BACKGROUND: Nonmyeloablative allogeneic stem cell transplantation (SCT) is an option for the treatment of metastatic renal cancer. Mature donor T cells cause graft versus-host disease (GVHD) although they are also the main mediators of the beneficial graft-versus-tumor (GVT) activity associated with this treatment. Hence, the segregation of GVT activity from GVHD is an important challenge in managing the clinical course of treatment. We previously reported a series of studies regarding the allograft tolerance induced by allogeneic spleen cells (with bone marrow cells) and cyclophosphamide in mice. METHODS: The aim of the present study was to modify the cyclophosphamide-using cell therapy to reduce the risk of GVHD while preserving the antitumor activity against RENCA, a murine carcinogen-induced renal cell carcinoma with recipient lymphocyte infusion (RLI). RESULTS: Regarding the in vivo antitumor effect, there was a significant difference between RLI and no lymphocyte infusion after the cyclophosphamide treatment, whereas the histologic findings of the small intestine showed that the cyclophosphamide-using cell therapy with RLI decreased the risk of GVHD as compared with donor lymphocyte infusion. In addition, the acquired immunity against RENCA was clearly observed in RLI-treated mice. CONCLUSIONS: Our results show that RLI during cyclophosphamide-using nonmyeloablative cell therapy can dissociate GVT effects from GVHD by reducing the risk of GVHD. We considered that this was the first report to provide the evidence of nonmyeloablative allogeneic SCT with RLI for the treatment of renal cell carcinoma which never induce complete chimerism.
BACKGROUND: Nonmyeloablative allogeneic stem cell transplantation (SCT) is an option for the treatment of metastatic renal cancer. Mature donor T cells cause graft versus-host disease (GVHD) although they are also the main mediators of the beneficial graft-versus-tumor (GVT) activity associated with this treatment. Hence, the segregation of GVT activity from GVHD is an important challenge in managing the clinical course of treatment. We previously reported a series of studies regarding the allograft tolerance induced by allogeneic spleen cells (with bone marrow cells) and cyclophosphamide in mice. METHODS: The aim of the present study was to modify the cyclophosphamide-using cell therapy to reduce the risk of GVHD while preserving the antitumor activity against RENCA, a murine carcinogen-induced renal cell carcinoma with recipient lymphocyte infusion (RLI). RESULTS: Regarding the in vivo antitumor effect, there was a significant difference between RLI and no lymphocyte infusion after the cyclophosphamide treatment, whereas the histologic findings of the small intestine showed that the cyclophosphamide-using cell therapy with RLI decreased the risk of GVHD as compared with donor lymphocyte infusion. In addition, the acquired immunity against RENCA was clearly observed in RLI-treated mice. CONCLUSIONS: Our results show that RLI during cyclophosphamide-using nonmyeloablative cell therapy can dissociate GVT effects from GVHD by reducing the risk of GVHD. We considered that this was the first report to provide the evidence of nonmyeloablative allogeneic SCT with RLI for the treatment of renal cell carcinoma which never induce complete chimerism.