Serological correlates in whooping cough.

Antibody concentrations to three Bordetella pertussis antigens in 94 predisease samples from women who, within a median of 220 days, developed culture-confirmed whooping cough were compared to antibodies in samples from matched controls. The median IgG antibody levels were significantly lower to all three antigens, pertussis toxin, filamentous haemagglutinin and lipopolysaccharide, in the predisease samples of cases as compared to non-cases (p values ranging from 0.0001 to 0.01). A significant difference in antibody distribution was, however, found only to pertussis toxin, measured either by ELISA or by a neutralization test (p values of 0.0004 and 0.007, respectively). The results could be interpreted as meaning that antibodies to the different antigens all participate in protection against disease but that antibodies to pertussis toxin play a major role.