Human polyomavirus BK (BKV) load and haemorrhagic cystitis in bone marrow transplantation patients

Several observations suggest an association between long-lasting haemorrhag ic cystitis (HC) in bone marrow transplantation (BMT) recipients and human polyomavirus BK (BKV) reactivation, but no conclusive evidence has been obt ained so far. The amount of BKV measured in the urine of BMT patients durin g an episode of HC was compared with that detected in the urine of BMT pati ents without HC and of immunocompetent individuals in order to better asses s the association of BKV reactivation with HC-. For this purpose a quantita tive competitive PCR was developed. The application of this assay to clinic al samples allowed us to distinguish asymptomatic reactivation both in heal thy individuals and in immunocompromised patients from reactivation associa ted with HC, in almost all cases. Low levels, below the sensitivity of the quantitative assay, were shown in asymptomatic healthy individuals and in a bout 50% of immunocompromised patients. A significantly higher viral load t han in the urine of asymptomatic immunocompromised patients was detected in the urine of patients with HC. These data strengthen the hypothesis that B KV reactivation can cause, together with other factors, the majority of lat e HC in BMT recipients as well as in patients treated for acute refractory lymphoblastic leukemia. (C) 1999 Elsevier Science B.V. All rights reserved.