CYCLOSPORINE-A NEPHROPATHY - STANDARDIZATION OF THE EVALUATION OF KIDNEY BIOPSIES

An advisory board of nephropathologists with personal experience in th e evaluation of biopsies from patients treated with cyclosporin A (CyA ) was set up to address the following problems: 1. Definition of CyA n ephropathy as seen in patients with autoimmune diseases; 2. Evaluation of the reliability and reproducibility of the diagnostic criteria for the different morphological lesions seen in CyA nephropathy; 3. Class ification of the morphological lesions according to their clinical rel evance; 4. Estimation of the possible progression of CyA nephropathy w ith continuous CyA therapy. The most frequent lesions attributable to CyA therapy in patients with autoimmune diseases are tubular atrophy, interstitial fibrosis, and arteriolar hyalinosis. All other lesions ar e rare. The reproducibility and diagnostic reliability is high for tub ular atrophy and interstitial fibrosis, but low for arteriolar lesions even among experienced nephropathologists. The biopsies may be classi fied according to the severity of tubular atrophy, interstitial fibros is and arteriolar hyalinosis with regard to their clinical relevance: In group I (within normal limits), CyA therapy can be continued; in gr oup III (moderate-to-severe CyA-related lesions), CyA should be stoppe d if possible. Among group II biopsies (slight CyA-related abnormaliti es), no recommendation can be made in the absence of a second biopsy a fter a further year of CyA therapy. No clear-cut answer can be given c oncerning the progression of CyA-induced lesions. However, no signific ant progression has been found in the cases studied to date.