Screening for latent BK virus infection in a renal transplant population for the first time in Romania: a single-center experience

Introduction The BK virus nephropathy (BKVN) is one of the most important infectious complications in renal transplant recipients. As BKVN lacks any effective antiviral treatment, early diagnosis is required in order to try to limit viral replication and subsequent damage to the renal allograft, by reducing the immunosuppressive therapy. Our study, the first of its kind in Romania, aimed to assess the prevalence of BKVN among renal transplant patients in our center. Materials and methods In this cross-sectional study, we included 143 renal transplant patients from our center who had received their renal allograft between 2005 and 2010. We searched for latent BK virus infection by detection of serum anti-BK virus antibodies, using an in-house developed enzyme-linked immunosorbent assay (ELISA) technique. Serology was considered positive if results were >0.33 optical density units. In patients with positive serology, we searched for BKVN with qualitative (polymerase chain reaction, PCR) and quantitative (TaqMan real-time PCR) molecular techniques. Additionally, we searched for other viral infections, including hepatitis B (with HBsAg test), hepatitis C (with anti-HCV Abs test), and cytomegalovirus (CMV, with pp65Ag test). Results All patients screened with ELISA were found to have positive BK virus serology and two of these were diagnosed with BKVN. Both patients with BKVN presented with acute impairment of the renal graft function, and one of them also developed a ureteral graft stenosis. In both cases, BKVN resolved after reduction of immunosuppressive doses. We also diagnosed hepatitis B in 18.18%, hepatitis C in 7.0%, and CMV in 27.97% of patients. Conclusions Our study demonstrates for the first time the existence of BK virus in Romania, and we believe it opens the prospective of diagnosing BKVN in high-risk patients in our country in the future. In renal transplant patients from our center, we found the prevalence of BK virus infection to be as high as 100%. The prevalence of hepatitis B and CMV was also remarkably high. In patients with BKVN, the reduction of immunosuppression enables the spontaneous resolution of the disease.