Renal function following kidney transplantation in children treated with cyclosporine

The study was performed to evaluate the longterm renal function of children treated with cyclosporine after kidney transplantation. Renal function was determined with clearances of inulin and aminohippurate sodium for evaluating glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Thirty-six children aged 0.4–16.2 (median 6.9) years at transplantation were examined within 5 months of transplantation and then yearly over 0.3–7.1 years. Twenty-five children and young adults, 1.5–20 (median 7.7) years of age, with solitary kidneys because of renal agenesis or nephrectomy, served as controls. The GFR and ERPF within 1 year of transplantation were significantly lower than those of controls (65±19 and 345±88 vs 96±12 and 474±91 ml/min per 1.73 m², respectively). GFR remained constant 4 years after transplantation, but ERPF decreased significantly. Significant inverse correlations were found between GFR within 5 months of transplantation and the mean cyclosporine concentration and the number of rejection episodes. The frequency of hypertension decreased from 82% within 5 months of transplantation to 0% after 4 years. The absolute GFR increased during follow-up. In conclusion, kidney transplantation results in a reduced renal function compared with that of solitary native kidneys. The reduction in renal function correlated with the number of rejection episodes and the cyclosporine load. The increase in absolute GFR during follow-up suggests a remaining capacity for growth and/or compensatory hypertrophy.