Acute hemolytic anemia related to diphtheria-pertussis-tetanus vaccination

Three infants developed severe hemolytic anemia following the second or third diphtheria-pertussistetanus vaccination. Direct antiglobulin tests were positive, and the infant most severely affected also had reduced serum complement levels, indicating an immunological mechanism for the hemolysis. The presence of IgM on the erythrocytes from 2 of the infants could be demonstrated by antiglobulin tests or immunization experiments. Heat eluates of the erythrocytes from one of the infants contained antibodies to tetanus and diphtheria toxoids, as well as to Bordetella pertussis, suggesting that these antibodies were antigenically bound to the erythrocytes. Virus antibodies or isoagglutinins, present in the serum, were not found in the eluate. No antibodies against the vaccine components could be demonstrated in eluates of erythrocytes from control subjects. In vivo experiments showed that tetanus and diphtheria toxoids were easily bound to human erythrocytes. This finding could help explain the pathogenesis of the autohemolysis.