title: Relationship of regulatory T cells to Plasmodium falciparum malaria symptomatology in a hypoendemic region.
abstract: BACKGROUND
  Previous data have suggested that regulatory T cells (Tregs) balance protective immune responses with immune mediated pathology in malaria. This study aimed to determine to test the hypothesis that Treg proportions or absolute levels are associated with parasitaemia and malaria symptoms.
  
  
  METHODS
  Treg cells were quantified by flow cytometry as CD4+ CD25+, Foxp3+, CD127(low) T cells. Three patient groups were assessed: patients with symptomatic Plasmodium falciparum malaria (S), subjects with asymptomatic P. falciparum parasitaemia (AS) and uninfected control individuals (C).
  
  
  RESULTS
  S, AS and C groups had similar absolute numbers and percentage of Tregs (3.9%, 3.5% and 3.5% respectively). Levels of parasitaemia were not associated with Treg percentage (p = 0.47).
  
  
  CONCLUSIONS
  Neither relative nor absolute regulatory T cell numbers were found to be associated with malaria-related symptomatology in this study. Immune mechanisms other than Tregs are likely to be responsible for the state of asymptomatic P. falciparum parasitaemia in the Peruvian Amazon; but further study to explore these mechanisms is needed.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Torres
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Villasis
authors.forename: Jorge
authors.initials: J
authors.lastname: Bendezú
authors.forename: José
authors.initials: J
authors.lastname: Chauca
authors.affiliation: Instituto de Medicina Tropical "Alexander Von Humboldt", Universidad Peruana, Cayetano Heredia, AP 4314, Lima 100, Peru. jvinetz@ac.ucsd.edu.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Vinetz
authors.forename: Dionicia
authors.initials: D
authors.lastname: Gamboa
mesh_terms: D000293:Adolescent; D000328:Adult; D058070:Asymptomatic Diseases; D002648:Child; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016778:Malaria, Falciparum / Q000276:immunology* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D018512:Parasitemia / Q000276:immunology* / Q000469:parasitology; D010568:Peru; D010963:Plasmodium falciparum / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D055815:Young Adult