Clinical Evidence of Autologous Graft versus Tumor Effect

Problem statement: The infused alloreactive lymphocytes in allogeneic stem cell transplantation (Allo-SCT) lead to an unspecific immune response causing Graft-Versus-Tumor (GVT) effect and Graft-Versus-Host Disease (GVHD). The current dogma regarding the anti-tumor effect of GVT is only observed in the Allo-SCT and not in the autologous hematopoietic stem cell transplantation (AHSCT). Approach: This article reviewed the medical literature to show clinical evidence of an autologous graft versus tumor effect. Results: Our group is the first one to publish that patients achieving a higher Absolute Lymphocyte Count (ALC), as a surrogate marker of immune recovery, recovery post-AHSCT experienced superior survival across multiple hematologic malignancies and solid tumors. Moreover, the ALC recovery post-AHSCT depended on the amount of infused ALC collected at the same time stem cells were collected in the autograft. Conclusion: The superior survival observed based on ALC recovery post-AHSCT provided the first clinical evidence of an autologous graft versus tumor effect. In addition, the association between the infused autograft ALC and ALC-recovery post-AHSCT suggested that the stem cell autograft should not be viewed only as the means to collect enough stem cells for hematologic engraftment, but also as an adoptive immunotherapeutic strategy to enhance immune recovery, transcelating into better clinical outcomes.