ABSTRACT
<p><b>OBJECTIVE</b>To prospectively study the correlation BKV with the occurrence and development of late onset hemorrhagic cystitis (LOHC) after allogeneic hematopoietic stem cell transplantation(allo-HSCT).</p><p><b>METHODS</b>The clinical data of a total of 276 patients with allo-HSCT in our department between January 1998 and March 2016 were analyzed ratrospectvely. Quantitative Real-time PCR assay was used to prospectively monitor the BKV DNA load of the urine and plasma for 23 patients accepting allo-HSCT from August 2015 to March 2016.</p><p><b>RESULTS</b>LOHC(24.28%) occurred in 67 of 276 cases with allo-HSCT. Univariate analysis showed that age older than 6 years, different diseases, unrelated donor, pretreatment with BU, Ⅲ-Ⅳ aGVHD significantly correlated with LOHC. Multivariate analysis demonstrated that age older than 6 years (P<0.01), pretreatment with BU(P<0.05), and aGVHD of grade Ⅲ-Ⅳ （P= 0.011） were the independent risk factors for LOHC. Among 23 patients after allo-HSTC, 10 of which were positive of urine BKV, and LOHC occurred in 6 cases. The positive rate of urine BKV (85.7%)in group LOHC was significantly higher than that in the group LOHC(25.0%）(χ=5.043, P<0.01). The incidence of LOHC positively correlated with the positive rate of BKV (r=0.564, P<0.01), and the severity of LOHC positively correlated with urinary BKV load (r = 0.502, P<0.01). And 5 of 6 petriatic patients with LOHC had aGVHD. All of them were subject to the strengthened antiviral treatment, and 4 of them accepted intensive immunosuppression therapy.</p><p><b>CONCLUSION</b>Age ≥6 years old, precenditioning regieme with BU and aGVHD of grade Ⅲ-Ⅳ are independent risk factors for LOHC after allo-HSCT, the positive rate of urine BKV load positively correlates with the severity of LOHC after allo-HSCT.</p>