Glomerular and tubular function in young adults treated with stem-cell transplantation in childhood

We evaluated renal function at a median follow-up of 18 (range 10.3-22.1) years after total body irradiation in 18 patients treated with stem-cell transplantation (SCT) (autologous SCT in 15 and allogeneic SCT in three) for hematologic malignancies and compared them with 18 healthy controls. No patient had chronic graft-versus-host disease. We found no difference in glomerular filtration rate estimated from cystatin C (105 vs 111 ml/min/1.73 m(2), p = 0.28). Patients had higher albumin excretion (0.8 vs 0.4 mg/mmol, p = 0.001), but no patient had overt albuminuria (>200 mg/L). Patients had higher diastolic blood pressure (74 vs 67 mmHg, p = 0.003). Two patients (11%) had hypertension. Patients had lower tubular reabsorption of phosphate (0.78 vs 0.91 mmol/L, p = 0.014) and higher excretion of alpha-1-microglobulin (AMG/urine creatinine, 0.4 vs 0.25 mg/mmol, p = 0.038), which correlated with time after SCT (r = 0.6, p = 0.01). We found no difference in fractional excretion (FE) of other electrolytes, amino acid excretion, or urine osmolality. We conclude that renal function was relatively well preserved at a median follow-up of 18 years after childhood SCT. The higher albumin excretion in our patients is of concern, as is the association between excretion of AMG and time after SCT, suggesting that both glomerular and tubular function may deteriorate further.