Photodynamic treatment of fresh frozen plasma by methylene blue: Effect onHIV, HCV and parvovirus B19

Background: The inactivation of viruses by methylene blue (MB) photoactivat ion is a new technology which is going to be introduced into the process of the fresh frozen plasma separation in order to improve the viral safety of this blood component. The efficacy of this procedure was confirmed in a va riety of studies by using different virus models, like BVDV, Sindbis virus, DHBV, VSV, or SV40. Material and Methods: We focused on photoinactivation of HIV-1, HCV and Parvovirus B19. Following the inactivation procedure, the infectivity of HIV-1 was tested by in-vitro infectivity assay, while the g enome integrity of HCV and Parvovirus B19 was evaluated by polymerase chain reaction (PCR) using HCV quantitative PCR and Parvovirus B19 nested PCR. R esults: In plasma samples treated with 1 mu M MB and visible light we found that the titer of HIV-1 was reduced by 4.25 log; the HCV quantitative PCR assay showed a consistent decrease in the number of viral RNA copies up to 95%; the specific band in the VP1 genomic portion of Parvovirus B19 DNA was undetectable. Conclusions: These data indicate that MB photodynamic treatm ent induces a loss of HIV infectivity, as already observed, and most import antly induces a damage in the genome of both HCV and Parvovirus B19 within the RNA/DNA regions identified by the primers currently available.