Objective To analyze blood concentration of tacrolimus and its influencing factors in pediatricliving donor liver transplantation recipients. Methods The general information，clinical manifestation and blood concentration of tacrolimus were analyzed retrospectively in 42 recipients with pediatric living donor liver transplantation from Jan 2012 to Nov 2013. The ratio of recipients who achieved effective blood concentration，the correlation between FK506 concentration and dose，the correlation between FK506 concentration dose ratio （C0/D）and postoperative time，and the effects of graft recipient body weight（GRBW），the effect of liver and kidney function on FK506 C0/D were analyzed by SPSS 19.0. Results ① On the third post operative day，60% of recipients reached effective plasma concentration. And on the 14th day after surgery，the blood concentration of the recipients had maintained within the range of this ratio ；② From the 1st to 14th days，there was no linear relationship between FK506 blood concentration and dosage of administration ；③ C0/D reached plateau on thethird day after surgery and maintained at a relatively stable level，and CO/D decreased on the fifth day after surgery ； ④ There were statistically significant differences between AST，BUN，Cr，and GRBW of recipients and FK506 C0/D by correlation analysis. Conclusion Within a certain time，FK506 dosage and blood concentration showedvariation trends with the postoperative time in the relatives of pediatric living donor liver transplant recipients. AST，BUN，Cr and GRBW value had affected the short-term postoperative C0/D，thus affectiong the metabolism and therapeutic effect of FK506 in pediatric living donor liver transplant recipients.

Objective To investigate the guidance of B cell function testing to the individualized immunosuppressive therapy after liver transplantation. Methods A total number of 24 cases adult liver transplantation recipients who were meeting with the indusion criterias with B-cell function enhancements in Tianjinfirst central hospital from January 2014 to December 2014 were included in this study. IgA，IgG，IgM which could reflect B cell function as well as the alanine aminotransferase（ALT），aspartate aminotransferase（AST），total bilirubin（TB），gamma-glutamyltranspeptidase（GGT），direct bilirubin（DB）and alkaline phosphatase（ALP）were detected before and after using MMF for three months. Results After administrating MMF for 3 months，ALT，AST，TB，GGT decreased significantly（P ＜ 0.05）; DB and ALP also decreased，but there were no statisticallysignificant differences（P ＞ 0.05）. Conclusion MMF administration can improve the liver functions of patients with B-cell function enhancements.