title: Differences in systemic and skin migrating-specific CD4 T cells in papular urticaria by flea bite.
abstract: BACKGROUND
  Papular urticaria by flea bite is a chronic allergic condition in which clinical improvement may occur at the age of 7 years, thus representing a natural model of acquired immunologic tolerance in humans. The aim of this study was to characterize regulatory cells and specific responses to flea antigens of CD4(+) T lymphocytes expressing cutaneous migration markers in patients with papular urticaria caused by flea bite and with different disease evolution times.
  
  
  METHODS
  Cell populations were characterized by flow cytometry in samples from patients and healthy controls. Specific cell stimulation was performed with a complete flea body extract. The Mann-Whitney U test was used for comparisons.
  
  
  RESULTS
  Total dendritic cells were lower in patients than in healthy controls. No quantitative differences were found in CD4 regulatory T cells. CD4(+) T cells from patients produced more IL-4, lL-10, IL-17, and IFN-γ. Patients who experienced the onset of symptoms within the first 5 years of age showed a greater percentage of local (cutaneous lymphocyte antigen +) IL-4- and IL-17-producing cells, while patients who experienced the onset of symptoms after the age of 5 years had a higher percentage of systemic (cutaneous lymphocyte antigen -) IL-10-producing cells.
  
  
  CONCLUSIONS
  Analysis of the cellular immune response against whole flea antigen in patients with papular urticaria by flea bites suggests a possible participation of inflammatory cytokines in the skin reaction (Th17) and a systemic control mechanism (IL-10). This pattern of cytokine production in patients could be a consequence of an impaired dendritic cell population.
authors.affiliation: Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia.
authors.forename: Omar
authors.initials: O
authors.lastname: Dominguez-Amorocho
authors.forename: Silvia
authors.initials: S
authors.lastname: Duarte
authors.forename: John Mario
authors.initials: JM
authors.lastname: González
authors.forename: Evelyne
authors.initials: E
authors.lastname: Halpert
authors.forename: María Claudia
authors.initials: MC
authors.lastname: Ortega
authors.forename: Adriana
authors.initials: A
authors.lastname: Rodríguez
authors.forename: Elizabeth
authors.initials: E
authors.lastname: García
authors.forename: Adriana
authors.initials: A
authors.lastname: Cuellar
mesh_terms: D017668:Age of Onset; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D002634:Chemotaxis, Leukocyte / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007299:Insect Bites and Stings / Q000150:complications / Q000276:immunology*; D008297:Male; D005423:Siphonaptera / Q000276:immunology*; D012867:Skin / Q000276:immunology* / Q000473:pathology; D014581:Urticaria / Q000209:etiology / Q000276:immunology* / Q000378:metabolism
chemical_list: D016207:Cytokines