Inactivation of Leishmania donovani infantum and Trypanosoma cruzi in red cell suspensions with thiazole orange.
BACKGROUND
Methods for pathogen inactivation are currently available in some European countries for treatment of plasma and platelet (PLT) components; no approved method for treatment of red cells (RBCs) or whole blood is ready for implementation. In a previous study, thiazole orange (TO), a dye commonly used to count reticulated RBCs and PLTs, exhibited potent photoactivity against human immunodeficiency virus-1 and several model viruses in RBC suspensions. The aim of this study is to further evaluate the ability of TO to inactivate pathogens by measuring its activity against the protozoa Leishmania donovani infantum and Trypanosoma cruzi.


METHODS
RBC suspensions were deliberately contaminated with L. donovani infantum promastigotes or T. cruzi trypomastigotes and either maintained as an untreated control, incubated with 80 mumol per L TO in the dark, or treated with TO and light. Control and treated samples were inoculated into medium and subsequently microscopically examined for growth.


RESULTS
No growth was observed in samples treated with TO in the presence or absence of light, while matched control samples lacking TO and diluted up to 5 log consistently demonstrated Leishmania or T. cruzi growth (n = 3).


CONCLUSIONS
TO inactivated Leishmania or T. cruzi to the limit of detection in RBC suspensions without intentional illumination.
Wagner
Stephen J
SJ
American Red Cross, Holland Laboratory for the Biomedical Sciences, Blood Components Department, Rockville, Maryland 20855, USA. wagners@usa.redcross.org
Skripchenko
Andrey
A
Salata
Jeanne
J
O'Sullivan
Anne Marie
AM
Cardo
Lisa J
LJ
D000818:Animals; D052160:Benzothiazoles / Q000494:pharmacology*; D004912:Erythrocytes / Q000166:cytology / Q000821:virology*; D006801:Humans; D018314:Leishmania infantum / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects; D008027:Light; D011804:Quinolines / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects; D038301:Virus Inactivation / Q000187:drug effects / Q000528:radiation effects
D052160:Benzothiazoles; D011804:Quinolines; C051000:thiazole orange