Noninvasive immune monitoring assessed by flow cytometry and real time RT-PCR in urine of renal transplantation recipients

Background: Monitoring recipient's alloreactivity has shown to be critical for limiting overimmunosuppression besides allowing preemptive treatment of acute rejection (AR). Methods: Flow cytometry and real time RT-PCR were performed in urine of kidney transplant recipients with AR (n=13) and compared with pyelonephritis(n = 10), chronic allograft nephropathy (n=13), acute tubular necrosis (n= 13) and stable graft function (n= 11). Expression of CD3, CD4, CD8, HLA-DR, Fas-L, ICAM-1 and CD25 were assessed using flow cytometry. mRNA of perform, granzyme B and Fas-L were quantified by real time RT-PCR. Results: Frequencies of CD3(+), HLA-DR+, Fas-L+, ICAM-1(+) and CD25(+) cells were significantly higher in AR group (P<0.05). ROC curves showed sensitivity from 70% to 91% and specificity from 30% to 100%, whereas the highest sensitivity and specificity was 91% and 100% respectively, for Fas-L+ cells. Levels of mRNA of perforin, granzyme B and Fas-L were significantly augmented in AR, while the sensitivity and specificity ranged from 85% to 88% and from 55% to 100%, respectively. Conclusions: Analyses of immune activation markers by flow cytometry and real time RT-PCR are equally useful for noninvasive monitoring kidney allografts. (C) 2006 Elsevier B.V. All rights reserved.