The center effect.

1. Transplant centers were grouped according to one-year graft survival rates of first cadaver transplant recipients treated with CsA. Not surprisingly, the major differences among center groups were associated with the success achieved with CsA in both patient and graft survival. Centers with the poorest survival rates were those with the least improvement over azathioprine and prednisone immunosuppression. 2. There was a definite "learning curve" associated with improvements using CsA immunosuppression for excellent and good centers. Fair centers have yet to see a significant improvement in graft survival overall with CsA. 3. Survival rates for living-related transplants varied little among the center groups, suggesting that most centers do equally well with low-risk transplants. 4. Pretransplant risk factors such as HLA matching, sensitization status, age, sex, and race of the recipients, and ischemia times varied little among the center groups. The center effect cannot be explained by recipient demographic risk factors.