Factors Influencing Graft Outcomes Following Diagnosis of Polyomavirus –Associated Nephropathy after Renal Transplantation

Abstract

BackgroundPolyomavirus associated nephropathy (PVAN) is a significant cause of early allograft loss and the course is difficult to predict. The aim of this study is to identify factors influencing outcome for PVAN.MethodsBetween 2006 and 2014, we diagnosed PVAN in 48 (7.8%) of 615 patients monitored for BK virus every 1–4 weeks after modification of maintenance immunosuppression. Logistic or Cox regression analysis were performed to determine which risk factors independently affected clinical outcome and graft loss respectively.ResultsAfter 32.1±26.4 months follow-up, the frequencies of any graft functional decline at 1 year post-diagnosis, graft loss and any graft functional decline at the last available follow-up were 27.1% (13/48), 25.0% (12/48), and 33.3% (16/48), respectively. The 1, 3, 5 year graft survival rates were 100%, 80.5% and 69.1%, respectively. The mean level of serum creatinine at 1 year post-diagnosis and long-term graft survival rates were the worst in class C (p<0.05). Thirty-eight of 46 (82.6%) BKV DNAuria patients reduced viral load by 90% with a median time of 2.75 months (range, 0.25–34.0 months) and showed better graft survival rates than the 8 patients (17.4%) without viral load reduction (p<0.001). Multivariate logistic regression analysis showed that extensive interstitial inflammation (OR 20.2, p = 0.042) and delayed fall in urinary viral load (>2.75 months for >90% decrease) in urine (OR 16.7, p = 0.055) correlated with worse creatinine at 1 year post-diagnosis. Multivariate Cox regression analysis showed that extensive interstitial inflammation (HR 46988, p = 0.032) at diagnosis, and high PVAN stage (HR 162.2, p = 0.021) were associated with worse long-term graft survival rates.ConclusionsThe extent of interstitial inflammation influences short and long-term graft outcomes in patients with PVAN. The degree of PVAN, rate of reduction in viral load, and viral clearance also can be used as prognostic markers in PVAN.

BK polyomavirus infection after renal transplantation: Surveillance in a resource‐challenged setting

“…In our study, 40/62 (64.5%) patients had BKPyV viremia (viral load >500 copies/mL) during the 12‐month follow‐up. The incidence of BK infection varies from 9% to 75% in various studies, depending on the population studied, the IS used, the type of investigation used to detection infection (viremia vs viruria), the cutoff limit for viremia applied, and time‐period assessed after transplantation …”

“…BK polyomavirus (BKPyV) infection is seen in 10%‐60% patients after renal transplantation (RTX), with histologically proven BKPyV‐associated nephropathy (BKVAN) found in 1%‐10% of cases . BKVAN is associated with significantly increased risk of graft loss . In the absence of any specific and safe antiviral therapy, immunosuppression (IS) minimization is the principal therapeutic strategy effective in these patients to prevent progression of BKPyV infection and graft loss …”

Histological Evolution of BK Virus–Associated Nephropathy: Importance of Integrating Clinical and Pathological Findings

“…The features of “resolving PyVAN” after decreased IS were described by Menter et al, based on the course of a group of patients with early diagnosis, 97% of whom cleared the virus . In other centers results are not so uniformly excellent, probably due to different screening protocols, patient populations, and maintenance IS protocols .…”

“…Biopsy interpretation in PyVAN can be significantly complicated by tissue sampling variations and acute allograft rejection, which may develop with or without persistence of the infection after reduction of immunosuppression (IS) .…”

Posttransplantation Anemia in Kidney Transplant Recipients

“…PTA has been shown to be negatively associated with the following long-term outcomes: increased rates of all-cause mortality [1, 2, 5-7], graft failure [3, 8, 9], congestive heart failure [10], left ventricular hypertrophy [11], and a decline in the estimated glomerular filtration rate (eGFR) [1, 12]. …”