The Role of Quantitative Assay of Urinary Decoy Cells as a Screening and Follow-Up Tool in Renal Transplant Recipients With Polyomavirus BK Infection

G. Huang, J. Qiu, C.-X. Wang, J.-G. Fei, S.-X. Deng, J. Li, G.-D. Chen, Q. Fu, R.-H. Deng, L.-Z. Chen.

Department of Organ Transplantation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.

Meeting: 2015 American Transplant Congress

Abstract number: A23

Keywords: Infection, Kidney transplantation, Nephropathy, Polyma virus

Session Information

Session Name: Poster Session A: BK Virus Infection

Session Type: Poster Session

Date: Saturday, May 2, 2015

Session Time: 5:30pm-7:30pm

Presentation Time: 5:30pm-7:30pm

Location: Exhibit Hall E

Polyomavirus BK nephropathy (BKVN) is an important infectious complication in kidney transplant patients. Urinary cytology is effective for early diagnosis of BKVN. However, quantitative assay of urinary cytology for screening and follow-up in renal transplant recipients are not well described.

Between 2006.1 and 2014.2, We routinely screen for decoy cells by quantitative assay, BKV DNA load in urine and plasma, and transplant biopsies by simian virus 40 staining in renal transplant patients received graft biopsy. Based on allograft biopsy results and BKV-viremia or viuria, patients (n = 118) were assigned to three groups: (i) definitive BKVAN (n = 45), (ii) presumptive BKVN defined by plasma BKV-loads of ≥×10⁴ copy/ml (n = 20) and (iii) high BKV-viruria (urine BKV-loads of ≥×10⁷ copy/ml )(n=53). After treated with reduction of immunosuppressant, they were monitored for BKV every 1-4 weeks during the follow-up.

At diagnosis, patients with definitive BKVN had larger number of decoy cells(median: 25/10HPF vs. 9/10HPF vs. 4/10HPF)than patients with presumptive BKVN and high viruria(p<0.05). The median number of decoy cells were the highest in the pattern B of BKVN(p<0.05). Using decoy cells without quantitation had a sensitivity of 95.8% and a specificity of 83.1% for BKVN. Using a decoy cell threshold of >20/10HPF for BKVN had a specificity of 99.7%.After reduction of immunosuppressant [mean: 30.3 months (range 12–84)], clearance of decoy cells were achieved in 38/45(84%), 17/18(94%), and 50/50(100%) in the three group of patients, respectively. Patients with definitive BKVN required longer time for decoy cells clearance (10.2 vs. 5.4 vs. 3.3 months; all p <0.05). In group i, 7 patients with persistent urinary decoy cells shedding lost their grafts. Except 11 graft were lost in group i, allograft function was 243.5± 76.3¯o;mol/L in this group at last follow-up. Allograft function remained stable from baseline in group ii and iii with mean serum creatinine of 138.6 ± 33.7¯o;mol/L, and 105.6 ± 9.7¯o;mol/L, respectively.

Quantitative assay of urine cytology is a very convenient and sensitive method for diagnosis of BKVN. Clearance of decoy cells and the time are closely related to stabilization of allograft function, and may possibly be a therapeutic target in the patients with BKV infection during the follow-up.

To cite this abstract in AMA style:

Huang G, Qiu J, Wang C-X, Fei J-G, Deng S-X, Li J, Chen G-D, Fu Q, Deng R-H, Chen L-Z. The Role of Quantitative Assay of Urinary Decoy Cells as a Screening and Follow-Up Tool in Renal Transplant Recipients With Polyomavirus BK Infection [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/the-role-of-quantitative-assay-of-urinary-decoy-cells-as-a-screening-and-follow-up-tool-in-renal-transplant-recipients-with-polyomavirus-bk-infection/. Accessed May 12, 2025.

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