Local reactions and IgE antibodies to pertussis toxin after acellular diphtheria-tetanus-pertussis immunization

Local reactions and pertussis toxin specific immunoglobulin E antibodies (P T-IgE) were investigated in healthy children following primary and booster immunization with a combined diphtheria tetanus acellular pertussis vaccine (DTPa) including pertussis toxin, filamentous haemagglutinin and pertactin . A primary series of DTPa was administered to 150 infants, and 104 of them received a booster dose of DTPa combined with inactivated polio vaccine at 2 years of age. PT-ISE was measured in serum samples from 72 children usin g a modified nitrocellulose RAST. Primary immunization was associated with low incidence of local reactions (1%-5%). After the booster dose 21% of chi ldren had a local reaction greater than or equal to 20 mm. Local reactions after the booster dose tended to be more common in children who had experie nced reaction at primary immunization. PT-IgE was detected in 18% and 86% o f children following primary and booster vaccinations, respectively. Allerg ic and non-allergic children did not differ in PT-IgE responses. After prim ary immunization, elevated PT-IgE levels were found more often in children with a family history of allergy than in those without known allergy in the family. Children with local reactions had significantly higher pre- and po st-booster PT-IgE levels and median post-booster pertactin IgG and diphther ia-IgG levels than children without local reactions. Conclusion Acellular pertussis immunization induces IgE antibodies to pertu ssis toxin, especially after booster vaccination. The higher median pre- an d post-booster levels of pertussis toxin specific immunoglobulin E and post -booster levels of IgG to pertactin and diphtheria in children with local s ide-effects reflect a multifactorial immunological mechanism of such reacti ons.