[Methylene blue/light treatment of virus inactivated human plasma: production and clinical experience]

A photodynamic procedure to inactivate viruses in fresh plasma for therapeutical use is carried out by illuminating single units of plasma with visible light in the presence of the phenothiazine dye methylene blue. The blood bag systems of all common suppliers can be used for this purpose. Photodynamic treatment only moderately influences the activities of plasma proteins. One of the most sensitive parameters is the thrombin time which is prolonged, dependent on dye concentration and illumination time. Under the chosen conditions (1 microM methylene blue, 1 h illumination time, about 50,000 lx), the increase is approximately 25%. A drug monitoring study indicated that photodynamically treated fresh plasma is as well tolerated as conventional fresh-frozen plasma. Between February and the end of July 1992 about 31,000 units of the virus-inactivated product were distributed to clinics within Lower Saxony.