Diagnostic value of peripheral blood T-cell activation and soluble IL-2 receptor for acute rejection in liver transplantation.

Background: T-cells play an important role in the pathogenesis of rejection. Monitoring T-cells activation markers in peripheral blood may contribute to diagnosis of acute rejection after liver transplantation (LTX).

Methods: Lymphocyte subset distribution, expression of T-cell activation markers (flow cytometry), concentration of soluble (s) interleukin-2 receptor (IL-2R) (solid phase chemiluminescence immunoassay), and liver enzymes as well as bilirubin were prospectively tested in peripheral blood samples of LTX patients with (n=69) and without acute rejection (n=50). Acute rejection was assessed by standard criteria including liver biopsies.

Results: Intra-individual monitoring of immune parameters revealed an up-regulation of IL-2 receptor (CD25) expression on CD4 and CD8 T-cells together with increases in sIL-2R levels in patients with acute rejections. Measuring sIL-2R levels resulted in highest diagnostic efficiency (>85%). This level of diagnostic efficiency was not reached by any other marker tested. From all conventional markers of hepatocellular integrity and function, alkaline phosphatase reached the highest level of diagnostic efficiency with 70%.

Conclusions: Monitoring of up-regulation of the IL-2/IL-2R pathway represents a useful tool for assessment of acute rejection after LTX.