Analysis of FOXP3 Gene and Protein Expressions in Renal Allograft Biopsies and Their Association with Graft Outcomes

Abstract

Background: The transcription factor FOXP3 is increased in acute renal rejection, but its influence on graft outcomes is unclear. This study correlated FOXP3 with dendritic cells and graft outcomes. Methods: We assessed 96 kidney transplants undergoing allograft biopsy for cause. FOXP3 mRNA was analyzed by real-time polymerase chain reaction (PCR) and FOXP3 protein and DCsCD83+ by immunohistochemistry. Graft function and survival were assessed at 5 years post-transplantation, as well as by independent predictors of graft loss. Results: Intragraft FOXP3 gene and protein expression were significantly correlated (r = 0.541, p < 0.001). Both FOXP3 mRNA and protein were increased in patients with acute rejection (AR). High expression of FOXP3 mRNA or protein in biopsies did not correlate with clinical variables, but there was a trend to higher positive variation in the glomerular filtration rate (GFR) from biopsy to last follow-up. Patients with FOXP3-mRNAhigh had more DCsCD83+ in biopsy, but these cells did not associate with AR. Five-year graft survival was not influenced by either FOXP3 mRNA or protein expressions. Conclusions: FOXP3 mRNA and protein had a good correlation in archival renal graft tissue. Increased FOXP3 expression was found in AR and FOXP3 associated with high numbers of DCs. However, both FOXP3 mRNA and protein was not associated with better allograft outcomes.