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(5) to 10(11) per 10 microL to be a median tissue culture-infectious dose of 10(0.3) to 10(5.4) per 10 microL. B19 was inactivated by 3 log at 750 J per m(2) of UVC radiation and was undetectable after 1000 or 2000 J per m(2) of irradiation. However, FVIII activity decreased to 55 to 60 percent of pretreatment activity after 2000 J per m(2) 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 m(2) 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.