RENAL FIBROSIS IN CYCLOSPORINE A-TREATED RENAL-ALLOGRAFT RECIPIENTS -MORPHOLOGICAL FINDINGS IN RELATION TO RENAL HEMODYNAMICS

Nineteen nondiabetic kidney graft patients treated with cyclosporin A for 2 years underwent percutaneous renal allograft biopsy as well as r enal hemodynamic examination. Renal allograft fibrosis was quantitativ ely evaluated as the relative volume of the renal cortical interstitiu m (V-v %) and as the interstitium/tubuli ratio (I/T ratio). The histol ogical changes were then classified into four groups, depending on the degree of interstitial fibrosis. The glomerular filtration rate (GFR) , renal plasma flow (RPF), renal blood flow (RBF), filtration fraction (FF), and fractional clearance of sodium, potassium, phosphate, chlor ide, osmoles, and free water clearance were determined in all patients and in 13 healthy controls. Kidney graft recipients had significantly lower GFR, lower RPF, and lower RBF than the healthy controls (P < 0. 001 for all comparisons) while FF was similar in patients and controls . Transplant recipients had a significantly higher fractional excretio n of sodium, potassium, chloride, and phosphate than controls. All exc ept one patient had clearly increased V, values, indicating increased interstitial fibrosis. The mean V, in renal allograft patients was 35 % +/- 10 % (normal < 16 % +/- 5 %) and the I/T ratio was 1.07 +/- 0.60 (normal < 0.24 +/- 0.08). No correlation was found between the quanti tative or semiquantitative biopsy analysis and any renal hemodynamic p arameter measured. We conclude that renal function is significantly de creased in kidney graft recipients, but that adaptive tubular changes occur in the graft. Interstitial renal fibrosis was common but did not correlate to any renal functional parameter.