statement regarding allogeneic stem-cell transplantation (Allo-SCT) as a treatment option for multiple myeloma (MM) on behalf of International Myeloma Working Group.

Patients and Methods

In this review, results from prospective and retrospective studies of Allo-SCT in MM are summarized.

Results

Although the introduction of reduced-intensity conditioning (RIC) has lowered the high treatment-related mortality associated with myeloablative conditioning, convincing evidence is lacking that Allo-RIC improves the survival compared with autologous stem-cell transplantation.

Conclusion

New strategies are necessary to make Allo-SCT safer and more effective for patients with MM. Until this is achieved, Allo-RIC in myeloma should only be recommended in the context of clinical trials.

Thymic recovery after allogeneic hematopoietic cell transplantation with non-myeloablative conditioning is limited to patients younger than 60 years of age

BACKGROUND

Long-term immune recovery in older patients given hematopoietic cell transplantation after non-myeloablative conditioning remains poorly understood. This prompted us to investigate long-term lymphocyte reconstitution and thymic function in 80 patients given allogeneic peripheral blood stem cells after non-myeloablative conditioning.

DESIGN AND METHODS

Median age at transplant was 57 years (range 10-71). Conditioning regimen consisted of 2 Gy total body irradiation (TBI) with (n=46) or without (n=20) added fludarabine, 4 Gy TBI with fludarabine (n=6), or cyclophosphamide plus fludarabine (n=8). Stem cell sources were unmanipulated (n=56), CD8-depleted (n=19), or CD34-selected (n=5) peripheral blood stem cells. Immune recovery was assessed by signal-joint T-cell receptor excision circle quantification and flow cytometry.

RESULTS

Signal-joint T-cell receptor excision circle levels increased from day 100 to one and two years after transplantation in patients under 50 years of age (n=23; P=0.02 and P=0.04, respectively), and in those aged 51-60 years (n=35; P=0.17 and P=0.06, respectively), but not in patients aged over 60 (n=22; P=0.3 and P=0.3, respectively). Similarly, CD4(+)CD45RA(+) (naïve) T-cell counts increased from day 100 to one and two years after transplantation in patients aged 50 years and under 50 (P=0.002 and P=0.02, respectively), and in those aged 51-60 (P=0.4 and P=0.001, respectively), but less so in patients aged over 60 (P=0.3 and P=0.06, respectively). In multivariate analyses, older patient age (P<0.001), extensive chronic GVHD (P<0.001), and prior (resolved) extensive chronic graft-versus-host disease (P=0.008) were associated with low signal-joint T-cell receptor excision circle levels one year or more after HCT.

CONCLUSIONS

In summary, our data suggest that thymic neo-generation of T cells occurred from day 100 onwards in patients under 60 while signal-joint T-cell receptor excision circle levels remained low for patients aged over 60. Further, chronic graft-versus-host disease had a dramatic impact on thymic function, as observed previously in patients given grafts after myeloablative conditioning.

Feasibility of reduced-intensity cord blood transplantation as salvage therapy for graft failure: results of a nationwide survey of adult patients

To evaluate whether rescue with cord blood transplantation (CBT) could improve the poor survival after graft failure (GF), we surveyed the data of 80 adult patients (median age, 51 years) who received CBT within 3 months of GF (primary 64, secondary 16), with fludarabine-based reduced-intensity regimens with or without melphalan, busulfan, cyclophosphamide, and/or 2-4 Gy total-body irradiation (TBI). A median number of 2.4 × 10(7)/kg total nucleated cells (TNC) were infused, and among the 61 evaluable patients who survived for more than 28 days, 45 (74%) engrafted. The median follow-up of surviving patients was 325 days, and the 1-year overall survival rate was 33% despite poor performance status (2-4, 60%), carryover organ toxicities (grade 3/4, 14%), and infections (82%) prior to CBT. Day 100 transplantation-related mortality was 45%, with 60% related to infectious complications. Multivariate analysis showed that the infusion of TNC ≥2.5 × 10(7)/kg and an alkylating agent-containing regimen were associated with a higher probability of engraftment, and that high risk-status at the preceding transplantation and grade 3/4 organ toxicities before CBT were associated with an increased risk of mortality. In conclusion, in an older population of patients, our data support the feasibility of CBT with a reduced-intensity conditioning regimen for GF.

The graft-versus-leukemia effect is mainly restricted to NIH-defined chronic graft-versus-host disease after reduced intensity conditioning before allogeneic stem cell transplantation

Incidence on relapse and nonrelapse mortality (NRM) of chronic graft-versus-host disease (GVHD), per National Institutes of Health (NIH) criteria, is not well defined after reduced-intensity conditioning (RIC) regimens. We analyzed the association of chronic GVHD with the risk of relapse and NRM using Cox models in 177 consecutive patients who underwent transplantation for hematological malignancies after RIC. The cumulative incidence of chronic GVHD at 36 months was 74% when using Seattle's criteria compared with 54% with NIH consensus. In Cox model, NRM was significantly higher in patients with late-onset, persistent and recurrent acute GVHD (hazard ratio (HR): 6, 25 and 11; P = 0.014, P<0.0001, P<0.0001, respectively). The cumulative incidence of relapse was significantly decreased in patients with chronic GVHD compared with no GVHD group using either Seattle's or NIH criteria (HR 0.43 and 0.38; P = 0.022 and 0.016, respectively), whereas the presence of late-onset, persistent and recurrent acute GVHD was not associated with a decreased rate of relapse (HR: not significant, 0.70 and 0.71; P = not significant, P = 0.73 and P = 0.54, respectively). Chronic GVHD per NIH consensus definition is associated with the graft-versus-tumor effect, whereas all forms associated with acute features beyond day 100 are associated with NRM.

Hematopoietic cell transplantation for treatment of primary immune deficiencies

Hematopoietic cell transplantation (HCT) has the potential to cure primary immune deficiency syndromes (PIDS) that are a group of disorders primarily affecting a single lineage, e.g., lymphoid or myeloid lineage. Generally, implementation of various conditioning regimens depends the type of IDS. Some syndromes that cause profound immune deficiency may not require a conditioning regimen. There appears to be a barrier even in cases of severe combined immune deficiency (SCID), particularly in the situation of HLA mismatched or haploidentical grafts. For example, donor B cell chimerism is less likely in γ-chain deficiency (X-SCID), as host cells persistently occupy the B lymphocyte niche, than in syndromes without B cells such as adenosine deaminase (ADA) deficiency. The immune defect may be corrected by partial reconstitution of normal immune cells, in other words full donor chimerism of the affected cell subset may not be required. This concept may add further rationale to limiting the intensity of the conditioning regimen.SCID encompasses a broad range of inherited defects that individually cause a profound immune deficiency of both T and B cell function. The individual genetic defects give rise to various phenotypes, and, since the goal of HCT is to restore both T and B cell function, the SCID phenotype must be taken into consideration in addition to the degree of recipient-donor mismatch. Other biologic factors associated with the SCID phenotype may influence the barrier to engraftment, such as host NK cells, which may survive intensive conditioning regimens. One of the difficulties in analyzing outcome of HCT in SCID patients is the relative rarity of the condition, thus needing large multicentric studies. Recent studies show that the most important factor for improved survival after an HLA-identical sibling graft was younger age at time of HCT. Factors significantly associated with improved survival after haploidentical transplants were B+ SCID phenotype, protected environment, and lack of pulmonary infections before HCT. The advent of neonatal screening and in utero diagnosis has allowed early detection of SCID and therefore prompt intervention at an early age.Primary T cell immunodeficiency (PTCD) syndromes may be differentiated from SCID by virtue of reduced but not completely absent T cell function, or absent T cell function with the presence of B lymphocyte or NK cell function. Allogeneic marrow transplantation remains the only curative therapy available for these disorders. Worse outcomes were seen in patients with PTCD compared to other types of immune deficiencies, regardless of donor. Although life-threatening infections may be less common early in life, children with PTCD often develop organ damage from chronic infections, particularly lung disease, prior to HCT.In Wiskott-Aldrich syndrome, HCT offers significantly improved survival chances for patients. Achieving full donor chimerism was shown to be a favorable factor. In general, however, the studies suggest that low intensity regimens offer the potential for achieving donor cell engraftment with less morbidity than standard regimens, an important consideration for patients who currently may consider the risks of conventional transplants unacceptably high.

Subclinical GvHD in non-irradiated F1 hybrids: severe lymphoid-tissue GvHD causing prolonged immune dysfunction

GvHD is an important complication of allogeneic hematopoietic SCT. Parent-in-F1 models are frequently used to study GvHD immunobiology; the characteristics of parent-in-F1 GvHD vary between strain combinations and induction protocols. Here, we observed that a high-dose challenge of non-irradiated B6DBA2F1 and B6SJLF1 recipients with C57BL/6 splenocytes left the majority of recipients clinically healthy, while inducing progressive high-grade donor T-cell chimerism. We investigated this previously undescribed pattern of parent-in-F1 T-cell alloreactivity and studied the effect of serial parental splenocyte infusions on epithelial and lymphohematopoietic tissues. The majority of recipients of 4 weekly splenocyte infusions showed long-term survival with gradual establishment of high-grade donor chimerism and without any signs of epithelial-tissue GvHD. A minority of recipients showed BM failure type of GvHD and, respectively, graft rejection. Moreover, long-term F1 chimeras showed protracted pancytopenia, and in peripheral lymphoid tissues severe lymphopenia and near-complete eradication of APCs and dysfunction in antigen-presenting capacity in remaining APC. Hematopoiesis and lymphoid tissue composition recovered only after multilineage donor chimerism had established. In conclusion, we report on a novel type of parent-in-F1 hybrid GvHD, where a cumulative high dose of C57BL/6 parental splenocytes in non-irradiated F1 mice induces subclinical but severe hematolymphoid-tissue GvHD, causing prolonged immuno-incompetence.