Journal Article

Use of a functional cell mediated immunity assay for monitoring reduction of immunosupression in transplant BK virus nephropathy

Fischer, SA, Monaco, AP, Gohh, R Y, Gautam, A, Yango, A F, Morrissey, P E

2005

Overview

Polyoma or BK virus nephropathy may lead to impaired renal function after transplantation. This opportunistic infection is a surrogate marker for over immunosuppression. Treatment consists of reduction in immunosuppression (IS); however, this increases the risk of acute allograft rejection. Recently we have estimated global immunosuppression by measuring ATP activity in stimulated CD4(+) cells(Immuknow-Cylex Inc). This assay serves as a marker of cell-mediated immunity. High levels (>525 ATP ng/ml) correspond to robust immunity and carry a heightened risk of acute rejection, while low levels (<225 ATP ng/ml) increases the risk of opportunistic infection, including Polyoma virus. We treated 4 patients with reduction in IS for Polyoma nephropathy, before we started using Immuknow monitoring. There was clearance of BK viremia in all patients, however one patient developed acute rejection 5 months after reduction of IS. Another patient lost the kidney allograft to a rapidly progressive chronic nephropathy and returned to dialysis. The remaining 3 patients have stable graft function. Immuknow assay was used to monitor IS reduction in three patients. Immunknow levels ranged from 16 to 172 at the time of detection of Polyoma nephropathy. With serial reduction in IS there was a stepwise increase in Immuknow levels and decrease in BK viremia. These preliminary data suggest that serial reduction of IS with immune monitoring is a safe approach for the treatment of polyoma nephropathy after renal transplantation.