Rapid discontinuation of corticosteroids in pediatric renal transplantation.

Corticosteroid immunosuppression has permitted the development of successful allotransplantation; however, corticosteroids are associated significant post-transplant complications. To circumvent these problems, we implemented a protocol of rapid discontinuation of corticosteroids in 19 consecutive pediatric primary kidney transplant recipients. Mean age at time of transplant was 13.4 (+/-4.5) yr, 52.6% were male, 63.2% underwent living donor transplantation. All patients were administered Thymoglobulin [anti-thymocyte globulin (rabbit)] as induction immunosuppression with a rapid tapering dose of corticosteroids (total of five daily doses), and maintained on mycophenolate mofetil and tacrolimus. Two patients had immediate recurrence of primary disease (FSGS), requiring further corticosteroid therapy. Otherwise, remaining 17 patients were maintained off corticosteroids, with excellent graft function; mean baseline eGFR of 112 mL/min/1.73 m(2) (+/-19) at 28 months (+/-14) post-transplantation. There was 100% patient and rejection-free graft survival at 27 months (range 5-58 months) post-transplantation; 47% underwent renal transplant biopsy secondary to acute rise in serum creatinine with or without worsening hypertension. All biopsies had no evidence of acute rejection; 62.5% had findings consistent with tacrolimus toxicity. Renal transplantation utilizing a rapid discontinuation of corticosteroid protocol in pediatric patients appears to be safe and effective, without increasing the risk of acute rejection or graft loss.

Phenylacetate and benzoate clearance in a hyperammonemic infant on sequential hemodialysis and hemofiltration.

An infant with a suspected inborn metabolism error was treated with a metabolic cocktail of intravenous sodium phenylacetate (NaPh) and sodium benzoate (NaBz) for hyperammonemia. Sequential hemodialysis (HD) then hemofiltration (HF) was performed due to hyperammonemia. Dialytic and convective clearance (K; ml/min) of ammonia, NaPh, and NaBz was measured. The K of ammonia was 57 and 37 for HD and HF, respectively. The K of NaBz was 37 and 12 for HD and HF, respectively. The K of NaPh was 38 and 14 ml/min for HD and HF, respectively. Despite high clearance of both NaPh and NaBz by HD and HF, the hyperammonemia was corrected.

Clearance of amino acids by hemodialysis in argininosuccinate synthetase deficiency.

We determined the dialytic clearance of amino acids involved in ammoniagenesis and nitrogen excretion in a neonate with argininosuccinate synthetase deficiency who underwent acute hemodialysis. Plasma ammonia and plasma and dialysate amino acid concentrations were obtained at baseline, 30-minute intervals during hemodialysis, and 30 minutes after the completion of hemodialysis. Plasma ammonia concentrations declined by 56% during the 90-minute hemodialysis treatment, whereas arginine, citrulline, glutamine, and glycine concentrations decreased by 65%, 55%, 40%, and 34%, respectively. Mean dialytic clearances for arginine, citrulline, glutamine, and glycine were 24, 282, 263, and 189 mL/min per 1.73 m(2), respectively. The high dialytic clearance of citrulline suggests a novel mechanism of hemodialysis removal of nitrogen. Dialytic clearances of glutamine and glycine may prevent further ammoniagenesis in hyperammonemic patients. However, our data suggest that hemodialysis affects the precursors of alternative pathway removal of ammonia. Further study is needed to optimize the intradialytic and interdialytic dosing of substrates.