 Written informed consent Reduction of graft function: Increase of serum creatinine 0,1mgdlmonth in the previous 6 months before start of the study andor new occurrence or increasing proteinuria in the last 6 months before start of the study Serum creatinine 4 mgdl Biopsy within the last 3 months histologically proved chronic allograft nephropathy 1 year after renal allografting 5 mgday Prednisolone or equivalent dose 