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

Abstract

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 perforin, 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.