title: Effective and cheap removal of leukocytes and platelets from Plasmodium vivax infected blood.
abstract: BACKGROUND
  Investigations of Plasmodium vivax are restricted to samples collected from infected persons or primates, because this parasite cannot be maintained in in vitro cultures. Contamination of P. vivax isolates with host leukocytes and platelets is detrimental to a range of ex vivo and molecular investigations. Easy-to-produce CF11 cellulose filters have recently provided us with an inexpensive method for the removal of leukocytes and platelets. This contrasted with previous reports of unacceptably high levels of infected red blood cell (IRBC) retention by CF11. The aims of this study were to compare the ability of CF11 cellulose filters and the commercial filter Plasmodipur at removing leukocyte and platelet, and to investigate the retention of P. vivax IRBCs by CF11 cellulose filtration.
  
  
  RESULTS
  Side-by-side comparison of six leukocyte removal methods using blood samples from five healthy donor showed that CF11 filtration reduced the mean initial leukocyte counts from 9.4 x 103 per microl [95%CI 5.2-13.5] to 0.01 x 103 [95%CI 0.01-0.03]. The CF11 was particularly effective at removing neutrophils. CF11 treatment also reduced initial platelet counts from 211.6 x 103 per microl [95%CI 107.5-315.7] to 0.8 x 103 per microl [95%CI -0.7-2.2]. Analysis of 30 P. vivax blood samples before and after CF11 filtration showed only a minor loss in parasitaemia (<or= 7.1% of initial counts). Stage specific retention of P. vivax IRBCs was not observed.
  
  
  CONCLUSIONS
  CF11 filtration is the most cost and time efficient method for the production of leukocyte- and platelet-free P. vivax-infected erythrocytes from field isolates.
authors.affiliation: Singapore Immunology Network, BIOPOLIS, Singapore. poo@shoklo-unit.com
authors.forename: Kanlaya
authors.initials: K
authors.lastname: Sriprawat
authors.forename: Supaporn
authors.initials: S
authors.lastname: Kaewpongsri
authors.forename: Rossarin
authors.initials: R
authors.lastname: Suwanarusk
authors.forename: Mara L
authors.initials: ML
authors.lastname: Leimanis
authors.forename: Usa
authors.initials: U
authors.lastname: Lek-Uthai
authors.forename: Aung Pyae
authors.initials: AP
authors.lastname: Phyo
authors.forename: Georges
authors.initials: G
authors.lastname: Snounou
authors.forename: Bruce
authors.initials: B
authors.lastname: Russell
authors.forename: Laurent
authors.initials: L
authors.lastname: Renia
authors.forename: François
authors.initials: F
authors.lastname: Nosten
mesh_terms: D000818:Animals; D004912:Erythrocytes / Q000469:parasitology*; D005069:Evaluation Studies as Topic; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D007937:Leukapheresis / Q000295:instrumentation* / Q000379:methods; D010966:Plasmodium vivax / Q000302:isolation & purification*; D010983:Plateletpheresis / Q000295:instrumentation* / Q000379:methods