Characteristics of Tfh cells in the peripheral blood in recipients of liver allograft: A pilot study

Objective To determine the expression characteristics of peripheral blood follicular helper T cells (Tfh) and their molecules during pre- and post-transplantation period in liver transplant patients to explore the role of Tfh in alloreactive response after liver transplantation. Methods Twenty liver transplant (LT) patients and 20 healthy individuals as control were enrolled in this study. Thirteen LT patients with stable liver function were included for cross-sectional study. Another seven LT patients with complete clinical data were included for follow-up study. The frequencies of Tfh cells were examined by flow cytometry. For the seven patients, Tfh cells and level of alanine aminotransferase (ALT) were monitored dynamically for one month after LT. Results The frequencies of CD4+CXCR5+Tfh and CD4+CXCR5+PD-1+ cells in peripheral blood increased significantly after liver transplantation as compared with those before liver transplantation (P<0.05). In addition, the frequencies of CD4+CXCR5+ICOS+ cells showed a rising trend, but no statistical difference. In early follow-up period it was found that the frequencies of CD4+CXCR5+Tfh obviously increased after liver transplantation in patients with stable liver function, and reached the peak value after one week and then decreased. The ALT level also decreased when reaching peak 10 days after surgery. Interestingly, the frequencies of CD4+CXCR5+ Tfh in one patient with acute rejection after liver transplantation showed the same trend with ALT levels changes. Furthermore, the frequencies of CD4+CXCR5+Tfh, CD4+CXCR5+PD-1+ and CD4+CXCR5+ICOS+ cells in stable liver function group were higher than those in the healthy control group (P