Inactivation of parvovirus B19 in coagulation factor concentrates by UVC radiation: assessment by an in vitro infectivity assay using CFU—E derived from peripheral blood CD34+ cells.

BACKGROUND: Nonenveloped and thermostable viruses such as parvovirus B19 (B19) can be transmitted to patients who are receiving plasma-derived coagulation factor concentrates treated by the S/D method for inactivating enveloped viruses. Therefore, it is important to develop and validate new methods for the inactivation of nonenveloped viruses. STUDY DESIGN AND METHODS: Suspensions of B19 in coagulation factor concentrates (FVIII) were irradiated with UVC light. B19 infectivity was determined by an indirect immunofluorescence assay using CFU-E, as a host cell, derived from peripheral blood CD34+ cells. The effects of catechins on B19 infectivity and on FVIII activity after UVC illumination were also examined. RESULTS: The indirect immunofluorescence assay estimated the B19 infectivity of samples containing virus copies of 10[sup 5] to 10[sup 11] per 10 µL to be a median tissue culture-infectious dose of 10[sup 0.3] to 10[sup 5.4] per 10 µL. B19 was inactivated by 3 log at 750 J per m² of UVC radiation and was undetectable after 1000 or 2000 J per m² of irradiation. However, FVIII activity decreased to 55 to 60 percent of pretreatment activity after 2000 J per m² of UVC radiation. This was inhibited in the presence of rutin or catechins. Epigallocatechin gallate could maintain FVIII activity at almost 100 percent of pretreatment activity after 2000 J per m² of UVC radiation, while B19 infectivity was decreased to undetectable levels, which resulted in >3.9 log inactivation. CONCLUSION: UVC radiation in the presence of catechins, especially epigallocatechin gallate, appears to be an effective method of increasing the viral safety of FVIII concentrates without the loss of coagulation activity. [ABSTRACT FROM AUTHOR]