Morphological findings in non-episode biopsies of kidney transplant allografts treated with FK506 or cyclosporine

Abstract

We conducted an analysis of biopsy specimens of non-episode renal allografts from patients treated with tacrolimus (FK506) or cyclosporine (CsA) to evaluate chronic drug-induced nephropathy in stable allografts. A total of 38 biopsy specimens from stable functioning renal allografts were examined. The patients had been treated with FK506 (n = 16) or CsA (n = 18) as main immunosuppressant for 0.3 to 7.4 years. Of the 38 biopsy specimens, 15 showed mild drug-induced arteriolopathy (hyalinosis or insudative change of arterioles and small arteries) with striped-form interstitial fibrosis, 10 showed minimum interstitial cellular infiltration (borderline rejection), 2 showed IgA nephropathy, 4 showed evidence of chronic rejection (transplant nephropathy) and 12 showed no abnormal findings. Of 34 renal allograft biopsy specimens with stable function, 22 (65 %) showed pathological evidence of drug-induced nephropathy. There were no significant qualitative or quantitative differences between FK506- and CsA-associated nephropathy.