BK polyomavirus reactivation in renal transplant recipients: A cross-sectional study using combined qualitative and quantitative PCR.

BACKGROUND AND AIM: BK polyomavirus (BKV) reactivation is a significant complication in renal transplant recipients receiving immunosuppressive therapy and may lead to BK virus-associated nephropathy and graft dysfunction. Early detection of viral replication is essential for timely intervention and preservation of graft function. This study determined the prevalence of BK virus reactivation among renal transplant recipients using qualitative and quantitative PCR, and assessed the association between viral detection, viral load, and clinical parameters.

METHODS

A Hospital-based observational cross-sectional study was conducted among 90 renal transplant recipients. Demographic and clinical data were recorded. Blood and urine samples were tested using qualitative real-time polymerase chain reaction (PCR) for initial detection of BKV DNA. Samples positive by qualitative PCR were further subjected to quantitative PCR (qPCR) to determine viral load. Demographic and clinical parameters were analyzed for association with BKV positivity using appropriate statistical tests.

RESULTS

BKV DNA was detected in 28 of 90 patients (31.1%) by qualitative PCR. Among positive cases, the mean cycle threshold value was 26.13 ± 8.33. Quantitative PCR demonstrated detectable viral load in 27 patients (96.4%), with high-level viremia (>105 copies/mL) observed in 13/27(48.1%). No significant association was found between BKV positivity and demographic or clinical variables, including age, gender, duration since transplantation, immunosuppressive therapy, serum creatinine levels, or clinical symptoms(p > 0.05).

CONCLUSION

Qualitative PCR is a useful screening tool for early detection of BKV reactivation, while qPCR-based viral load estimation provides valuable information for monitoring infection and guiding clinical management in renal transplant recipients. The high prevalence of BK viremia and significant viral load observed in our cohort highlights the importance of indication-based molecular testing in renal transplant recipients to prevent graft dysfunction.