Fine-needle intrarenal manometry: a new test for rejection in cyclosporin-treated recipients of kidney transplants.

Intrarenal pressure was measured in kidney-transplant recipients in an attempt to differentiate between graft rejection and cyclosporin nephrotoxicity. Intrarenal pressure was measured directly through a fine needle inserted into the kidney and connected to a manometer. Blood cyclosporin levels were monitored regularly, and renal biopsy specimens were obtained whenever renal function deteriorated. 32 recipients of renal allografts were studied 1 to 270 days after transplantation. 129 pressure readings were obtained during normal renal function, rejection, nephrotoxicity, and acute tubular necrosis (ATN). Rejection but not toxicity or ATN caused a highly significant rise in intrarenal pressure. No complications were encountered apart from transient haematuria in 1 patient. This simple test may therefore be of value in monitoring renal-transplant patients who are receiving cyclosporin.