Different risk factor profiles distinguish early-onset from late-onset BKV-replication

Area of Science:

• Nephrology
• Transplant Immunology
• Virology

Background:

• BK virus (BKV) infection is a common complication after kidney transplantation.
• Reactivation of latent BKV infection often occurs early post-transplant, but distinct risk factors for early vs. late onset are unclear.

Purpose of the Study:

• To differentiate risk factors for early-onset and late-onset BKV reactivation in kidney transplant recipients (KTRs).
• To investigate the impact of BKV reactivation on kidney allograft function and outcomes.

Main Methods:

• Retrospective study of 862 KTRs from 2004-2012 at a single transplant center.
• Analysis of BKV viremia, BKV-associated nephropathy (BKVN), and clinical data.
• Comparison of KTRs with and without BKV replication, and between early- and late-onset groups.

Main Results:

• 11.9% of KTRs developed BK viremia, with 2.8% progressing to BKVN.
• Early-onset BKV replication (65%) was associated with lymphocyte-depleting induction, CMV reactivation, and acute rejection.
• Late-onset BKV replication (35%) was linked to presensitization and retransplantation.
• Higher mycophenolate doses increased BKVN progression risk.
• BKVN led to inferior allograft function and impaired creatinine recovery.

Conclusions:

• Distinct risk factors contribute to early and late BKV reactivation post-kidney transplant.
• Intensified immunosuppression drives early reactivation, while chronic inflammation in sensitized patients may cause late reactivation.
• BKVN significantly impairs long-term kidney allograft outcomes.