This study will determine whether a preparatory regimen including total lymphoid irradiation (TLI), total body irradiation (TBI), anti-thymocyte globulin (ATG) and infusion of the donor hematopoietic stem cells when given along with recipient regulatory T cells (Tregs) will allow for eventual discontinuation of anti-rejection drugs after living donor kidney transplantation.
It has been demonstrated that hematopoietic mixed chimerism or the coexistence of both donor and recipient immune cells can lead to tolerance to the graft in absence of graft versus host disease (GVHD). The goal of this pilot study is to determine if recipients of living donor kidney transplant can be successfully withdraw from immunosuppressive drugs. The patients will receive a preparatory regimen consisting of TLI and a low single dose of TBI and ATG following their kidney transplantation. Two weeks later, they will receive purified hematopoietic stem cells (CD34+) and Tcells that have been collected 6 weeks prior from their kidney donor. Regulatory T cells (Tregs) that have been collected from the recipient prior to the transplantation and expanded in vitro will be infuse the following day to enhance the chance of engraftment of the donor bone marrow cells. If chimerism develops and persists, the immunosuppressive drug will be tapered and stop. Mycophenolate mofetil (MMF) will be stopped 12 months after transplantation and if the chimerism remains stable, tacrolimus will be stopped 6 months later. The dose of Tregs will be escalated if the % of donor chimerism is not at least 25% during the first 60 days.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
22
Living donor kidney transplant recipients will receive after a preparatory regimen of total lymphoid irradiation, total body irradiation and anti-thymocyte globulin an infusion of purified donor CD34+ of \>10 x10\^6 cells /Kg, 100 x 10\^6 donor T cell/ Kg and and an escalated dose of recipient Tregs starting at 25 x10\^6/Kg.
Stanford University
Palo Alto, California, United States
RECRUITINGNothwestern University
Chicago, Illinois, United States
RECRUITINGCount of participants with sustained mixed chimerism of >25% at 18 months
Chimerism is defined as the co-existence of the immune cell from both the donor and the recipient.
Time frame: Month 18
Count of participants able to withdraw from immunosuppressive drugs without evidence of rejection at 18 months
Time frame: Month 18
Count of participants with adverse events associated with the infusion of the Tregs cell product
Time frame: up to 2 years
Count of participants with bacterial, viral, or fungal infections
Time frame: up to 2 years
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