Immune monitoring in kidney transplant recipients could predict acute rejection by a new method: flow cytometric microcarrier assay

Abstract

Background: Peripheral blood lymphocytes (PBL) of kidney transplant recipients stimulated in vitro release tumor necrosis factor (TNF)-α and interferon (IFN)-γ into the supernate 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-α and IFN-γ in culture supernates 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-α and IFN-γ 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-α and IFN-γ 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-α and IFN-γ. The intensity in noncultured plasma from ARG or STA was significant lower than that in culture supernates from ARG and STA with sensitivity and specificity to predict acute rejection episodes of 63.6% and 73.3%, respectively, when combining TNF-α and IFN-γ.

Conclusions: Monitoring the expression of TNF-α and IFN-γ in cell culture supernates after stimulation of kidney transplant recipient PBL in vitro using FCMA predicted acute rejection episodes.