Serial kidney biopsies in patients with nephrotic syndrome treated with cyclosporin

A total of 21 patients with severe steroid-resistant or steroid-dependent nephrotic syndrome have been treated with cyclosporin (CsA) over a period of 6 to 71 months. A permanent treatment was started in patients with complete [c] (proteinuria less than 0.3 g/day) or partial [p] (0.3 to less than 3.0 g/day) remission. In four cases proteinuria was markedly reduced but still greater than 3 g/day. Informed consent was obtained and all patients agreed to further control biopsies. Out of 14 patients treated for longer than 6 months, a fall in creatinine clearance was seen in three cases, including two patients with focal sclerosis who required dialysis treatment. Control biopsies were performed once in 11 and twice in seven patients. In two cases definite CsA-related damage was diagnosed after 1 and 24 months of treatment. Possible CsA-induced damage could not be excluded in three additional cases. In all other biopsies no CsA-related alterations could be demonstrated up to 47 months of treatment. The mean values of the creatinine clearance showed no deterioration. The drop off in a few cases has been related to the basic disease.