Photochemical inactivation of bacteria and HIV in buffy-coat-derived platelet concentrates under conditions that preserve in vitro platelet function

Background and Objectives: A photochemical process has been tested for the inactivation of viruses and bacteria in huffy-coat derived platelet concent rates (BC PCs), Materials and Methods: BC PCs in 35% CPD plasma and 65% pla telet-additive solution (PAS III) were exposed to photochemical treatment ( PCT) with 150 mu M of the psoralen S-59 and a 3 J/cm(2) treatment with long -wavelength ultraviolet light (UVA, 320-400 nm). Platelet function was eval uated following PCT using a panel of in vitro assays. Results: This PCT pro cess was highly effective at inactivating gram-positive bacteria (Staphyloc occus epidermidis, Staphylococcus aureus, Enterococcus faecalis) and gram-n egative bacteria (Enterobacter aerogenes, Pseudomonas aeruginosa, Serratia marcescens). No viable bacteria were detected following PCT and 7 days of p latelet storage while bacterial growth was detected in paired untreated con trol BC PCs. Complete inactivation of the gram-positive Bacillus cereus was achieved only in one of two replicate experiments with BC PCs. PCT was als o highly effective for inactivation of human immunodeficiency virus HIV-1 i n BC PCs inoculated with approximately 10(6) tissue culture infectious dose s per milliliter (TCID50/ml) of cell-associated HIV-1. Rapid inactivation w as observed with increasing UVA doses: with 150 mu M S-59 and a 1 J/cm(2) t reatment of UVA, a reduction of 5.6+/-0.5 log TCID50/ml was achieved, and a reduction of >6.4 log TCID50/ml was achieved with 150 mu M S-59 and a 3 J/ cm(2) treatment of UVA. No physiologically relevant differences in platelet functions were found between the test and the control BC PCs during 7 days of storage. Conclusion: PCT with 150 mu M S-59 and a 3 J/cm(2) UVA treatme nt does not adversely affect in vitro properties of BC PCs stored at 22 deg rees C for 7 days. The PCT process inactivated bacteria and HIV-1 inoculate d into the BC PCs. These results extend the earlier reported efficacy of PC T apheresis PCs to BC PCs. Copyright (C) 2000 S. Karger AG, Basel.