Background and Objectives  Leishmania is 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 the Leishmania parasite 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 infantum promastigotes 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 µm riboflavin was added to each unit, which was then illuminated with 5·9 J/cm2 of 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 of Leishmania was demonstrated in five of six units of plasma, and a 7 log reduction of Leishmania was demonstrated in one plasma unit. A 5 log reduction of Leishmania was demonstrated in five of six units of platelets, and a 6 log reduction of Leishmania was demonstrated in one unit. Conclusions  There is no donor screen for Leishmania and other pathogens constantly emerging in our blood supply. The Mirasol PRT System for Platelets and Plasma is an effective means of killing Leishmania and other emerging pathogens in these blood products.

Leishmania infection is most often transmitted to humans via the bite of the phlebotomine sandfly, but transmission of Leishmania by transfusion has also been reported. There has been a huge increase in the incidence of cutaneous and visceral leishmaniasis in Iraq and Afghanistan. The deployment of US troops to these countries and published case reports of transmission to soldiers in endemic areas, by transfusion to infants with immature immune systems, and to individuals immunocompromised by disease or immunosuppressive therapy beckon a reexamination of blood donor deferral procedures. The length of the ongoing military conflict and the nature of exposure indicate that prior decisions regarding blood donor deferral made during the first Gulf War may no longer apply. Operation Iraqi Freedom and Operation Enduring Freedom present a much greater Leishmania threat than did Operation Desert Storm. Because most transmission by transfusion occurs in endemic areas, and visceral infection is asymptomatic in healthy individuals such as blood donors, it is difficult to determine the absolute risk of transmission by transfusion, but review of the literature provides many clues as to the appropriate measures to be taken for blood donor deferral.

Mirasol PRT treatment demonstrated an ability to inactivate 5-7 logs of T. cruzi in plasma and platelets.

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In this study, we preincubated the sera of 3 patients with neuropathies associated with elevated titers of IgM anti-GM1 antibodies, with increasing concentrations of intravenous Ig (IVIg) and assayed the inhibitory effect of this mixture on antibody binding to immobilized GM1 by an enzyme-linked immunosorbent assay. Pharmacologic concentrations of IVIg, ranging from 0.1 microgram/ml to 100 mg/ml, inhibited anti-GM1 binding to its target antigen from 26 +/- 3 to 71 +/- 7%, respectively, in a dose-dependent manner. A similar inhibition of binding was also observed with IVIg F(ab')2 fragments. These findings provide a possible mechanism for the clinical efficacy of IVIg in motor neuropathies.

This HCV RDT comparison identified significant sensitivity differences, particularly using whole blood under extreme storage and testing conditions. These data support OraQuick HCV superiority and illustrate the value of RDT evaluation under simulated field conditions.