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.