Cytokines can affect the quantity and class of allergen-specific immunoglobulins through the T cell polarization that accompanies atopy. Antigen-specific IgG subclasses and IgE antibodies were compared with intracellular T cell cytokine changes to sensitizing antigens in 23 children with multiple food allergies and 20 healthy controls. Allergic children showed higher levels of total and food-specific IgE, IgG1 and IgG4 to peanut, milk and egg than non-atopic children or adults, coinciding with a TH2 cytokine response to sensitizing antigens. IgG1 and IgG4 antibodies specific to milk and egg and peanut protein were elevated relative to age-matched healthy children (p <or= 0.05) and, in milk- and egg-sensitized children, correlated with cytokine responses (p < 0.05). Peanut-sensitized children additionally had elevated levels of IgG2 and IgG3 also which correlated inversely (p < 0.003 and p < 0.04, respectively) with IFNgamma production. Elevated allergen-specific IgG subclass antibodies in sensitized children correlated with total IgE levels (p <or= 0.05) in all three food allergen groups. The ratio of specific IgG1 to IgG4 was highest in those with high IgE, inverted with resolution of allergy, and correlated with total IgE levels (p <or= 0.01) in milk- and egg-sensitized children. The correlation of TH2 responses with allergen-specific antibodies would implicate polarized T cells in food allergic children in IgE hypersensitivity and overproduction of particular IgG subclasses alike. IgG1:IgG4 ratio declines with allergy sensitization and may denote emerging tolerance.
(c) 2010 John Wiley & Sons A/S.