The effects of renal transplantation on peripheral blood dendritic cells.

Recent advances allow accurate quantification of peripheral blood (PB) myeloid and plasmacytoid dendritic cell (DC) populations (mDC and pDC, respectively), although the response to renal transplantation (RT) remains unknown. Using flow cytometry, PBDC levels were quantified in patients with end stage renal disease (ESRD) undergoing RT. PBDC levels were significantly reduced in ESRD patients pre-RT compared to healthy controls, with further reduction noted immediately following a hemodialysis session. RT resulted in a dramatic decrease in both subsets, with a greater reduction of pDC levels. Both subset levels were significantly lower than in control patients undergoing abdominal surgery without RT. Subgroup analysis revealed significantly greater mDC reduction in RT recipients receiving anti-lymphocyte therapy, with preferential binding of antibody preparation to this subset. Samples from later time points revealed a gradual return of PBDC levels back to pre-transplant values concurrent with overall reduction of immunosuppression (IS). Finally, PBDC levels were significantly reduced in patients with BK virus nephropathy compared to recipients with stable graft function, despite lower overall IS. Our findings suggest that PBDC levels reflect the degree of IS in renal allograft recipients. Furthermore, PBDC monitoring may represent a novel strategy to predict important outcomes such as acute rejection, long-term graft loss and infectious complications.