[Can the determination of IgG antibodies to the pertussis toxin help the diagnosis of the disease?].

Background: In the differential diagnosis of protracted irritating cough we should always consider the possibility of pertussis. Serology performed primarily in a late stage of the disorder does not always provide a clear answer. We wanted to verify whether a quantitative determination of IgG antibodies to the pertussis toxin (IgG-PT) could help establish a clear diagnosis.

Material And Methods: Between 1 January and 30 June 2005 we performed serological investigations in 139 children presenting with an irritable cough or after application of an acellular pertussis vaccine. In 95 children we compared the serological response of agglutination antibodies and IgG-PT.

Results: After vaccination the children presented with different levels of antibodies and these were not always identical in two types of serological response. Children with clinical manifestations of pertussis presented a good formation of antibodies, but the two kinds of antibodies often persisted for long periods at unchanged levels.

Conclusions: The determination of IgG-PT can assist the diagnosis of the disease, but this investigation alone cannot yield a clear-cut confirmation of pertussis.