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

Allogeneic stem cell transplantation after reduced-intensity conditioning in lymphoid malignancies

Allogeneic stem cell transplantation (allo-SCT) is an effective therapeutic option for a wide range of hematological malignancies. The toxicity of the conditioning regimen and graft-versus-host disease (GVHD) occurring after the infusion of the graft remain the most important factors leading to high morbidity and mortality. Reduced-intensity conditioning regimens have recently been developed in an effort to reduce the toxicity associated with conventional allo-SCT while preserving the curative potential of the graft-versus-tumor (GVT) effect. Most patients with lymphoproliferative disorders are not ideal candidates for allo-SCT due to higher age at diagnosis, which together with the advanced stage of disease at the time of transplantation can lead to a high transplant-related mortality (TRM). Preliminary experience indicates that reduced-intensity allo-SCT is feasible in such patients. The immediate TRM is low in comparison with conventional procedures and overall results seem promising, thus indicating the existence of a GVT effect. Nevertheless, all series are still low in numbers and follow-up is too short to draw definitive conclusions. Acute and chronic GVHD remain a significant problem with incidences comparable to the conventional setting in some series. Thus, therapeutic strategies must be sought to decrease GVHD without abrogating the GVT effect.

New strategies for prevention and treatment of graft-versus-host disease and for induction of graft-versus-leukemia effects

Graft-versus-host disease (GVHD) continues to be a problem in allogeneic hemopoietic stem cell transplantation; however, our understanding of the basic pathophysiology of GVHD has improved. Although not all data obtained from murine or other animal models can be extrapolated to the clinic, there are leads that deserve to be pursued. The skin, intestinal tract, and liver are the 3 major target organs of GVHD and share the feature of presenting a barrier to the "environment" of the host. There is evidence that the damage inflicted to these organs, the epithelial and endothelial cells in particular, by the conditioning regimen causes a release of various cytokines and a penetration of endotoxin into the systemic circulation. According to these observations, the nonimmunologic aspects of GVHD have been likened to an inflammatory process. If this characterization is valid, blocking these nonspecific inflammatory changes would ameliorate GVHD without interfering with the graft-versus-leukemia (GVL) reaction. In fact, one study has shown a substantial amelioration of GVHD with a molecule that directly blocks endotoxin. Clinical data also suggest that patients with organ dysfunction early after transplantation that is presumed to be treatment related may benefit from preemptive interventions aimed at controlling GVHD. Furthermore, there is growing evidence that the mechanisms involved in GVHD may differ from organ to organ (for example, Fas/Fas-ligand interactions in the liver versus tumor necrosis factor alpha/receptor interactions in the intestinal tract), and from a therapeutic point of view, the time of onset of clinical GVHD may be important in choosing the appropriate therapy. Thus, combinations of interventions chosen and timed appropriately may be more effective in preventing and managing GVHD than are the standard across-the-board approaches that have been used so far. Such a strategy may also be successful in maintaining a GVL effect and possibly in incorporating direct antileukemic therapy, such as the use of cytotoxic T-cells directed at minor histocompatibility antigens, without increasing the risk of GVHD. The development of nonmyeloablative conditioning regimens and the observations on GVHD kinetics and the progression or eradication of leukemia with that strategy are likely to add new insights into how one can optimally combine various modalities to achieve engraftment, prevent GVHD, and at the same time maintain a GVL effect.

Non-myeloablative allografting from human leucocyte antigen-identical sibling donors for treatment of acute myeloid leukaemia in first complete remission

Many patients with acute myeloid leukaemia (AML) in first complete remission (CR1) are ineligible for allogeneic transplantation as a result of age or medical problems other than leukaemia. Eighteen patients (median age 59 years, range 36-73 years) with de novo (n = 13) and secondary (n = 5) AML in morphological CR1, who were not candidates for conventional allografting, received non-myeloablative peripheral blood stem cell transplants from human leucocyte antigen identical sibling donors after conditioning with 2 Gy total body irradiation (TBI; n = 10) or 2 Gy TBI and 90 mg/m2 of fludarabine (n = 8). Postgrafting immunosuppression was with cyclosporine and mycophenolate mofetil. Two rejections were observed in patients not given fludarabine and one died with relapse. Overall, 10 patients died between 77 and 841 d, seven from relapse and three from non-relapse mortality (NRM). Day +100 NRM was 0% with a 1-year estimated NRM of 17%[95% confidence interval (CI) 0-35%]. The median follow-up among the eight survivors was 766 d (range, 188-1141 d). Seven of these eight survivors remain in complete remission (CR). One-year estimates of overall and progression-free survivals were 54% (95% CI 31-78%) and 42% (95% CI 19-66%) respectively. While follow-up is short, this analysis demonstrates that the procedure is sufficiently safe to be studied in a wider group of patients.

Prognostic factors in allogeneic transplantation for patients with high-risk multiple myeloma after reduced intensity conditioning

OBJECTIVES

The aim of this study was to identify prognostic factors for outcome of high-risk patients with multiple myeloma after allogeneic transplantation prepared by reduced intensity conditioning (RIC).

MATERIALS AND METHODS

Data from 45 consecutive patients (median age 52 years, range 38-68), who received grafts from a sibling (n = 34) or unrelated donor (n = 11) were analyzed. Fourteen patients received an RIC allotransplant while chemosensitive (>/=partial remission [PR]), whereas 31 chemoresistant patients (<PR) had either relapsed (n = 28) or were refractory (n = 3) after one or more autografts; of these 28 patients, 4 had secondary myelodysplasia concurrent with relapse. Of the 14 chemosensitive patients, 12 received an RIC allotransplant as consolidation after an autotransplant (AT).

RESULTS

Twenty-nine (64%) were in a complete remission (CR) or near CR, 5 were in PR, and 5 had progressive disease. Twenty-five patients died, 17 of transplant-related complications, 7 of progressive disease, and 1 of a nontransplant-related cause. With a median follow-up of 15 months, the following factors were significantly associated with a better event-free survival (EFS) probability at 3 years: chemosensitive disease (64% vs 12%), pretransplant performance score (PS, Zubrod) </=2 (36% vs 0%), CR + near CR post transplant (36% vs 0%), and presence of chronic graft-vs-host disease (GVHD; 29% vs 0%). The same factors and absence of grade III to IV acute GVHD (52% vs 0%) were significant for a better overall survival (OS). On multivariate analysis including only pretransplant factors, both chemosensitive response and PS </=2 were significant for overall survival and event-free survival (p < 0.01). When response to RIC allotransplant and GVHD were added to the model, chronic GVHD was significant for better event-free survival, with an odds ratio of 1.5 (p < 0.01).

CONCLUSIONS

Our data suggest that although RIC allotransplant induces high rates of CR and near CR, even in refractory disease, it appears to result in a durable response only if it is applied early in the disease in high-risk patients, when they still are chemosensitive and have an adequate PS.

Review of "minitransplantation": nonmyeloablative allogeneic hematopoietic stem cell transplantation

Nonmyeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation (HSCT) have been developed over the past few years as important alternatives to conventional myeloablative conditioning regimens for older or medically unfit patients with hematologic malignancies, as well as for patients with certain nonmalignant hematologic diseases or renal cell cancer. This review summarizes the biological background, current clinical applications, and indications for this novel treatment approach for treating hematologic malignancies. Historically, allogeneic HSCT has been based on the use of cytotoxic and myeloablative chemotherapy and radiotherapy conditioning regimens that are intended both to eradicate malignancy and to eliminate host hematopoiesis and immune cells. Such a regimen was followed by the infusion of histocompatible donor marrow or peripheral blood stem cells to rescue hematopoiesis. For older patients or for those who had previously been treated with intensive chemotherapy or radiotherapy, the toxicity of myeloablative conditioning was prohibitive. Although most hematologic malignancies occur in older patients, these patients had not been previously eligible for the potentially curative therapy offered by allogeneic HSCT. Based in large part on preclinical studies with the dog model of HSCT and on an improved understanding of the mechanisms for controlling immune modulation, successful development of nonmyeloablative conditioning regimens for clinical use has occurred. Clear evidence of a therapeutic graft-versus-tumor effect mediated by allogeneic T-cells prompted an exploration for HSCT regimens that rely solely on nonmyeloablative immunosuppression to facilitate allogeneic engraftment. In lieu of intensive chemoradiotherapy before transplantation, engrafted donor T-cells are used to accomplish the task of eradicating the host's malignant cells. We review the updated results of an ongoing multicenter study to investigate the safety and efficacy of nonmyeloablative HSCT using a regimen of 2 Gy total body irradiation in patients with advanced hematologic malignancies who were ineligible for conventional myeloablative conditioning. In addition, we review the results of reduced-intensity HSCT trials from other transplantation centers.

Minitransplants: allogeneic stem cell transplantation with reduced toxicity

Allogeneic hematopoietic stem cell transplantation (HSCT) is used for the treatment of selected hematological malignancies. Its curative potential is based on two very different mechanisms, involving the conditioning regimen and the graft-versus-host reactions, respectively. The high-dose chemo-radiotherapy conditioning regimen is aimed at destroying tumor cells, ablating the host immune system (to prevent rejection) and eliminating the host bone marrow (to "make space" for donor stem cells). However, the definitive eradication of tumor cells is also largely mediated by an immune-mediated destruction of malignant cells by donor lymphocytes termed graft-versus-leukemia (GVL) or graft-versus-tumor (GVT) effect. However, because of its toxicity, conventional allogeneic HSCT is restricted to younger (< 55 years) and fitter patients. These observations led several groups to set up new (less toxic) transplant protocols based on a two step approach: first the use of immunosuppressive (but nonmyeloablative) conditioning regimens providing sufficient immunosuppression to achieve engraftment of allogeneic hematopoietic stem cells and, in a second step, destruction of malignant cells by the GVL effect. These transplants are called nonmyeloablative HSCT or reduced-conditioning HSCT or minitransplants. Preliminary results show that minitransplants are feasible with a relatively low transplant-related mortality (TRM) even in patients up to 70 years. In addition, strong anti-tumor responses are observed in several hematological malignancies as well as in some patients with renal cell carcinoma. As the benefits of minitransplants over alternative forms of treatment remain to be demonstrated, this strategy should be restricted to patients included in clinical trials.

Radiation-free regimens result in similar outcomes of allogeneic hematopoietic progenitor cell transplantation in patients aged >or=50 years compared to younger adults with low-risk disease

Age >or=50 years has been reported to be an adverse risk factor for allogeneic BMT, and consequently many of these patients are either not transplanted or treated on nonmyeloablative protocols. To study if older patients perform poorly relative to younger adults following myeloablative allogeneic transplants, we compared the outcomes of consecutive adults aged >or=50 years (n=51) to those <50 years (n=262) who received BU, CY+/-etoposide and allogeneic transplantation for AML, CML, MDS and NHL from 1984 to 2000. Median ages were 53 (range 50-66) and 35 (range 18-49) years for older and younger patients, respectively. Patients were low-risk if they had AML in CR1, CML in first chronic phase, refractory anemia, or NHL in remission or sensitive relapse at the time of transplantation. All others were high-risk. In patients with low-risk disease, there was no significant difference in overall survival (OS) between older and younger adults (P=0.64), while older patients tended to have a shorter OS among high-risk patients (P=0.06). The 3-year OS was 53% (95% CI, 29-77%) compared to 60% (95% CI, 50-69%) for older and younger patients with low-risk disease, respectively. The corresponding 3-year OS were 27% (95% CI, 11-43%) and 37% (95% CI, 25-45%) for high-risk patients. In low-risk patients, the incidence of acute and chronic graft-versus-host disease, and treatment-related mortality were similar in older and younger patients, while older patients experienced more treatment-related deaths by day 100. On multivariable analysis, age >or=50 years was a significant adverse factor only when high-risk patients were considered. We conclude that when radiation-free conditioning is used, age >or=50 years is not a significant adverse risk factor for allogeneic BMT in patients with low-risk disease, and that such patients should not be excluded from conventional myeloablative approaches until the efficacy of nonmyeloablative transplantation is better established.

Quantitative real-time reverse-transcription polymerase chain reaction for diagnosis of BCR-ABL positive leukemias and molecular monitoring following allogeneic stem cell transplantation

Real-time reverse-transcription polymerase chain reaction (RT-PCR) (qPCR) of the BCR-ABL mRNA is a suitable technique to measure the amount of circulating leukemic cells in chronic myelogenous leukemia (CML). In this study, we evaluated a BCR-ABL-specific qPCR method using the LightCycler technology in 95 patients with Philadelphia chromosome positive acute leukemia (n = 7) or CML in different stages (n = 88). Primers and hybridization probes were chosen to detect the most prevalent variants of BCR-ABL (b2a2, b3a2, b2a3, b3a3, e19a2, e1a2) with a sensitivity of 10-5 for b2a2 and b3a2. With median BCR-ABL/G6PDH ratios of 10.7% in the untreated chronic phase, 43.2% in the newly diagnosed accelerated phase, and 131.4% in newly diagnosed blast crisis the BCR-ABL mRNA levels varied significantly between different stages of CML whereas no difference was found between blast crisis and untreated acute leukemias (136.9%). There was a strong relationship between qPCR results and cytogenetics in patients treated with imatinib, interferon-alpha, or following allografting. Thirteen patients with CML were sequentially examined by qPCR following myeloablative or non-myeloablative allogeneic peripheral blood stem cell transplantation. Five patients received donor lymphocytes and became BCR-ABL negative as confirmed by nested RT-PCR. The gradual disappearance of BCR-ABL positive cells could be monitored by qPCR following non-myeloablative transplantation. Comparison of BCR-ABL levels with the degree of donor chimerism showed that 91% of samples with complete donor chimerism were BCR-ABL negative. In 22% of BCR-ABL negative samples chimerism between 71% and 98% was observed, indicating the persistence of normal recipient's hematopoietic cells. In conclusion, the qPCR protocol used in this study is a reliable and fast method for monitoring molecular response in CML.

Hematopoietic Cell Transplantation for Benign Hematological Disorders and Solid Tumors

Allogeneic hematopoietic cell transplantation (HCT) has been successfully used as replacement therapy for patients with aplastic anemia and hemoglobinopathies. Both autologous and allogeneic HCT following high-dose chemotherapy can correct manifestations of autoimmune diseases. The impressive allogeneic graft-versus-tumor effects seen in patients given HCT for hematological malignancies have stimulated trials of allogeneic immunotherapy in patients with otherwise refractory metastatic solid tumors. This session will update the status of HCT in the treatment of benign hematological diseases and solid tumors.

In Section I, Dr. Rainer Storb reviews the development of nonmyeloablative conditioning for patients with severe aplastic anemia who have HLA-matched family members. He also describes the results in patients with aplastic anemia given HCT from unrelated donors after failure of responding to immunosuppressive therapy. The importance of leuko-poor and in vitro irradiated blood product transfusions for avoiding graft rejection will be discussed.

In Section II, Dr. Guido Lucarelli reviews the status of marrow transplantation for thalassemia major and updates results obtained in children with class I and class II severity of thalassemia. He also describes results of new protocols for class III patients and efforts to extend HCT to thalassemic patients without HLA-matched family members.

In Section III, Dr. Peter McSweeney reviews the current status of HCT for severe autoimmune diseases. He summarizes the results of autologous HCT for systemic sclerosis, multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus, and reviews the status of planned Phase III studies for autologous HCT for these diseases in North America and Europe. He also discusses a possible role of allogeneic HCT in the treatment of these diseases.

In Section IV, Dr. Richard Childs discusses the development and application of nonmyeloablative HCT as allogeneic immunotherapy for treatment-refractory solid tumors. He reviews the results of pilot clinical trials demonstrating graft-versus-solid tumor effects in a variety of metastatic cancers and describes efforts to characterize the immune cell populations mediating these effects, as well as newer methods to target the donor immune system to the tumor.

Nonmyeloablative allogeneic stem-cell transplantation for hematologic malignancies: a systematic review

BACKGROUND

Increasingly, clinicians advocate the use of nonmyeloablative allogeneic stem-cell transplants (NM-allo-SCTs, "mini-transplants") to manage hematologic malignancies. They hypothesize that NM-allo-SCT is equally efficacious to standard allo-SCT but produces less regimen-related toxicity.

METHODS

To analyze available evidence on the benefits and harms of "mini-transplants," we identified 23 manuscripts, 1 abstract, and 1 letter that reported the outcome of mini-transplants in hematologic malignancies.

RESULTS

Data were compiled on 603 treated patients, with 118 transplants using stem cells from matched unrelated donors. All studies were small prospective case series, and most lacked concurrent or historical controls. Outcomes of interest were not uniformly reported. The studies were heterogeneous and used different patient selection criteria, conditioning regimens, and timing of transplant with respect to disease status. The transplant-related mortality rate was 32%, the relapse rate was 15%, and toxicities included acute and chronic graft-vs-host disease and veno-occlusive disease. The aggregate rate of complete remission was 45%. Survival at 1 year or longer ranged from 30% to 60% at 1 to 5 years of follow-up. All studies reported successful chimerism.

CONCLUSIONS

Disease-specific studies with longer follow-up are needed to evaluate this potentially promising therapy.

Role of allogeneic stem cell transplantation in relapsed or refractory Hodgkin's disease

Little information is available regarding allogeneic stem cell transplantation (alloSCT) and Hodgkin's disease (HD). Autologous stem cell transplantation (autoSCT) is usually preferred to alloSCT due to its widespread availability, lack of the immunological problems intrinsic to the development of graft-versus-host disease (GvHD), and the infrequent bone marrow involvement present in HD patients undergoing high-dose chemotherapy/radiotherapy. AlloSCT has been associated with a high transplant-related mortality (TRM) in patients with HD due to a high incidence of GvHD and of fatal infectious events after transplantation. The poor outcome of these patients after alloSCT may reflect in part the advanced status of the disease at transplantation and the poor performance status of the patient population allografted. Furthermore, the high TRM present in t h e conventional alloSCT setting hasnever allowed a proper evaluation of a possible graft-versus-Hodgkin's effect. In an effort to reduce the TRM associated with alloSCT, low-intensity regimens have been developed; the curative potential of these protocols would rely on the graft-versus-leukemia effect of the allogeneic infusion more than in the conditioning regimen per se. Although the number of HD patients allografted with reduced-intensity protocols is low and the follow-up still short, TRM seems lower than in the conventional allograft setting despite a similar incidence of acute GvHD (aGvHD). Overall and progression-free survival seem promising, and patients developing aGvHD after transplantation or donor lymphocyte infusions seem to be at a lower risk of relapse than those not presenting this complication.

Engraftment of early erythroid progenitors is not delayed after non-myeloablative major ABO-incompatible haematopoietic stem cell transplantation

We hypothesized that patients undergoing major ABO-incompatible non-myeloablative haematopoietic stem cell transplantation (nm-HSCT) might experience prolonged haemolysis after transplant due to the delayed disappearance of host plasma cells producing anti-donor isohaemagglutinins (HAs). To address this question, we analysed data from 107 consecutive patients transplanted with allogeneic peripheral blood stem cells from human leucocyte antigen-matched (related, n = 84; unrelated, n = 23) donors after non-myeloablative conditioning (200 cGy total body irradiation +/- fludarabine). In total, 23 out of the 107 patients received major or major/minor ABO-incompatible transplants. Red blood cell (RBC) transfusion requirements during the first 120 d post transplant were higher in major ABO-mismatched than in ABO-matched recipients (0.12 vs 0.03 median units RBC concentrate/d, P = 0.04). Two patients developed transient pure red cell aplasia, which had resolved spontaneously by 9 months after transplant. Major ABO incompatibility did not influence rates of engraftment. Patients with sustained engraftment experienced gradual declines of anti-donor HAs, and the estimated median time to reaching IgM and IgG titres of < 1:1 was at least 133 d in evaluable patients, approximately twice longer than reported after myeloablative conditioning. There was a strong correlation between degrees of donor chimaerism in erythroid burst-forming units, granulocyte macrophage colony-forming units and granulocytes, indicating that donor erythroid engraftment, defined by early erythroid progenitors, was as prompt as myeloid engraftment. In conclusion, our data suggest that major ABO-incompatibility is not a barrier to successful non-myeloablative HSCT.

Clinically demonstrable anti-autoimmunity mediated by allogeneic immune cells favorably affects outcome after stem cell transplantation in human autoimmune diseases

To determine the role of allogeneic, autologous and syngeneic hemopoietic stem cell transplantation (SCTx) as a treatment for severe autoimmune disease (AID) we performed a literature search employing Medline, Cancer Lit and abstract books for reports on transplants for blood disorders and a concomitant AID. All reviews, case reports and abstracts available between June 1977 and September 2001 were used and attempts made to update them by e-mail by the corresponding authors. Disease-free survival (DFS) after allogeneic SCTx for 23 patients with severe aplastic anemia was 78% at 16 years and survival in unmaintained remission of concomitant AID was 64% at 13 years. DFS after allogeneic SCTx for 24 patients with hematologic malignancies was 87% at 15 years and survival in unmaintained remission for concomitant AID was 70% at 11 years. DFS after autologous SCTx for 24 patients with hematologic malignancies was 48% at 6 years and survival in unmaintained remission for concomitant AID was 29% at 3 years. Among 30 patients given allogeneic SCTx 19 developed graft-versus-host disease (GVHD) and 11 did not. Upon clinically justified discontinuation of all immunosuppressive therapy, 3/11 patients without GVHD relapsed with their concomitant AID (freedom of AID-relapse 69% at 9 years), whereas none of 19 patients with GVHD did so (log rank: P = 0.0135). Freedom of AID-relapse was superior after allo SCTx compared to autologous SCTx (89% at 18 years vs 38% at 5 years; log rank: P = 0.0002). Our data suggest that a graft-versus-autoimmunity effect after allogeneic hemopoietic SCTx mediates elimination of autoimmunity.

Unrelated stem cell transplantation in multiple myeloma after a reduced-intensity conditioning with pretransplantation antithymocyte globulin is highly effective with low transplantation-related mortality

We investigated the feasibility of unrelated stem cell transplantation in 21 patients with advanced stage II/III multiple myeloma after a reduced-intensity conditioning regimen consisting of fludarabine (150 mg/m(2)), melphalan (100-140 mg/m(2)), and antithymocyte globulin (ATG; 10 mg/kg on 3 days). The median patient age was 50 years (range, 32-61 years). All patients had received at least one prior autologous transplantation, in 9 cases as part of an autologous-allogeneic tandem protocol. No graft failure was observed. At day 40 complete donor chimerism was detected in all patients. Grade II to IV acute graft-versus-host disease (GVHD) was seen in 8 patients (38%), and severe grade III/IV GVHD was observed in 4 patients (19%). Six patients (37%) developed chronic GVHD, but only 2 patients (12%) experienced extensive chronic GVHD. The estimated probability of nonrelapse mortality at day 100 was 10% and at 1 year was 26%. After allografting, 40% of the patients achieved a complete remission, and 50% achieved a partial remission, resulting in an overall response rate of 90%. After a median follow-up of 13 months, the 2-year estimated overall and progression-free survival rates are 74% (95% CI, 54%-94%) and 53% (95% CI, 29%-87%), respectively. A shorter progression-free survival was seen in patients who already experienced relapse to prior autograft (26% versus 86%, P =.04). Dose-reduced conditioning with pretransplantation ATG followed by unrelated stem cell transplantation provides durable engraftment and donor chimerism, reduces substantially the risk of transplant-related organ toxicity, and induces high remission rates.

Nonmyeloablative stem cell transplantation in adults with high-risk ALL may be effective in early but not in advanced disease

The feasibility of nonmyeloablative stem cell transplantation (NST) was evaluated in 22 adults with high-risk ALL. 16/22 patients had advanced disease and 11/22 had Ph+ ALL. Eleven patients received NST as first stem cell transplantation (SCT). Eleven patients had relapses after allogeneic or autologous SCT and underwent a salvage NST. 18/22 patients (82%) engrafted after NST. 13/16 patients (81%) with active disease reached complete remission (CR). 11 of 13 patients developed GVHD. After first NST 10/11 patients (91%) engrafted. Six of seven patients with active disease reached CR. Three of five relapsing patients reached subsequent CR after donor lymphocyte infusions, termination of immunosuppression or imatinib. Three of 11 patients (27%) are alive in CR 5 to 30 months after NST. Eight of 11 patients have died, 3/8 from leukemia and 5/8 from transplant-related causes. After salvage NST, 8/11 patients (73%) engrafted. Seven of nine patients with active disease reached CR. Only one of 11 patients transplanted, who was in CR before undergoing salvage NST is alive 19 months after NST. Five of 11 have died from leukemia, one of 11 after graft failure and four of 11 from transplant-related causes. Four of 22 patients (18%) are alive in CR 5, 14, 19 and 30 months after NST. NST is feasible in adults with high risk ALL. However, transplant-related mortality remains high and only patients transplanted in CR seem to have long-term disease-free survival.

An association between human leucocyte antigen alleles and acute and chronic graft-versus-host disease after allogeneic haematopoietic stem cell transplantation

The association between various human leucocyte antigen (HLA) alleles and the occurrence of acute and chronic graft-versus-host disease (GVHD) was evaluated in 493 haematopoietic stem-cell transplant (HSCT) patients with HLA identical sibling donors. There were 307 men and 186 women with a median age of 30 years (0.2-77). Most of the patients had a haematological malignancy and received total body irradiation or busulphan combined with cyclophosphamide as conditioning before transplantation. GVHD prophylaxis consisted of monotherapy with methotrexate (MTX) or cyclosporin (CsA) in 118 patients, MTX + CsA in 323, T-cell depletion in 28 and other combinations in 24. In total, 84 patients (17%) received a peripheral blood stem-cell graft, whereas the rest received bone marrow. The cumulative incidence of acute GVHD grades II-IV was 20%, and chronic GVHD 46%. In the multivariate analysis, HLA-A10 (OR 2.14, CI 1.04-4.41, P = 0.03) and HLA-B7 (OR 1.80, CI 1.04-3.12, P = 0.03) correlated with an increased risk of acute GVHD grades II-IV. We also found an association between HLA-B27 (RR 0.60, CI 0.37-0.95, P = 0.04) and a lower incidence of chronic GVHD. These HLA alleles were independent of other known risk factors for acute or chronic GVHD, as shown by multivariate analysis. These results show that major histocompatibility comlex (MHC) alleles may influence the incidence of GVHD in HSCT with HLA identical sibling donors.

Increasing use of reduced intensity conditioning transplants: report of the 2001 EBMT activity survey

Since 1990, the EBMT has annually collected numbers of HSCT by disease indication, donor type and stem cell source. The 2001 survey concentrates on the use of reduced intensity conditioning (RIC) transplants and its dissemination in Europe. In 2001, there were 19576 HSCT for new patients, 6413 with allogeneic HSCT (33%), 13163 with autologous HSCT (67%) and 3256 additional re- or multiple transplants, 868 (667/201) allogeneic and 2658 (537/2121) autologous, collected from 596 centers in 35 European countries. The main indications in 2001 were leukemias (32%; 73% of them allogeneic); lymphomas (53%; 92% of them autologous); solid tumors (11%; 93% of them autologous) and non-malignant disorders (4%; 90% of them allogeneic). Compared to 2000, there was a drop in allogeneic HSCT of over 20% for chronic myeloid leukemia and an increase of 2% in autologous HSCT. A total of 1759 or 27% of allogeneic transplants were reported as RIC HSCT. These have risen in number in 3 years from <1% in 1998. There are wide variations from 0 to 71% RIC HSCT in European countries with no obvious explanation. These data document the current status of blood and marrow transplantation in Europe and indicate a marked change towards RIC HSCT in allogeneic transplantation.

Dose-reduced conditioning regimen followed by allogeneic stem cell transplantation in patients with myelofibrosis with myeloid metaplasia

Three patients with myelofibrosis received allogeneic stem cell transplantation after a dose-reduced conditioning regimen of busulphan (8 mg/kg), fludarabine (180 mg/m2) and antithymocyte globulin (4 x 10 mg/kg). The median age at transplantation was 51 years (range 44-58). All patients engrafted with a leucocyte count > 1.0 x 10(9)/l after a median of 18 d (range 16-20). Grade II acute skin graft-versus-host disease (GvHD) occurred in one patient. One limited and one extensive chronic GvHD was observed. All patients achieved complete haematological remission. In one patient the fibrosis resolved completely 180 d post transplant. All patients are alive 126, 466 and 764 d after transplantation.

Respiratory virus infections in transplant recipients after reduced-intensity conditioning with Campath-1H: high incidence but low mortality

Respiratory virus infections can cause serious morbidity and mortality after conventional allogeneic stem cell transplantation. However, the incidence and outcome of these infections after reduced intensity conditioning has not been reported. Between 1997 and 2001, 35 episodes of respiratory virus infections were noted in 25 of 83 transplant recipients conditioned with fludarabine, melphalan and Campath-1H, and 80% of them received early antiviral therapy. Parainfluenza virus (PIV) 3 was the commonest isolate (45.7%) followed by respiratory syncytial virus (37%). Patients with myeloma were more susceptible to these infections [odds ratio (OR) 4.1, P = 0.01] which were often recurrent in patients with severe acute or chronic graft-versus-host disease (GVHD) (OR 10.6, P = 0.03). Infection within the first 100 d (OR 5.0, P = 0.05) and PIV 3 (OR 9.2, P = 0.01) isolation were risk factors for developing lower respiratory infection. Although more than half of the episodes progressed to lower respiratory infection, the mortality was only 8%. This could have been due to early initiation of antiviral therapy, but the attenuation of pulmonary damage due to the reduced-intensity conditioning, low incidence of GVHD and, paradoxically, the low CD4+ T-cell subset in this setting might also have been contributory factors.

Stem cell plasticity and blood and marrow transplantation: a clinical strategy

The newly described phenomenon of stem cell plasticity raises interesting biological questions and offers exciting opportunities in clinical application. This review uses the well-established practice of blood and marrow transplantation as a paradigm to explore the clinical consequences of this finding. Recently proposed non-myeloablative conditioning regimens have shown that mixed donor-host hematolymphoid chimerism can be established with relatively low toxicity in both animal studies and human trials. Hematopoietic growth factor treatment of transplanted patients can mobilize a large number of donor stem cells to migrate from marrow to non-hematopoietic organs. We propose that these advances, in conjunction with the developmental plasticity of stem cells, can constitute components of a clinical strategy to use blood and marrow transplantation as a platform to treat systemic diseases involving non-hematopoietic tissues.

Acute myeloid leukaemia: optimising treatment in elderly patients

Acute myeloid leukaemia (AML) is a disease of the elderly (median age at presentation 64 years). The outcome in older patients with AML is much worse than that for similarly treated younger patients. Older patients have a high incidence of recognised poor prognostic features (poor performance status, unfavourable cytogenetics, CD34 positive phenotype, raised serum lactate dehydrogenase levels and increased incidence of multidrug resistance protein expression). In addition, treatment is less well tolerated as there is an increased incidence of comorbidity in the elderly. The outlook for most patients is poor (4% survival at 5 years). However, it is possible to select a group of patients who are fit, with no pre-existing problems and good performance status who will respond well to intensive chemotherapy, and these patients should be treated aggressively. Less intensive treatment is probably more suitable for patients not fitting these criteria. Patients and their relatives should be counselled appropriately as to the prognosis of AML, the choices of treatment available and that intensive regimens are not an appropriate choice for many patients.

Reduced intensity preparative regimens for allogeneic hematopoietic stem cell transplantation: a single center experience

According to recent reports, fast engraftment with minimal transplant-related toxicity and mortality (TRT, TRM) can be achieved by using reduced-intensity preparative regimens in allogeneic hematopoietic stem cell transplantation (HSCT). We report our experience with related (39%) and unrelated (61%) HSCT in 44 high risk patients (AML, ALL, CML, CLL) receiving either busulfan/fludarabine or busulfane/fludarabine/ATG or TBI/fludarabine as reduced-intensity preparative regimens. Organ toxicity was minimal with mild mucositis and no major bleeding. Acute GVHD was recorded in 64% of the patients. Twenty-three patients achieved complete remission after transplantation, and complete chimerism was obtained in all patients with stable engraftment (35 patients). Twenty-nine patients died: 15 due to relapse/progression, 14 due to TRM. Survival with median follow-up of 18.5 months was significantly better in patients with matched related transplants compared to patients with other transplants. However, there was no difference between related and unrelated transplants with regard to engraftment, TRM and GVHD. In conclusion, our results in high-risk patients transplanted in CR or with smoldering leukemia from a related donor are encouraging, although a longer follow-up and a larger group of patients is needed in order to evaluate the role of different reduced-intensity preparative regimens in unrelated and related HSCT.

Hepatic circulatory diseases associated with chronic myeloid disorders

These liver diseases are diseases of the hepatic circulation. Myeloproliferative disorders are among the most common prothrombotic disorders that lead to Budd-Chiari syndrome and PVT. SOS, previously known as hepatic veno-occlusive disease, is mainly seen in North America and Western Europe as a complication of the conditioning regimen for hematopoietic stem cell transplantation. SOS is caused by damage to SECs, and the initiating circulatory blockage occurs because of the embolism of sinusoidal lining cells. Myeloproliferative disorders are an uncommon cause of NRH, which is believed to be caused by uneven perfusion of the liver at the venous or sinusoidal level. Peliosis hepatis is believed to result from damage to SECs and is seen mainly in immunosuppressed patients, patients with a wasting illness, or patients with a drug toxicity.

Reliable engraftment, low toxicity, and durable remissions following allogeneic blood stem cell transplantation with minimal conditioning

OBJECTIVE

Allogeneic blood stem cell transplantation (BSCT) can cure patients with hematologic malignancies by high-dose chemotherapy and allogeneic graft-vs-tumor (GvT) reactions. To avoid high-dose conditioning and evaluate engraftment, toxicity, and GvT reactions, we treated a group of high-risk patients with a minimal intensive conditioning regimen followed by allogeneic BSCT.

MATERIALS AND METHODS

Thirty-four patients with lymphoma (11), myeloma (10), chronic myeloid leukemia (4), myelodysplastic syndrome (5), and acute myeloid leukemia (4) were treated with fludarabine (3 x 30 mg/m(2)) and 200 cGy total-body irradiation followed by the infusion of peripheral blood stem cells from related (28) or unrelated (6) donors. Cyclosporine or tacrolimus and mycophenolate mofetile were given posttransplant. Most patients had advanced disease, were intensively pretreated, and had contraindications against conventional myeloablative transplantation.

RESULTS

Thirty-two patients (94%) had engraftment of donor cells. Patients with lymphatic malignancies developed complete donor chimerism significantly faster than patients with myeloid malignancies (p < 0.05). Clinical responses were observed in 16 of 27 patients (59%) who had active disease at transplantation. Of 7 patients who were treated in remission, 5 remain free of disease. After a median follow-up of 325 days (range 100-844) 22 patients are alive (65%, 14 CR, 4 PR, 4 PD). Two patients (6%) died of treatment-related complications and 10 patients (29%) died of progressive disease. Acute graft-vs-host-disease (GvHD) of grade II or more developed in 17 patients (50%). Chronic GvHD is present in 10 of 22 patients (45%) who are alive beyond day 100.

CONCLUSIONS

Toxicity and survival in this group of high-risk patients are superior to those expected with conventional allogeneic transplantation. GvT reactions frequently occur in conjunction with GvHD and can induce durable remissions in patients with advanced hematologic malignancies.

Nonmyeloablative transplantation with or without alemtuzumab: comparison between 2 prospective studies in patients with lymphoproliferative disorders

Although nonmyeloablative conditioning regimen transplantations (NMTs) induce engraftment of allogeneic stem cells with a low spectrum of toxicity, graft-versus-host disease (GVHD) remains a significant cause of morbidity and mortality. In vivo T-cell depletion, using alemtuzumab, has been shown to reduce the incidence of GVHD. However, this type of maneuver, although reducing GVHD, may have an adverse impact on disease response, because NMTs exhibit their antitumor activity by relying on a graft-versus-malignancy effect. To explore the efficacy of alemtuzumab compared with methotrexate (MTX) for GVHD prophylaxis, we have compared the results in 129 recipients of a sibling NMT enrolled in 2 prospective studies for chronic lymphoproliferative disorders. Both NMTs were based on the same combination of fludarabine and melphalan, but the United Kingdom regimen (group A) used cyclosporin A plus alemtuzumab, whereas the Spanish regimen (group B) used cyclosporin A plus MTX for GVHD prophylaxis. Patients receiving alemtuzumab had a higher incidence of cytomegalovirus (CMV) reactivation (85% versus 24%, P <.001) and a significantly lower incidence of acute GVHD (21.7% versus 45.1%, P =.006) and chronic GVHD (5% versus 66.7%, P <.001). Twenty-one percent of patients in group A and 67.5% in group B had complete or partial responses 3 months after transplantation (P <.001). Eighteen patients in group A received donor lymphocyte infusions (DLIs) to achieve disease control. At last follow-up there was no difference in disease status between the groups with 71% versus 67.5% (P =.43) of patients showing complete or partial responses in groups A and B, respectively. No significant differences were observed in event-free or overall survival between the 2 groups. In conclusion, alemtuzumab significantly reduced GVHD but its use was associated with a higher incidence of CMV reactivation. Patients receiving alemtuzumab often required DLIs to achieve similar tumor control but the incidence of GVHD was not significantly increased after DLI.

Treatment of secondary myelodysplastic syndrome after heart transplantation with chemotherapy and nonmyeloablative stem-cell transplantation

BACKGROUND

Treatment of secondary cancer after solid-organ transplantation is difficult because of coexisting medical conditions, reduced organ function, or advanced age in most patients.

METHODS

A 60-year-old man developed treatment-related myelodysplastic syndrome (refractory anemia with excess blasts in transformation) 10 years after orthotopic heart transplantation. After remission induction with chemotherapy, the patient received peripheral blood stem cells from his HLA-identical ABO-mismatched (A-->O) sister after conditioning with fludarabine and low-dose total-body irradiation (200 cGy). Postgrafting immunosuppression consisted of mycophenolate mofetil and cyclosporine A.

RESULTS

The patient experienced little toxicity from the conditioning regimen and achieved complete donor chimerism within 65 days. Five months after transplant, the patient developed pure red cell aplasia that resolved after treatment. At present, he is alive in complete remission with 100% donor hematopoiesis 940 days after stem-cell transplantation.

CONCLUSIONS

Allogeneic blood stem-cell transplantation using minimal conditioning is a new, promising treatment option for patients with hematologic malignancies after solid-organ transplantation.

Cryopreservation and mycophenolate therapy are detrimental to hematopoietic progenitor cells

BACKGROUND

The aim of the present study was to determine whether certain components of nonmyeloablative regimens for hematopoietic cell transplantation might compromise the growth of hematopoietic progenitors.

METHODS

Porcine peripheral blood progenitor cells (PBPC) were cytokine-mobilized, collected by leukapheresis, and cryopreserved using 5% dimethyl sulfoxide and 6% hydroxyethyl starch. The influence of cryopreservation on PBPC was tested in vitro by enumeration of colony-forming units (CFUs) in methylcellulose and cobblestone area-forming cell (CAFC) subsets in stromal-associated long-term cultures on fresh and frozen PBPC. The effects of mycophenolate mofetil (MMF) on porcine PBPC and baboon and human bone marrow (BM) were tested in vitro by adding varying doses of MMF to the CFU assays. One baboon was treated with increasing doses of MMF (100-500 mg/kg per day continuously intravenous), and sequential BM aspirations were tested for CFU content.

RESULTS

Fresh cytokine-mobilized PBPC had similar frequencies of progenitor cells when compared with porcine BM. Freezing-thawing of PBPC had no effect on porcine CFUs but reduced the recovery of CAFCs by more than 90%. In vitro, MMF completely inhibited the development of porcine and human CFUs at a concentration of 1 microg/mL and of baboon CFUs at levels between 10 and 100 microg/mL. Plasma-free mycophenolic acid levels of 10 to 30 microg/mL were associated with decreased CFUs in the BM.

CONCLUSIONS

Cryopreservation and MMF potentially prevent engraftment of porcine PBPC by reducing the content or development of progenitor cells. These results indicate that the use of fresh PBPC might improve the induction of mixed hematopoietic chimerism and raise the possibility that use of high doses of MMF in the poststem cell transplant may compromise engraftment.

Current trends in hematopoietic stem cell transplantation in Europe

Major changes have occurred in the transplantation of hematopoietic stem cells (HSCs) during the last decade. This report reveals the changes, reflects current status, and provides medium-term projections of HSC transplantation (HSCT) development in Europe. Data on 132 963 patients, 44 165 with allogeneic HSC transplant (33%) and 88 798 with an autologous HSC transplant (67%), collected prospectively from 619 centers by the European Group for Blood and Marrow Transplantation (EBMT) in 35 European countries between 1990 (4234 HSCTs) and 2000 (19 136 HSCTs) illustrate utilization of HSCT. HSCT increased in all European countries and for all indications. There were major differences depending on disease indication and donor type. Transplantation rates (numbers of HSCTs per 10 million inhabitants) varied from less than 1 for some rare indications to 37.7 +/- 4.1 for acute myeloid leukemia in allogeneic HSCT or 95.5 +/- 13.5 for non-Hodgkin lymphoma in autologous HSCT. There were indications with a steady, continuing increase and others with initial increase but subsequent decrease. Projections on medium-term development for each disease based on a weighted sensitivity analysis predict an ongoing increase in allogeneic HSCT except for chronic myeloid leukemia. In autologous HSCT they predict an increase for lymphoproliferative disorders, acute myeloid leukemia, myelodysplastic syndromes, and some solid tumors but a decrease for most solid tumors, acute lymphoid leukemia, and chronic myeloid leukemia. Transplantation rates can be predicted with reasonable sensitivity for most disease indications. Despite marked changes in the rapidly developing field of HSCT, this information on current use, trends, and midterm predictions forms a rational basis for patient counseling and health care planning.

Influence of the different CD34+ and CD34- cell subsets infused on clinical outcome after non-myeloablative allogeneic peripheral blood transplantation from human leucocyte antigen-identical sibling donors

Currently, no information is available regarding the influence of the different CD34+ cell subsets infused on the haematopoietic recovery, following non-myeloablative allogeneic peripheral blood stem cell transplantation (allo-PBSCT). We have explored, in a group of 13 patients receiving non-myeloablative allo-PBSCT from human leucocyte antigen-identical sibling donors, the influence of the total dose of CD34+ haematopoietic progenitor cells (HPC) infused, compared with that of the different CD34+ HPC and CD34- leucocyte subsets in the leukapheresis samples, on both engraftment and clinical outcome. The overall numbers of total CD34+ HPC (P = 0.002) and myelomonocytic-committed CD34+ HPC infused (P = 0.0002) were strongly associated with neutrophil recovery (> 1 x 109 neutrophils/l), the latter being the only independent parameter influencing neutrophil recovery. Regarding long-term engraftment, only the number of immature CD34+ HPC infused/kg correlated with the duration of hospitalization in the first 2 years after discharge (r = -0.75, P = 0.005). Both the overall amount of CD34+ HPC and the number of myelomonocytic CD34+ HPC infused showed a significant influence on the risk of graft-versus-host disease (GVHD). Thus, the overall probability of GVHD was 100%vs 25% for patients receiving >/= 5 x 106 CD34+ HPC or >/= 3.5 x 106 of myelomonocytic-committed CD34+ HPC vs lower doses (P = 0.013). None of the other CD34+ and CD34- cell subsets analysed correlated with development of GVHD. In summary, our results suggest that in non-myeloablative allo-PBSCT, high numbers of CD34+ HPC, especially the myelomonocytic-committed CD34+ progenitors, lead to rapid neutrophil engraftment. However, they also strongly impair clinical outcome by increasing the incidence of GVHD.

Severe immune hemolysis after minor ABO-mismatched allogeneic peripheral blood progenitor cell transplantation occurs more frequently after nonmyeloablative than myeloablative conditioning

BACKGROUND

Hemolysis as a result of donor-recipient minor ABO mismatching is a complication of allogeneic peripheral blood progenitor cell (PBPC) transplantation (PBPCT). The increased B-lymphocyte content of PBPC grafts and immunosuppressive regimens without methotrexate (MTX) may increase incidence and severity of this event.

STUDY DESIGN AND METHODS

A total of 93 patients were analyzed after allogeneic PBPCT. In 25 (27%) cases, minor (n=21) or bidirectional (n=4) ABO mismatching was present. Of these, 15 patients received myeloablative and 10 received nonmyeloablative conditioning regimens. For GVHD, prophylaxis cyclosporin A (CsA) alone (n=2) or CsA with MTX (n=13) was given after myeloablative conditioning and CsA with mycophenolate mofetil (MMF) after nonmyeloablative conditioning (n=10).

RESULTS

Hemolysis occurred in 4 out of 25 (16%) patients with minor or bidirectional ABO mismatching only. Three patients underwent nonmyeloablative conditioning and were given CsA with MMF, and one patient underwent myeloablative conditioning and was given CsA alone for GVHD prophylaxis. Hemolysis began 7 to 10 days after transplantation, and donor type alloantibodies were detectable concomitantly with recipients type RBCs.

CONCLUSION

Patients receiving minor or bidirectional ABO-mismatched PBPC grafts and GVHD prophylaxis without MTX are at risk of hemolysis. Prophylactic interventions in patients before minor ABO-mismatched PBPCT not receiving MTX should be taken into consideration. Careful monitoring of hemolysis parameters during the first 15 days after PBPCT transplantation is mandatory.

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.

Evidence for a graft-versus-leukemia effect after allogeneic peripheral blood stem cell transplantation with reduced-intensity conditioning in acute myelogenous leukemia and myelodysplastic syndromes

We report the results of a prospective study of a reduced-intensity conditioning (RIC) regimen followed by allogeneic peripheral blood stem cell transplantation (PBSCT) from an HLA-identical sibling in 37 patients with acute myeloid leukemia (AML; n = 17) or myelodysplastic syndrome (MDS; n = 20). The median age was 57 years, and 22 (59%) were beyond the early phase of their disease. The incidence of grade II to IV acute graft-versus-host disease (GVHD) was 19% (5% grade III-IV), and the 1-year incidence of chronic extensive GVHD was 46%. With a median follow-up of 297 days (355 days in 24 survivors), the 1-year probability of transplant-related mortality was 5%, and the 1-year progression-free survival was 66%. The 1-year incidence of disease progression in patients with and without GVHD was 13% (95% CI, 4%-34%) and 58% (95% CI, 36%-96%), respectively (P =.008). These results suggest that a graft-versus-leukemia effect plays a crucial role in reducing the risk of relapse after a RIC allograft in AML and MDS.

High stem cell dose will not compensate for T cell depletion in allogeneic non-myeloablative stem cell transplantation

The best strategies for non-myeloablative stem cell transplants (NST) are not known. We hypothesized that a high stem cell dose and post-transplant donor lymphocyte infusions (DLI) in a T cell-depleted NST setting may result in stable engraftment without severe GvHD. We used conditioning with 200 mg/kg cyclophosphamide, and ATG, a high peripheral stem cell dose of >10 x 10(6) CD34(+) cells/kg, T cell-depleted to <1 x 10(5) CD3(+) cells/kg followed by incremental DLI. Ten patients, 53 (42-61) years of age with hematological malignancy (CML in 3, MDS in 2, myeloma in 3 and CLL in 2) were included. All patients achieved initial engraftment, at a median 13.5 (10-20) days. Three patients achieved complete chimerism, four achieved a complete hematologic remission. In seven patients the graft ultimately failed. Acute GvHD grade II was seen in three patients after DLI. At a median follow-up of 28 months (range 15-35), eight patients are alive, none died of treatment-related complications. NST with T cell depletion to prevent GVHD results in a high graft failure rate. High stem cell dose (> or =10 x 10(6) CD34(+)cells/kg) and post-transplant DLI will not compensate for the lack of T cells to ensure stable engraftment.

Reduced-intensity allogeneic transplantation for lymphoma

Reduced-intensity allogeneic transplants are promising, increasingly used treatments for hematologic malignancies, exploiting graft-versus-tumor effects for eradicating malignancies. This article reviews approximately 40 published reports of reduced-intensity allogeneic transplants in lymphomas. Overall, reduced-intensity allogeneic transplants have been well tolerated and have produced encouraging results despite a diversity of transplant approaches used largely in heavily pretreated and older patients. Of 368 lymphoma patients who underwent reduced-intensity allogeneic transplants, 66.3% had responses, most of which were complete. Many had chemotherapy-refractory lymphomas, including some that relapsed after autologous transplants. Although the short follow-up periods of many studies do not permit assessments of response duration, protracted remissions were reported in some studies. Additionally, some patients entered molecular remissions, suggesting that graft-versus-tumor effects could, by themselves, cure some lymphomas. Graft-versus-host disease is the major risk of reduced-intensity allogeneic transplants, and treatment methods need refinement to reduce transplant risks while preserving graft-versus-tumor effects. Controlled trials involving patients with earlier-stage disease appear warranted to define better the role of reduced-intensity allogeneic transplants in treating lymphomas.

Outpatient allografting in hematologic malignancies and nonmalignant disorders--applying lessons learned in the canine model to humans

The novel allogeneic transplant approach outlined in this chapter proposes the dual concepts that currently used intensive cytoreductive conditioning programs can be successfully replaced by nonmyeloblative immunosuppression and that stem cell grafts create marrow space for engraftment through subclinical GVH reactions. Immunosuppression can be conceptually divided into two parts, one targeted exclusively towards host cells before transplantation, and the other aimed at both host and donor T lymphocytes after transplantation. The resultant effect is to either establish mutual graft-host tolerance as reflected by stable mixed donor-host chimerism or accomplish complete donor chimerism. Preclinical studies have demonstrated the feasibility of this new approach in the context of MHC-identical transplants in young canines. Early data from the dog model of severe hereditary hemolytic anemia suggest that mixed chimerism can partially correct the phenotypic expression of disease, but that complete chimerism will be necessary to halt the continued hemolytic process of the host type minority red blood cell population. In contrast, mixed chimerism would be expected to correct disease manifestations of other severe hereditary red blood cell disorders such as sickle cell disease. The early results in human patients with hematological malignancies have demonstrated the feasibility of establishing hematopoietic engraftment using a nonmyeloblative conditioning regimen. Using this regimen, transplants were performed in the outpatient setting, and the need for transfusion support was minimal. Preliminary information suggests that mixed chimerism does not appear to be stable in this older patient population, with most patients progressing to full donor chimerism and a small minority rejecting. Complete disease responses and molecular remissions have been observed in a significant proportion of patients, suggesting that adoptive immunotherapy may not be necessary in most cases. However, in those patients that engraft with at least mixed chimerism and develop progression of the underlying malignancy, DLIs can be used for subsequent adoptive immunotherapy. The feasibility and safety of the outpatient approach for MHC-nonidentical transplantation has been demonstrated. Graft rejection appears to have been corrected by the addition of fludarabine to the nonmyeloablative conditioning regimen for the recipients of HLA-identical sibling allografts. Despite most recipients of MHC-nonidentical transplantation having sustained engraftment, some rejections have been observed. Studies are ongoing to identify the risk factors for rejection after unrelated HSCT to ensure uniform engraftment in future studies.

Persistent aplasia after chemotherapy for acute myeloid leukaemia treated with stem cell transplantation from a matched unrelated donor after dose-reduced conditioning

Persistent aplasia is a rare complication with poor prognosis after intensive chemotherapy for acute leukaemia. A 59-year-old man with acute myeloid leukaemia (AML), was treated after 186 d of chemotherapy-induced persistent aplasia with an allogeneic peripheral blood stem cell transplantation (PBSCT) from a matched unrelated donor (MUD) after dose-reduced conditioning. The patient remains in complete haematological remission more than 8.5 months after haematological recovery. We believe that this is the first reported case of treatment for chemotherapy-induced persistent aplasia with MUD-PBSCT after dose-reduced conditioning, a procedure that can be successfully performed even in elderly patients.

Infectious risks and outcomes after stem cell transplantation: are nonmyeloablative transplants changing the picture?

PURPOSE OF REVIEW

Opportunistic infections contribute to morbidity and mortality after myeloablative allogeneic stem cell transplantation. The development of nonmyeloablative or toxicity-reduced conditioning regimens for allogeneic hematopoietic stem cell transplantation might change this picture significantly. These regimens are in general highly immunosuppressive, but effects on myelopoiesis and mucosal toxicities are usually reduced compared with myeloablative hematopoietic stem cell transplantation conditioning regimens. This review summarizes the infectious risks associated with each type of hematopoietic stem cell transplantation conditioning regimen, and presents the results of early clinical studies.

RECENT FINDINGS

Although the data are preliminary, the results of recent studies suggest that nonmyeloablative conditioning regimens may decrease the risks of bacterial infections associated with mucosal damage and persistent neutropenia; however, risks for late viral and fungal infections persist during severe graft versus host disease. Results of several case reports and series emphasize that therapeutic outcomes of infections may be improved in patients who receive nonmyeloablative conditioning regimens.

SUMMARY

Infectious risks and outcomes after hematopoietic stem cell transplantation appear to be in evolution given the introduction of alternative, nonmyeloablative conditioning regimens. Although infections remain a prominent cause of transplant-related mortality, the timing and types of infections may differ. Further studies are necessary to define appropriate preventative strategies, and to determine whether patients with ongoing infections might benefit from nonmyeloablative hematopoietic stem cell transplantation.

Autologous stem cell transplantation followed by a dose-reduced allograft induces high complete remission rate in multiple myeloma

We evaluated toxicity, engraftment, chimerism, graft-versus-host disease (GVHD), and response to a dose-reduced allograft after cytoreductive autografting in 17 patients with advanced stage II/III multiple myeloma (MM). After autografting with melphalan (200 mg/m2) the patients received after a median interval of 119 days (range 60-210) a dose-reduced regimen consisting of fludarabine (180 mg/m2), melphalan (100 mg/m2), and antithymocyte globulin (3 x 10 mg/kg) followed by allografting from related (n = 7), mismatched related (n = 2), or unrelated (n = 8) donors to induce a graft-versus-myeloma effect. After dose-reduced allografting all patients became neutropenic (< 0.2 x 10(9)/L) for at least 8 days. All patients engrafted with a median time for leukocyte (> 1 x 10(9)/L) and platelet (> 20 x 10(9)/L) counts of 16 (range, 11-24) and 23 days (range, 12-43), respectively. Complete donor chimerism was detected after a median of 30 days (range, 19-38). Acute GVHD stage II occurred in 4 patients (25%) and grade III GVHD in 2 patients (13%). Chronic GVHD developed in 40% of the patients, but only 1 patient experienced extensive chronic GVHD requiring further immunosuppressive therapy. Two patients died of alveolar hemorrhage and pneumonia, resulting in a day 100 mortality rate of 11%. The rate of complete remission with negative immunofixation increased from 18% after autografting to 73% after allografting. After a median follow-up of 17 months after autologous and 13 months after allogeneic transplantation 13 patients are alive and 12 of them free of relapse or progression. The tandem auto-allotransplant protocol is highly active and provides rapid engraftment with complete donor chimerism and tolerable toxicity.

Related and unrelated nonmyeloablative hematopoietic stem cell transplantation for malignant diseases

Patients with advanced hematological malignancies ineligible for conventional myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) due to advanced age or medical contraindications were enrolled in multi-center study to investigate the safety and efficacy of nonmyeloablative HSCT using a 2 Gy total body irradi ation (TBI)-based regimen. A total of 192 patients (median age 55) were treated with HLA-matched sibling peripheral blood stem cell (PBSC) grafts, and 63 patients (median age 53) received a 10 of 10 HLA-antigen matched unrelated donor (URD) HSCT (PBSC graft, n = 48; marrow graft, n = 15). Diagnoses included multiple myeloma (n = 61), myelodysplastic syndrome (n = 55), chronic myeloid leukemia (n = 31), non-Hodgkin lymphoma (n = 31), acute myeloid leukemia (n = 28), chronic lymphocytic leukemia (n = 24), Hodgkin Disease (n = 14). The conditioning regimen was fludarabine 30 mg/m2/d x 3 days and 2 Gy TBI. Ninety-five related HSCT patients received 2 Gy TBI without fludarabine. Postgrafting immunosuppression was combined mycophenolate mofetil an cyclosporine. Transplants were well tolerated with a median of 0 days of hospitalization in the first 60 days for eligible patients. For related HSCT recipients, median follow-up was 289 (100-1,188) days. Nonfatal graft rejection occurred in 6.8%. Of those with sustained engraftment, graft-versus-host disease (GVHD) occurred in 49% (33% grade II, 11% grade III, 5% grade IV). Day-100 non-relapse mortality was 6%. Overall, 59% (114/192) of patients were alive. The relapse/disease progression mortality was 18%, and non-relapse mortality was 22%. The projecte 2-year survival and progression-free survival were 50% and 40%. For the URD HSCT recipients, median follow-up was 190 (100-468) days. Graft rejection occurred in 27% (17/63) of patients, mostly in recipients of marrow grafts (9/15). Acute GVHD occurred in 63% (50% grade II, 13% grade III) of 46 engrafted patients. Chronic GVHD requiring therapy occurred in 50% of patients. Of the 63 URD HSCT patients, 54% were alive, 37% in CR, 3% PR, and 14% with disease progression or relapse. Related and unrelated nonmyeloablative HSCT is feasible and potentially curative in patients with advanced hematological malignancies who have no other treatment options.

The role of the EBMT activity survey in the management of hematopoietic stem cell transplantation. European Group for Blood Marrow Treansplantation

Disease or treatment oriented registries form an integral part of modern medicine. They complement industry driven, corporate group sponsored and institutional research and are, together with prospective randomised trials cornerstones of modern evidence based medicine. Focus has been on rapid collection, analysis and dissemination of information on rare procedures with stress on patient outcome. In complex expensive procedures, such as hematopoietic stem cell transplants (HSCT), novel structures are required to catch outcome at team or national level. The annual activity survey of the European Group for Blood and Marrow Transplants EBMT forms such an instrument. Since 1990, EBMT has been collecting, on an annual basis, numbers of HSCT from the preceding year according to indication, donor type and stem cell source. The survey covers all European countries. In 1990, 143 teams reported 4,234 HSCT; in the year 2000, 619 teams reported 19,136 HSCT (33% allogeneic, 67% autologous). This information, which covers over 90% of all HSCT performed in Europe and is based on 132,963 HSCT (33% allogeneic, 67% autologous), gives a clear overview of current status and ongoing trends. It shows the general increase in HSCT from 1990 to 2000 with few exceptions, such as autologous HSCT for breast cancer and allogeneic HSCT for chronic myeloid leukemia. It illustrates the shift in technology from bone marrow as stem cell source in 1990 (100%) to peripheral blood in 2000 (96% of autologous, 53% of allogeneic HSCT). Supplemented by population data and economic factors (Gross national Product, Health Care Expenditures, Health Care systems) of the individual countries it allows comparison of transplant rates (Number of transplants per 10 million inhabitants), team densities (Number of transplant teams per 10 million inhabitants) and trends between countries. It permits quantification of the impact of economics and health care systems and provides a basis for quality control and allows assessment of the main factors influencing team decisions: evidence, disease prevalence, economics and expectations. As such, it is an essential tool for patient counselling and health care planning.

Chimerism and minimal residual disease monitoring after reduced intensity conditioning (RIC) allogeneic transplantation

Since graft-versus-leukemia (GVL) is the main weapon for disease eradication after reduced intensity conditioning (RIC) allogeneic SCT, the availability of sensitive and specific techniques to monitor changes in tumor load after transplant are especially helpful. These minimal residual disease techniques would allow an early intervention in the event of low tumor burden, for which immunotherapy is highly effective. Some authors have found an association between persistence of MRD, mixed chimerism and risk of relapse. Nevertheless, data from the literature remain contradictory and further correlations should be established, especially in RIC transplants. In this study we have analyzed the impact of MRD and chimerism monitoring on the outcome of 34 patients undergoing RIC allogeneic SCT who were considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions. At day +100 25 (75%) patients reached complete remission (CR), there were five (15%) partial responses and three patients progressed. Incidence of grade 2-4 aGVHD and extensive cGVHD were 35% and 58%, respectively. Sixteen percent of patients developing aGVHD relapsed as compared to 47% in those without aGVHD (P = 0.03) and also 10% of patients developing cGVHD relapsed as compared to 50% relapses in those without cGHVD (P = 0.03). Four patients (12%) died due to early (n = 1) and late (n = 3) transplant-related mortality. After a median follow-up of 15 months, 24 out of the 34 patients remain alive. Projected overall survival and disease-free survival at 3 years are 68% and 63%, respectively. Early chimerism analysis showed 67% of patients with complete chimerism (CC) in bone marrow (BM), 86% in peripheral blood (PB), 89% in granulocytes and 68% in T lymphocytes. On day +100, these figures were 68%, 79%, 90% and 73%, respectively, and on day +180 there were 83% patients with CC in BM, 100% in PB, 100% in granulocytes and 100% in T lymphocytes. We observed a trend to a higher incidence of relapse in patients with mixed chimerism (MC) as compared to patients with CC. MRD monitoring by flow cytometry and/or RT-PCR analysis was performed in 23 patients. MRD assessment on days +21 to +56 after transplant allowed identification of patients at risk of relapse. In this sense, seven out of 12 patients (58.3%) who had positive MRD on days +21 to +56 relapsed as compared to none out of 11 patients who had negative MRD (P = 0.002). Of the seven patients with criteria to monitor MRD who relapsed after transplant, all but one remained MRD positive until relapse. By contrast, 10 patients remained MRD negative and all of them are in continuous CR. In nine additional patients, persistence of MRD or mixed chimerism was observed after transplant and withdrawal of cyclosporin with or without DLI was performed. Only two out of these nine patients relapsed. MRD clearance was preceded by CC and GVHD. In conclusion, in our study we found that RIC allogeneic transplantation can be used in patients considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions with both low toxicity and low transplant-related mortality. Simultaneous studies of both chimerism and MRD are a useful tool in order to predict risk of relapse in patients undergoing RIC transplants and so can be helpful for individualizing treatment strategies after transplant.

Minor histocompatibility antigens--targets of graft versus leukemia responses

Immune-mediated elimination of tumor cells by donor T cells recognizing recipient minor H antigens contributes to the curative potential of allogeneic HCT. The importance of the allogeneic response to a successful outcome is clearly illustrated by the results of stem cell transplant for malignancy after nonmyeloablative conditioning. Remarkably little is understood about the molecular nature of minor H antigens and this has impeded efforts to determine the role of specific disparities in graft versus tumor reactions or to manipulate T cell responses to augment antitumor activity without exacerbating GVHD. The isolation of minor H antigen-specific CD8+ and CD4+ T cell clones from recipients of allogeneic HCT has provided the reagents to characterize their expression on leukemic progenitors and to identify the genes encoding these antigens. Using cDNA expression cloning, genetic polymorphisms in the human IFI-75, Uty, KIAA0020, and UGT2B17 genes have been identified to encode new minor H antigens presented by HLA A3, B8, A2, and A29 respectively. Two of these genes are preferentially expressed in hematopoietic cells including leukemic progenitors suggesting it may be possible to augment T cell responses to promote a selective graft versus leukemia effect. A third gene, UGT2B17 is highly expressed in liver and GI tract and may be a target for GVHD in these organs. The studies to identify the molecular nature of minor H antigens have provided insights into the complexities of the graft versus host response associated with allogeneic HCT, but the challenge for the future will be to develop strategies that can selectively induce durable graft versus tumor effects without GVHD. A critical issue in developing specific immunotherapy to augment GVL responses is to determine which minor H antigens are expressed on leukemic stem cells. Studies using transplantation of human AML into SCID mice have identified a putative leukemic stem cell which is contained in the CD34+ CD38- subset of the blast population and is present in very low frequency (<1/200,000) in blood or bone marrow from AML patents. We have examined the ability of minor H antigen-specific CTL to prevent engraftment of human AML in NOD/SCID mice. These studies show that engraftment of leukemias derived from individuals encoding the minor H antigen can be specifically prevented demonstrating that AML stem cells express minor H antigens and are targets for CTL. One approach to determine directly which minor H antigens can be selectively targeted to induce a GVL effect without GVHD is to adoptively transfer T cell clones of defined specificity and function to patients who relapse after HCT. Studies of this approach are now in progress in acute leukemia and have provided important insights into potential obstacles of T cell therapy for relapsed leukemia after HCT.

Role of the passive apoptotic pathway in graft-versus-host disease

Donor T cells have been shown to undergo apoptosis during graft-vs-host disease (GVHD). Although active apoptosis mediated through Fas/Fas ligand interactions has been implicated in GVHD, little is known about the role of the passive apoptotic pathway. To examine this question, we compared the ability of normal donor T cells and T cells overexpressing the antiapoptotic protein, Bcl-x(L), to mediate alloreactive responses in vitro and lethal GVHD in vivo. In standard MLCs, T cells that overexpressed Bcl-x(L) had significantly higher proliferative responses but no difference in cytokine phenotype. Overexpression of Bcl-x(L) prolonged survival of both resting and alloactivated CD4(+) and CD8(+) T cells as assessed by quantitative flow cytometry, accounting for the higher proliferative responses. Analysis of engraftment in murine transplantation experiments demonstrated an increase in donor T cell chimerism in animals transplanted with Bcl-x(L) T cells, suggesting that overexpression of Bcl-x(L) prolonged T cell survival in vivo as well. Notably, transplantation of Bcl-x(L) T cells into nonirradiated F(1) recipients also significantly exacerbated GVHD as assessed by mortality and pathological damage in the gastrointestinal tract. However, when mice were irradiated no difference in GVHD mortality was observed between animals transplanted with wild-type and Bcl-x(L) T cells. These data demonstrate that the passive apoptotic pathway plays a role in the homeostatic survival of transplanted donor T cells. Moreover, the susceptibility of donor T cells to undergo passive apoptosis is a significant factor in determining GVHD severity under noninflammatory but not inflammatory conditions.

Non-myeloablative hematopoietic cell transplant for treatment of nonmalignant disorders in children

Hematopoietic stem cell transplantation (HCT) may offer the only curative therapy for certain life-threatening immune deficiency disorders. Conventional HCT poses a risk to patients for severe morbidity, mortality, and late sequelae resulting from myeloablative preparative regimens. This review summarizes the development of nonmyeloablative regimens that have the potential to reduce both short- and long-term risks of HCT. Results of NM-HCT in a small number of patients indicate that this procedure may play an important role in treatment of life-threatening immune deficiencies.