Expression of human leukocyte antigen-G and acute rejection in patients following liver transplantation

Acute liver rejection is one of the most severe complications that may affect the liver transplantation procedure. Thus, one of the most important focal points in the field of liver transplantation research is to discover a non-invasive or less-invasive method of diagnosing and predicting cases of acute liver rejection. In the present study, 59 tissue samples, including blood and liver tissues, were collected from patients who underwent liver transplantation between March 2005 and November 2009. The patients were divided into acute rejection and no rejection groups, the latter of which was further divided into normal and abnormal liver function groups. The samples were assayed by enzyme-linked immunosorbent assay and immunohistochemistry methods. The results were analyzed and a receiver operating characteristic (ROC) curve was plotted. The area under the ROC curve and the sensitivity and specificity of the cut-off point were analyzed statistically. The results indicated that the expression level of human leukocyte antigen-G (HLA-G) in the serum and liver samples in the acute rejection group was markedly lower than that in the no rejection group (P<0.001 and P=0.004, respectively). Furthermore, in the no rejection group, no statistically significant difference was identified in the level of HLA-G between patients with normal or abnormal liver function (P=0.0593). The area under the ROC curve was 0.805. When 2.41 U/ml HLA-G was considered as the cut-off point for the diagnosis of acute liver rejection, the sensitivity and specificity were 72.7 and 83.8%, respectively. In conclusion, in the present study, a high expression of the HLA-G was shown to correlate with a reduced occurrence of acute liver rejection. HLA-G may thus be an effective factor for the diagnosis and prediction of acute liver rejection.