title: Cytokine response after severe respiratory syncytial virus bronchiolitis in early life.
abstract: BACKGROUND
  Immune response after viral infection usually involves T(H)1-mediated response; however, severe respiratory syncytial virus (RSV) infection appears to be associated with the development of asthma, a T(H)2-predominant phenotype.
  
  
  OBJECTIVE
  To understand the early and subsequent immunologic response to a serious RSV infection in children over time.
  
  
  METHODS
  A total of 206 previously healthy infants hospitalized with severe RSV bronchiolitis were enrolled in a prospective cohort called the RSV Bronchiolitis in Early Life study. Peripheral blood T cells were obtained immediately after RSV infection and at 2, 4, and 6 years of age, stimulated with phorbol 12-myristate 13-acetate and ionomycin, and analyzed for IL-2, IL-4, IL-13, and IFN-gamma by flow cytometry and real-time PCR.
  
  
  RESULTS
  Of the children, 48% (n = 97) developed asthma (physician-diagnosed), and 48% (n = 97) had eczema by age 6 years; 32% (n = 48 of 150) developed allergic sensitization by 3 years of age. Children with asthma had lower IL-13 expression at 6 years of age than those without (P = .001). IFN-gamma, IL-2, and IL-4 levels did not differ by asthma or eczema status during follow-up (all P > .05). Allergic sensitization was not associated with differences in cytokine levels during follow-up (all P > .05).
  
  
  CONCLUSIONS
  Severe RSV infection early in life is associated with a high incidence of asthma and eczema. Contrary to expectations, subsequent immunologic development in those who developed asthma, eczema, or allergic sensitization was not associated with a T(H)2 phenotype in the peripheral blood.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo. Electronic address: castrom@wustl.edu.
authors.forename: Mario
authors.initials: M
authors.lastname: Castro
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
authors.forename: Toni
authors.initials: T
authors.lastname: Schweiger
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
authors.forename: Huiquing
authors.initials: H
authors.lastname: Yin-DeClue
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
authors.forename: Thiruvamoor P
authors.initials: TP
authors.lastname: Ramkumar
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
authors.forename: Chandrika
authors.initials: C
authors.lastname: Christie
authors.affiliation: Department of Biostatistics, Washington University School of Medicine, St Louis, Mo.
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cohen
authors.affiliation: Department of Biostatistics, Washington University School of Medicine, St Louis, Mo.
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Schechtman
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St Louis, Mo.
authors.forename: Robert
authors.initials: R
authors.lastname: Strunk
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St Louis, Mo.
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Bacharier