BK Viremia as a Predictor of Hemorrhagic Cystitis in Adults During the First 100 Days After Allogeneic Hematopoietic Stem Cell Transplantation

In a retrospective case-control study, we aimed to assess the utility of plasma BK viral load value to predict hemorrhagic cystitis (HC) symptoms after allogeneic hematopoietic stem cell transplantation (alloHSCT). During first 100 post-transplantation days of all adult AlloHSCT recipients at the University of Nebraska Medical Center from October 1, 2011, to June 30, 2014, 8 unexcluded cases of HC were identified and matched with 88 unexcluded unaffected control cases. Viral loads were determined for archived DNA extracted from plasma collected within 3 weeks before transplantation until ∼100 days after transplantation. Clinical factors, time of onset of BK viremia, and BK viral load were compared between case and control subjects to identify risks for HC. Symptomatic HC occurred in 8/96 (8.3%) of patients at a median of 34 days after transplantation. BK viremia either before or during symptoms was detected in all 8 (100%) HC patients and in 20/88 (22.7%) of control subjects. BK viremia was detected at a median of 8 days before HC clinical symptoms. The log of first positive viral load was not a statistically significant predictor (P = .17) of symptomatic BK. Median BK viral load peak was significantly higher for 8 patients with HC versus 20 viremic patients without HC (6.66 vs 5.06; P < .052). Further study is required to evaluate the predictive value of the BK viral load for HC.