PHOTODYNAMIC TREATMENT OF RED-BLOOD-CELL CONCENTRATES FOR VIRUS INACTIVATION ENHANCES RED-BLOOD-CELL AGGREGATION - PROTECTION WITH ANTIOXIDANTS

Photodynamic treatment (PDT) using phthalocyanines and red light appea rs to be a promising procedure for decontamination of red blood cell ( RBC) concentrates for transfusion. A possible complication of this tre atment may be induced aggregation of RBC. The production of RBC aggreg ates was measured with a novel computerized cell how properties analyz er (CFA). The PDT of RBC concentrates with sulfonated aluminum phthalo cyanine (AlPcS4) and the silicon phthalocyanine Pc 4 under virucidal c onditions markedly enhanced RBC aggregation and higher shear stress wa s required to disperse these aggregates. The clusters of cells were hu ge and abnormally shaped, unlike the rouleaux formed by untreated RBC, This aggregation was prevented when a mixture of antioxidants was inc luded during PDT. Addition of the antioxidants after PDT reduced aggre gation only partially. It is concluded that inclusion of antioxidants during PDT of RBC concentrates prior to transfusion may reduce or elim inate the hemodynamic risk that the virucidal treatment may present to the recipient.