Regular Surveillance of BK Viruria Allows Early Detection of BK Infection in Kidney Allograft and Alleviates BK Nephropathy

Abstract

Introduction BK polyomavirus is one of the major etiologies causing chronic kidney allograft failure. However, it was recognized only after mid-1990. The prevalence rate of BK nephropathy varies from 5 to 20 percents in different studies. Once occurred, it increases the risk of kidney allograft loss by 1.7 to 1.9 folds. Although, several medications had been studied, no any effective anti-viral therapy is available so far. Therefore, we hypothesized that early detection and managements of BK viruria could reduce the incidence of BK infection in kidney allograft. Material and Method All kidney transplant recipients who were regularly followed up in our nephrology clinic were included into this study. Once included, urine samples were collected every three months and BK polyomavirus DNA was detected by using quantitative PCR. If BK DNA was detected in the urine sample, immunosuppressive regimen of the patient was tapered. Besides, in some patients, their immunosuppressive regimens were switched to everolimus base regimen if their conditions were suitable. Results In total, one hundreds and ten patients were included into this study and followed up for 18 months. Among them, seven patients had BK viruria. Thus the BK viruria prevalence rate was 6.3%. These patients received further blood tests. Only two of them had BK viremia. Therefore, the BK viremia prevalence rate was 1.8%. Immunosuppressive dosage adjustments were carried out simultaneously. The graft function of these BK viruria patients showed no difference when compared to the BK viruria negative patients during 18 months follow up period. All the BK viruria were eliminated successfully. No graft was lost during the study period. Conclusion Regular surveillance of BK viruria allows early detection of BK infection in kidney allograft and prompts immunosuppressive regimen adjustments. Our study demonstrates that this is an effective method to manage BK infection in kidney allograft.