Donor cell microchimerism in kidney transplantation: Implications for graft function.

Abstract

Given the uncertainty regarding the relationship between donor cells at microchimeric levels and its influence on graft function and clinical outcome, we explored the extent and importance of donor microchimerismin kidney transplantation. Twenty patients with chronic kidney disease who had received allografts from living donors were studied. We examined peripheral whole blood samples from the recipients one month after the transplant, applying mitochondrial DNA variant-specific polymerase chain reaction (PCR) to identify and quantify donor cells in relation to allograft function and survival during three years of follow-up.Higher quantities of donor-derived cellmicrochimerism in the peripheral blood correlated with better graft function in the early postoperative period at 1month (R2 =.536, p=.001) and predicted improved graft function 1year following the transplant (R2 =.430, p=.008). Furthermore, early post-transplant quantities of donor cell microchimerism were an important predictor of improved kidney function 3years after transplantation (R2 =.397, p=.021). However, donorcell microchimerism failed to predict patient and graft survival after 3years (odds ratio=0.536, p=.860). Our findings suggest that donor cell microchimerism plays an immunoregulatory role in kidney transplantation and contributes to donor-specific immune hypo-responsiveness and graft acceptance.