[Recent trends in the serologic diagnosis of pertussis].

Anti-whooping cough agglutinin titrations were performed in various groups of children by employing a special antigen and a microtechnique. Moderate agglutinating titers were detected in the first trimester of life and were interpreted as transmitted from the mother. Rare and moderate titers were observed in a group of children of school age, randomly selected and non institutionalized, while, on the contrary, an analogous institutionalized group showed more frequent and higher rate of antibodies. In clinically diagnosed whooping cough titers resulted high when the disease turned out to have set in more than three week earlier. Anti-whooping cough vaccination determined agglutinating titers mainly moderate and not long-lasting.