Immune monitoring as a novel marker in conjunction with BK virus qPCR for establishing treatment guidelines for BK virus nephropathy in kidney transplant recipients
Trends in Transplantation
and Objectives: BK virus nephropathy (BKVN) occurs in kidney transplant recipients as a result of BK virus (BKV) reactivation and can often result in graft loss. Reconstitution of cell mediated immune response (CMIR) has been shown to correlate with resolution of nephropathy. We aim to show that there is a delay between immune reconstitution and viral clearance and that immune monitoring in conjunction with BK virus qPCR is a better tool than qPCR alone to guide treatment recommendations for
... ommendations for BKVN. Materials and Methods: This is a prospective observational study of 4 living donor renal transplant recipients with BK Viremia with Cylex ImmuKnow TM Test (Cylex Inc., Columbia, MD) in conjunction with BKV qPCR monitoring until viral clearance. All patients received thymoglobulin induction and tacrolimus, mycophenolate mofetil, and steroids for maintenance. We collected data on CMIR with cylex testing, BKV qPCR, S. Cr, renal biopsy, and rate of acute rejection following end of treatment. Results: We found an inverse correlation between cylex levels and BK viremia. All patients with BKVN were managed with immunosupression reduction reduction and antiviral therapy, based on our institutional protocol. When the BKV titer was <3000 copies and cylex was >200, we restarted MMF or resumed its normal dose. Leflunomide was the antiviral used and it was stopped as soon as BKV titer was less than 10,000 copies/mL. Conclusions: CMIR monitoring using the readily available Cylex Test with BKV quantitative polymerase chain reaction (qPCR) enabled us to personalize BKV treatment and prevent rejection episodes.