Impact of BK polyomavirus viremia on the outcomes of allogeneic hematopoietic stem cell transplantation.

Although it is known that BK polyomavirus (BKPyV) causes hemorrhagic cystitis (HC) after allogeneic hematopoietic stem cell transplantation (HSCT), the clinical significance of BKPyV viremia has not been fully evaluated. We retrospectively analyzed the results of quantitative polymerase chain reaction (PCR) evaluations for detecting BKPyV in the whole blood samples of patients undergoing allogeneic HSCT during the period from January 2010 to June 2020 at a single institute, Tokyo Medical and Dental University. BKPyV was detected in the blood of 28 of the 107 evaluated patients, and the cumulative incidence of was 27.9% (95%CI: 20.2-37.9%). HC due to BKPyV developed in four of the 28 patients with BKPyV viremia (14.3%) and in two of the 79 patients without it (2.5%; P < 0.05). BKPyV viremia itself did not affect the patients' post-transplant estimated glomerular filtration rate (eGFR), but BKPyV viremia with a high viral load was significantly associated with decreased eGFR values (P < 0.05). BKPyV viremia was also associated with significantly lower progression-free survival at 3 years (35.1% [95%CI: 17.8-53.1%] vs. 60.4% [95%CI: 48.4-70.5], P < 0.05). Our findings demonstrated that BKPyV viremia was associated with onset of HC, an early decline of renal function, and poorer survival after allogeneic HSCT. Further studies are needed to test these results and elucidate the mechanisms of renal dysfunction associated with BKPyV viremia.

The environmental risk assessment of cell-processing facilities for cell therapy in a Japanese academic institution.

Cell therapy is a promising treatment. One of the key aspects of cell processing products is ensuring sterility of cell-processing facilities (CPFs). The objective of this study was to assess the environmental risk factors inside and outside CPFs. We monitored the temperature, humidity, particle number, colony number of microorganisms, bacteria, fungi, and harmful insects in and around our CPF monthly over one year. The temperature in the CPF was constant but the humidity fluctuated depending on the humidity outside. The particle number correlated with the number of entries to the room. Except for winter, colonies of microorganisms and harmful insects were detected depending on the cleanliness of the room. Seven bacterial and two fungal species were identified by PCR analyses. Psocoptera and Acari each accounted for 41% of the total trapped insects. These results provide useful data for taking the appropriate steps to keep entire CPFs clean.