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Keywords:

  • Ara h 2;
  • Ara h 8;
  • IgE;
  • IgG;
  • IgG4;
  • peanut;
  • sensitization

To cite this article: Sverremark-Ekström E, Hultgren EH, Borres MP, Nilsson C. Peanut sensitization during the first 5 yr of life is associated with elevated levels of peanut-specific IgG. Pediatr Allergy Immunol 2012: 23: 224–229.

Abstract

Background:  Allergen-specific IgE antibodies are implicated in allergic diseases while allergen-specific IgG antibodies have been proposed to prevent allergic reactions. The objective for this study was to study whether the immune response (IgG and IgG4) to peanut differs in IgE-sensitized and non-sensitized young children.

Methods:  A total of 239 children have been followed prospectively from birth to 5 yr of age. The levels of IgG and IgG4 to peanut, Ara h 2, and Ara h 8 were analyzed at 2 and 5 yr of age and related to IgE sensitization and peanut consumption.

Results:  The levels of peanut-specific IgG and IgG4 were significantly higher in peanut-sensitized children at 2 and 5 yr of age when compared with non-sensitized children and children sensitized to other food/inhalant allergens. A strong correlation was seen between levels of peanut-specific IgG/IgG4-ratios and peanut-specific IgE at 5 yr of age. Children avoiding peanuts, a subgroup of the peanut sensitized, had statistically significant higher levels of IgE to peanut and a tendency of higher IgG and IgG4 levels to peanut. In the avoidance group, significant correlations between IgE and IgG/IgG4 to peanut were found compared with children eating peanuts.

Conclusion:  Peanut-specific IgG or IgG4 levels were elevated in peanut-sensitized children especially those avoiding peanuts. In our study, IgG and IgG4 do not seem to indicate tolerance or protection from sensitization.