Pathogen inactivation ofLeishmania donovani infantumin plasma and platelet concentrates using riboflavin and ultraviolet light

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Abstract
Background and Objectives Leishmaniais transmitted by the bite of the phlebotomine sandfly or by transfusion of infected blood products. Leishmaniasis currently poses a significant problem in several parts of the world, and is an emerging problem in others. The Mirasol PRT technology is based on the use of riboflavin and ultraviolet light to generate chemical reactions in the nucleic acids of pathogens, which prevents replication and leads to inactivation. The intent of this study was to examine the ability of the Mirasol PRT System to kill theLeishmaniaparasite in human plasma and platelet concentrates.Materials and Methods In visceral Leishmaniasis, amastigotes are present in the blood and in the reticuloendothelial system within monocytes. For each unit of plasma or platelets treated, isolated mononuclear cells obtained from 100 ml of normal donor whole blood were incubated with 1·0 × 108Leishmania donovani infantumpromastigotes to produce amastigote‐laden macrophages. The infected macrophages were added to 250 ml of human plasma or to 250 ml of platelet concentrates. Infected units were cultured pretreatment in 10‐fold serial dilutions to determine the limits of detection. Thirty millilitres of 500 µmriboflavin was added to each unit, which was then illuminated with 5·9 J/cm2of ultraviolet light (6·24 J/ml). After treatment and after 2 months of frozen storage, plasma units were cultured in 10‐fold serial dilutions. Platelets were cultured on the day of treatment and on day 5 of storage post‐illumination.Results A 5 log reduction ofLeishmaniawas demonstrated in five of six units of plasma, and a 7 log reduction ofLeishmaniawas demonstrated in one plasma unit. A 5 log reduction ofLeishmaniawas demonstrated in five of six units of platelets, and a 6 log reduction ofLeishmaniawas demonstrated in one unit.Conclusions There is no donor screen forLeishmaniaand other pathogens constantly emerging in our blood supply. The Mirasol PRT System for Platelets and Plasma is an effective means of killingLeishmaniaand other emerging pathogens in these blood products.