Is liver-targeted FOXp3 staining beneficial after living-donor liver transplantation?

As treatments for acute cellular rejection (ACR) and recurrent hepatitis caused by hepatitis C virus (HCV) are dramatically different, making a precise diagnosis is considered to be essential in patients after liver transplantation. Therefore, we investigated whether immunohistochemical detection of FOXp3, a marker for regulatory T cells (CD4+ CD25+), could be used to differentiate between recurrent hepatitis C and ACR. From a group of 103 cases of living-donor liver transplantation (LDLT), 48 samples were taken via liver biopsy from 20 patients with HCV infection. An initial diagnosis was made based on hematoxylin and eosin staining, which was scored with the hepatitis activity index (HAI) grading, whereas ARC was scored with the rejection activity index (RAI). The FOXp3 immunohistochemical staining on serial specimens was retrospectively analyzed, scoring from 0 to III. The time after LDLT was a median of 270 (range: 14-2000) days, whereas the median number of biopsies per patient was 3 (range: 1-8). The HAI was significantly different between 0 vs. I, and II vs. III, in terms of the FOXp3 score. On the other hand, a significant difference in the RAI was only found between 0 vs. I. In conclusion, FOXp3 may represent a surrogate marker for recurrent HCV infection after LDLT.