Donor lymphocyte infusions

Can GCSF-stimulated donor lymphocyte infusions improve outcomes for relapsed disease following allogeneic hematopoietic cell transplantation? A systematic review and meta-analysis

Donor lymphocyte infusions (DLI) can produce graft-versus tumor effects to treat relapse after allogeneic hematopoietic cell transplantation, however, durable responses remain uncommon. A systematic review and meta-analysis are needed to clarify whether DLI collected after stimulation with granulocyte colony-stimulating factor (GCSF; G-DLI) can improve clinical outcomes. Sixteen studies (4 controlled) involving 585 patients were identified in a systematic search up to 17 September 2020. A meta-analysis demonstrated no significant difference in the risk of all-cause mortality (RR: 0.94, 95% CI 0.52-1.68, p = 0.82; n = 3 studies) or relapse-related mortality (RR: 0.72, 0.44-1.18, p = 0.19; n = 3 studies) between G-DLI and conventional DLI (C-DLI) groups. G-DLI products had similar mean CD3+ cells compared to C-DLI products, but median CD34+ cells/kg were increased. No improvement in disease progression, complete response rates, or risk of developing GVHD was observed with G-DLI, however, greater non-relapse mortality was observed compared to C-DLI. Alternative approaches to enhancing graft-versus-tumor effects are needed.

Identification of TCR Vβ11-2-Dβ1-Jβ1-1 T cell clone specific for WT1 peptides using high-throughput TCRβ gene sequencing

We previously identified a TCR Vβ21 T cell clone which was specific to CML patients, and demonstrated that TCR Vα13/β21 gene-modified CD3+ T cells had specific cytotoxicity for HLA-A11+ K562 cells. However, it remains unclear which antigen is specifically recognized by the TCR Vβ21 T cell clone. In this study, CD3+ T cells from healthy donor peripheral blood were stimulated with the WT1 peptide or mixed BCR-ABL peptides in the presence or absence of IL-2 and IL-7. The distribution of the TCR Vβ repertoire was analyzed after different stimulations. We found that the mixed BCR-ABL peptides induced clonally expanded Vβ7-9-Dβ2-Jβ2-7 T cells while the Wilms Tumor 1 peptide induced clonally expanded Vβ11-2-Dβ1-Jβ1-1 T cells by high-throughput TCRβ sequencing and GeneScan. Interestingly, the sequence and CDR3 motif of Vβ11-2 T cell clone are similar to the TCR Vβ21 (a different TCR V region naming system) T cell clone that we previously found in CML patients. Thus, our findings suggest that the TCR Vβ21 T cell clone found in CML patients might be a T cell clone that specifically recognizes WT1.

Retargeting NK-92 cells by means of CD19- and CD20-specific chimeric antigen receptors compares favorably with antibody-dependent cellular cytotoxicity

Multiple natural killer (NK) cell-based anticancer therapies are currently under development. Here, we compare the efficiency of genetically modified NK-92 cells expressing chimeric antigen receptors (CARs) at killing NK cell-resistant B-lymphoid leukemia cells to the antibody-dependent cell-mediated cytotoxicity (ADCC) of NK-92 cells expressing a high affinity variant of the IgG Fc receptor (FcγRIII). First, we compared in vitro the abilities of NK-92 cells expressing CD20-targeting CARs to kill primary chronic lymphocytic leukemia (CLL) cells derived from 9 patients with active, untreated disease to the cytotoxicity of NK-92 cells expressing FcγRIII combined with either of the anti-CD20 monoclonal antibodies (mAbs) rituximab or ofatumumab. We found that CAR-expressing NK-92 cells effectively kill NK cell-resistant primary CLL cells and that such a cytotoxic response is significantly stronger than that resulting from ADCC. For studying CAR-expressing NK cell-based immunotherapy in vivo, we established xenograft mouse models of residual leukemia using the human BCR-ABL1+ cell lines SUP-B15 (CD19+CD20-) and TMD-5 (CD19+CD20+), two acute lymphoblastic leukemia (ALL) lines that are resistant to parental NK-92 cells. Intravenous injection of NK-92 cells expressing CD19-targeting CARs eliminated SUP-B15 cells, whereas they had no such effect on TMD-5 cells. However, the intrafemoral injection of NK-92 cells expressing CD19-targeting CAR resulted in the depletion of TMD-5 cells from the bone marrow environment. Comparative studies in which NK-92 cells expressing either CD19- or CD20-targeting CARs were directly injected into subcutaneous CD19+CD20+ Daudi lymphoma xenografts revealed that CD20-targeting CAR is superior to its CD19-specific counterpart in controlling local tumor growth. In summary, we show here that CAR-expressing NK-92 cells can be functionally superior to ADCC (as mediated by anti-CD20 mAbs) in the elimination of primary CLL cells. Moreover, we provide data demonstrating that the systemic administration of CAR-expressing NK-92 cells can control lymphoblastic leukemia in immunocompromised mice. Our results also suggest that the direct injection of CAR-expressing NK-92 cells to neoplastic lesions could be an effective treatment modality against lymphoma.

Tumor-associated-antigens or osteosarcoma cell line lysates: two efficient methods for in vitro generation of CTLs with special regard to MHC-I restriction

The expression of tumor associated antigens (TAA) in osteosarcoma cell lines allowed us to design an in vitro model for the generation of TAA-specific CTLs. Since the MHC-I-restriction of these peptides represents the major obstacle to clinical applications, we studied a second method for the generation of CTLs starting from osteosarcoma cell line lysates and PBMCs of HLA-I compatible healthy donors. TAA-specific CTLs showed high and homogeneous cytotoxic response against each peptide; high levels of IFN-γ were released by osteosarcoma cell line lysate specific-CTLs in response to the osteosarcoma cell line they were activated for. The MHC-I dependent osteosarcoma cell line lysate-specific CTLs activity was proved by the indifference against the HLA-I-negative erytroleukaemia cell line K562 and by the absence of IFN-γ production with the addition of HLA-class I blocking antibodies. These two methods may be considered the model for the autologous setting in the context of immunotherapeutic approaches for osteosarcoma patients.

Fetal microchimerism: the cellular and immunological legacy of pregnancy

During pregnancy there is transplacental traffic of fetal cells into the maternal circulation. Remarkably, cells of fetal origin can then persist for decades in the mother and are detectable in the circulation and in a wide range of tissues. Maternal CD8 T cell responses directed against fetal antigens can also be detected following pregnancy. However, the impact that the persistence of allogenic cells of fetal origin and the maternal immune response towards them has on the mother's health remains unclear and is the subject of considerable investigation. The potentially harmful effects of fetal microchimerism include an association with autoimmune disease and recurrent miscarriage. Beneficial effects that have been explored include the contribution of persistent fetal cells to maternal tissue repair. A link between fetal microchimerism and cancer has also been proposed, with some results supporting a protective role and others, conversely, suggesting a role in tumour development. The phenomenon of fetal microchimerism thus provokes many questions and promises to offer further insights not only into the biology of pregnancy but fields such as autoimmunity, transplantation biology and oncology.

The influence of CD4 T-cell subsets on control of CD4 T-cell-mediated graft-versus-host disease

In this study, we tested the effect of different T-cell subpopulations on antigen driven effector cell expansion in lymphopenic hosts, making use of an experimental model of graft-versus-host disease (GVHD). Fluorescence-activated cell sorted (FACS) naïve CD4 T cells from C57BL/6 mice, transferred into lymphopenic F1 (C57BL/6 x BALB/c) Rag-deficient hosts, proliferated extensively and migrated systemically causing acute GVHD within 4 weeks after transfer. Adoptive hosts of CD4 memory T cells on the other hand developed milder symptoms of GVHD with later onset. T-cell expansion and migration to peripheral sites as well as development of GVHD were prevented when naïve T cells were transferred together with CD4(+) CD25(+) T cells, but co-transfer of memory T cells with naïve T cells could not prevent GVHD, although its onset was delayed. OX40, a costimulatory marker that is upregulated at an early time point after T-cell activation and enhances T-cell proliferation, cytokine secretion and survival, was strongly upregulated during GVH responses. Naïve T cells deficient in OX40 expression caused markedly reduced GVH in onset and severity despite some level of expansion in the adoptive host, suggesting an important role of this molecule in the immune pathology of GVHD.

Non-myeloablative allogeneic stem cell transplantation for metastatic renal cell carcinoma

Between 1999 and 2004, 11 patients with metastatic renal cell carcinoma (RCC) underwent non-myeloablative stem cell transplantation (NST) with conditioning using fludarabine-based regimens in two institutions of Korea. Among 11 patients, only one patient showed partial response (response rate: 9%), three showed stable disease, and six progressive disease. Three patients developed acute graft-versus-host disease (GVHD), and among them, one developed grade III acute GVHD which caused early death at day 60 after transplantation, and this patient showed partial response at day 30. Six patients developed chronic GVHD, three limited, and three extensive GVHD, respectively. Survival after one yr was 18% in transplanted patients. Median overall survival for entire cohort was 4.3 months. Eight patients died from progressive disease and three (27%) from treatment-related mortality. Only one patient survived 51.2 months after NST with slowly progressive disease. This patient received donor lymphocyte infusion three times after NST and achieved complete donor chimerism. NST does not lead to durable response and prolonged overall survival in the majority of patients with RCC in our series.

Morphologic examination of sequential bone marrow biopsies after nonmyeloablative stem cell transplantation complements molecular studies of donor engraftment

CONTEXT

Nonmyeloablative stem cell transplantation (NMSCT) is a mode of immunotherapy increasingly employed in treating hematologic, lymphoid, and solid tumors. Patients are monitored principally by molecular analysis of donor engraftment.

OBJECTIVE

To determine the role of morphologic examination of bone marrow after NMSCT.

DESIGN

Seventy-three patients undergoing NMSCT under the Campath 1H (humanized anti-CD52 antibody) protocol were studied. Pretransplant and sequential posttransplant bone marrow specimens were evaluated and the findings were correlated with corresponding engraftment data.

RESULTS

Pretransplant bone marrow specimens from 43% of the patients were involved by disease, and these marrow specimens were significantly more cellular than those that were free of disease. Morphologically detectable disease was still present in day 14 posttransplant marrow specimens in more than one half of these patients, but there was no difference in engraftment in those with or without marrow disease. Early posttransplant marrow in nearly one half of the patients showed myeloid hyperplasia and atypical localization of immature myeloid precursors. Marrow cellularity for the first 2 months after NMSCT was significantly lower in those patients receiving stem cells mismatched at 1 to 3 loci as compared with those who received fully matched grafts (mean cellularity, 38.1% vs 54.1% at day 14). Marrow failure without recurrent disease at 3 to 6 months after transplant was detected by engraftment study in only approximately 15% of cases. Similarly, early recurrence of disease was detected first by morphologic examination in 4 of 13 cases before a decline in donor engraftment occurred.

CONCLUSION

Morphologic examination of bone marrow provides additional information that is complementary to donor engraftment analysis for optimal management after NMSCT.

CD4+CD25+ regulatory T cells in human hematopoietic cell transplantation

Naturally occurring CD4+CD25+ regulatory T cells (T(reg)) are differentiated T lymphocytes actively involved in the control of peripheral immunity. Over the past few years, a number of animal studies have demonstrated the critical role of these cells in the outcome of allogeneic hematopoietic stem cell transplantation (HCT). In these models, T(reg) can exert a potent suppressive effect on immune effector cells reactive to host antigens and prevent graft versus host disease (GVHD) while preserving the graft-versus-leukemia effect (GVL). The present review summarizes current knowledge on the role of T(reg) populations in humans following allogeneic HCT. Recent investigations focusing on T(reg) in transplant patients have generated conflicting results mostly due to the use of different parameters to assess T(reg). Nonetheless, these studies suggested that an imbalance between T(reg) and effector cells during immune reconstitution can substantially impair regulatory mechanisms and contributes to the development of GVHD. Building on these studies, a number of therapeutic strategies are being developed to positively modulate T(reg) pools in vivo and prevent or even correct GVHD. Conversely, clinical interventions can also be envisaged to decrease T(reg) activity in vivo and enhance the GVL effect. These potential strategies are discussed herein. Coming years will undoubtedly yield additional knowledge on how to use T(reg) subsets in vivo and successfully control and modulate immune responses in patients post-HCT.

Outcome and long-term follow-up of alloreactive donor lymphocyte infusions given for relapse after myeloablative allogeneic hematopoietic stem cell transplantations (HSCT)

In order to study efficacy, toxicity and the long-term results of donor lymphocyte infusions (DLI), we retrospectively analyzed DLI given for relapse after conventional allogeneic hematopoietic stem cell transplantation (HSCT) in 30 patients with a median delay of 107.5 months after transplant and 58 months after DLI. After DLI, 15 patients established full donor chimerism, three patients developed grade III and one grade IV acute GVHD. A total of 15 patients achieved a disease response. Among the 14 patients with chronic myeloid leukemia (CML), 11 are alive at the last follow-up: five are in complete molecular response (CMR) and two in complete cytogenetic response (CCR) with no other intervention after DLI, three in CMR after imatinib mesylate given after DLI and one in complete hematological response after imatinib mesylate and reduced-intensity conditioning allogeneic SCT performed after DLI. At the time of the last follow-up, 19 (63%) patients died and 11 (37%) remain alive. The 3-year probability of survival for the entire population, CML patients and non-CML patients, was 60, 93, 62% after transplantation, and 48, 80 and 48% after DLI, respectively. A multivariate analysis demonstrated a significantly worse survival rate after transplantation for female recipients, advanced disease and acute leukemia before transplantation.

Phenotype and function of human natural killer cells purified by using a clinical-scale immunomagnetic method

Infection, disease relapse, graft failure, and graft-versus-host disease (GVHD) are significant adverse events associated with allogeneic bone marrow transplantation. Donor natural killer (NK) cells may be an ideal cell type for prevention or treatment of all these adverse events. Therefore, we investigated the phenotype and function of human NK cells purified by using a clinical-scale immunomagnetic method. We found that the NK cell purification procedures did not adversely affect the expression of killer cell immunoglobulin-like receptors, adhesion molecules, intracellular cytokines, perforin, and granzyme B. Purified NK cells had extensive proliferative capacity and potent antitumor activity when assessed using an immunodeficient mouse model. While all mice transplanted with unpurified mononuclear cells developed GVHD, none of the mice transplanted with purified NK cells did. NK cells were highly susceptible to lysis by antithymocyte globulin (ATG), whereas G-CSF had a minimal effect on their natural cytotoxicity. These results support future clinical investigation of the use of purified NK cells for adoptive immunotherapy in the absence of ATG.

Impact of chimaerism analysis and kinetics on allogeneic haematopoietic stem cell transplantation outcome after conventional and reduced-intensity conditioning regimens

This retrospective study aimed to analyse the impact on overall survival (OS) and event-free survival (EFS) of chimaerism status and kinetics following allogeneic conventional and reduced-intensity conditioning haematopoietic stem cell transplantation, and to compare this with the impact of other well-known factors. We investigated the chimaerism status of 187 patients [84 females, 103 males; median age 39.5 years (range, 17-62 years)]. After transplantation, 121 patients (65%) presented full donor chimaerism (FDC) and 63 (34%) mixed chimaerism (MC). For MC, we divided the population into patients who presented regressive mixed chimaerism (RMC) (21 patients: 11%), stable mixed chimaerism (SMC) (20 patients: 11%) and progressive mixed chimaerism (PMC) (22 patients: 12%). At last follow-up, 71 patients were alive and 116 had died (48% from disease progression and 52% from transplant-related causes). With a mean follow-up of 39.4 and 34.8 months, the 5-year probabilities of OS and EFS for the total group were, respectively, 55% and 43%: 69.5% and 61% for FDC, 35.4% and 25% for RMC, 42.6% and 28.6% for SMC, and 21% and 10.4% for PMC (P < 0.0001 and P < 0.0001). Multivariate analysis only showed a significant impact of chimaerism status on OS, as well as acute and chronic graft-versus-host disease on EFS, with a trend for conditioning regimen.

Characterization of CD20-transduced T lymphocytes as an alternative suicide gene therapy approach for the treatment of graft-versus-host disease

We have previously proposed the CD20 molecule as a novel suicide gene for T lymphocytes in the context of allogeneic bone marrow transplantation, because CD20 can be used both as a selection marker and as a killer gene after exposure to the anti-CD20 therapeutic antibody rituximab. We now report on preclinical studies using this novel system, in which the best transduction protocol, reproducibility, yield, feasibility, and functionality of the transduced T lymphocytes have been investigated with a large donor series. Wild-type human CD20 cDNA was transduced into human T lymphocytes, using a Moloney-derived retroviral vector. Alternative protocols were tested by employing either one or four spinoculations (in which cells are centrifuged in the presence of retroviral vector supernatant) and stimulating T cells with phytohemagglutinin (PHA) or anti-CD3/CD28. One spinoculation alone was sufficient to obtain approximately 30% CD20-positive cells within four experimental days. Four spinoculations significantly increased transduction to 60%. A small difference in transduction efficiency was observed between the two stimulation methods, with PHA being superior to anti-CD3/CD28. Transduced cells could be purified on immunoaffinity columns, with purity reaching 98% and yield being on average 50%. Finally, 86-97% of immunoselected T lymphocytes could be killed in vitro with rituximab and complement. More importantly, the CD20 transgene did not alter the functionality of T lymphocytes with respect to allogeneic recognition and cytotoxic response, anti-Epstein-Barr virus cytotoxic response, antigenic response to tetanus toxoid antigen, interleukin 2 (IL-2), IL-4, and interferon gamma production; chemotaxis in the presence of stromal cell-derived factor 1, phenotype for several activation markers including HLA-DR, CD25, CD69, and CD95, and T cell repertoire.

Ex vivo expansion of the highly cytotoxic human natural killer-92 cell-line under current good manufacturing practice conditions for clinical adoptive cellular immunotherapy

BACKGROUND

Adoptive transfer of ex vivo expanded cytotoxic immune cells has become a viable strategy for treatment of malignant disease. Natural killer (NK)-92, a highly cytotoxic, IL2-dependent human NK cell-line, is an excellent candidate as an immunotherapeutic agent, being active for prolonged periods following irradiation and IL2 deprivation, non-toxic and non-immunogenic, and easily expanded. A number of clinical trials using NK-92 for different indications are currently underway. The aim of this study was to develop current good manufacturing practice (cGMP)-compliant expansion methodology for NK-92.

METHODS

The ability to expand NK-92 ex vivo was evaluated. Serum-free culture media, as well as media supplements (IL2, serum/plasma/albumin), culture containers and feeding regimens were compared for their ability to support expansion, viability and cytotoxicity of NK-92 cells.

RESULTS

NK-92 cells can be expanded in X-Vivo 10 serum-free media with 500 U/mL of rhIL2 (Proleukin), and 2.5% human serum/plasma to achieve concentrations sufficient to treat patients with >5210(10) cells. The protocol involves cultures initiated at 2.5210(5) cells/mL in 25 mL in 1 L Vuelife culture bags, with addition of fresh media plus IL2 every 3 days to maintain an optimal density of NK-92 cells for expansion. Daily disruption of cell aggregates enhances NK-92 cells expansion and viability during the culture period. Final yields of approximately 1.1-1.3210(6) cells/mL in a 1.2 L volume (1.36-1.56210(9) cells; 218-250 fold expansion) over 15-17 days is achievable under cGMP-compliant conditions with >85% viability. The feasibility of this approach has been shown in ongoing clinical trial with NK-92.

DISCUSSION

We describe a protocol that allows for >200-fold expansion of NK-92 cells within a 2-2.5 week period under GMP standards, in quality and quantity suitable for clinical adoptive immunotherapy.

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.

Treatment with campath-1H for relapsed chronic lymphocytic leukemia after allogeneic peripheral blood stem cell transplantation does not abrogate the development of chronic GVHD

The graft vs. leukemia (GVL) effect is one of the most important factors of anti-tumor activity after allogeneic hematopoetic stem cell transplants (alloSCT). Its effectiveness depends mainly on the tumor biology as well as the tumor burden. Patients with a high tumor burden may not respond to GVL-effect despite otherwise sensitive biology. Campath-1H is known as an effective treatment of chronic lymphocytic leukemia (CLL). Due to its ability to induce profound immunosuppression, it has also been used as part of conditioning regimens before alloSCT. We report a patient, who received campath-1H in combination with docetaxel for treatment of chemotherapy and donor lymphocyte infusion resistant CLL after alloSCT, who developed shortly after discontinuation of treatment with campath-1H severe eosinophilia of the peripheral blood and typical clinical as well as histological signs of cutaneous chronic graft vs. host disease followed by complete clearance of CLL. The clinical course demonstrates the impact of the tumor burden on the GVL-effect, as well as the effectiveness of campath-1H in the presence chemo-resistance in a patient with CLL. Furthermore, the GVL effect was not abrogated by the use of campath-1H.

Purification of human natural killer cells using a clinical-scale immunomagnetic method

BACKGROUND

Infection, graft failure, disease relapse, and GvHD are significant adverse events associated with allogeneic BMT. Although donor leukocyte infusion has been used to prevent or to treat infection, graft failure, and relapse, the potential clinical benefits are often outweighed by the risk of T cell-mediated GvHD. Results from animal studies suggest that donor natural killer (NK) cells may be an ideal cell type for prevention or treatment of these adverse events. We have therefore sought to develop an automated, efficient, and clinical-scale human NK cell-purification method.

METHODS

Twelve leukopheresis products were purified for NK cells using a two-step immunomagnetic method. CD3(+) cells were first depleted from the apheresis products. CD56(+) cells were then enriched from the CD3(+) cell-depleted products.

RESULTS

The median percentage of CD3(-)CD56(+) NK cells in the final products was 91.0%, and the median recovery was 48.7%. The median depletion for CD3(+)CD56(-) T cells was 5.3 log. Natural cytotoxicity of the purified cells was approximately five-fold higher than that of unpurified mononuclear cells, and it could be further increased by stimulation of the purified cell with IL2.

DISCUSSION

We described a large-scale purification method for automated, efficient, and rapid isolation of human NK cells that yielded minimal contamination with T cells or B cells. These purified NK cells may be expedient for preclinical and clinical uses.

Specific targeted therapy of chronic myelogenous leukemia with imatinib

Chronic myeloid leukemia (CML) is characterized by the Philadelphia translocation that fuses BCR sequences from chromosome 22 upstream of the ABL gene on chromosome 9. The chimerical Bcr-Abl protein expressed by CML cells has constitutive tyrosine kinase activity, which is essential for the pathogenesis of the disease. Imatinib, an ATP-competitive selective inhibitor of Bcr-Abl, has unprecedented efficacy for the treatment of CML. Most patients with early stage disease achieve durable complete hematological and complete cytogenetic remissions, with minimal toxicity. In contrast, responses are less stable in patients with advanced CML. This review highlights the pathogenesis of CML, its clinical features, and the development of imatinib as a specific molecularly targeted therapy. Aspects of disease monitoring and side effects are covered as well as resistance to imatinib and strategies to overcome resistance, such as alternative signal transduction inhibitors and drug combinations. Perspectives for further development are also discussed.

Quantification of donor and recipient hemopoietic cells by real-time PCR of single nucleotide polymorphisms

Analysis of changes in recipient and donor hemopoietic cell origin is extremely useful to monitor the effect of stem cell transplantation (SCT) and sequential adoptive immunotherapy by donor lymphocyte infusions (DLI). We developed a sensitive and accurate method to quantify the percentage of recipient and donor cells by real-time PCR using single nucleotide polymorphisms (SNPs) as markers. Allele-specific PCR of seven SNPs resulted in specific markers for donor or recipient in 97% of HLA-identical sibling pairs. Both, recipient- and donor-derived hemopoietic cells can be simultaneously analyzed in 67% sibling pairs. We expect this can be increased to approximately 99% by developing three additional SNP-PCR. Serial dilution of SNP-positive DNA into either SNP-negative DNA or water revealed a detection limit of 0.1-0.01% depending on the amount of input DNA and start C(t) of the used SNP-PCR. Application of our real-time SNP-PCR method for a CML patient treated by allogeneic SCT and DLI demonstrated its feasibility to follow donor T-cell chimerism and early detection of residual and recurrent autologous hemopoiesis in response to treatment. This detailed monitoring of the genetic origin of hemopoietic cells, in particular immune effector cells and target cells after SCT and DLI, may substantially contribute to understanding of the mechanisms that play a role in the success of treatment.

Survival and tumor localization of adoptively transferred Melan-A-specific T cells in melanoma patients

Adoptive T cell therapy has been successfully used for treatment of viral and malignant diseases. However, little is known about the fate and trafficking of transferred Ag-specific T cells. Using the tetramer (TM) technology which allows for detection and quantification of Ag-specific CTL, we assessed the frequency of circulating Melan-A-specific CTL in advanced melanoma patients during adoptive T cell therapy. Melan-A-specific CTL were generated from HLA-A2.1(+) patients by in vitro stimulation of CD8(+) T cells with dendritic cells pulsed with a mutated HLA-A2-binding Melan-A (ELAGIGILTV) peptide. Eight patients received three infusions of 0.25-11 x 10(8) Melan-A-specific CTL i.v. at 2-wk intervals along with low-dose IL-2. The transferred T cell product contained a mean of 42.1% Melan-A-TM(+) CTL. Before therapy, the frequencies of Melan-A-specific CTL in patients' circulating CD8(+) T cells ranged from 0.01 to 0.07%. Characterization of the TM frequencies before and at different time points after transfer revealed an increase of circulating Melan-A-specific CTL up to 2%, correlating well with the number of transferred CTL. An elevated frequency of TM(+) T cells was demonstrated up to 14 days after transfer, suggesting long-term survival and/or proliferation of transferred CTL. Combining TM analysis with a flow cytometry-based cytokine secretion assay, unimpaired production of IFN-gamma was demonstrated in vivo for at least 24 h after transfer. Indium-111 labeling of Melan-A-specific CTL demonstrated localization of transferred CTL to metastatic sites as early as 48 h after injection. Overall, the results suggest that in vitro-generated Melan-A-specific CTL survive intact in vivo for several weeks and localize preferentially to tumor.

Nonmyeloablative conditioning followed by hematopoietic cell allografting and donor lymphocyte infusions for patients with metastatic renal and breast cancer

The feasibility and toxicity of allogeneic stem cell transplantation after nonmyeloablative conditioning including thiotepa, fludarabine, and cyclophosphamide have been investigated in 6 patients with breast cancer and 7 patients with renal cell cancer. The program included the use of escalating doses of donor lymphocyte infusions (DLI) and/or interferon alpha (IFNalpha) for patients showing no tumor response and no graft-versus-host disease (GVHD). Patients were at high risk of transplant-related mortality (TRM) because of age, advanced stage, and previous treatments. We observed a partial remission in 4 renal cancer and in 2 breast cancer patients (one at the molecular level in the bone marrow), occurring after cyclosporine withdrawal or after DLI and/or IFNalpha. All the responses were accompanied by the occurrence of acute GVHD. We conclude that reduced-intensity allogeneic stem cell transplantation is a feasible procedure in renal and breast cancer, and that the exploitation of graft-versus-tumor effect after DLI is a promising finding.

Induction of HA-1-specific cytotoxic T-cell clones parallels the therapeutic effect of donor lymphocyte infusion

Donor lymphocyte infusions (DLI) can induce a graft-versus-leukaemia (GvL) reaction in patients with relapsed disease. However, the mechanisms involved in remission induction are not completely known. A patient with chemotherapy-refractory relapse 1 year after human leucocyte antigen (HLA)-identical, unrelated stem cell transplantation (SCT) for bcr/abl-positive common acute lymphoblastic leukaemia (ALL) received a DLI from the original donor, and achieved complete cytogenetic and molecular remission concomitantly with extensive graft-versus-host disease (GvHD). Seven CD8+, donor-derived, alloreactive T-cell clones were generated by stimulating post-DLI remission cells with the patient's pretransplant mature dendritic cells. The minor histocompatibility antigen (mHag) recognized by these T-cell clones was identified as HA-1, a mHag associated with acute GvHD after SCT. Our finding provides evidence of HA-1-associated GvL effects after DLI that paralleled the eradication of full-blown, chemotherapy-refractory ALL relapse after allogeneic SCT.

Increased angiogenesis and Fas-ligand expression are independent processes in acute myeloid leukemia

We evaluated the clinical significance of tumor angiogenesis and Fas-ligand (FasL) expression using parameters including the microvessel count (MVC), vascular endothelial growth factor (VEGF) level, and FasL expression in patients with acute myeloid leukemia (AML). Paraffin-embedded bone marrow (BM) sections from 43 AML patients at diagnosis, 20 patients after subsequent induction therapy, and 18 controls with non-invasive lymphoma were stained immunohistochemically for von Willebrand factor (vWF) and FasL. VEGF in BM mononuclear cells from 32 AML patients at diagnosis and 10 controls, including bone marrow transplantation donors, was assayed by an ELISA method. We found that the mean MVC, VEGF level, and FasL expression in AML patients at diagnosis were significantly higher than those of controls, with a significant correlation between the MVC and VEGF levels (r=0.43). However, there were no correlations between FasL expression and MVC or VEGF level. The mean MVC and FasL expression after induction therapy were lower than those evaluated at diagnosis, but were higher than those of controls. There was a correlation between the MVC and percentage of BM blasts (r=0.479), but no correlation between the MVC, VEGF level, or FasL expression and other hematologic or clinical variables. Our findings provide evidence of increased angiogenesis and tumor immune escape in AML, and both angiogenesis and tumor immune escape are independent processes in AML.

Blood stem cell transplantation for breast cancer: new approaches using pre- peri- post-transplant immunotherapy

Autologous peripheral blood stem cell transplantation (auto-PBSCT) after high dose chemotherapy is usually offered to breast cancer patients carrying a high risk of relapse or having chemosensitive metastatic disease. Whether progression free and overall survival of such patients is improved after auto-PBSCT compared to conventional chemotherapy is a matter of debate. Currently available results of randomised trials could not uniformly prove or disprove auto-PBSCT being advantageous. Yet such studies have not employed any manipulation of the stem cell graft or any post-transplant immunomodulation exploiting the unique immunological environment for tumour eradication which exists only after auto-PBSCT. Preliminary data have discussed the ex vivo and in vivo generation of cytotoxic effector cells employing IL-2 and/or IFN-alpha/gamma in the auto-PBSCT setting. Other cytokines such as IL-12, IL-15 and prolactin have likewise been considered. Several anticancer vaccine protocols after auto-PBSCT are ongoing using monovalent vaccines or anti-idiotypic antibodies. Polyvalent anticancer vaccines, cytokine secreting tumour cells, tumour pulsed or hybridised dendritic cells (DC) enhanced with cytokines are studied. Monoclonal antibodies (mAb) could assist: unlabelled for pretransplant exvivo purging, post-transplant for enhancing antibody-dependent cell mediated cytotoxicity (ADCC) or radioimmunoconjugated as an additive cytotoxic part of the conditioning regimen. Autologous graft versus host induction and allogeneic stem cell transplantation (probably with non-myeloablative conditioning followed by donor lymphocyte infusions) are other approaches. Evaluation of successful combinations, optimal dosages and appropriate timing schedules is the subject of future investigations. Since breast cancer patients belong to countless subgroups, a large number of protocols need to be addressed in order to avoid over treatment and prevent relapse.

Integrated src kinase and costimulatory activity enhances signal transduction through single-chain chimeric receptors in T lymphocytes

Adoptive immunotherapy using receptor-modified T lymphocytes has shown promise in preclinical studies for the treatment of infectious and malignant diseases. These modified T cells express chimeric receptors that link ligand recognition and signal transduction domains in a single gene product. Typically, a single chain Fv fragment is genetically attached to the cytoplasmic domain of the T-cell receptor (TCR) zeta chain. Modulating the signaling characteristics of chimeric receptors will be important for their application to human immunotherapy. It was hypothesized that linking coreceptor and costimulatory signaling motifs together with the zeta signaling domain will enhance receptor function. The present study compares signaling characteristics of 9 single-chain receptors consisting of the H-2K(b) extracellular and transmembrane domains and various combinations of T cell signal transduction domains. Signal transduction regions studied include the TCR zeta chain, the CD4 coreceptor, the lck protein tyrosine kinase, and the CD28 costimulatory receptor. Biochemical characteristics of the receptors, analyzed using calcium flux, receptor, and ZAP-70 phosphorylation, and lck association may be predicted from the known functions of receptor constituents. The combination of zeta together with coreceptor and costimulatory function in a single receptor maximizes chimeric receptor sensitivity and potency. Combining zeta with either the costimulatory or coreceptor function independently also enhances receptor function, though to a lesser extent. It is therefore possible to link TCR, coreceptor, and costimulatory activities in a single functional entity using modular domains. Such receptors demonstrate distinct signaling properties and should prove useful in the development of chimeric receptors for therapeutic purposes.

Beneficial effect of intravenous lidocaine in cutaneous chronic graft-versus-host disease secondary to donor lymphocyte infusion

We report two cases of refractory chronic graft-versus-host disease after donor lymphocyte infusions in which the skin lesions improved dramatically with the use of intravenous pulses of lidocaine. This form of therapy has been used successfully for the cutaneous involvement of scleroderma and may have vasodilator and anti-inflammatory effects.

High response rate in refractory and poor-risk multiple myeloma after allotransplantation using a nonmyeloablative conditioning regimen and donor lymphocyte infusions

Standard allogeneic stem cell transplant (allo-SCT) regimens have been associated with a high transplant-related mortality (TRM) in multiple myeloma (MM). Nonmyeloablative therapy can establish stable engraftment after allo-SCT and maintain the antitumor effect with less toxicity, which is important in heavily pretreated and elderly patients. We report on 16 poor-risk MM patients receiving allo-SCT from an HLA-matched (n = 14) or mismatched (n = 2) sibling following conditioning with melphalan 100 mg/m(2) (MEL-100). Ten patients had refractory relapse, 4 responsive relapse, and 2 patients were in near complete remission (nCR) with poor-prognosis disease. Patients had received 1 (n = 9) or 2 (n = 7) prior autotransplants. Donor lymphocyte infusions (DLIs) were given to 14 patients with no clinical evidence of graft versus host disease (GVHD) either to attain full donor chimerism (n = 4) or to eradicate residual disease (n = 10). Fifteen patients showed myeloid engraftment, and 12 patients were full donor chimeras at day +21. No TRM was observed during the first 100 days. Acute GVHD developed in 10 patients; 1 had fatal grade IV GVHD. Seven progressed to chronic GVHD, limited in 3 and extensive in 4 patients. At a median follow-up of 1 year, 5 patients achieved and sustained CR, 3 nCR, and 4 partial remission. Of 4 patients progressing after transplantation, 3 achieved a remission following further chemotherapy and DLI. Remarkable graft versus myeloma responses were seen in chemotherapy-refractory patients. Two patients died of progressive disease, and 3 died of GVHD complications without active disease. GVHD remains a major problem with this procedure.

Current Treatment of Chronic Myeloid Leukemia

We are entering an exciting era in the management of chronic myeloid leukemia (CML). This, in part is related to our considerable understanding of the molecular lesion associated with the disease-arguably the best characterized of any malignancy. Although allogeneic hematopoietic cell transplantation remains the sole potentially curative therapy at present, newer agents such as the tyrosine kinase inhibitor STI571 show promise and may eventually replace less specific cytotoxic therapy. This review focuses on the numerous options currently available for treating CML and includes a treatment algorithm.

Adoptive allogeneic immunotherapy--history and future perspectives

For more than 30 yrs allogeneic hematopoietic stem cell transplantations have been successfully performed in patients with hematologic malignancies and bone marrow aplasia. Over the years the field of transplantation has changed dramatically. More and more unrelated donors became available, regimens for haploidentical transplantations were introduced and G-CSF mobilized peripheral blood stem cells and fetal cells from umbilical cord became available as alternate sources of hematopoietic stem cells. However, especially the introduction of donor lymphocyte infusions (DLI) for the successful treatment of leukemic relapses after allogeneic stem cell transplantations improved our understanding of transplantation immunology and opened amazing perspectives in allogeneic transplantation. It was long believed, that myeloablative therapy with high-dose chemotherapy and total body irradiation (TBI) are the sole antileukemic principles in allogeneic transplantations. But by now it became clear, that donor lymphocytes exert a very potent antileukemic effect, now referred as the graft-versus-leukemia (GVL) or graft-versus-malignancy (GVM) reaction. The efficacy of DLI in controlling leukemic relapses suggests that myeloablative therapy is not essential for long-term disease control. By exploiting the GVL or GVM reaction more intensively the role of chemotherapy and TBI is changing to immunosuppression. Sufficient immunosuppression to allow grafting, however, can be achieved with much lower doses as those which have been used in conventional transplants. Therefore allogeneic transplants have become also available for the elderly or for patients with concurrent medical conditions, which would have excluded them from conventional transplants. Moreover, this allogeneic transplantation strategy with reduced intensity conditioning is now also under investigation in patients with susceptible solid tumors and autoimmune diseases. However, one major obstacle in allogeneic transplantations, namely the graft-versus-host disease (GVHD), remains to be solved.

Complete remission of idiopathic myelofibrosis following donor lymphocyte infusion after failure of allogeneic transplantation: demonstration of a graft-versus-myelofibrosis effect

A patient with idiopathic myelofibrosis (IM) in the osteosclerotic phase received an allogeneic stem cell transplant. Hemopoietic engraftment was rapid, and full donor chimerism was observed on day +70. However, a few months later, replacement of donor hemopoiesis by the patient's 20q- cell clone was observed, followed by reappearance of the blood IM features, marrow fibrosis and osteosclerosis. At 8 months from transplant donor lymphocytes were infused, which induced chronic GVHD. This resulted in normalization of the blood, with disappearance of the fibrosis and osteosclerosis, effects which persisted 20 months later. This case provides evidence for a graft-versus-disease effect in IM.