BK-Viruria and Hemorrhagic Cystitis – a Retrospective Analysis of a Patient Cohort After Allogeneic Bone Marrow Transplantation for Hematological Malignancies.

BK-virus-associated hemorrhagic cystitis is a major issue among patients with hematologic malignancies after allogeneic bone marrow transplantation and associated with significant morbidity and mortality. Risk factors for its development are still poorly understood and sufficient data lacking. This is a retrospective analysis of all patients with viruria after allogeneic BMT of the years 2007-2008 transplanted at the centre for BMT of the University of Munich.

All patients displaying at least one event of viruria in the period of January 2007 until December 2008 were included in this analysis. We recorded demographic factors, transplantation setting, clinical manifestation of HC, conditioning regimens, GvHD, immunosuppression and relevant co-infections.

56 patients (39 ‰/ 17 š) with median age of 48,5 years were recorded. Underlying diseases were AML (31 pts. / 55,3%), ALL (8 pts./14,2%), CLL (2 pts./ 3,5%), malignant lymphoma (5 pts./ 8,9%), multiple myeloma (4 pts./ 7,1%) and other hematological malignancies (6 pts./ 10,7%). 18 patients were transplanted from a related, 38 from an unrelated donor, two of those from cord blood. 29 patients (51.8%) were registered alive at the time of data collection, 23 patients (41%) were recorded deceased, 4 patients (7,1%) could not be tracked.

The concomitant or preceeding incidence of GvHD received a special interest in our analysis. Notably, 47 pts. (84%) showed clinically apparent manifestation of GvHD, only 9 pts. (16%) displayed no sign of GvHD. Of these, 22 pts. (39%) developed an overall grade III (severe) and grade IV (life-threatening) GvHD. Furthermore, 27 pts. (48%) developed a grade III GvHD and 11 pts. (19,6%) a grade IV GvHD of a single organ, giving an overall of 67,6% of grade III or IV single organ-GvHD in this patient collective. The organ system most affected was the skin, 47pts. (84%), followed by the gut, 21 pts. (37,5%), the liver, 10 pts. (17,8%) and other organ systems 4 pts. (7,1%).

BK-viruria is a frequent event among patients with bone marrow transplantation for hematological malignancies. Among our patient collective, we observed a high incidence of high grade GvHD. Whether there is an independent risk factor for both or there is a causative link between these two events is not clear. However, our retrospective analysis represents one of the largest data collections regarding BK-virus-infections in allogeneic BMT patients so far and further studies are required.

No relevant conflicts of interest to declare.