Transfer of the HSV-tk Gene into Donor Peripheral Blood Lymphocytes for In Vivo Modulation of Donor Anti-Tumor Immunity after Allogeneic Bone Marrow Transplantation. The San Raffaele Hospital, Milan, Italy

Abstract

The infusion of donor lymphocytes after allogeneic bone marrow transplantation is a promising therapeutic tool for achieving a graft versus leukemia (GvL) effect in case of leukemic relapse (1-7), and for the treatment of other complications related to the severe immunosuppressive status of transplanted patients, such as Epstein Barr virus-induced lymphoproliferative disorders (EBV-BLPD) (8) or reactivation of CMV infection (9). Although the delay in the administration of T lymphocytes is expected to reduce the risk of severe GvHD, this risk is still present at higher doses of donor T-cells. The transfer of a suicide gene into donor lymphocytes could allow the in vivo selective elimination of cells responsible for severe GvHD. Additionally, under appropriate conditions, it may allow in vivo modulation of donor anti-tumor responses, and to separate GvL from GvHD. Finally, crucial questions concerning survival and function of donor lymphocytes could be answered by their gene marking. Previous studies documented that T lymphocytes are suitable targets for gene transfer through retroviral vectors (10, 11). This protocol has been designed to evaluate in the contest of allogeneic BMT: 1--the safety of increasing doses of donor lymphocytes transduced with a suicide retroviral vector; 2--the efficacy in terms of survival and immunologic potential of donor lymphocytes after in vitro activation, gene transduction, and immunoselection; 3--the possibility of in vivo down regulation of GvHD by the administration of ganciclovir to patients treated by tk-transduced donor lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Herpes simplex thymidine kinase (HStk) transgenic donor lymphocytes

“…Bonini et al 16 HStk/neo r fusion gene and NGFR retroviral LTR 5/8 patients show anti-tumor response Bordignon et al 15 3/8 patients develop GVHD 2/3 with GVHD have a complete response to GCV 1/3 with GVHD have a partial response to GCV Tiberghien et al 18 HStk/neo r retroviral LTR 2/3 patients develop GVHD 2/2 with GVHD have complete response to GCV Link, Drobyski, Burt et al 20,76 HStk/neo r retroviral LTR 4 patients infused 1/4 anti-tumor response 0/4 GVHD al 16 proposed the first clinical study using HStk gene modified lymphocytes as a method to modulate GVHD after allogeneic bone marrow transplantation. Three goals were defined in the original clinical protocol: safety of infusing donor lymphocytes transduced with a suicide retroviral vector; in vivo survival and immunologic potential of donor lymphocytes; and in vivo effect of ganciclovir on GVHD.…”

“…In addition, the pharmaceutical company Chiron has initiated a multicenter study providing HStk transduced lymphocytes for treatment of hematologic malignancies that relapse after allogeneic transplantation. Bordignon et al 15 and Bonini et Table 1 Gene therapy protocols using HSTK transduced donor lymphocytes for patients with hematologic malignancies…”

“…Several centers have initiated trials using genetically engineered lymphocytes containing the suicide gene, herpes simplex thymidine kinase (HStk). [14][15][16][17][18][19][20][21] Since the HStk death gene is inserted via a retroviral vector, a brief review of retroviral gene therapy follows.…”

True

“…279 Suicide gene-based strategies have been explored to promote a graftversus-leukemia effect while minimizing graft-versus-host disease (GVHD) and have already entered the clinical phase. [280][281][282] Despite the positive results of the pilot clinical trial, the induction of a strong immune response against the neo r gene encoded by the retroviral vectors was observed. As an alternative, new generation retroviral vectors lacking the neo r gene but carrying a modified form of the low-affinity nerve growth factor receptor (⌬LNGFR) cDNA as a selectable cell surface marker have been developed.…”

Functional and phenotypic variations in human T cells subjected to retroviral-mediated gene transfer

“…6 The use of suicide genes, such as the thymidine kinase from the Herpes Simplex virus (HSV-tk), constitutes a new tool for the management of the GVHD. The transduction of T lymphocytes with this gene turns them susceptible to ganciclovir, allowing the selective elimination of donor T lymphocytes in patients who develop severe episodes of GVHD [7][8][9][10][11][12] In previous studies, we investigated the relevance that several biological parameters had on the generation of human T cells bearing and expressing a transgene of interest. 13 The transduction process included a first step for activating the proliferation of peripheral blood T lymphocytes, a second process of retroviral infection and, finally, a period to facilitate the expression of the selectable transgene.…”