ANAPHYLAXIS TO MEASLES, MUMPS, AND RUBELLA VACCINE MEDIATED BY IGE TOGELATIN

Background: Allergic reactions to measles, mumps, and rubella (MMR) va ccine are rare; some have been attributed to allergy to trace quantiti es of egg proteins. We report a 17-year-old female who had an anaphyla ctic reaction to MMR vaccine. A primary vaccination with MMR at age 15 months had been uneventful. She is not allergic to eggs; however, ear and throat pruritus and tongue swelling develop after she eats gelati n. MMR vaccine contains gelatin as a stabilizer.Methods and Results: P rick skin tests were positive to 1:10 wt/vol dilutions of MMR vaccine and gelatin but negative to egg. By immunoassay, her serum IgE antibod ies were elevated to both MMR vaccine and gelatin, but not to isolated MMR antigens. IgE binding to the gelatin carrier could be inhibited i n a dose-dependent fashion by addition of not only MMR vaccine but als o gelatin from a variety of animal sources. Immunoblotting confirmed t he presence of IgE antibodies to multiple gelatin components as well a s to MMR vaccine components. Conclusions: We conclude that the patient has an anaphylactic sensitivity to gelatin, and that her anaphylaxis to MMR vaccine was caused by the gelatin component. This sensitivity m ay explain other cases of MMR anaphylaxis.