MONITORING OF POLYOMAVIRUS BK VIRURIA IN BONE-MARROW TRANSPLANTATION PATIENTS BY DNA HYBRIDIZATION ASSAY AND BY POLYMERASE CHAIN-REACTION -AN APPROACH TO ASSESS THE RELATIONSHIP BETWEEN BK VIRURIA AND HEMORRHAGIC CYSTITIS

An association between long-lasting hemorrhagic cystitis (HC) in bone marrow transplantation (BMT) patients and viral infections, mostly wit h reactivation of the human polyomavirus BK (BKV), is suggested by sev eral previous reports. We have carried out a prospective study in 55 ( 30 allogeneic, 24 autologous, 1 syngeneic) BMT recipients with the aim of evaluating the role of BKV in this frequent complication after BMT . To overcome the well known difficulties in BK virus isolation in cel l cultures, a DNA hybridization assay and the polymerase chain reactio n (PCR) were used for the detection and monitoring of viral urinary sh edding, respectively. The presence of human polyomavirus JC and adenov irus DNA was also sought in urine specimens, BK viruria was demonstrat ed in 52.7% of patients (in 53.3% allogeneic and in 54.1% autologous B MT), whereas JCV and adenovirus were seldom present. Seven cases of HC (20% in allogeneic and 4% in autologous BMT) occurred and in all case s the clinical event was associated with BKV urinary shedding. This st udy suggests that BKV infection alone does not invariably lead to HC i n BMT patients; for HC to occur the presence of other, at present unid entified, factors seems to be necessary.