Objective: To evaluate the prevalence of BK virus (BKV) infection in renal transplant recipients based on the detection of urinary decoy cells. Methods: Fifty transplantation patients (56% males) aged 39.9 ± 11 years were screened for urinary decoy cells. The majority (86%) had received grafts from living donors. The inclusion criteria were graft dysfunction, hematuria, and/or leukocyturia. Creatinine and urea serum levels were monitored for 6 months. Results: Decoy cells were found in the urine of 12 (24%) patients 1–2 years after transplantation. The immunosuppression regimens most frequently adopted by BKV-positive patients were cyclosporine + azathiprine (50%) and FK + mycophenolate mofetyl + prednisone (25%). A renal biopsy revealed normal structures in 7 patients (58.4%), BKV nephropathy with lymphomononuclear infiltrate and fibrosis in 4 patients (33.3%), and acute cellular rejection with lymphomononuclear infiltrate without fibrosis in 1 patient (8.3%). In the latter patient, BKV-associated nephropathy was confirmed by immunohistochemistry. During the first month, creatinine and urea serum levels were higher among patients with urinary decoy cells. Creatinine levels decreased between the first and the sixth months. Conclusion: The finding of BKV-associated nephropathy in 33.3% of the patients with urinary decoy cells stresses the importance of screening for BKV with urinary cytology.

1.
Gardner SD, Field AM, Coleman DV, Hulme B: New human papovavirus (BK) isolated from urine after renal transplantation. Lancet 1971;297:1253–1257.
2.
Hirsch HH, Steiger J: Polyomavirus BK. Lancet Infect Dis 2003;3:611–623.
3.
Drachenberg CB, Hirsch HH, Ramos E, Papadimitriou JC: Polyomavirus disease in renal transplantation – review of pathological findings and diagnostic methods. Hum Pathol 2005;36:1245–1255.
4.
Sukov WR, Lewin M, Sethi S, Rakowski TA, Lager DJ: BK virus – associated nephropathy in a patient with AIDS. Am J Kidney Dis 2008;51:15–18.
5.
Gai M, Lanfranco G, Segoloni GP: Decoy cells in urine. Transplant Proc 2005;37:4309–4310.
6.
Fogazzi GB, Cantú M, Saglimbeni L: Decoy cells in the urine due to polyomavirus BK infection: easily seen by phase-contrast microscopy. Nephrol Dial Transplant 2001;16:1496–1498.
7.
Arias LF, Alvarez T, Gonzalez L, Mendonza ML, Blanco J, Garcia-Asenjo JL, Prats D: BK viral infection in kidney transplantation: importance of decoy cells. Acta Cytol 2003;47:1145–1146.
8.
Ferreira-Gonzalez A, Sidiqui R: BK vírus in the transplant patient. Clin Microbiol Newsl 2007;29:121–128.
9.
Hirsch HH, Knowles W, Dickenmann M, Passweg J, Klimkait T, Mihatsch MJ, Steiger J: Prospective study of polyomavirus type BK replication and nephropathy in renal-transplant recipients. N Engl J Med 2002;15:488–496.
10.
Drachenberg CB, Papadimitriou JC, Wali R, Cubitt CL, Ramos E: BK polyoma virus allograft nephropathy: ultrastructural features from viral cell entry to lysis. Am J Transplant 2003;3:1383–1392.
11.
Santos SLR, Manfrinatto AJ, Quadras SRK, Carvalho BR, Mazalli M: Urine cytology as a screening method for polyoma virus infection. Transplant Proc 2004;36:899–901.
12.
Randhawa PS, Finkelstein S, Scantlebury V, Shapiro R, Vivas C, Jordan M, Picken MM, Demetris AJ: Human polyoma virus-associated interstitial nephritis in the allograft kidney. Transplantation 1999;67:103–109.
13.
Splendiani G, Ciprinani S, Condó S, Paba P, Ciotti M, Favalli C, Vega A, Dominijanni S, Casciani CU: Polyoma virus BK and renal dysfunction in a transplanted population. Transplant Proc 2004;36:713–715.
14.
Khaled AS: Polyomavirus (BK virus) nephropathy in kidney transplant patients: a pathologic perspective. Yonsei Med J 2004;45:1065–1075.
15.
Mengel M, Marwedel M, Radermacher J, Eden G, Schwarz A, Haller H, Kreipe H: Incidence of polyomavirus-nephropathy in renal allografts: influence of modern immunosuppressive drugs. Nephrol Dial Transplant 2003;18:1190–1196.
16.
Pillai KR, Jayasree K, Pisharody R, Abraham EK: Decoy cells in the urine cytology of a renal transplant recipient: an immunohistochemical study. Indian J Pathol Microbiol 2010;53:347–350.
17.
Herawi M, Parwani AV, Chan T, Ali SZ, Epstein JI: Polyoma virus-associated cellular changes in the urine an bladder biopsy samples: a cytohistologic correlation. Am J Surg Pathol 2006;30:345–350.
18.
Koss LG: On decoy cells. Acta Cytol 2005;49:233–234.
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