Leukodepletion filters reduce Leishmania in blood products when used at collection or at the bedside.
BACKGROUND
Leishmania is an intracellular parasite of monocytes transmissible by transfusion. The feasibility of reducing Leishmania with leukodepletion filters was studied. At collection, infected blood contains the amastigote form of Leishmania within monocytes. Amastigotes cause the rupture of monocytes releasing free amastigotes that convert to promastigotes, which exist extracellularly at blood storage temperatures. Leukodepletion filters were tested at various time points in this process.


METHODS
Blood products were infected with Leishmania organisms and then filtered with whole-blood filters at collection, with bedside filters after storage, and to determine whether free promastigotes could be eliminated.


RESULTS
Filtration at collection reduced Leishmania by 3 to 4 log or to the level of detection. Filtration of infected red cells after 2 weeks of storage showed a reduction of Leishmania by 4 log. Filtration resulted in a 6- to 8-log reduction in promastigotes either in the presence or in the absence of white cells within the filter.


CONCLUSIONS
Filtration at the time of collection and after storage of Leishmania-infected blood resulted in a substantial reduction of free and intracellular organisms. There is currently no donor screen for Leishmania. Until adequate testing is developed, the use of leukodepletion filters could add to the safety of the blood supply.
Cardo
Lisa J
LJ
Division of Military Casualty Research, Department of Blood Research, Transfusion Medicine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910-7500, USA. Lisa.Cardo@us.army.mil
Salata
Jeanne
J
Harman
Ronald
R
Mendez
Juan
J
Weina
Peter J
PJ
D000818:Animals; D001803:Blood Transfusion / Q000379:methods; D004912:Erythrocytes / Q000469:parasitology; D005374:Filtration; D006801:Humans; D007891:Leishmania / Q000302:isolation & purification*; D007896:Leishmaniasis / Q000517:prevention & control* / Q000635:transmission; D047589:Leukocyte Reduction Procedures / Q000379:methods*; D065227:Transfusion Reaction