Bordetella pertussis FHA antibodies in maternal/infants sera and colostrum.

The high incidence of pertussis in the first year of life confirms that susceptibility remains high for children in this age group despite > 90% pertussis vaccine compliance. In this respect, immunoresponse to Bordetella pertussis was investigated. Filamentous hemagglutinin (FHA) antibodies were studied due to their important protective role, in blocking the adherence of the bacteria to respiratory tract ciliated cells. The relative rate of detection and degree of positivity of IgG and IgA antibodies to Bordetella pertussis FHA were studied in maternal and infant sera and in colostrum samples of the respective mothers. The study comprised 143 mothers of child bearing age and 25 newborns. The highest percentages of serum IgG and IgA were present in the younger females group (15-25 yrs). Both IgG and IgA were detected in the same mother in 60% of them. The study showed that 96.9% of colostrum samples who were positive for IgA, were associated with IgA positivity in serum, also an increase in the degree of serum IgA positivity was associated with a higher rate of detection of IgA in colostrum. Maternal serum IgA could therefore be used as a marker for the future presence of IgA in colostrum. This work demonstrated that newborns show little passive immunity to pertussis, evidenced by the low placental transfer of IgG (35.7%) and the low rate of detection of IgA in the colostrum (41%). We concluded that, it would be advantageous to reimmunize pregnant women, without adequate serum antibody to Bordetella pertussis, with appropriate new vaccine which would offer a better passive immunity to their infants.