The Immune Monitoring in Kidney Transplant Recipients Could Predict Acute Rejection by a New Method: Flow Cytometric Microcarrier Assay

Background. Peripheral blood lymphocytes (PBL) of kidney transplant recipients stimulated in vitro release tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma into the supemate as detected by a flow cytometric microcarrier assay (FCMA) that we used to predict acute rejection episodes. Methods. Fifty-two kidney transplant recipients were divided into 2 groups; stable function (STA; n = 30) and acute rejection (ARG; n = 22) for comparison with healthy volunteers (n = 10). PBL were stimulated for 8 hours with phorbol myphnistate acetate and ionomycin, thereafter detecting TNF-alpha and IFN-gamma in culture supemates by FCMA. Receiver operating characteristics (ROC) procedures were used to assess the sensitivity and specificity to predict acute rejection. Results. The fluorescence intensity of TNF-alpha and IFN-gamma in culture supernates was significant higher among healthy controls than STA: 68.38 +/- 28.59 vs 51.08 +/- 34.05, respectively (P < .05). The intensity of TNF-alpha and IFN-gamma in ARG (144.47 +/- 81.21 and 116.61 +/- 53.89, respectively) was significant higher than STA (P < .001). The sensitivity and specificity to predict acute rejection were 86.4% and 86.7%, respectively, when analyzed by ROC curves combining TNF-alpha and IFN-gamma. The intensity in noncultured plasma from ARG or STA was significant lower than that in culture supemates from ARG and STA with sensitivity and specificity to predict acute rejection episodes of 63.6% and 73.3%, respectively, when combining TNF-alpha and IFN-gamma. Conclusions. Monitoring the expression of TNF-alpha and IFN-gamma in cell culture supemates after stimulation of kidney transplant recipient PBL in vitro using FCMA predicted acute rejection episodes.