JC polyomavirus infection in candidates for kidney transplantation living in the Brazilian Amazon Region

This study evaluated the relative occurrences of BK virus (BKV) and JC virus (JCV) infections in patients with chronic kidney disease (CKD). Urine samples were analysed from CKD patients and from 99 patients without CKD as a control. A total of 100 urine samples were analysed from the experimental (CKD patients) group and 99 from the control group. Following DNA extraction, polymerase chain reaction (PCR) was used to amplify a 173 bp region of the gene encoding the T antigen of the BKV and JCV. JCV and BKV infections were differentiated based on the enzymatic digestion of the amplified products using BamHI endonuclease. The results indicated that none of the patients in either group was infected with the BKV, whereas 11.1% (11/99) of the control group subjects and 4% (4/100) of the kidney patients were infected with the JCV. High levels of urea in the excreted urine, low urinary cellularity, reduced bladder washout and a delay in analysing the samples may have contributed to the low prevalence of infection. The results indicate that there is a need to increase the sensitivity of assays used to detect viruses in patients with CDK, especially given that polyomavirus infections, especially BKV, can lead to a loss of kidney function following transplantation.

Immunologic Control for Polyomavirus Infection after Kidney Transplantation / 대한이식학회지

Purpose: The purposes of this study were to compare the relative efficacy of urine decoy cell (UDC) and polymerase chain reaction (PCR) for the polyomavirus infection (PVI), and to search the efficacy of preemptive immunologic control for PVI in earlier stage before irreversible graft injury. Methods: Between Mar. 2003 to Sep. 2005, 265 patients were monitored for the PVI after kidney transplantation. Of the 265 patients, the results of preemptive immunologic modifications were searched among 222 recipients who had the complete data. Results: Of the total 222 patients, 75 patients (33.8%) were positive for UDCs in at least one examination. Overall cumulative incidence of PVI was 32.9%. According to the episode of acute rejection, the one year incidences of PVI were 51.4% and 29.5% in recipients with and without the episode of acute rejection, respectively (P=0.0047). Using decoy cells as a marker of PV viruria, cytology has a sensitivity of 57.1% and negative predictive value of 74.1%. The specificity and positive predictive value for viruria (not viral nephropathy) are 67.2% and 48.8%. False-negative results occurred in samples with suboptimal cellularity, and a low viral load. Three cases of PV nephropathy (PVN) were documented. From January 2001 to December 2002, when we did not prospectively monitor UDCs, 7 cases of PVN were documented among the 116 recipients. Conclusion: The combination test of UDC and PV PCR should be considered as screening test for PVI due to low positive predictive value of UDC. The modulation of net immunosuppression based on UDC values and PV viral loads may reduce the development of PVN.

Prospective Monitoring of Urine Decoy Cell after Kidney Transplantation / 대한이식학회지

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.