Allergen-induced cytokine secretion in relation to atopic symptoms and immunoglobulin E and immunoglobulin G subclass antibody responses

There are few studies on allergen-induced cytokine production in allergic c hildren, and little is known of antigen-specific cytokine regulation of hum an immunoglobulin (Ig) G subclass antibody responses. An association with T -helper 1 (Th1)-like immunity and complement-activating antibodies remains to be demonstrated in humans. We have previously observed that atopic sympt oms are associated with high levels of IgG subclass, especially IgG(4), ant ibodies to birch and beta-lactoglobulin. The differences were seen early in life for the food allergen and increased with age for the inhaled allergen . The aim of this study was to investigate the association between atopic s ymptoms, birch allergen-, and beta-lactoglobulin-induced cytokine productio n in peripheral blood mononuclear cells (PBMC), and serum IgE and IgG subcl ass antibody responses to these allergens in children in order to further c larify the role of Th1- and Th2-like immunity in responses to various antig ens. PBMC from 55 eight-year old children, who had been followed prospectiv ely from birth, were stimulated with birch- and beta-lactoglobulin. Product ion of interleukin (IL)-5, IL-6, IL-10, IL-13 and interferon (IFN)-gamma wa s analysed by ELISA and expression of IL-4 and IL-9 mRNA by semiquantitativ e reverse transcriptase-polymerase chain reaction (RTPCR). Ige subclass ant ibody levels to birch- and beta-lactoglobulin in serum were determined by E LISA, and IgE antibodies by Magic-Lite(TM) and CAP-RAST(TM), respectively. Birch-induced expression of IL-4 but not of the other cytokines, was associ ated with IgE antibodies to birch. Furthermore, the IL-4 expression and IL- 6 production correlated with serum IgG(4) antibody levels to this allergen, and IFN-gamma secretion with IgG(1) antibody responses. There were no corr elations between beta-lactoglobulin-stimulated cytokine production and IgG subclass antibody levels to that allergen, except for a negative associatio n between beta-lactoglobulin-stimulated IL-4 expression and IgG(1) antibodi es. Atopic children tended to have high levels of birch and beta-lactoglobu lin-induced IL-5, IL-6 and IL-10 secretion. Birch-induced IL-4 expression m ay be the major factor in determining IgE antibody formation to that allerg en, while allergen-induced IL-5, IL-6 and IL-10 secretion in PBMC is associ ated with atopic symptoms. Th1-like immunity to inhaled allergens could be associated with production of the opsonizing and complement-activating IgG( 1) antibody subclass, and Th2-like immunity with IgG(4) antibody responses.