In vitro and in vivo characterization of graft‐versus‐tumor responses in melanoma patients after allogeneic peripheral blood stem cell transplantation

Abstract

It has been shown that after allogeneic peripheral blood stem cell transplantation (PBSCT), donor T cells can induce potent graft-versus-tumor (GVT) effects in hematologic malignancies and possibly solid tumors such as renal cell carcinoma. Two patients (27 and 30 years old) with metastatic melanoma received allogeneic PBSCT from an HLA-identical sibling donor after reduced conditioning with fludarabine, carmustine and melphalan. One patient showed a delayed mixed response with complete regression of lymph node metastases but persistent liver metastasis at day ؉60 and ؉120, consistent with a GVT response. In order to generate donor-derived tumor-reactive cytotoxic T lymphocytes (CTLs), peripheral blood mononuclear cells were stimulated with donor dendritic cells (DCs) loaded with host tumor lysate. Using these culture conditions, a marked increase in CD8 ؉ CTLs was observed in both donors exhibiting a strong MHC class I-restricted cytotoxic activity against the host tumor without cross-reactivity against nonmalignant host cells. CDR3 spectratyping was used to analyze the complexity of T-cell subpopulations in both CTL lines. Results demonstrate that oligoclonal T cells are expanded in vitro, exhibiting a marked overexpression of TCRV␤3 (donor 1) and TCRV␤4/V␤11 (donor 2) subfamilies. Functional (ELISPOT assay) and phenotypic (CDR3 spectratyping, sequencing V␤ transcripts) analysis of patients' T cells at different time points after transplantation demonstrated an expansion of alloreactive T cells with a limited TCR V␤ pattern. The V␤3 cDNA clone, being predominant in the CTL line from donor 1, could not be identified in patient 1 peripheral blood lymphocytes after transplant. Altogether, our results provide the first evidence that GVT effects against melanoma can induce tumor regression and that oligoclonal donor-derived CTLs specific against host tumor cells can be generated in vitro that may be used for adoptive T-cell transfer after allogeneic transplantation.

Unraveling Graft-versus-Host Disease and Graft-versus-Leukemia Responses Using TCR Vβ Spectratype Analysis in a Murine Bone Marrow Transplantation Model

“…For example, approaches attempting to deplete the entire compartment or major subsets of T cells in the donor inoculum have not only led to an increase in the incidence of leukemic relapse, but also resulted in an increase in graft failure and opportunistic infections (20, 21). In recent years, we and others have demonstrated that CDR3-size spectratyping of the TCR Vβ chain can be utilized to differentiate alloreactive from uniquely tumor-reactive T cells, opening the door for potential tailoring of the donor inoculum to recipient’s malignancy (13, 22, 23). In other words, donor T cells could be selected for their specific tumor-reactivity, or depleted if confirmed to be uniquely alloreactive, in order to impart maximum benefit with reduction/elimination of deleterious side effects.…”

Paracrine Molecules of Mesenchymal Stem Cells for Hematopoietic Stem Cell Niche

“…One of the major challenges with HSC transplants is failure to engraft, which is mediated by donor T cells as a result of graft-versus-host disease (GVHD). Graft-versus-tumor effect of allogeneic HSC transplants may be a result of an immune reaction between donor cytotoxic T cells and patient's malignant cells [69]. MSCs are known to interact with HSCs and immune cells, and represent potential cellular therapy to enhance allogeneic hematopoietic engraftment and prevent GVHD [70–72].…”

Aberrant expression of BCL2A1-restricted minor histocompatibility antigens in melanoma cells: application for allogeneic transplantation

“…To date, peptide vaccination has resulted in a limited or marginal efficacy [19] while adoptive T lymphocyte infusion including Ag-specific CTL clones or TILs, especially after a lymphodepleted conditioning regimen, demonstrated promising results [20][21][22]. After allogeneic HSCT for patients with melanoma, there have been some reports indicating that CTLs against melanoma cells do exist and that these melanoma-reactive CTLs can be expanded in vitro [23,24]. These observations suggest that allogeneic HSCT after a nonmyeloablative conditioning regimen might be a promising therapeutic strategy for patients with refractory metastatic melanoma.…”