title: Reduced T regulatory cell response during acute Plasmodium falciparum infection in Malian children co-infected with Schistosoma haematobium.
abstract: BACKGROUND
  Regulatory T cells (Tregs) suppress host immune responses and participate in immune homeostasis. In co-infection, secondary parasite infections may disrupt the immunologic responses induced by a pre-existing parasitic infection. We previously demonstrated that schistosomiasis-positive (SP) Malian children, aged 4-8 years, are protected against the acquisition of malaria compared to matched schistosomiasis-negative (SN) children.
  
  
  RESULTS
  To determine if Tregs contribute to this protection, we performed immunologic and Treg depletion in vitro studies using PBMC acquired from children with and without S. haematobium infection followed longitudinally for the acquisition of malaria. Levels of Tregs were lower in children with dual infections compared to children with malaria alone (0.49 versus 1.37%, respectively, P = 0.004) but were similar months later, during a period with negligible malaria transmission. The increased levels of Tregs in SN subjects were associated with suppressed serum Th1 cytokine levels, as well as elevated parasitemia compared to co-infected counterparts.
  
  
  CONCLUSIONS
  These results suggest that lower levels of Tregs in helminth-infected children correlate with altered circulating cytokine and parasitologic results which may play a partial role in mediating protection against falciparum malaria.
authors.affiliation: Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America. KLyke@medicine.umaryland.edu
authors.forename: Kirsten E
authors.initials: KE
authors.lastname: Lyke
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Dabo
authors.forename: Charles
authors.initials: C
authors.lastname: Arama
authors.forename: Modibo
authors.initials: M
authors.lastname: Daou
authors.forename: Issa
authors.initials: I
authors.lastname: Diarra
authors.forename: Amy
authors.initials: A
authors.lastname: Wang
authors.forename: Christopher V
authors.initials: CV
authors.lastname: Plowe
authors.forename: Ogobara K
authors.initials: OK
authors.lastname: Doumbo
authors.forename: Marcelo B
authors.initials: MB
authors.lastname: Sztein
mesh_terms: D000818:Animals; D001773:Blood Cells / Q000276:immunology; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000276:immunology*; D016207:Cytokines / Q000097:blood; D006801:Humans; D008137:Longitudinal Studies; D016778:Malaria, Falciparum / Q000276:immunology*; D018512:Parasitemia; D010963:Plasmodium falciparum / Q000276:immunology*; D012548:Schistosoma haematobium / Q000276:immunology*; D012553:Schistosomiasis haematobia / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology
chemical_list: D016207:Cytokines