Allergy to latex, avocado pear, and banana: evidence for a 30 kd antigen in immunoblotting.

Allergens of natural latex, latex gloves, avocado pear, and banana extracts were investigated by an immunoblotting technique in sera of patients experiencing associated latex and fruit allergies. Extracts were separated by sodium dodecyl-sulfate-polyacrylamide gel electrophoresis and electroblotted onto nitrocellulose. After incubation with patients' sera, IgE antibodies were revealed by a goat anti-human IgE alkaline-phosphatase conjugate. Seventeen serum samples from patients with well-documented latex allergy were studied. Among these patients, 10 demonstrated an allergy to avocado pear sometimes associated with banana. In sera from patients with latex and fruit allergy, prominent IgE binding was revealed at about 30 kd with latex and fruit extracts. Serum controls remained negative. Cross-inhibition of immunoblotting confirmed that this main allergen is linked to a common epitope present in latex and fruits. This must be related to clinical findings and previous observations of cross-reactivity.