Background: Asthma, together with, in some cases, anaphylaxis, was observed in seven subjects following ingestion of royal jelly, a secretion of honey bees which is used as a health tonic.
Objective: To determine if reactions were IgE-mediated and to identify allergenic components of royal jelly.
Methods: Skin-prick tests, immunoassays for specific IgE antibodies and protein blotting studies using patients' sera and anti-IgE second antibodies were employed.
Results: Immunoassays detected IgE antibodies to royal jelly proteins in sera of subjects who reacted to the substance. A total of 18 different IgE-binding components were detected on blots following electrophoretic separation of royal jelly under dissociating conditions. Examination of 63 sera from subjects allergic to bee venom showed that there is no direct relationship between IgE antibody reactivity to bee venom allergens and to royal jelly proteins although 38% of the sera reacted with a royal jelly solid phase. IgE antibody reactivity to royal jelly proteins was also detected in 52% of 75 subjects with allergies to inhalant and/or food allergens. Antibody binding of blotted royal jelly proteins was most marked in the molecular weight region 25-55 kDa and one component of MW approximately 55 kDa was detected by all of the reactive sera from royal jelly-allergic and control allergic subjects.
Conclusions: Symptoms of asthma and anaphylaxis seen in subjects following ingestion of royal jelly were true IgE-mediated hypersensitivity reactions. The clinical significance of the antibodies found in the sera of control subjects is not known but they may arise in response to common inhalant allergens that show allergenic cross-reactivity with royal jelly.