SUCCESS OF KIDNEY-TRANSPLANTATION IN OXALOSIS IS UNRELATED TO RESIDUAL HEPATIC ENZYME-ACTIVITY

We evaluated hepatic alanine glyoxylate aminotransferase (AGT) activity in percutaneous hepatic biopsy material obtained from four children with long-term renal allograft function following transplantation for primary hyperoxaluria type 1 (PH 1). The study was performed to determine whether these successes had occurred because relatively high residual levels of AGT activity had introduced a selection bias. The children ranged from seven months to eight years at transplant and are currently well 7 to 11 years later, with no oxalate deposition on repeated allograft biopsies and creatinine clearances of 80 to 128 ml/min/1.73 m2. AGT activity ranged from 0 to 13.8%, and in two of three patients with detectable levels the AGT was in mitochondria rather than peroxisomes. These results indicate that long-term renal allograft success can occur in spite of severe AGT deficiency. Thus, the therapeutic choice of kidney alone versus combined kidney-liver transplant cannot currently be made by measuring residual hepatic AGT in PH 1. Kidney transplant alone remains a reasonable initial therapeutic alternative for patients with recent onset of renal insufficiency due to PH 1.