Combined detection of urine specific gravity and BK viruria on prediction of BK polyomavirus nephropathy in kidney transplant recipients

Background:BK polyomavirus(BKPyV)-associated nephropathy(BKPyVAN)is an important cause of dysfunction and failure of renal transplants.This study aimed to assess the diagnostic performance of morning urine specific gravity(MUSG)in diagnosing BKPyVAN in kidney transplant recipients.Methods:A total of 87 patients,including 27 with BKPyVAN,22 with isolated BKPyV viruria,18 with T cell-mediated rejection(TCMR),and 20 with stable graft function,were enrolled in the First Affiliated Hospital of Sun Yat-Sen University from March 2015 to February 2017.MUSG at biopsy and during a follow-up period of 24 months after biopsy was collected and analyzed.Receiver operating characteristic(ROC)curve analysis was used to determine the ability of MUSG to discriminate BKPyVAN.Results:At biopsy,the MUSG of BKPyVAN group(1.008±0.003)was significantly lower than that of isolated BK viruria group(1.013±0.004,P<0.001),TCMR group(1.011±0.003,P=0.027),and control group(1.014±0.006,P<0.001).There was no significant difference in MUSG among the isolated BK viruria group,TCMR group,and control group(P=0.253).In BKPyVAN group,the timing and trend of MUSG elevate were consistent with the timing and trend of the decline of viral load in urine and plasma,reaching a statistical difference at 3 months after treatment(1.012±0.003,P<0.001)compared with values at diagnosis.ROC analysis indicated that the optimal cut-off value of MUSG for diagnosis of BKPyVAN was 1.009,with an area under the ROC curve(AUC)of 0.803(95%confidence interval[CI]:0.721–0.937).For differentiating BKPyVAN and TCMR,the optimal MUSG cut-off value was 1.010,with an AUC of 0.811(95%CI:0.687–0.934).Conclusion:Combined detection of MUSG and BKPyV viruria is valuable for predicting BKPyVAN and distinguishing BKPyVAN from TCMR in renal transplant recipients.

Management strategies for common viral infections in pediatric renal transplant recipients

Viral infections have been considered as a major cause of morbidity and mortality after kidney transplantation in pediatric cohort.Children are at high risk of acquiring virus-related complications due to immunological immaturity and the enhanced alloreactivity risk that led to maintenance of high immunosuppressive regimes.Hence,prevention,early detection,and prompt treatment of such infections are of paramount importance.Among all viral infections,herpes viruses(herpes simplex virus,varicella zoster virus,Epstein-Barr virus,cytomegalovirus),hepatitis B and C viruses,BK polyomavirus,and respiratory viruses(respiratory syncytial virus,parainfluenza virus,influenza virus and adenovirus)are common in kidney transplant recipients.These viruses can cause systemic disease or allograft dysfunction affecting the clinical outcome.Recent advances in technology and antiviral therapy have improved management strategies in screening,monitoring,adoption of prophylactic or preemptive therapy and precise treatment in the immunocompromised host,with significant impact on the outcome.This review discusses the etiology,screening and monitoring,diagnosis,prevention,and treatment of common viral infections in pediatric renal transplant recipients.

Outcomes of renal transplant recipients with BK virus infection and BK virus surveillance in the Auckland region from 2006 to 2012

AIM To evaluate incidence, risk factors and treatment outcome of BK polyomavirus nephropathy(BKVN) in a cohort of renal transplant recipients in the Auckland region without a formal BK polyomavirus(BKV) surveillance programme.METHODS A cohort of 226 patients who received their renal transplants from 2006 to 2012 was retrospectively reviewed.RESULTS Seventy-six recipients(33.6%) had a BK viral load(BKVL) test and 9 patients(3.9%) developed BKVN. Cold ischaemia time(HR = 1.18, 95%CI: 1.04-1.35) was found to be a risk factor for BKVN. Four recipients with BKVN had complete resolution of their BKV infection; 1 recipient had BKVL less than 625 copies/mL; 3 recipients had BKVL more than 1000 copies/mL and 1 had graft failure from BKVN. BKVN has a negative impact on graft function [median estimated glomerular filtration rate(eG FR) 22.5(IQR 18.5-53.0) mL /min per 1.73 m^2, P = 0.015), but no statistically significant difference(P = 0.374) in renal allograft function was found among negative BK viraemia group [median e GFR 60.0(IQR 48.5-74.2) mL /min per 1.73 m^2), positive BK viraemia without BKVN group [median eG FR 55.0(IQR 47.0-76.0) mL /min per 1.73 m^2] and unknown BKV status group [median eG FR 54.0(IQR 43.8-71.0) mL /min per 1.73 m^2]. The incidence and treatment outcomes of BKVN were similar to some centres with BKV surveillance programmes.CONCLUSION Recipients with BVKN have poorer graft function. Although active surveillance for BKV has been shown to be effective in reducing incidence of BKVN, it should be tailored specifically to that transplant centre based on its epidemiology and outcomes of BKVN, particularly in centres with limited resources.