VIRAL LOAD MONITORING IN PATIENTS WITH POLYOMAVIRUS NEPHROPATHY WHO HAVE BEEN TREATED FOR REJECTION EPISODES

Abstract

P823 Aims: Rejection occurring after reduction of immunosuppression for treatment of polyomavirus nephropathy (PVN) is a difficult clinical problem, as an increase in immunosuppression could result in a worsening of PVN. Recent anecdotal literature has suggested that treatment of rejection episodes followed by a rapid reduction of immunosuppression may prevent a relapse of PVN. The aim of this study was to determine the effects of a transient increase in immunosuppression for the treatment of acute rejection on viral load monitoring parameters in renal transplant recipients diagnosed with PVN. Methods: Four patients experienced six rejection episodes post PVN. BKV serum and urine viral loads were analyzed by Taqman PCR and anti-BKV antibody titers (ab) were analyzed by hemagglutination assay at the time of rejection, and at 8 and 24 weeks post rejection episode. Results: Four patients experienced six rejection episodes (multiple episodes in two patients) post PVN. Median time to acute rejection post PVN was 18 (2-60) weeks. Four of the rejections were mild, 1 was moderate and one patient developed humoral rejection after multiple acute cellular rejection episodes. Rejection treatment consisted of: none in 1, increased tacrolimus in 2, IVIG and increased tacrolimus in 1, leflunomide in 1 and IVIG alone in 1. Median BKV serum and urine viral loads did not deteriorate following the treatment of rejection (BKV serum viral load 5.04 x 10 4 at rejection vs 7.70 x 10 2 copies/mL post-rejection) and (BKV urine viral load 1.22 x 10 6 at rejection vs 1.52 x 10 4 copies/mL post-rejection). Median anti-BKV antibody titers were higher in patients post rejection (8192 at rejection vs 32968 HA units post rejection) and median serum creatinine values were not worse post rejection treatment followed by a reduction of immunosuppression (median serum creatinine at rejection 2.6 vs 2.1 mg/dL post rejection) Of patients who experienced post PVN rejection episodes, graft loss occurred in one patient (25%) who experienced multiple acute rejection episodes followed by humoral rejection and worsening PVN. Conclusions: 1) Transient increases in immunosuppression for the successful treatment of acute rejection episodes, in patients with PVN does not result in an increase in BKV viral loads. 2) Graft loss occurred only in 1 out of 4 patients experiencing rejection following diagnosis of PVN 3) Our results suggest that transient increases in immunosuppression for the treatment of rejection episodes in patients with PVN is indicated for the optimal management of these complex patients.