Kidney pathology in liver allograft recipients after long-term treatment with cyclosporin A.

Organ transplant recipients given immunosuppressive treatment with cyclosporin A are at risk of injury due to nephrotoxicity. Eight liver allografted patients whose renal function became impaired during therapy with cyclosporin A for up to 4.5 years were investigated by renal biopsy. Ischemic changes in glomeruli were found to be greater than in controls, and there was focal tubular atrophy, but an excess of lesions in small arteries could not be demonstrated. In one patient there were glomerular changes suggestive of thrombotic microangiopathy. Interstitial fibrosis and cellular infiltration were slight. The pathogenesis of the ischemia remains to be elucidated, but reasons are advanced for favoring the view that the mechanism of cyclosporin A nephrotoxicity is primarily vasomotor, causing a reduction of renal blood flow and glomerular filtration rate without permanent organic arterial narrowing; nephrons become damaged irreversibly nevertheless.