Renal biopsy findings in long-term cyclosporin treatment of psoriasis.

Renal biopsies were performed in 30 psoriatics during long-term low-dose cyclosporin (CsA) therapy (range 2.5-6 mg/kg per day) of from 6 months to 8 years. The study included pretreatment biopsies in 25 of the patients. After 2 years all biopsies shared features consistent with CsA nephropathy despite completely normal pretreatment morphology in 17 of the 25 patients. The severity of the findings which consisted of arteriolar hyalinosis, focal interstitial fibrosis and sclerotic glomeruli increased with length of therapy. Mild renal lesions were seen during the first 2 years. After 4 years all but one had arteriolar hyalinosis, with interstitial fibrosis pronounced in five and moderate in six of 11 patients. At the same time glomerular sclerosis had become significant. A decrease in glomerular filtration rate (GFR) correlated with severity of structural lesions. The data from our study together with experiences from cardiac-transplanted patients treated with CsA indicate that patients with psoriasis after 2 years therapy with CsA should be rotated to other treatments or be followed carefully by GFR and sequential renal biopsies.