Severe hemorrhagic cystitis caused by the BK polyomavirus is associated with decreased survival post‐allogeneic hematopoietic stem cell transplantation

BACKGROUND: BK polyomavirus reactivation can occur following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and may lead to hemorrhagic cystitis (BKPyV-HC). We hypothesized that development of BKPyV-HC is associated with increased mortality post allo-HSCT. METHODS: We retrospectively reviewed data on 133 adult patients (≥18 years old) who underwent allo-HSCT from 2007 until 2014 at Hospital Israelita Albert Einstein in Sao Paulo, Brazil. RESULTS: Thirty-six patients presented with BKPyV-HC after a median time of 42 days, with a 1-year cumulative incidence probability of 28.9% (95% CI 21.5%-36.7%). In a multivariate Cox model, risk factors for development of BKPyV-HC included younger age, male sex, development of grade 2-4 acute graft-versus-host disease and recipients of umbilical cord blood grafts. Development of grade 3-4 BKPyV-HC (but not grade 1-2) was associated with a decreased overall survival (OS) in a multivariate Cox model (hazard ratio [HR] 7.51, P < 0.0001) and an increased risk of TRM (HR 3.66, P < 0.0001). Grade 3-4 BKPyV-HC was also associated with an increased risk of relapse that did not reach statistical significance (HR 3.01, P = 0.07). Median overall survival (OS) post-BKPyV-HC was 4.7 months, and cidofovir had no impact on survival. CONCLUSION: Development of BKPyV-HC appears to be associated with decreased survival following allo-HSCT.