Background: Insight into the mechanisms of organ engraftment and acquired tolerance has made it possible to facilitate these mechanisms, by tailoring the timing and dosage of immunosuppression in accordance with two therapeutic principles: recipient pretreatment and minimum use of posttransplant immunosuppression. We aimed to apply these principles in recipients of renal and extrarenal organ transplants. Methods: 82 patients awaiting kidney, liver, pancreas, or intestinal transplantation were pretreated with about 5 mg/kg of a broadly reacting rabbit antithymocyte globulin during several hours. Posttransplant immunosuppression was restricted to tacrolimus unless additional drugs were needed to treat breakthrough rejection. After 4 months, patients on tacrolimus monotherapy were considered for dose-spacing to every other day or longer intervals. Findings: We frequently saw evidence of immune activation in graft biopsy samples, but unless this was associated with graft dysfunction or serious immune destruction, treatment usually was not intensified. Immunosuppression-related morbidity was virtually eliminated. 78 (95%) of 82 patients survived at 1 year and at 13 -18 months. Graft survival was 73 (89%) of 82 at 1 year and 72 (88%) of 82 at 13 -18 months. Of the 72 recipients with surviving grafts, 43 are on spaced doses of tacrolimus monotherapy: every other day (n โซุโฌ 6), three times per week (11), twice per week (15), or once per week (11). Interpretation: The striking ability to wean immunosuppression in these recipients indicates variable induction of tolerance. The simple therapeutic principles are neither drug-specific nor organ-specific. Systematic application of these principles should allow improvements in quality of life and long-term survival after organ transplantation. (Lancet 2003;361:1502-1510)
away from current regimens that work very well is especially challenging in an environment in which outcomes of one center are weighed against outcomes of another. We believe that this aspect of the study above all others is to be commended and emulated.