Psoralen-mediated photodecontamination of platelet concentrates: inactivation of cell-free and cell-associated forms of human immunodeficiency virus and assessment of platelet function in vivo

BACKGROUND: Treatment of platelet concentrates (PCs) with psoralens and broad-band ultraviolet A (UVA) radiation is being examined for the elimination of pathogens that might be present in donated blood. Previous studies have demonstrated the inactivation of cell-free viruses and the maintenance of platelet integrity with common in vitro assays. STUDY DESIGN AND METHODS: Human immunodeficiency virus (HIV) in three forms-cell-free, actively replicating, and latently infected cell lines-was added to PCs and treated with 50 mu g per mL of 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT), 0.35 mM rutin, and broad-and narrow-band UVA light (320-400 nm and 360-370 nm [UVA1], respectively). The inactivation of added HIV was assessed in tissue culture; platelet hemostatic activity was assessed in thrombocytopenic rabbits. RESULTS: Each form of HIV was inactivated completely (greater than or equal to 10(5) infectious units) on treatment with 30 J per cm(2) of UVA1 light. Similar results were obtained on treatment of 2.5 mL of PCs in test tubes or intact PC units (50 mL) in blood bags. Latently infected cell lines were substantially more sensitive than cell-free HIV or HIV that was actively replicating. Human platelets treated with 40 J per cm(2) of UVA1 light had a fully corrected bleeding time shortly after treatment or after 5 days' storage, as assessed in thrombocytopenic rabbits. Platelet hemostatic function began to decrease with 81 J per cm(2) of UVA1 light and was abolished with 113 J per cm(2). At similar fluences, broad-band UVA light was more injurious to platelets than was UVA1 light. CONCLUSION: HIV transmission might be eliminated by PCs after treatment with AMT and UVA1 light and without a reduction in platelet hemostatic function.