Delayed Hypersensitivity to Tuberculin, Total Immunoglobulin E, Specific Sensitization, and Atopic Manifestation in Longitudinally Followed Early Bacille Calmette-Guérin-Vaccinated and Nonvaccinated Children
Background. Bacille Calmette-Guérin (BCG) is a strong T helper 1 incentive and, thus, may contribute to a decreased risk of T helper 2-dependent atopic disease.Objective. To investigate the natural course of specific immunoglobulin E (IgE) responses and atopic disease in BCG-vaccinated and nonvaccinated children.Participants. Seven hundred seventy-four children from a prospectively followed birth cohort.Outcome Measures. Physical examination and case history were performed at 3, 6, 12, 18, 24, 36, 48, 60, 72, and 84 months of age. Total and specific serum IgE levels to 9 common inhalant and food allergens were determined (CAP; Pharmacia, Freiburg, Germany) at 12, 24, 36, 60, 72, and 84 months of age. Purified protein derivative (PPD) skin testing was performed at 84 months.Results. Period and lifetime prevalences of atopic dermatitis and recurrent wheezing tended to be lower in the BCG-vaccinated group early in life, whereas no such trend was found after the second birthday or for allergic rhinitis. The proportion of children remaining free of clinical manifestations tended to be higher in the BCG-vaccinated group but differences decreased over time. No statistically significant differences were found for total IgE levels (median). Atopic sensitization tended to be lower among BCG-vaccinated children during the first 2 years of life. The diameter of the skin reaction to PPD did not correlate with total serum IgE. Clinical and serologic correlates of atopy were not significantly different between children with a skin test diameter of ≥5 mm and those with a smaller diameter.Conclusion. These results do not support the hypothesis that BCG vaccination in early infancy is associated with a subsequently markedly decreased risk of atopic sensitization or allergy. In addition, PPD skin test reactivity was not impaired in atopic individuals.
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