Donor Lymphocyte Infusion In Patients Research Articles

Detectable minimal residual disease before allogeneic hematopoietic stem cell transplantation predicts extremely poor prognosis in children with acute lymphoblastic leukemia

The level of minimal residual disease (MRD) prior to allogeneic hematopoietic stem cell transplantation (HSCT) has been shown to be an independent prognostic factor for outcome of pediatric patients with high-risk acute lymphoblastic leukemia (ALL). Retrospective studies which used (semi-) quantitation of clone-specific immunoglobulin/T-cell receptor (Ig/TCR) rearrangements have documented the feasibility and practicality of this technique. This approach has also been disputed due to the occurrence of clonal evolution and generally high MRD levels prior to HSCT. In our prospective study, MRD before and after HSCT was monitored using quantitative real-time PCR in a cohort of 36 children with ALL consecutively transplanted in our center between VIII/2000 and VII/2004. In 25 of 36 patients, MRD level prior HSCT was assessed. Seventeen patients were classified as MRD-negative and eight were MRD-positive up to 9 x 10(-2). In MRD-positive subgroup, seven events (six relapses) occurred post-transplant in striking contrast to only one relapse in MRD-negative subgroup (event-free survival (EFS) log-rank P < 0.0001). MRD proved to be the only significant prognostic factor in a multivariate analysis (P < 0.0001). Adoptive immunotherapy including donor lymphocyte infusions in patients with adverse dynamics of MRD after HSCT had only limited and/or temporary effect. Clonal evolution did not present a problem precluding MRD monitoring in any of patients suffering a post-transplant relapse. We show that MRD quantitation using clonal Ig/TCR rearrangements successfully assesses the risk in pediatric ALL patients undergoing allogeneic HSCT. As our ability to treat detectable MRD levels after HSCT is very limited, alternative strategies for MRD-positive patients prior HSCT are necessary.

Identification of Target Antigens Recognized in MGUS for Immunotherapeutic Approaches.

Monoclonal gammopathy of undetermined significance (MGUS) is a benign condition with 30% of patient developing symptomatic multiple myeloma (MM). The events leading to the transformation from MGUS to MM remain unclear, however several evidences have supported the idea that the immune system, in patients with MGUS, may play a role in controlling the progression to MM; and the identification of antigenic targets could open the way for future immunotherapeutic approaches to delay or prevent such progression. To identify target antigens that are recognized by the immune system in MGUS, we have screened a cDNA expression library, produced from purified CD138+ bone marrow myeloma cells, with high dilution (1:500) serum from 3 MGUS patients with stable disease for 1 to 4 years. Using this approach we were able to identify a panel of 11 gene products to which an antibody response was observed in serum from individuals with MGUS. Responses appeared to be directed against intracellular proteins involved in variety of cellular functions such as apoptosis (SON, Hip1), DNA and RNA binding (KIAA0530, GPATC4), signal transduction regulators (AKAP11), transcriptional co-repressors (IRF2BP2), developmental proteins (OFD1) and proteins involved in the ubiquitin-proteosome pathway (PSMC1). Interestingly PSMC1, the 26S subunit of proteosome, has recently emerged as a potential target for antimyeloma therapies and AKAP11 located on the 13q14.11, a locus frequently involved in the pathogenesis of aggressive MM. Importantly, two of these identified genes with antibody response have been previously identified by SEREX screenings; KIAA0530 has been reported to induce a strong antibody response in solid tumors such as head and neck, testicular, breast and colorectal cancers and SON, a protein involved in apoptosis with similarities to oncoproteins such as myc and mos, has been previously reported by us to induce an antibody response associated with a complete response after donor lymphocyte infusion in patients with MM. Our studies are now focused on testing these proteins in a series of MGUS serum at different stages of disease as well as in early stage myeloma. Although preliminary, these data open the possibility to identify target antigens that are important in the disease process of MGUS and may allow us to design future vaccines and immunotherapeutic approaches targeting these antigens in MGUS as well as in MM.

A Two Step Nonmyeloablative Allogeneic Transplantation Protocol Using In Vitro T-Cell Depleted Mobilized Stem Cells Followed by Donor Lymphocyte Infusions in Patients with Advanced CLL.

Transplantation of stem cells that are T-cell depleted using Campath 1H incubation following non-myeloablative (NM-alloSCT) conditioning leads to durable donor engraftment with minimal GVHD using HLA-identical family sibling and unrelated donors. The high levels of donor chimerism allow the subsequent use of DLI to treat residual disease (Exp. Hematol. 2003; 31: 865–872). Patients with chemotherapy-refractory chronic lymphocytic leukemia (CLL) have a short life expectancy. We analyzed 12 patients with advanced CLL (9), PLL (1) or M. Waldenstrom (2) treated with NM-alloSCT. Median age was 56 years. Recipient conditioning consisted of fludarabine (30 mg/m2, 6 days), ATG (10 mg/kg, 4 days) and busulphan (3.2 mg/kg, 2 days). High numbers of G-CSF mobilized peripheral blood CD34+ cells from 11 related and 1 unrelated donors were collected (median 12 x 106/kg). The graft was T-cell depleted by 30 minutes incubation with 20 mg Campath 1H. No post-transplant GVHD prophylaxis was administered. The transplant procedure was very well tolerated. All patients engrafted rapidly. Only 1 patient experienced GVHD gr I (skin) after alloSCT. Sequential chimerism studies of bone marrow showed sustained mixed chimerism with a median donor percentage at 3 months after alloSCT of 86% (range 8–100%). At a fixed time period of 6 months after NM-alloSCT, low dose DLI was administered (5 x 106 CD3+ cells/kg) in 8 patients (3 pts too early after alloSCT and one pt died before DLI). The disease status pre-DLI was persistent disease in 4 pts and CR in 4 pts. After DLI, four patients experienced severe aGVHD (≥ grade 2) and 1 limited cGVHD. Importantly, the observed GVHD after low dose DLI was well managable. One patient received a second transplant from the original donor after myeloablative conditioning due to progressive disease with concommitant decreasing mixed chimerism. Donor chimerism increased after DLI with a median donor percentage of 98% (range, 3–100%) at 3 months after DLI. Presently at a median follow-up of 423 (range 46–1572) days, 9 patients are alive. Four patients are in complete remission, 3 with partial remission and 2 with progressive disease. Three patients have died, two due to infection and one by unknown cause.In conclusion, in-vitro T-cell depleted NM-alloSCT followed by low dose DLI is a well tolerated strategy in older patients with advanced CLL. The low incidence of GVHD and the high levels of donor chimerism after NM-alloSCT allow the use of DLI to treat residual CLL. Our results demonstrate a profound GVL effect in patients with advanced CLL. NM-alloSCT may prolong survival for this group of patients.

Detectable Minimal Residual Disease before Haematopoietic Stem Cell Transplantation Predicts Extremely Poor Prognosis in Children with Acute Lymphoblastic Leukaemia.

The level of minimal residual disease (MRD) prior to allogeneic haematopoietic stem cell transplantation (HSCT) was shown to be an independent prognostic factor for the outcome of paediatric patients with high-risk acute lymphoblastic leukemia (ALL). Retrospective studies which used (semi-)quantitation of clone-specific immunoglobulin/T-cell receptor (Ig/TCR) rearrangements documented feasibility and practicality of such an approach. Recently, this approach was disputed by Imashuku et al (BMT 2003) due to great occurrence of the clonal evolution and generally high MRD levels prior HSCT in their cohort. In our prospective study, MRD before and after HSCT was monitored in a cohort of 36 children with ALL consecutively transplanted in our centre between VIII/2000 and VII/2004. We used a quantitative real-time PCR approach introduced and standardised by European Study Group on MRD in ALL. In 25 of 36 patients MRD level prior HSCT was assessed (9 patients lacked adequately sensitive Ig/TCR target; two lacked analysable DNA prior HSCT). Seventeen patients were MRD-negative prior HSCT (including two with MRD level below the quantitative range 10(−4)) and 8 were MRD-positive up to 9x10(−2). In the MRD-positive subgroup, 7 events (6 relapses) occurred post-transplant in striking contrast to only one relapse in MRD-negative subgroup (EFS log-rank p<0.0001). MRD proved to be the only significant prognostic factor in a multivariate analysis (p<0.0001). Adoptive immunotherapy including donor lymphocyte infusions in patients with adverse dynamics of MRD after HSCT had only limited and/or temporary effect. Clonal evolution did not present a problem precluding MRD monitoring in any of patients suffering a post-transplant relapse. We show that MRD quantitation using clonal Ig/TCR rearrangements represents a feasible approach for the risk assessment in paediatric ALL patients undergoing allogeneic HSCT. However, our ability to respond to detectable MRD levels after HSCT and to avert an impending relapse is very limited. The change of the approach to MRD-positive patients prior HSCT is necessary because of very questionable benefit of HSCT in these children. Supported by grants MSM0021620813, FNM 9735 and GAUK 62/2004.

Campath-1H-Based Reduced-Intensity Conditioning Followed by Allogeneic Blood Stem-Cell Transplantation and Preemptive CD8-Depleted Donor Lymphocyte Infusions.

Recent reports have demonstrated the feasibility of using the anti-CD52 antibody Campath-1H for in vivo T-cell depletion (TCD) in the context of a fludarabine/melphalan-based reduced-intensity conditioning regimen (Kottaridis et al. Blood 2000, 96:2419). Major disadvantage of this protocol is the severe immunosuppression which results in an increased rate of opportunistic infections and disease relapses. Donor lymphocyte infusions (DLI) are frequently used to overcome this limitation. The application of DLI, however, is associated with a profound risk of GvHD. Depletion of CD8+ lymphocytes from either the allotransplant or from DLI has proven feasible to reduce the incidence of GvHD (Nimer et al. Transplantation 1994, 57:82; Giralt et al. Blood 1995, 86:4337).We set up a phase-I allotransplantation study which combines the Campath-1H (100mg)/fludarabine (150mg/m2)/melphalan (140mg/m2) preparative regimen with the preemptive administration of CD8-depleted DLI in patients with hematological malignancies not eligible for myeloablative conditioning. After early withdrawal of CsA immunosuppression, CD8-depleted DLI are scheduled in a dose-escalating regimen starting on day +60 after HLA-identical sibling transplantation and on day +120 after unrelated donor transplantation, respectively. For CD8-depletion of donor leukaphereses a new CliniMACS-based protocol using clinical grade CD8 Microbeads is used. Our data show that this procedure is efficient in reducing the content of CD8+ T-cells by at least 2.5 to 3.5 logs, while CD4+ cells remain largely unchanged.In this ongoing study, 8 patients (4 myeloma, 2 CMPD, 1 ALL, 1 NHL) were included and received peripheral blood stem cells (PBSC) from HLA-identical sibling (1), HLA-matched (5) or DRB1-mismatched unrelated donors (2), according to high-resolution HLA typing. Chimerism analyses on total bone marrow-derived cells as well as on purified CD4, CD8, CD19, CD14 and CD15-positive peripheral blood cells showed durable complete donor chimerism in all but one patient (see below). After successful withdrawal of CsA, 2 patients already received CD8-depleted DLI without any acute toxicity. In the first patient (UPN 3), who was transplanted from an HLA-identical sibling, DLI were given on days 60 and 120 (1 and 5 x 106 CD4+ T cells, respectively). The second patient (UPN 4), who was transplanted from a matched unrelated donor, received the first dose of 1 x106 CD8-depleted DLI on day 120. DLI were regularly followed by a more than 2-fold increase of CD4+ cells during the first two weeks after application, while CD8+ cells remained unchanged. After the second DLI, patient UPN 3 developed a grade 2 GvHD of the skin (d+22 after DLI). Both patients were at high risk for CMV reactivation (donor: CMV negative, host: CMV positive) and repeatedly received preemptive treatment. Immediately prior to the second DLI, the CD8+ cell count in patient UPN 3 increased during an ongoing CMV reactivation. Line-specific chimerism analysis revealed that more than 50% of these CD8+ cells were of host origin. As expected, transfer of CD8-depleted DLI from CMV-negative donors was unable to entirely prevent CMV reactivation in seropositive patients. Nevertheless, our preliminary data suggest that the preemptive transfer of CD8-depleted DLI is able to accelerate immune reconstitution after reduced intensity TCD allogeneic PBSCT without rapid increase of CD8+ donor cells.

Extended follow-up of patients treated with imatinib mesylate (gleevec) for chronic myelogenous leukemia relapse after allogeneic transplantation: durable cytogenetic remission and conversion to complete donor chimerism without graft-versus-host disease.

Over the last several years, donor lymphocyte infusions have become the standard approach for patients with chronic myelogenous leukemia (CML) who relapse after allogeneic stem cell transplantation (SCT). Recent reports indicate that imatinib mesylate (Gleevec) can induce remissions in these patients as well. Less is known about the extent and durability of these responses. We studied 15 patients treated with imatinib for recurrent CML after SCT, 10 patients with stable phase CML (SP-CML), 1 with accelerated phase (AP-CML), and 4 with blast phase (BP-CML). The dose of imatinib was 600 mg (n = 10) or 400 mg (n = 5) daily. Patients were followed for hematological, cytogenetic, and molecular response. A susbset of responders was followed for changes in donor-derived hematopoietic chimerism. Of the 10 patients with SP-CML, all achieved a hematological response. Within 3 months, five of these patients had achieved a complete cytogenetic response (CCR). By six months, 9 of 10 patients had achieved CCR. The BCR-ABL transcript could not be detected by reverse transcription-PCR in 7 of these 9 patients. Patients who achieved CCR showed evidence of conversion to complete donor chimerism. No patient developed graft-versus-host disease. With a median follow up of 25 months, all patients are alive and 9 of 10 patients remain in CCR. Only one of the 5 patients with AP/BP-CML achieved a complete cytogenetic response. We find that imatinib is well tolerated in patients with SP-CML who relapse after SCT. Responses were rapid, durable, and associated with conversion to full donor chimerism without graft-versus-host disease. Imantinib was far less effective in patients who relapsed with AP/BP-CML. Imatinib should be evaluated as either an alternative or as an adjunct to donor lymphocyte infusions for patients with SP-CML who relapse after SCT.

Donor chimerism does not predict response to donor lymphocyte infusion for relapsed chronic myelogenous leukemia after allogeneic hematopoietic cell transplantation.

We studied the effect of donor chimerism level on the outcome of donor lymphocyte infusion (DLI) therapy in 42 patients with persistent or relapsed hematologic malignancies after non-T cell-depleted allogeneic hematopoietic cell transplantation. Seventy-five percent of chronic myelogenous leukemia (CML) and 39% of non-CML patients entered remission after DLI therapy. Remission and survival rates were similar for CML patients irrespective of their pre-DLI donor chimerism levels; however, remission occurred sooner in patients with > or =10% pre-DLI donor chimerism. None of the non-CML patients with <10% pre-DLI donor chimerism and 47% of those with > or =10% pre-DLI donor chimerism attained remission. The 2-year survival rates after DLI were 75% for CML and 17% for non-CML patients. We conclude that a low level of donor marrow chimerism is not an adverse prognostic factor for response to DLI in CML patients, but for non-CML patients it may confer worse outcomes. Better methods to augment the response to DLI for patients with hematologic malignancies other than CML that recur after allogeneic hematopoietic cell transplantation are needed, whereas for relapsed CML patients, combination therapies including imatinib mesylate or other promising antileukemic agents may provide outcomes superior to those with DLI alone.

Immunological effects of donor lymphocyte infusion in patients with chronic myelogenous leukemia relapsing after allogeneic bone marrow transplantation

Allogeneic bone marrow transplantation (alloBMT) is the only curative therapy for chronic myelogenous leukemia (CML). This success is explained by the delivery of high doses of antineoplastic agents followed by the rescue of marrow function and the induction of graftversus-leukemia reaction mediated by allogeneic lymphocytes against host tumor cells. This reaction can also be induced by donor lymphocyte infusion (DLI) producing remission in most patients with CML who relapse after alloBMT. The immunological mechanisms involved in DLI therapy are poorly understood. We studied five CML patients in the chronic phase, who received DLI after relapsing from an HLAidentical BMT. Using flow cytometry we evaluated cellular activation and apoptosis, NK cytotoxicity, lymphocytes producing cytokines (IL-2, IL-4 and IFN-γ), and unstimulated (in vivo) lymphocyte proliferation. In three CML patients who achieved hematological and/or cytogenetic remission after DLI we observed an increase of the percent of activation markers on T and NK cells (CD3/DR, CD3/ CD25 and CD56/DR), of lymphocytes producing IL-2 and IFN-γ, of NK activity, and of in vivo lymphocyte proliferation. These changes were not observed consistently in two of the five patients who did not achieve complete remission with DLI. The percent of apoptotic markers (Fas, FasL and Bcl-2) on lymphocytes and CD34-positive cells did not change after DLI throughout the different study periods. Taken together, these preliminary results suggest that the therapeutic effect of DLI in the chronic phase of CML is mediated by classic cytotoxic and proliferative events involving T and NK cells but not by the Fas pathway of apoptosis.

Immunological effects of donor lymphocyte infusion in patients with chronic myelogenous leukemia relapsing after bone marrow transplantation

Allogeneic bone marrow transplantation (alloBMT) is the only curative therapy for chronic myelogenous leukemia (CML). This success is explained by the delivery of high doses of antineoplastic agents followed by the rescue of marrow function and the induction of graft-versus-leukemia reaction mediated by allogeneic lymphocytes against host tumor cells. This reaction can also be induced by donor lymphocyte infusion (DLI) producing remission in most patients with CML who relapse after alloBMT. The immunological mechanisms involved in DLI therapy are poorly understood. We studied five CML patients in the chronic phase, who received DLI after relapsing from an HLA-identical BMT. Using flow cytometry we evaluated cellular activation and apoptosis, NK cytotoxicity, lymphocytes producing cytokines (IL-2, IL-4 and IFN-gamma), and unstimulated (in vivo) lymphocyte proliferation. In three CML patients who achieved hematological and/or cytogenetic remission after DLI we observed an increase of the percent of activation markers on T and NK cells (CD3/DR, CD3/CD25 and CD56/DR), of lymphocytes producing IL-2 and IFN-gamma, of NK activity, and of in vivo lymphocyte proliferation. These changes were not observed consistently in two of the five patients who did not achieve complete remission with DLI. The percent of apoptotic markers (Fas, FasL and Bcl-2) on lymphocytes and CD34-positive cells did not change after DLI throughout the different study periods. Taken together, these preliminary results suggest that the therapeutic effect of DLI in the chronic phase of CML is mediated by classic cytotoxic and proliferative events involving T and NK cells but not by the Fas pathway of apoptosis.

Donor Lymphocyte Infusions for Patients who Relapse After Allogeneic Stem Cell Transplantation for Chronic Myeloid Leukaemia

The understanding of the use of donor lymphocyte infusions (DLI) for graft-versus-leukaemia (GVL) in the treatment of chronic myeloid leukaemia (CML) post haemopoietic stem cell transplant (HSCT) has advanced during the last years. In relapsed leukaemia post-stem cell transplant, DLI can achieve durable remissions in 60-73% patients. Technical improvements in molecular methods of detection of the BCR-ABL transcripts permit the prediction of relapse with increased sensitivity and reproducibility. Use of DLI early at relapse is important since responses to DLI are less likely in the face of bulky or blast-phase disease. Exogenous interleukin-2 may enhance the response to DLI but total cell dose is also relevant to the efficacy of DLI with the effective cell dose (ECD) required being lower in HLA matched unrelated DLI donors compared to siblings. Donor T-lymphocytes target minor histocompatibility (H) antigens and the relative tissue distribution of these may influence the toxicity of DLI, which includes graft-versus-host-disease (GVHD). Modified methods of delivery such as selective deletion of CD8 + cells or escalating cell dosage regimens have reduced the incidence of serious morbidity due to GVHD without compromising the GVL effect mediated by DLI. These approaches have not removed the risk of GVHD entirely and conditional suicide protocols utilising the HSV- tk or fas receptor derived genes are being developed in the clinic. Since significant morbidity and mortality is attributable to the conditioning regimen used prior to HSCT, awareness of the potency of DLI has driven the development of reduced intensity conditioning (RIC) regimens. The purpose of RIC is to enhance tolerisation of the host to the graft while permitting the establishment of donor haemopoiesis. DLI may then be used subsequently to enhance the GVL effect.

Current Controversies: Which Patients With Acute Myeloid Leukaemia Should Receive A Bone Marrow Transplantation? – An Adult Treater's View

Current Controversies: Which Patients With Acute Myeloid Leukaemia Should Receive A Bone Marrow Transplantation? – An Adult Treater's View

T-cell–depleted allogeneic bone marrow transplantation followed by donor lymphocyte infusion in patients with multiple myeloma: induction of graft-versus-myeloma effect

Previous trials of allogeneic bone marrow transplantation (BMT) in patients with multiple myeloma (MM) have demonstrated high response rates but also high transplantation-related mortality (TRM) and high relapse rates. Exploitation of this strategy remains of interest because donor lymphocyte infusions (DLIs) can induce a potent graft-versus-myeloma (GVM) effect. CD6 T-cell--depleted allogeneic BMT was combined with prophylactic CD4(+) DLI administered 6 to 9 months after BMT in an effort to reduce TRM and to induce a GVM response after BMT. Twenty-four patients with matched sibling donors and chemotherapy-sensitive disease underwent BMT. CD6 T-cell depletion of donor bone marrow was the sole method of graft-versus-host disease (GVHD) prophylaxis. GVHD after BMT was minimal, 1 (4%) grade III and 4 (17%) grade II GVHD. Fourteen patients received DLI, 3 in complete response and 11 with persistent disease after BMT. Significant GVM responses were noted after DLI in 10 patients with persistent disease, resulting in 6 complete responses and 4 partial responses. After DLI, 50% of patients developed acute (> or = II) or extensive chronic GVHD. Two-year estimated overall survival and current progression-free survival (PFS) for all 24 patients is 55% and 42%, respectively. The 14 patients receiving DLI had an improved 2-year current PFS (65%) when compared with a historical cohort of MM patients who underwent CD6-depleted BMT survived 6 months with no GVHD and did not receive DLI (41%) (P =.13). Although this study suggests that prophylactic DLI induces significant GVM responses after allogeneic BMT, only 58% of patients were able to receive DLI despite T-cell--depleted BMT. Therefore, less toxic transplantation strategies are needed to allow a higher proportion of patients to receive DLI and the benefit from the GVM effect after transplantation. (Blood. 2001;98:934-939)

Durability of responses following donor lymphocyte infusions for patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia

AbstractAn analysis was performed of the response to treatment with donor lymphocyte infusions (DLI) and the survival in 66 consecutive patients who relapsed after primary treatment by allogeneic stem cell transplantation for BCR-ABL–positive chronic myeloid leukemia. The transplant donor was an HLA-identical sibling (n = 35) or a “matched” unrelated volunteer (n = 31). Fifty-seven patients were transplanted in chronic phase, eight in accelerated phase, and one in second chronic phase. The recognition of relapse was based on precise molecular, cytogenetic, or hematologic criteria. The median interval from transplant to relapse was 12 months (range 3-85). The median interval from relapse to initiation of DLI was 9.4 months (range 1-70). Patients received DLI from their original transplant donors on a bulk-dose (n = 34) or on an escalating-dose (n = 32) regimen. Patients were monitored serially by hematologic, cytogenetic, and molecular criteria. Molecular remission was defined by the finding of negative results by nested primer reverse transcriptase polymerase chain reaction (RT-PCR) for BCR-ABL transcripts on two consecutive occasions, subject to satisfactory controls. Forty-four patients (67%) achieved molecular remission. Patients who had relapsed to advanced phase disease and patients with short intervals between transplant and relapse had significantly lower probabilities of achieving molecular remission. Of the 44 patients who achieved molecular remission, 4 reverted to a PCR-positive status at 15, 18, 37, and 87 weeks after remission. The probability of survival for patients who achieved molecular remission was significantly better than for those who failed to do so (95% versus 53% at 3 years post-DLI,P = .0001). We conclude that the majority of molecular remissions after DLI are durable, and thus the majority of responding patients may prove to have been cured.

Durability of responses following donor lymphocyte infusions for patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia

An analysis was performed of the response to treatment with donor lymphocyte infusions (DLI) and the survival in 66 consecutive patients who relapsed after primary treatment by allogeneic stem cell transplantation for BCR-ABL–positive chronic myeloid leukemia. The transplant donor was an HLA-identical sibling (n = 35) or a “matched” unrelated volunteer (n = 31). Fifty-seven patients were transplanted in chronic phase, eight in accelerated phase, and one in second chronic phase. The recognition of relapse was based on precise molecular, cytogenetic, or hematologic criteria. The median interval from transplant to relapse was 12 months (range 3-85). The median interval from relapse to initiation of DLI was 9.4 months (range 1-70). Patients received DLI from their original transplant donors on a bulk-dose (n = 34) or on an escalating-dose (n = 32) regimen. Patients were monitored serially by hematologic, cytogenetic, and molecular criteria. Molecular remission was defined by the finding of negative results by nested primer reverse transcriptase polymerase chain reaction (RT-PCR) for BCR-ABL transcripts on two consecutive occasions, subject to satisfactory controls. Forty-four patients (67%) achieved molecular remission. Patients who had relapsed to advanced phase disease and patients with short intervals between transplant and relapse had significantly lower probabilities of achieving molecular remission. Of the 44 patients who achieved molecular remission, 4 reverted to a PCR-positive status at 15, 18, 37, and 87 weeks after remission. The probability of survival for patients who achieved molecular remission was significantly better than for those who failed to do so (95% versus 53% at 3 years post-DLI,P = .0001). We conclude that the majority of molecular remissions after DLI are durable, and thus the majority of responding patients may prove to have been cured.

Donor lymphocyte infusions for relapsed multiple myeloma after allogeneic stem-cell transplantation: predictive factors for response and long-term outcome.

To determine the efficacy, toxicity, and long-term outcome and prognostic factors of donor lymphocyte infusions (DLI) in patients with relapsed multiple myeloma (MM) after allogeneic stem-cell transplantation (AlloSCT). Twenty-seven patients received 52 DLI courses at a median of 30 months after the previous AlloSCT. Reinduction therapy was administered to 13 patients before DLI. Reinduction therapy was successful in eight of 13 patients. Fourteen patients (52%) responded to DLI, including six patients (22%) who achieved a complete remission (CR). Five patients responded after T-cell dose escalation in subsequent DLIs. Four patients experienced relapse or disease progression (three from partial response and one from CR). Five patients remain in remission more than 30 months after DLI. Major toxicity was acute and chronic graft-versus-host disease (GVHD), which was present in 55% and 26% of patients, respectively. Two patients died from bone marrow aplasia. Median overall survival of all patients was 18 months. Overall survival was 11 months for DLI-resistant patients and has not been reached for the responding patients. In two patients, sustained molecular remission was observed. The factors that were correlated with response to DLI were a T-cell dose of more than 1.10(8) cells/kg, response to reinduction therapy, and chemotherapy-sensitive disease before AlloSCT. These data confirm the potential and durable graft-versus-myeloma effect of DLI in patients with relapsed MM after AlloSCT. Future studies should be aimed at increasing response rates, especially in patients with chemoresistant disease, and reducing toxicity by limiting GVHD. Adjuvant DLI seems an attractive and promising approach for patients who do not achieve a molecular remission after AlloSCT.

Advances in the immunotherapy of hematologic malignancies: cellular and humoral approaches.

Therapy with unconjugated monoclonal antibodies (mAbs) and radiolabeled mAbs has shown activity in patients with B-cell non-Hodgkin's lymphoma and leukemia. Drug-conjugated mAbs are active in relapsed leukemia. Using these new agents with and after chemotherapy induces a high rate of remission, but this needs to be confirmed in randomized, clinical trials. The antitumor effect of allogeneic stem cell transplantation is being explored through the use of donor lymphocyte infusions for patients who have relapse after transplantation. Attempts to maintain antitumor activity without graft-versus-host disease include CD4 lymphocyte infusions, suicide gene-transfected cells, and the use of cloned T cells more specific for the tumor. Transplantation with nonmyeloablative conditioning regimens relying on the graft-versus-tumor effect of allogeneic lymphocytes has shown preliminary success in the treatment of many hematologic malignancies.

Transplant-lite: induction of graft-versus-malignancy using fludarabine-based nonablative chemotherapy and allogeneic blood progenitor-cell transplantation as treatment for lymphoid malignancies.

To investigate the use of a nonmyeloablative fludarabine-based preparative regimen to produce sufficient immunosuppression to allow engraftment of allogeneic stem cells and induction of graft-versus-leukemia/lymphoma (GVL) as the primary treatment modality for patients with chronic lymphocytic leukemia (CLL) and lymphoma. Fifteen patients were studied. Six patients were in advanced refractory relapse, and induction therapy had failed in two patients. Patients with CLL or low-grade lymphoma received fludarabine 90 to 150 mg/m2 and cyclophosphamide 900 to 2,000 mg/m2. Patients with intermediate-grade lymphoma or in Richter's transformation received cisplatin 25 mg/m2 daily for 4 days; fludarabine 30 mg/m2; and cytarabine 500 mg/m2 daily for 2 days. Chemotherapy was followed by allogeneic stem-cell infusion from HLA-identical siblings. Patients with residual malignant cells or mixed chimerism could receive a donor lymphocyte infusion of 0.5 to 2 x 10(8) mononuclear cells/kg 2 to 3 months posttransplantation if graft-versus-host disease (GVHD) was not present. Eleven patients had engraftment of donor cells, and the remaining four patients promptly recovered autologous hematopoiesis. Eight of 11 patients achieved a complete response (CR). Five of six patients (83.3%) with chemosensitive disease continue to be alive compared with two of nine patients (22.2%) who had refractory or untested disease at the time of study entry (P = .04). These findings indicate the feasibility of allogeneic hematopoietic transplantation with a nonablative preparative regimen to produce engraftment and GVL against lymphoid malignancies. The ability to induce remissions with donor lymphocyte infusion in patients with CLL, Richter's, and low-grade and intermediate-grade lymphoma is direct evidence of GVL activity against these diseases. This approach appears to be most promising in patients with chemotherapy-responsive disease and low tumor burden.

Adoptive immunotherapy for leukemia: donor lymphocytes transduced with the herpes simplex thymidine kinase gene for remission induction. HGTRI 0103.

This study will evaluate the safety and efficacy of allogenic donor lymphocyte infusions in patients who have relapsed hematologic malignancies after allogeneic bone marrow transplantation (BMT). Donor lymphocyte transfusions have resulted in the cure of some patients with relapsed leukemia or lymphoproliferative disorder after allogeneic BMT, but has been complicated by the development of graft versus host disease (GvHD). We hypothesize that a retroviral vector containing the Herpes simplex thymidine kinase (HStk) gene will allow for retention of the anti-leukemia response of transfused donor lymphocytes while allowing for the adverse effects of GVHD to be mitigated. Patients with relapsed hematologic malignancies after allogeneic BMT will be infused with ex vivo gene modified donor lymphocytes. The Herpes Simplex thymidine kinase (HStk) gene will be transduced into the cells ex vivo using LTKOSN. 1 vector supernate. Insertion of the HStk gene into lymphocytes confers a sensitivity to the anti-herpes drug ganciclovir (GCV). This selective destruction of donor lymphocytes in situ will be used to abrogate the effect of graft versus host disease, if it develops.

High-dose therapy in multiple myeloma.

Autologous transplantation in myeloma can prolong survival as compared with standard chemotherapy but cannot be considered curative, as the majority of patients relapse within 5 years. Contaminating myeloma cells can be detected in stem cell harvests in the majority of patients, and the possibility that these cells lead to relapse has prompted widespread current interest in the use of positive stem cell selection as a means of purging. Allogeneic bone marrow transplantation is associated with a high transplant-related mortality but a lower relapse risk. A graft-versus-myeloma effect has recently been proven by the demonstration of response to donor lymphocyte infusion in patients relapsing after allogeneic bone marrow transplantation.

The Graft Versus Leukemia (GVL) Effect After Allogeneic Bone Marrow Transplantation for Chronic Myelogenous Leukemia (CML)

Immune mechanisms superimposed to the myeloablative conditioning regimens exert an additional powerful effect in eradicating leukemia and in achieving immunological control of minimal residual disease. The impact of GVHD-independent GVL has been evaluated to be absent, or near absent, in ALL, about 30% in AML and about 40% in CML. While until little time ago most of the evidence in favor of an immune antileukemia mechanism exerted by allo BMT in CML was indirect, based on the lack of GVL, there is now solid evidence of a positive type, based on the antileukemia effect of donor lymphocyte infusions in patients having relapsed after transplant. There are three lines of indirect clinical evidence for GVL in CML: they include the classical linkage between GVHD and reduced relapse rate, increased relapse rate after identical twin allografts, and increased relapse risk after effective GVHD prophylaxis, with T lymphocyte depletion in the foreground. The eradicating effects of donor lymphocyte infusions in relapsed patients are the ultimate demonstration that allogeneic immune competent cells are capable of recognizing and destroying the Ph-positive clone. However the frequency of irreversible aplasia indicates that donor lymphocytes act in the same way on residual host hematopoiesis, so that a second graft, without repeat conditioning, should be programmed for such cases.