Feasibility of Immunotherapy of Relapsed Leukemia With Ex Vivo–Generated Cytotoxic T Lymphocytes Specific for Hematopoietic System-Restricted Minor Histocompatibility Antigens

Abstract

Allogeneic bone marrow transplantation (BMT) is a common treatment of hematologic malignancies. Recurrence of the underlying malignancy is a major cause of treatment failure. Donor-derived cytotoxic T lymphocytes (CTLs) specific for patients’ minor histocompatibility antigens (mHags) play an important role in both graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) reactivities. mHags HA-1 and HA-2 induce HLA-A*0201-restricted CTLs in vivo and are exclusively expressed on hematopoietic cells, including leukemic cells and leukemic precursors, but not on fibroblasts, keratinocytes, or liver cells. The chemical nature of the mHags HA-1 and HA-2 is known. We investigated the feasibility of ex vivo generation of mHag HA-1– and HA-2–specific CTLs from unprimed mHag HA-1– and/or HA-2–negative healthy blood donors. HA-1 and HA-2 synthetic peptide-pulsed dendritic cells (DCs) were used as antigen-presenting cells (APC) to stimulate autologous unprimed CD8+ T cells. The ex vivo–generated HA-1– and HA-2–specific CTLs efficiently lyse leukemic cells derived from acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL) patients. No lytic reactivity was detected against nonhematopoietic cells. Sufficient numbers of the CTLs can be obtained for the adoptive immunotherapy purposes. In conclusion, we present a feasible, novel therapy for the treatment for relapsed leukemia after BMT with a low risk of GVHD.

Minor histocompatibility antigens as targets for immunotherapy using allogeneic immune reactions

“…Because of its restricted expression in hematopoietic cells and leukemic cells, (11) and the lack of cytotoxicity in a skin explant model, (12) the Leiden group moved to in vitro studies to induce HA-1 H -specific CTL lines for application in adoptive immunotherapy against recurring leukemia patients positive for both HLA-A*0201 and HA-1 H mHag following HCT. (15) Such HA-1 H -specific CTL lines were tested for antileukemic activity in an NOD/SCID mouse model in which mice implanted with leukemia cells 3 days prior to infusion of the CTL line showed a delayed outgrowth of leukemia compared with those receiving control CTL. (16) Although complete cure of leukemia was not achieved with a single CTL infusion in these mice, the data provided a rationale for use of mHag as effective targets for immunotherapy if in vivo maintenance of mHag-specific CTL activity could be further improved.…”

“…HA-1 H is the most well-known and extensively studied mHag, as described above and reviewed elsewhere, (1,10,11,14,15) partly due to its relatively high 'overall applicability' (>10%) considering both the donor/recipient mismatching rate (~25%) and the HLA-A*0201 frequency (~45% in Caucasian population).…”

“…(3) A protocol to generate HA-1 H and HA-2 V specific T-cell lines from mHag-negative donors was proposed for adoptive immunotherapy. (15) Another adoptive immunotherapy trial using CTL clones that lyse hematopoietic cells but not dermal fibroblasts has been performed in the Fred Hutchinson Cancer Research Center, (50) where a dramatic decline of cytomegalovirus (CMV)-related disease has already been demonstrated by adoptive transfer of CMV-specific CTL clones. (51) The authors also started a phase I/II study to test the toxicity and effectiveness of CTL clones specific for ACC-1 Y or ACC-2 D .…”

Flow cytometric analysis of the graft‐versus‐Leukemia‐Effect After Hematopoietic Stem Cell Transplantation in Mice

“…As mature donor T-cells are responsible for the development of GvHD, T-cell depletion of the graft has been considered a valid approach to prevent GvHD. Unfortunately, this practice is associated with higher relapse rates or graft failure making it inefficient (39)(40)(41)(42)(43)(44)(45)(46). Also, treatment with anti-CD40 mAb inhibited the development of aGvHD and cGvHD as donor CD8 1 T-cells were activated and in turn diminished host hematopoietic cells resulting in a stronger GvL effect (7).…”

Expansion of antileukaemia CTL lines and clones for adoptive cell therapy in paediatric patients given allogeneic haematopoietic stem cell transplantation

“…Although the antigens recognized by antileukaemia CTLs are not defined, the possibility of generating CTLs with multiple specificities should diminish the possibility of selecting for escape variants, likely induced by the poor immunogenicity of leukaemia cells in vivo . Moreover, in contrast to most of the approaches based on the use of mHAgs (Dolstra et al ., 1999;Mutis et al ., 1999) our strategy is not limited in its clinical applicability by the association with defined donor/recipient HLA.…”