BK-virus prophylaxis: still no answer.

Hemorrhagic cystitis (HC) occurring after engraftment in recipients of allogeneic hematopoietic stem cell transplants (HSCT) has been associated with latent BK-virus (BKV) reactivation. In 1986, Arthur et al.1 published a series of 53 patients showing that HC occurred four times more frequently in patients who excreted BKV than those who did not.