Sustained complete cytologic and molecular remission induced by donor leucocyte infusions alone in an acute myeloblastic leukaemia in relapse after bone marrow transplantation

Adoptive immunotherapy as consolidation of remission in pediatric AML relapsing post-transplant

Treatment of acute leukemia relapse following an allogeneic transplantation is a challenge. We reinduced three pediatric patients with acute myeloid leukemia (AML) relapsing after a marrow transplantation from a sibling donor into remission with chemotherapy and used donor lymphocyte infusions (DLIs) as consolidation. In two of the cases, the allogeneic recognition was enhanced through the use of interferon in the absence of clinical graft vs. host disease (GVHD). Subsequently, all the three developed (acute grade III-IV or chronic extensive) GVHD and remain in remission with a good quality of life 19, 15 and 14 months post-relapse. We consider an active approach in the treatment of pediatric AML relapsing post-transplant justified.

Unusual presentation of central nervous system relapse with oculomotor nerve palsy in a case of CD56-positive acute myeloid leukemia following allogeneic stem cell transplantation

Allogeneic stem cell transplantation (allo-SCT) plays an important role in the treatment of infants and children with acute myelogenous leukemia (AML). Leukemic relapse after allo-SCT is responsible for a high rate of treatment failure. Extra-medullary relapse (EMR), without involvement of bone marrow, is rare compared to medullary relapse. CD56, the neural cell adhesion molecule, may contribute to the higher frequency of CNS relapse in CD56-positive AML. We observed an isolated EMR on the oculomotor nerve of a 17-month-old girl 12 weeks after cord blood transplantation (CBT), who was transplanted because of CD56-positive AML. Diagnosis of relapse was suspected clinically and confirmed by magnetic resonance imaging (MRI), and fluorescence-activated cell sorter (FACS) and chimerism analysis of cerebrospinal fluid (CSF). Therapy consisted of intra-thecal chemotherapy, CNS irradiation, and systemic immunomodulation by cyclosporin A (CsA) and basiliximab withdrawal. Twenty-one months after relapse, the patient shows full remission of symptoms and previously described oculomotor nerve infiltration.

Effect of slow lymphocyte recovery and type of graft-versus-host disease prophylaxis on relapse after allogeneic bone marrow transplantation for acute myelogenous leukemia

Allogeneic BMT is potentially curative for patients with acute myelogenous leukemia (AML) in first remission. However, many patients relapse after transplantation. Various immunotherapeutic options have been attempted with variable success in preventing relapse. Early identification of patients at high risk for relapse could allow prompt intervention. We examined the effect of slow lymphocyte recovery after sibling-matched allogeneic BMT on the risk of relapse in patients with AML. We also examined the effect of prednisone-containing GVHD prophylaxis on the rate of lymphocyte recovery. Patients with absolute lymphocyte count (ALC) <150 x 10(6)/l by day +30 had a 3.5-fold higher risk of relapse (P = 0.0088) and a lower overall survival (P = 0.0079) than patients with a higher ALC. We did not find correlation between lymphocyte count determined earlier in the post-transplantation course (day +21) and the risk of relapse. Patients receiving prednisone had a significantly lower ALC at day +30 than those who did not receive prednisone (289 vs 549 x 10(6)/l, P = 0.002). We conclude that a slow lymphocyte recovery after allogeneic BMT for AML is strongly predictive of subsequent relapse and that the type of GVHD prophylaxis should be considered when analyzing lymphocyte recovery.

Long-term molecular remission induced by donor lymphocyte infusions for recurrent acute myeloblastic leukemia after allogeneic bone marrow transplantation

A case of acute myelogenous leukemia with a t(8;21) translocation relapsed 5 months after allogeneic bone marrow transplantation (allo-BMT). After chemotherapy-induced hematologic remission, the patient received donor lymphocyte infusions (DLI); 4.9 x 108/kg T cells were infused. After DLI, she achieved molecular CR for the first time after allo-BMT, which lasted for 40 months. However, she suffered from grade III acute GVHD of the skin and the liver. Hepatic GVHD was sustained and resulted in fatal outcome. The case demonstrates that DLI is a double-edged sword. Further study is necessary before DLI can be considered to be a beneficial therapy for acute leukemia. Bone Marrow Transplantation (2000) 26, 809-810.

Graft-versus-leukemia effect in minor antigen mismatched chimeras given delayed donor leucocyte infusion: immunoregulatory aspects and role of donor T and ASGM1-positive cells

BACKGROUND

Previous studies have demonstrated that delayed donor leukocyte infusion (DLI) can increase graft-versus-leukemia (GVL) without increasing graft-versus-host-disease (GVHD) in MHC mismatched bone marrow (BM) chimeras. In our report, the immune status of minor antigen mismatched BM chimeras given DLI was studied. Particularly the role of donor ASGM1 positive or T cells in the graft-versus-leukemia effect (GVL) was investigated.

METHODS

AKR mice (H2k, Mls1a, Thy1.1) received TBI (9,5 Gy) and T cell-depleted (TCD) C3H (H2k, Mls2a, Thy1.2) BM alone (BM chimeras), or TCD BM together with immunocompetent C3H spleen cells at the time of BM transplantation (BM+SP chimeras), or TCD BM and 3 weeks later C3H spleen cells (DLI chimeras). Chimerism and T lymphocyte subsets were scored using FACS and anti-Thy, anti-Vbeta6, anti-IL2-beta receptor, anti-CD4, anti-CD3, and anti-CD8 mAbs. Leukemia challenge consisted of 5 x 10(6) AKR T cell lymphoma (BW4157) cells injected i.v. ASGM1 positive (ASGM1+) cells and T cells were depleted using anti-ASGM1 or anti-Thy1.2 antibodies, respectively. Immune tolerance was studied using MLR and CML tests.

RESULTS

BM + SP chimeras developed acute and lethal GVHD, whereas DLI chimeras were totally free from GVHD. In DLI chimeras, host-reactive cytotoxic T cells (CTL) could not be induced and host-reactive CD8Vbeta6 cells were deleted whereas CD4Vbeta6 cells and MLR reactivity persisted temporarily. In contrast, in BM+SP chimeras, anti-host CTL were easily generated and an expansion of both host-reactive CD8Vbeta6 and CD4Vbeta6 T cells was found as well as high anti-host MLR reactivity. Depletion of either ASGM1 + cells or T cells from the DLI inoculum resulted in an abrogation of GVL reactivity, suggesting that both cell populations were involved in the protection against BW4157 leukemia. Three weeks after DLI, the GVL effect waned which correlated with the disappearance of host-reactive CD4 cells and MLR reactivity.

CONCLUSION

In minor antigen mismatched BM chimeras, anti-host reactivity after DLI is characterized by (1) an absence of clinical GVHD, (2) clonal deletion of host-reactive CD8 cells, (3) an absence of anti-host CTL induction, and ( 4) a temporary persistence of host-reactive CD4 T cells and of MLR reactivity. In addition, either donor ASGM1+ cells or an interaction between these cells and T cells contribute to the GVL effect.

Membrane-Bound Fas (Apo-1/CD95) Ligand on Leukemic Cells: A Mechanism of Tumor Immune Escape in Leukemia Patients

There is evidence from bone marrow transplantation that T cells may be involved in the immunologic control of leukemia. But many patients relapse despite a potent graft-versus-leukemia effect mediated by allogeneic T cells. The expression of the FasL protein has been suggested as a mechanism of tumor immune escape. We, therefore, evaluated the capacity of leukemic cells from patients with acute or chronic myelogenous leukemia to escape the allogeneic or autologous immune response by bearing the FasL molecule. Although almost all leukemic cells express the 37-kD form of FasL, only 54% of acute myeloblastic leukemia and 27% of chronic myeloid leukemia (CML) cells bore a FasL with killing properties, as assessed by the ability of leukemic cells to cause the apoptosis of a Fas-sensitive target cell line or autologous activated T cells in 3 tested leukemic cases. Experiments with a recombinant Fas-Fc molecule confirmed the role of Fas/FasL in leukemic-mediated cell death. Only CML leukemic cells from certain individuals contained the 26-kD truncated form of FasL. Thus, myeloid leukemic cells from some, but not all patients can set up a mechanism of immune escape involving the Fas/FasL pathway. This leukemic escape may have implications for patients eligible for adoptive cellular immunotherapy.

Membrane-Bound Fas (Apo-1/CD95) Ligand on Leukemic Cells: A Mechanism of Tumor Immune Escape in Leukemia Patients

There is evidence from bone marrow transplantation that T cells may be involved in the immunologic control of leukemia. But many patients relapse despite a potent graft-versus-leukemia effect mediated by allogeneic T cells. The expression of the FasL protein has been suggested as a mechanism of tumor immune escape. We, therefore, evaluated the capacity of leukemic cells from patients with acute or chronic myelogenous leukemia to escape the allogeneic or autologous immune response by bearing the FasL molecule. Although almost all leukemic cells express the 37-kD form of FasL, only 54% of acute myeloblastic leukemia and 27% of chronic myeloid leukemia (CML) cells bore a FasL with killing properties, as assessed by the ability of leukemic cells to cause the apoptosis of a Fas-sensitive target cell line or autologous activated T cells in 3 tested leukemic cases. Experiments with a recombinant Fas-Fc molecule confirmed the role of Fas/FasL in leukemic-mediated cell death. Only CML leukemic cells from certain individuals contained the 26-kD truncated form of FasL. Thus, myeloid leukemic cells from some, but not all patients can set up a mechanism of immune escape involving the Fas/FasL pathway. This leukemic escape may have implications for patients eligible for adoptive cellular immunotherapy.

Novel biologic approaches to hematologic malignancies

Biologic agents have made a major impact on the treatment of hematologic malignancies and will continue to play a major role as we better understand their function in normal and malignant cell regulation. The examples provided in this chapter are a brief introduction to the potential of these agents. Many have yet to be used in conjunction with current cytotoxic therapy in these diseases, and perhaps combinations will prove even more successful. This possibility provides substantial ground for further investigation and therapy.

Donor lymphocyte infusion for the treatment of relapse after allogeneic hematopoietic stem cell transplantation

The results of donor lymphocyte infusion (DLI) for treatment of relapse after bone marrow transplantation (BMT) are reviewed. Durable complete remission can be achieved at the molecular level for a majority (more than 70%) of patients with CML, when treated at early relapse. Results are less favourable for acute leukemias, although useful responses have been reported. Data are scarce though promising for myelodysplastic syndromes and multiple myeloma. Major treatment-associated toxicities are GVHD and bone marrow aplasia. The latter complication can be predicted by evaluating the level of residual donor-derived hematopoiesis. Modification of infused cells (CD8 negative selection or transduction with a suicide gene), addition of peripheral blood stem cells, and early implementation of escalating doses may counteract the complications and increase the response rate. Response rate is variably influenced by the presence of chronic GVHD after initial BMT, T-cell depleted BMT, underlying disease and stage at relapse, and the level of mixed chimerism. DLI is a direct demonstration of the graft-versus-leukemia effect (GVL). Because GVL after BMT is sometimes the predominant cause of cure, it may be advisable in such situations to redirect the conditioning regimens for BMT towards engraftment and less immediate cytotoxicity.