P-1806. Incidence of BK Virus Nephropathy in Kidney Transplant Recipients

Abstract Background BK virus (BKV) reactivation in urine and plasma occurs in 30–60% and 4.5–27% of kidney transplant (KT) recipients, respectively. Of these, 1–5% will develop BKV-associated nephropathy (BKVAN), which can lead to graft loss. BKVAN is defined as histological changes in the graft secondary to BKV reactivation. Methods This was a prospective cohort study. KT recipients with BKV reactivation in urine and plasma confirmed by quantitative PCR at a University Hospital (January 2020 – December 2024) were included. Chi-square tests were used for categorical variables and Student’s t-test for differences in means and medians; interquartile range (IQR) was reported for continuous variables. Results During the study period, 202 KTs were performed, of which 68 (33.7%) had BKV reactivation in urine, and 27 (13.4%) also in plasma. BKV reactivation occurred more than once in 34.1% of cases. Sixteen recipients (23.5%) developed BKVAN. Of these, 81.3% were male. The median age was 53.9 years (IQR 50.5–57.2). Donor type was deceased (75%), unrelated living (5.9%), and related living (19.1%). Induction immunosuppression included corticosteroids (100%), thymoglobulin (86%), mycophenolate (82.8%), tacrolimus (10.9%), and rituximab (4.7%). 6.8% of KT receptors had concurrent CMV infection. Among BKVAN patients, 81.3% experienced rejection and 14.3% lost the graft. The median time from transplant to BKVAN diagnosis was 143 days (IQR 83–853). Recent organ rejection was the only factor associated with BKVAN (p< 0.0001). Clinical presentation included renal insufficiency (56.8%), dysuria (15.9%), hematuria (4.5%), and fever (2.3%). Treatment involved reduction of immunosuppression (77%), regimen changes (40.9%), and leflunomide administration (37%). No hospitalizations or BKVAN-related deaths were recorded. Conclusion The incidence of BKVAN was higher than that reported in the literature. Rejection was the only factor associated with BKVAN, suggesting its role in disease progression. Disclosures All Authors: No reported disclosures