Since 1984 32 liver transplantations were performed at the University of Hamburg in 29 patients. 2-year survival rate of electively grafted patients is 71.4%. Immunosuppression is performed with ciclosporin A, steroids and azathioprine. The diagnosis of rejection episodes or viral infections is established by determination of activated lymphocytes, lymphoblasts or LGL-cells in the peripheral blood or in the graft (aspiration cytology). Additional liver biopsy gives information regarding the extent and kind of a white blood cell infiltrate and furthermore allows a differentiation of T-lymphocytes by immunohistological staining. Rejection episodes are primarily treated with ATG (Fresenius), non responding cases either with ATG (Stanford) or OKT 3. Successful treatment with ATG results in an elimination of T3, T4 and T8-lymphocytes. A sufficient result of OKT 3 treatment is stated after elimination of T3 cells.