Abstract

BK virus infection is highly prevalent in humans, and has been associated with development of HC after HSCT. Previously we determined that UD HSCT is independently associated with higher prevalence of HC (El-Zimaity et al. Blood 2004). In order to further investigate the association of BK with HC, we hypothesized that patients who have positive urine PCR for BK virus before UD transplant have a higher incidence of HC.

Methods: we studied 62 consecutive patients transplanted from 09/05 to 05/06. Preparative regimens were ablative (n=26) or reduced intensity (n=36); 15 patients (23%) received cyclophosphamide-containing regimens. GVHD prophylaxis was tacrolimus and mini-methotrexate. Stem cell source was bone marrow (n=28), peripheral blood (n=25) or umbilical cord (n=9). BK virus quantitative PCR was performed on urine samples collected upon admission.

Results: Median age was 53 years (range, 19–67). Diagnoses were leukemias (n=36), multiple myeloma (n=2), Hodgkin’s disease (n=4), non-Hodgkin’s lymphomas (n=16), and other (n=4). Median time to platelet engraftment was 16 days (range, 0–62; n=51). Median follow-up is 97 days. BK PCR was positive in 28 patients (45%). Number of viral copies ranged from 300 to > 200 million copies. Eleven patients (18%) developed HC, at a median of 25 days after HSCT. HC was of grade 1 (n=1), grade 2 (n=4), grade 3 (n=5), grade 4 (n=1; required bilateral nephrostomies). In the PCR positive group, 7 patients (25%) had HC, versus 4 (12%) in the PCR-negative group (hazard ratio = 3.4 for a positive PCR; log-rank p = 0.057). 100-day cumulative incidence of HC is shown in the figure. 45% of CB recipients developed HC.

Incidence of HC was not statistically significantly increased among recipients of ablative or cyclophosphamide-containing regimens. Likewise, development of grade II-IV acute GVHD (n=18, 29%) was not associated with higher rates of HC. Six patients developed HC before platelet engraftment. Viral load did not correlate with development of HC. Four patients had viruria of 50–200million/mL; only one developed HC.

Conclusion: BK viruria pre-HSCT may be a risk factor for development of HC; further study is needed in a large cohort of patients.

Disclosure: No relevant conflicts of interest to declare.

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