Association of BK viruria with hemorrhagic cystitis in recipients of bone marrow transplants.

Fifty-three recipients of bone marrow transplants were monitored prospectively for urinary excretion of human polyomaviruses by enzyme-linked immunosorbent assays of urinary supernatants and DNA hybridization assays of urinary cells. Excretion of BK virus was demonstrated in 47 percent of the transplant recipients and was the result of the reactivation of latent virus. Hemorrhagic cystitis of long duration (greater than or equal to 7 days) was associated with BK viruria. The disease occurred four times more frequently in patients who excreted BK virus than in those who did not, and the virus was identified in 55 percent of the urine specimens during episodes of cystitis as compared with 8 to 11 percent of the specimens during cystitis-free periods. BK viruria often preceded or coincided with the onset of the disease. Among 19 patients with BK viruria lasting seven days or longer, hemorrhagic cystitis occurred in 15. Occurrence of the disease was related to the source of marrow. The disease occurred in 50 percent of 38 recipients of allogeneic marrow and in 7 percent of 15 recipients of syngeneic or autologous marrow. Among recipients of allogeneic marrow, the disease was observed in 71 percent of the 21 patients excreting BK virus and in 24 percent of the 17 not excreting the virus. An association of BK virus with hemorrhagic cystitis was demonstrated in 16 of the 18 cases of the disease that were adequately characterized. We conclude that reactivation of BK virus may account for a substantial proportion of late-onset, long-lasting hemorrhagic cystitis in recipients of bone marrow transplants.