Correlation of high viral BK load in the urine samples ofpatients with graftversus-host with haemorrhagic infectious diseases of bladderafter hematopoietic stem cell transplantation

A possible temporal correlation between high BK virus (BKV) load in urine alone or in combination with acute graft versus host disease (GVHD) and the development of hemorrhagic cystitis (HC) was examined in this study. 31 allogeneic hematopoietic stem cell transplanted (SCT) patients were include in this study. BKV DNA was detected by nested and quantitative Real-Time PCR in the urine of 16 out of 31 patients. HC occurred in 6/16 patients with BKV DNAin their urine samples. BKV load was evaluated in the urine samples from 5 of 6 HC patients. Presence of BKV or BKV load >106 copies alone in urine samples showed some predictive ability for HC, while acute GVHD alone or conditioning regiments did not. However, during the period after SCT to HC onset a combination of BKV load >106 copies and acute GVHD, discriminated the best between HC (4/5) and non-HC (2/25) patients (p=0.003).This study indicates that BKV DNA and particularly>106 BKV copies/µl of urine from SCT patients may have some predictive ability for HC. However, the best association to HC was achieved when a viral load of > 106 BKV copies/µl of urine was present in combination with acute GVHD.