Stability of antibodies to Bordetella antigens in German adults.

To estimate the rate of asymptomatic exposure to Bordetella pertussis antigens in the German adult population and to evaluate the stability of antibodies to these antigens, antibody levels against Bordetella antigens and their variability over time were measured in German adult blood donors. One hundred forty-six regular blood donors (41 females, 105 males) were tested repeatedly for antibodies of isotypes IgG and IgA to pertussis toxin, filamentous hemagglutinin (FHA) and pertactin over a period of 2-5 years. Overall, 86% and 56% had IgG or IgA antibodies to pertussis toxin, respectively, 100% and 92% had IgG or IgA antibodies to FHA, respectively, and 83% and 93% had IgG or IgA antibodies to pertactin, respectively. One significant titer increase of both IgG anti-FHA and IgG anti-pertactin, one of IgG anti-FHA, and two of IgA anti-FHA as well as one significant decrease of IgG anti-pertussis toxin were observed during an observation period of 480.5 person-years. Antibody concentrations in men and women were not different. The data show that the level of antibodies to pertussis toxin, FHA, and pertactin remains stable over several years. Furthermore, depending on the definition of serological evidence, the rate of significant increases or decreases suggesting unrecognized exposure to Bordetella antigens was estimated to be between <0.2 and 1.0 per 100 person-years in the population studied.