Inactivation of viruses in red cell and platelet concentrates with aluminum phthalocyanine (AlPc) sulfonates

Aluminum phthalocyanine tetrasulfonates (AlPcS) are photoactive compounds with absorption maxima at 665-675 nm. The inactivation of viruses (vesicular stomatitis virus, VSV; human immunodeficiency virus, HIV) added to either whole blood or red blood cell concentrates (RBCC) and platelet concentrates (PC) on treatment with tetrasulfonated AlPc (AlPcS₄) was evaluated. Treatment of RBCC with 10 μM AlPcS₄ and 44 J/cm² visible light resulted in the inactivation of ≥ 10^5.5 infectious doses (TCID₅₀) of cell-free VSV, ≥ 10^5.6 TCID₅₀ of cell-associated VSV, and ≥ 10^4.7 TCID₅₀ of cell-free sindbis virus. Both ≥ 10^4.2 TCID₅₀ of cell-free and ≥ 10^3.6 TCID₅₀ of cell-associated forms of HIV were also shown to be inactivated. Encephalomyocarditis virus, used as a model for nonenveloped viruses, was not inactivated. Equivalent virus kill with Photofrin II required a substantially higher concentration of dye and longer exposure to visible light. Following AlPcS₄ treatment, red cell integrity was well maintained as judged by the low level (< 2%) of hemoglobin release immediately following treatment and on subsequent storage, by measurements of erythrocyte osmotic fragility, and by the normal recovery and circulatory survival on infusion of treated, autologous red blood cells in baboons. Treatment of PC with 10 μM AlPcS₄ and 44 J/cm² visible light also resulted in effective virus kill (≥ 10^5.5 TCID₅₀) of VSV; however, both the rate and extent of platelet aggregation in response to collagen addition declined by at least 50%. Based on these results, further characterization of AlPcS₄-treated RBCC is justified.