Histopathologic findings from 2-year protocol biopsies from a U.S. multicenter kidney transplant trial comparing tacrolimus versus cyclosporine: A report of the FK506 kidney transplant study group

This paper reports the histopathologic results of 2-year protocol biopsies from patients who were enrolled in the U.S. FK506 kidney transplant study. Recipients of cadaveric kidney transplants were randomized to tacrolimus or cyclosporine therapy. Patients active in the trial at 2 years after transplantation were approached for a protocol biopsy. Biopsies were scored by the Banff classification in a blinded fashion by one pathologist. A total of 144 patients (41.3% of those active at 2 years) had a 2-year protocol biopsy performed; 79 patients were treated with tacrolimus and 65 patients were treated with cyclosporine. Evidence of acute rejection was found in seven (8.9%) of the 2-year biopsies in tacrolimus-treated patients and six (9.2%) cyclosporine-treated patients. Chronic allograft nephropathy was found in 49 (62.0%) tacrolimus biopsies and 47 (72.3%) cyclosporine biopsies (P=0.155). There were no apparent histopathologic differences between the tacrolimus and cyclosporine biopsies. The occurrence of chronic allograft nephropathy was significantly higher in patients who received a graft from an older donor (P