Proceedings of the Food and Drug Administration public workshop on pathogen reduction technologies for blood safety 2018 (Commentary, p. 3026)

Atreya, Chintamani; Glynn, Simone; Busch, Michael; Kleinman, Steve; Snyder, Edward; Rutter, Sara; AuBuchon, James; Flegel, Willy; Reeve, David; Devine, Dana; Cohn, Claudia; Custer, Brian; Goodrich, Raymond; Benjamin, Richard J.; Razatos, Anna; Cancelas, Jose; Wagner, Stephen; Maclean, Michelle; Gelderman, Monique; Cap, Andrew; Ness, Paul

One such flexible dye is thiazole orange, which binds to the minor groove of nucleic acids and can act as a photochemical when bound but does not participate in photochemical reactions when free in solution. 171 Use of 80 μmol/L thiazole orange in RBCs suspended in Erythrosol AS and 7.9 J/cm 2 cool white light resulted in inactivation of more than 7 log vesicular stomatitis virus, more than 5.8 log bovine virus diarrhea virus, 5.5 log pseudorabies virus, more than 6.5 log extracellular HIV, more than 6.3 log intracellular HIV, more than 5 log of Leishmania donavani infantum, and more than 5 log T. cruzi. 171, 172 Bacterial inactivation ranged from 2.3 to more than 7 log, depending on the species. 171 RBC storage studies with thiazole orange demonstrated a hemolysis of 0.43% on Day 42 compared to 0.1% hemolysis of untreated controls, no change in ATP levels during 42-day storage compared to untreated controls, and a two-to threefold increase in potassium leakage in thiazole orange-treated RBCs compared with untreated controls. Unilluminated RBC controls containing thiazole orange had 0.3% hemolysis on Day 42, suggesting that some of the observed hemolysis may be due to the presence of thiazole orange rather than photo-induced hemolysis. Future development of thiazole orange as a RBC photo-inactivating agent will require toxicology, scale-up, and in vivo studies.