Characteristics of immune response to diphtheria anatoxin in children with different immune status during the second age-scheduled revaccination

The dynamics of the intensity of specific antidiphtheria immunity after the second age-scheduled revaccination was studied in 129 practically healthy children. The study revealed that the formation of immunity depended on the initial functional state of the immune system before the injection of diphtheria toxoid. Three variants of immune response were determined and the immune status corresponding to each of these variants was characterized. As shown in this study, children with the hyperergic character of immune response were characterized by relatively high initial titers of antitoxin, and the injection of an additional dose of the antigen led to the prolonged state of hyperimmunization with the subsequent decrease of the intensity of immunity by half, registered in the catamnestic observation for 4 years. Children with the hypo- and normoergic variants of immune response were characterized by the most stable immune response to diphtheria toxoid, and during the catamnestic observation they formed the levels of antibody titers 2.5- to 3-fold higher than before immunization. But the protection characteristics in children with the third variant were the lowest among the children under study.