Conversion of renal transplant recipients from cyclosporin to low-dose tacrolimus for refractory rejection.

Twenty-five patients with refractory rejection following renal transplantation were converted from cyclosporin to tacrolimus in an attempt to salvage the allografts. All patients had received two or three pulses of methylprednisolone, 6 had OKT3, 14 had antithymocyte globulin (ATG) and 2 had both OKT3 and ATG prior to conversion. The median time from transplantation to conversion to tacrolimus was 32 days (range 12-322). Patients underwent a simple switch from cyclosporin- to tacrolimusbased therapy with tacrolimus administered at a median dose of 0.15 mg/kg per day. Doses were adjusted according to clinical response and trough blood levels. Twenty-one of the 25 patients (84%) with refractory rejection showed evidence of reversal of rejection as indicated by a significant reduction in serum creatinine (Student's paired t-test, P < 0.05) following conversion to tacrolimus. None of these patients had further episodes of rejection. Three patients had ongoing rejection and returned to dialysis, and 1 patient showed deteriorating renal function associated with a cytomegalovirus infection. Of 18 patients currently on tacrolimus, 15 have improved renal function and 3 have shown no further deterioration. We conclude that low-dose tacrolimus appears to be effective in salvaging renal allografts with resistant rejection.