Assessment of immunologic status of liver transplant recipients by peripheral blood mononuclear cells in response to stimulation by donor alloantigen

Objective To determine whether there is a role for assessing peripheral blood mononuclear cell (PBMC) cytokine patterns as a means of measuring the immunologic and clinical status of liver transplant recipients. Summary Background Data The role of assessing cytokine patterns in the prediction of clinical graft rejection or acceptance remains unclear. The purpose of this study was to examine the cytokine profiles of PBMC stimulated in vitro with donor alloantigen and to correlate prospectively the data with clinical assessment of graft status in orthotopic liver transplant (OLT) recipients. Methods PBMCs from OLT recipients were examined for proliferation and cytokine mRNA expression after stimulation by donor alloantigen, third-party alloantigen, or phytohemagglutinin (PHA), mRNA extracted from PBMC was amplified by reverse transcriptase-polymerase chain reaction with oligospecific primer pairs for interleukin (IL)-2, IL-4, IL-6, IL-10, interferon (IFN) gamma, tumor necrosis factor (TNF) alpha and transforming growth factor (TGF) beta. Results were prospectively correlated with each patient's allograft status. Results Increased IL-4 and TGF-beta and decreased IL-2, IFN gamma, and TNF-alpha mRNA expression by PBMCs in response to donor alloantigen stimulation predicted immunologic graft stability over a minimum 60-day interval compared with mRNA expression of PBMCs from patients with established rejection or those who experienced a rejection episode within a 30-day period (p < 0.05). Stimulation of recipient PBMCs with third-party alloantigens or PHA yielded similar but less specific results. PBMC proliferation to varying antigenic stimulation did not correlate with clinical graft status, nor did cytokine production by unstimulated PBMC. Conclusions Prospective assessment of cytokine expression by PBMC from OLT recipients in response to stimulation by donor alloantigen is helpful for predicting the clinical status of the allograft and may be useful in the development of more precise immunologic monitoring protocols.