1544. Kinetics of BK Virus in Urine Associated with BKV DNAemia and BKVAN in Pediatric Kidney Transplantation

BACKGROUND: BK polyoma virus (BKV) is an important pathogen for immunocompromised children. After kidney transplantation (KTx), asymptomatic BKV DNAemia and further BKV associated nephropathy (BKVAN) may result in damage or loss of allograft. BKV DNA are usually detected in urine preceding the development of BKV DNAemia and BKVAN, therefore urine BKV loads can be used for screening. However, the correlation between its kinetics and clinical outcome is not fully investigated, especially in pediatric KTx recipients, who often develop primary BKV infection after KTx. The purpose of this study was to analyze the kinetics of urine BKV load after KTx to correlate the clinical outcome such as BKVAN, BKV DNAemia and rejection. METHODS: Medical records of 82 children who underwent first, isolated KTx between January 1, 2008 and December 31, 2014 at our institution were retrospectively reviewed. Children who underwent second KTx or nonrenal Tx, lost to follow-up, and had insufficient data were excluded. Clinical and microbiological data before December 12, 2017 were obtained. Plasma and urine BKV loads have been monitored per clinical protocol, typically every 4–8 weeks within first year after KTx, and quarterly after. Longitudinal data of first 36 months after KTx was collected and further analyzed by linear model with P value < 0.05 being significant. RESULTS: There were four children developed BKVAN (5%), 25 developed BKV DNAemia (30%) and 42 developed rejection (51%). Urine BKV loads were significantly higher in children who developed BKVAN and BKV DNAemia as compared with KTx recipients without BKVAN or BKV DNAemia (P < 0.0001 and 0.006, respectively). Conversely, urine BKV loads were lower in children with rejection compared with the ones without rejection (P = 0.016). CONCLUSION: High level of urine BKV loads in asymptomatic KTx children was associated with subsequent disease development in our cohort. The lower urine BKV loads in rejection group may reflect the lower level of immunosuppression, although other clinical factors need to be evaluated as covariates. Urine BKV load monitoring may provide predictive value of disease progression of BKV along with risk assessment for rejection in pediatric KTx recipients. [Image: see text] DISCLOSURES: All authors: No reported disclosures.