Five-year clinical effects of donor bone marrow cells infusions in kidney allograft recipients

Abstract

Augmentation of microchimerism in solid organ transplant recipients by donor bone marrow cells (DBMC) infusion may promote immune hyporesponsiveness and consequently improve long-term allograft survival. Between March 2005 and July 2007, outcomes for 20 living unrelated donor (LURD) primary kidney recipients with concurrent DBMC infusion (an average of 2.19 ± 1.13 x 10⁹ donor cells consisting of 2.66 ± 1.70 x 10⁷ CD34⁺ cells) were prospectively compared with 20 non-infused control allograft recipients given similar conventional immunosuppressive regimens. With five years of clinical follow up, a total of 11 cases experienced rejection episodes (3 DBMI patients vs. 8 controls, p = 0.15). One DBMC-infused patient experienced chronic rejection vs. two episodes (1 biopsy-confirmed) in the control patients. Actuarial and death-censored 5-y graft survival was significantly higher in infused patients compared with controls (p = 0.01 and p = 0.03, respectively). Long-term graft survival was significantly associated with pre-transplant anti-HLA antibodies (p = 0.01), slightly with peripheral microchimerism (p = 0.09) and CD4⁺CD25⁺FoxP3⁺ T cells (p = 0.09). Immunosuppressant dosing was lower in infused patients than controls, particularly for mycophenolate mofetil (p = 0.001). The current findings as well as our previous reports on these patients indicates clinical improvement in long-term graft survival of renal transplant patients resulting from low-dose DBMC infusion given without induction therapy.