No abstract

While breast feeding should be promoted for children at risk for atopy, mothers can be encouraged to stay on normal diet during pregnancy and the breast feeding period.

Background: In order to investigate, whether atopic and nonatopic children show differences in their specific IgE and IgG4 immune responses to tetanus (T) and diphtheria (D) antigens, we studied 538 children who had been followed from birth on and from whom records had been kept of all immunizations. Methods: The prevalence of eczema and asthma was registered at regular intervals and the cumulative incidence of symptoms was determined at 24 months of age. Total serum IgE and specific IgE to a panel of nine allergens as well as T-and D-specifíc IgE and IgG4 were determined from the 24-month blood samples. Results: Our results show that both atopic and nonatopic children are capable of mounting high levels of toxoid-specific IgE antibody responses. Children with cord blood IgE > 0.9 kU/l, serum IgE 10–100 kU/l and > 100 kU/l and at least one sensitization to an allergen at 24 months of age have significantly higher IgE responses to T and D (p < 0.001). In contrast, specific IgG4 antibody concentrations to T and D were not significantly different in children with elevated total IgE levels at 24 months. No differences in subgroups of children with or without early symptoms of atopy were observed. Conclusions: Our data indicate that IgE responses to toxoids such as T and D are not limited to infants with clinical manifestations of atopy in the first 2 years of life but are related to immunological parameters of atopy.

Pertussis (P) toxin acts as adjuvant for IgE formation against simultaneously administered Ags in animal models. P vaccination may also have an adjuvant impact on IgE formation against coadministered diphtheria (D) and tetanus (T) Ags in humans. Sera of 103 D-T-P-immunized and 319 D-T-immunized children aged 2 years were analyzed for IgE, IgG4, and IgG to D and T (radioallergosorbent test), total IgE and IgE against common inhalant allergens (CAP radioallergosorbent test fluoroenzyme immunoassay). Fewer D-T-P- than D-T-immunized children had sera positive for T-IgE (12.6 vs 53.6%, p &lt; 0.001), T-IgG4 (71.6 vs 89.2%, p &lt; 0.001), D-IgE (31.0 vs 70.5%, p &lt; 0.001), and D-IgG4 (85.2 vs 93.4%, p = 0.039). Suppression of T-IgE was not dependent on the cutoff chosen for a positive test result, but was dependent on the proportion of D-T immunizations given with P. The risk for sensitization to common environmental allergens did not differ (odds ratio 0.953, 95% confidence interval 0.815–1.114). No significant differences between D-T- and D-T-P-immunized children were found with regard to T-IgG or D-IgG. In summary, IgE and IgG4 (but not IgG) serum levels to coadministered D- and T-Ags are suppressed among P-immunized children as compared with nonimmunized children. These results suggest that the presence of a microbial product during Ag exposure can down-regulate an IgE/IgG4 response in humans.