Prospective Monitoring of Urine Decoy Cell after Kidney Transplantation

Ahn, Hyung Joon; Kim, Yu Seun; Jeong, Hyeon Joo; Kim, Joo Hee; Kim, Hyun Jung; Jeon, Kyung Ock; Lee, Jong Hoon; Kim, Myoung Soo; Kim, Soon Il

Abstract

PURPOSE
To find the incidence and risk factors for polyomavirus (PV) infection, we monitored urine decoy cell (UDC) after renal transplantation.
METHODS
From March 2003 to September 2004, 142 de novo renal recipients were prospectively monitored for UDC at post-transplant 1, 3, 6, 9, 12 months. According to the number of UDC in Cytospin, patients were divided into 3 groups: A (0), B (1~9) and C (> or =10). We decreased immunosuppression (IS) when group C status persisted for more than 1 month or more than 4 UDC was continuously detected for more than 3 months. Differences in demographics and clinical characteristics among the groups were compared.
RESULTS
Forty four (31%) patients were found to have positive UDC at least at one examination (30 in group B and 14 in C). The number of patients with positive UDC at postoperative 1, 3, 6, 9, 12 months were 10 (22.7%), 14 (31.8%), 17 (38.6%), 27 (61.3%), 20 (45.4%) respectively with a highest at 9 months. One PV nephropathy was documented by renal biopsy. During the period from January 2001 to December 2002 when we did not prospectively monitor UDC, 7 PV nephropathy cases were documented among 116 recipients. Tacrolimus (Tac) and episode of acute rejection (AR) were significant risk factor for positive UDC (P=0.036, 0.010, respectively). Cumulative incidence of PV infection was significantly different by the use of Tac and episode of AR (P=0.03, 0.013, respectively).
CONCLUSION
Use of Tac and episode of AR were risk factor for positive UDC and PV infection. Modulation of IS by the result of UDC monitoring could decrease the development of PV nephropathy after renal transplantation.