We are currently investigating multiple approaches to enhance immune reconstitution in the laboratory and have recently moved one of these strategies to the clinic. In preclinical mouse models of allogeneic T cell depleted bone marrow transplantation(BMT) we have shown that posttransplant administration of the "lymphoid growth factor" Interleukin-7 (IL-7) can enhance thymopoiesis as well as promote peripheral T cell expansion without causing GVHD.1-2 Therefore, we are conducting a Phase I clinical trial of post-transplant administration of recombinant human IL-7 (CYT 99 007, Cytheris, Inc.) in recipients of an HLA-matched T cell depleted HSC transplant to determine the safety, toxicity, and biological activity of IL-7 on T cell reconstitution. The study includes recipients of a T cell depleted transplant from a 6/6 HLA-identical related or unrelated donor after myeloablative conditioning for the treatment of a nonlymphoid hematological malignancy. We predict that administration of IL-7 will promote T cell reconstitution and decrease morbidity and treatment- related mortality following allogeneic transplant.
