Cytokine response after severe respiratory syncytial virus bronchiolitis in early life.
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.
Castro
Mario
M
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo. Electronic address: castrom@wustl.edu.
Schweiger
Toni
T
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
Yin-DeClue
Huiquing
H
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
Ramkumar
Thiruvamoor P
TP
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
Christie
Chandrika
C
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
Zheng
Jie
J
Department of Biostatistics, Washington University School of Medicine, St Louis, Mo.
Cohen
Rebecca
R
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo.
Schechtman
Kenneth B
KB
Department of Biostatistics, Washington University School of Medicine, St Louis, Mo.
Strunk
Robert
R
Department of Pediatrics, Washington University School of Medicine, St Louis, Mo.
Bacharier
Leonard B
LB
Department of Pediatrics, Washington University School of Medicine, St Louis, Mo.