Characteristics and Risk Factors for Patients with BK Polyomavirus Infection After Hematopoietic Stem Cell Transplantation

Introduction: BK polyomavirus (BKPyV) infections are an important cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). The aim of the study was to assess the clinical characteristics of BKPyV infections after HSCT. Materials and Methods: The study was conducted in the adult HSCT clinics of a tertiary hospital in the central of Turkey between January 2017 and December 2019. Results: A total of 54 patients with HSCT were retrospectively evaluated and BKPyV disease was seen in 24 (44%). Hemorrhagic cystitis (HC) was seen in 19 (79.2%) of these patients. The median age was 42 and 50% of them were male. The most common underlying disease was acute myeloid leukemia. Five patients had autologous and 15 patients had allogeneic HSCT. The median time to engraftment was 15 days. Graft Versus Host disease (GVHD) was seen in seven patients. The median time elapsed to BKPyV disease after HSCT was found as 60 days. Nineteen patients with BKPyV disease had grade three and one patient had grade two HC. While BKPyV viremia was positive in five patients, viruria was detected in all patients. Eighteen of the patients with BKPyV disease were treated with cidofovir and 11 with ciprofloxacin. Four of the patients received intravesical cidofovir. The complete response was obtained in 53% of patients with BKPyV disease. Conclusion: We found that coincidental BKPyV disease and CMV activation may occur after HSCT with haematological malignancies. It is thought that follow-up in patients with suspected activation, especially in terms of hematuria and cystitis, may be important. Also, immunosuppressive agents used for GVHD prophylaxis can trigger BKPyV disease.