title: Neutrophil paralysis in Plasmodium vivax malaria.
abstract: BACKGROUND
  The activation of innate immune responses by Plasmodium vivax results in activation of effector cells and an excessive production of pro-inflammatory cytokines that may culminate in deleterious effects. Here, we examined the activation and function of neutrophils during acute episodes of malaria.
  
  
  METHODS
  Blood samples were collected from P. vivax-infected patients at admission (day 0) and 30-45 days after treatment with chloroquine and primaquine. Expression of activation markers and cytokine levels produced by highly purified monocytes and neutrophils were measured by the Cytometric Bead Assay. Phagocytic activity, superoxide production, chemotaxis and the presence of G protein-coupled receptor (GRK2) were also evaluated in neutrophils from malaria patients.
  
  
  RESULTS
  Both monocytes and neutrophils from P. vivax-infected patients were highly activated. While monocytes were found to be the main source of cytokines in response to TLR ligands, neutrophils showed enhanced phagocytic activity and superoxide production. Interestingly, neutrophils from the malaria patients expressed high levels of GRK2, low levels of CXCR2, and displayed impaired chemotaxis towards IL-8 (CXCL8).
  
  
  CONCLUSIONS
  Activated neutrophils from malaria patients are a poor source of pro-inflammatory cytokines and display reduced chemotactic activity, suggesting a possible mechanism for an enhanced susceptibility to secondary bacterial infection during malaria.
authors: Laboratório de Imunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil.
authors: Fabiana Maria de Souza
authors: FM
authors: Leoratti
authors: Silvia Cellone
authors: SC
authors: Trevelin
authors: Fernando Queiroz
authors: FQ
authors: Cunha
authors: Bruno Coelho
authors: BC
authors: Rocha
authors: Pedro Augusto Carvalho
authors: PA
authors: Costa
authors: Humberto Doriguêtto
authors: HD
authors: Gravina
authors: Mauro Shugiro
authors: MS
authors: Tada
authors: Dhelio Batista
authors: DB
authors: Pereira
authors: Douglas Taylor
authors: DT
authors: Golenbock
authors: Lis Ribeiro do Valle
authors: LR
authors: Antonelli
authors: Ricardo T
authors: RT
authors: Gazzinelli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002633:Chemotaxis; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D005434:Flow Cytometry; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000096:biosynthesis; D006801:Humans; D016780:Malaria, Vivax / Q000150:complications / Q000276:immunology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology / Q000469:parasitology; D009504:Neutrophils / Q000276:immunology* / Q000469:parasitology*; D010587:Phagocytosis; D010966:Plasmodium vivax / Q000276:immunology* / Q000472:pathogenicity*; D013481:Superoxides / Q000378:metabolism; D055815:Young Adult
chemical_list: D016207:Cytokines; D013481:Superoxides; C496567:GRK2 protein, human; D054769:G-Protein-Coupled Receptor Kinase 2