Infection accounted for the first cause of death in patients after liver transplantation, and 2 / 3 of the cause of death was fungal infections. The investigators group early found that T cell subsets playing a role of inducing immune tolerance were significantly increased in vivo of liver transplantation patients with aspergillus infection, which may be a kind of Treg cells expressing IL-17. To explore the immune tolerance mechanism induced by the immune balance cells is important to liver transplantation patients for improving efficacy and reducing the mortality. Therefore, the investigators are going to get the blood sample and liver tissue of the liver transplantation patients before and after treatment of aspergillus infection, flow cytometry analysis of blood T cell subsets, Cytometric Bead Array to detect changes in blood cytokines, laser capture microdissection to obtain liver biopsies of inflammatory cells in portal area and further for analysis of T cell subsets and protein. And the investigators are also to investigate the characteristics of CCR6 + CD4 + FOXP3 + Treg cell clones secreting IL-17 and the capacity of which suppressing conventional T cell proliferation. This study may find new methods, such as certain types of T cell subsets or cytokines for the treatment of liver transplant patients, which not only to anti-rejection but also to reduce fungal infection.