Characteristics and significance of peripheral blood Th17 cells and regulatory T cells in liver transplantation patients with acute rejection

Objective　To investigate the characteristics of changes and clinical significance of Th17 cells and CD4+CD25+Foxp3+ regulatory T cells (Treg) in peripheral blood in liver transplant patients suffering from acute transplant rejection. Methods　A total of 25 liver transplant patients admitted in 302 Hospital of People's Liberation Army from January to September 2011 underwent needle biopsy for the transplanted hepatic tissue. The patients were divided into two groups: acute rejection group (12 cases) and stable-graft group (13 cases). In addition, 13 healthy people were enlisted in the study and regarded as control. Flow cytometric analysis was used to measure the proportion of Th17 cells and Treg cells in peripheral blood among CD4+ T cells, and to observe the relationship between change in Th17/Treg ratio and liver injury. Results　The proportion of Th17/CD4+T in acute rejection group (3.50%±0.86%) after transplantation was higher than that in the stable-graft group (2.10%±0.52%) and control group (1.79%±0.42%, P 0.05). The Treg/CD4+T cell ratio in the peripheral blood of the patients from acute rejection and stable-graft group (0.90%±0.25% and 1.51%±0.23%, respectively) were significantly lower than that of control group (2.57%±0.79%, P < 0.01), and that of acute rejection group was notably lower than that of stable-graft group (P < 0.05). The Th17/Treg ratio in acute rejection group (4.20±1.69) was significantly higher than that of stable-graft group (1.43±0.47) and control group (0.75±0.28, P < 0.01), and that of stable-graft group was higher than that of control group (P < 0.01). The ratio of Th17/Treg was positively correlated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and glutamate transaminase (GGT) levels (r=0.5023, P=0.0105; r=0.4561, P=0.0219; r=0.4393, P=0.0280; and r=0.5516, P=0.0043, respectively). Conclusions Th17/ Treg imbalance exists in liver transplant patients suffering from acute rejection, which may be related to liver injury to a certain degree. Furthermore, Th17/Treg imbalance may be involved at the onset and development of acute rejection after liver transplantation.