Background: Many cases of anaphylactic or nonanaphylactic reactions have been reported to measles-mumps-rubella vaccine or its component vaccines that contain gelatin as a stabilizer. Increased levels of specific IgE antibodies to gelatin have been reported in children with anaphylactic reactions. However, IgE is not increased in cases of nonanaphylactic reaction, and the mechanisms of the reaction are still controversial.
Objective: The study was aimed to elucidate the relationship between nonanaphylactic reaction and gelatin.
Methods: We investigated in vitro induction of activated memory helper T cells (CD4(+ )CD25(+ )CD45RO+ cells) in response to gelatin in children with nonanaphylactic reactions to vaccines containing gelatin.
Results: In patients with delayed-type sensitivity to gelatin confirmed with a positive skin test response, CD4(+ )CD25(+ )CD45RO+ cells were significantly more strongly induced in culture containing gelatin than in control cultures. However, there was no significant difference between cultures with gelatin and those with control solvent in patients without reactions after vaccination. Of 76 patients with nonanaphylactic reactions after immunization with vaccine containing gelatin, 61 had an increased lymphocyte stimulation index to gelatin versus control children.
Conclusion: These results suggest the possibility that nonanaphylactic reactions to gelatin-containing vaccine in Japan might be mediated by delayed hypersensitivity reactions against gelatin.