Human Polyomavirus BK Monitoring by Quantitative PCR in Renal Transplant Recipients

Abstract

Objective: To study the relation between human polyomavirus BK (BKV) infection and the risk of developing nephropathy, we monthly investigated the BKV load in urine and serum samples from 15 renal transplant recipients during 6 months in relation with immunosuppressive treatment and renal function. Methods: BKV-DNA in serum samples was detected by nested PCR. BKV-DNA in urine and positive serum samples was quantified by a PCR protocol developed in our laboratory. Results: Fifty-three percent of the patients had quantifiable BKV-DNA both in urine and serum samples but there was no relation between viruria and viraemia. Seventy-five percent of the patients on FK506 therapy and 71.4% of those on CyA therapy showed activation of BKV infection. No patients developed interstitial nephritis during the study. In ten patients serum creatinine levels were <2 mg/dl for the whole study, even if 80% presented BKV viruria and/ or viraemia. On the other hand, in 4 patients serum creatinine levels reached higher values, but they were BKV viruria and/or viraemia negative during the study. Conclusions: Our results suggest that viruria and viraemia may reflect independent BKV reactivation in different tissues. The activation of the infection does not seem to be related to the type of immunosuppressive treatment nor to impairment of renal function. To better understand the pathogenetic role of BKV infection in renal transplant recipients further investigations are needed.

The Monitoring Interest of BK Virus Load in Renal Allograft Tunisian Recipients: Prospective Study

“…However, it has been shown that the PVAN in renal transplant recipients was more correlated with the degree of immunosuppression than with the use of particular drugs [17,23]. In this study, the distribution values of viruria/viremia was also not related to immunosuppressive therapy although the combinaison [Tac + prednisolone + MMF] was more but not statistically significant prescribed in all groups.…”

“…In this cohort, the average viral load in urine predominated in the 1st and 3rd month post-graft while that in plasma was at the 3rd and 6th month after transplantation would support a viral reactivation in urinary tract involving the passage of trans-urothelial BKV through the peritubular capillary. This mechanism has not been found by Anskar and Merlino et al reporting that the absence of the quantitative relationship between the two biomarkers may reflect independent BKV reactivation in the urothelium and circulating mononuclear cells during immunosuppression [16][17][18]. This mechanism of viral reactivation independent in different tissues suggested by these authors could explain the 4 cases of positive viremia without detectable viruria in G4 patients of this study.…”

Clinical Relevance of BK Virus Quantitative PCR in Renal Transplantation

“…We carefully read the Letter to the Editor by Kazory and Ducloux [1] about our paper previously published in Intervirology [2] . Moreover, we read with great interest the review by the same authors entitled 'Renal transplantation and polyomavirus infection: recent clinical facts and controversies', published in Transplant Infectious Disease in 2003 [3] , in which they conclude and emphasize that '…despite great advances in recent years, many questions regarding polyomavirus-induced syndromes in humans remain unanswered, and that the exact nature, clinical course, and treatment of these syndromes are still challenging issues for future studies' [3] .…”

“…In our paper [2] we say that since the study has not included patients with nephropathy or active graft rejection it will be interesting to investigate such patients to defi ne if the degree of reactivation determines whether more serious graft pathologies may happen. Moreover, as Kazory and Ducloux [3] report, to date it is not clear why only a small number of immunosuppressed patients with BKV infection develop renal disease.…”

Clinical Relevance of BK Virus Quantitative PCR in Renal Transplantation

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Sir,We read with great interest the paper of Merlino et al [1] recently published in your journal. They discuss the monthly monitoring of BK virus infection in 15 renal transplant recipients (RTRs) by serum and urine quantitative polymerase chain reaction assay and conclude on a number of biological and clinical issues.

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