Photodynamic inactivation of therapeutic fresh plasma has been used as a routine procedure in a number of blood banks in Germany and Switzerland since 1992 and, starting in 1997 and 1998, respectively, in Spain, Denmark and Scotland. Plasma units derived from single blood donations are illuminated with visible light in the presence of the phenothiazine dye methylene blue (MB). MB concentration is 1 micromolar, i.e. approx. 300 mikrogram per litre. Illumination time is 60 minutes at a light intensity of at least 45.000 Lux. MB\light treatment effectively inactivates lipid enveloped viruses like HIV-1 and 2, herpes and toga virus. Model viruses for hepatitis C virus like bovine viral diarrhea and west nile virus, respectively, are completely inactivated within 2 to 5 minutes. In contrast to enveloped viruses most nonenveloped viruses are resistent to photodynamic treatment; some, however are also affected. Among these are calici virus, reo virus and SV40. More importantly, PCR analysis indicates that Parvovirus B19 might be sensitive to MB\light treatment.
In MB\light treated plasma the activities of fibrinogen and other clotting factors are slightly diminished but those of other plasma proteins like the plasmatic inhibitors are well preserved. More than 1.8 Million units of the product have been produced and distributed to date. As the clinical data indicate it is as effective and tolerable as untreated fresh frozen plasma.
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Mohr, H. VIRUS INACTIVATION OF PLASMA BY METHYLENE BLUE/LIGHT EXPOSURE. Pediatr Res 45, 946 (1999). https://doi.org/10.1203/00006450-199906000-00289