INACTIVATION OF TRYPANOSOMA-CRUZI TRYPOMASTIGOTE FORMS IN BLOOD COMPONENTS WITH A PSORALEN AND ULTRAVIOLET-A LIGHT

Inactivation of the blood-borne parasite Trypanosoma cruzi by UVA and 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT) was studied in the blood components fresh frozen plasma (FFP) and platelet concentrate (PC). T he AMT was utilized at a concentration of 50 mu g/mL and the inactivat ion procedure included the flavonoid rutin (at 0.35 mM), a quencher of type I and type II photoreactants, which we have previously found to maintain platelet integrity during this treatment regimen. Within both FFP and PC, complete inactivation of the infective form of T. cruzi, the trypomastigote, was achieved at a UVA (320-400 nm radiation) fluen ce of 4.2 J/cm(2). We note that while the infectivity of the parasite is eliminated at 4.2 J/cm(2) the trypomastigote motility continues for at least 16 h post-treatment and is inhibited only after much higher light doses. Isolation of total DNA from the parasite cells after trea tment in the presence of H-3-AMT indicated that at the lethal UVA flue nce about 0.5 AMT adducts per kilobase pairs occurred. These results s uggest that this psoralen plus UVA methodology, which shows promise in enhancing the viral safety of PC, may in addition eliminate bloodborn e T. cruzi, the causative agent of Chagas disease.