The identification of high immunologic responders is desirable for the selection of appropriate immunosuppressive regimens. With the collaboration of 29 transplant centers in 15 countries, we investigated whether the pretransplant serum content of soluble CD30 (sCD30), a marker for the activation state of Th2-type cytokine producing T cells, is a useful predictor of kidney graft outcome. Pretransplant sera of 3899 cadaver kidney recipients were tested for serum sCD30 concentration using a commercially available enzyme-linked immunosorbent assay kit. Subsequent kidney graft survival was analyzed. The 5-yr graft survival rate in 901 recipients with a high pretransplant serum sCD30 (> or =100 U/ml) was 64 +/- 2%, significantly lower than the 75 +/- 1% rate in 2998 recipients with low sCD30 (<100 U/ml) (P < 0.0001). High sCD30 was associated primarily with graft loss and not with patient death. The sCD30 effect on graft survival was evident in first transplants as well as in retransplants, in presensitized patients with lymphocytotoxic antibodies as well as in nonsensitized patients, and in patients who received HLA well-matched kidneys as well as in patients who received poorly matched grafts. Recipients with a high pretransplant sCD30 needed significantly more rejection treatment after the first posttransplant year and continued to lose grafts at a higher rate during the 5-yr follow-up period, indicating that pretransplant sCD30 predicts not only the risk of acute rejection but also of chronic allograft nephropathy.