Banana allergy in patients with immediate-type hypersensitivity to natural rubber latex: characterization of cross-reacting antibodies and allergens.
BACKGROUND
An association between allergy to latex and banana has been reported. Even though cross-reacting IgE antibodies have been demonstrated, in no study has the existence of structurally similar allergens been confirmed. In the present study banana allergy was studied in a large series of patients with latex allergy. Specific IgE antibodies were characterized for cross-reactivity and compared with pollen RAST results. Latex and banana extracts were investigated for common antigens and allergens.


METHODS
Latex-, banana-, and pollen-specific (birch, timothy, mugwort) IgE were measured in 47 sera from patients with latex allergy. Thirty-one patients were skin prick tested with banana and questioned for possible reactions after eating bananas. Several RAST inhibition and immunospot inhibition studies were used to characterize cross-reacting IgE antibodies. Structurally similar antigens and allergens were evaluated with crossed-line immunoelectrophoresis and crossed-line radioimmunoelectrophoresis, respectively.


RESULTS
Latex RAST results were positive in 31 (66%) and banana RAST results were positive in 26 (55%) of the 47 sera. Of the 31 latex RAST-positive sera, 25 (81%) were also banana RAST-positive. Results from latex RAST correlated significantly with results from banana RAST (p < 0.001), but not with those from pollen RAST (p > 0.05). Banana skin prick test results were positive in 11 (35%) of the 31 patients tested. Symptoms after eating bananas were reported by 16 (52%) of the 31 patients. In inhibition studies the binding of IgE antibodies to solid-phase banana and to several latex preparations was inhibited by latex and banana, respectively. In crossed-line immunoelectrophoresis at least one antigen from banana fused with an antigen from latex, which also bound IgE antibodies in autoradiography (crossed-line radioimmunoelectrophoresis).


CONCLUSIONS
Patients with latex allergy have symptoms caused by banana and show positive skin test and specific IgE test results. Cross-reacting IgE antibodies were confirmed by several inhibition techniques. For the first time, a structurally similar antigen/allergen was demonstrated.
Mäkinen-Kiljunen
S
S
Department of Dermatology and Allergic Diseases, Helsinki University Central Hospital, Finland.
D000328:Adult; D002648:Child; D003429:Cross Reactions; D005260:Female; D005638:Fruit / Q000276:immunology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D007122:Immunoelectrophoresis; D007073:Immunoglobulin E / Q000276:immunology; D007428:Intradermal Tests; D008297:Male; D011852:Radioallergosorbent Test; D012189:Retrospective Studies; D012408:Rubber / Q000009:adverse effects*
D007073:Immunoglobulin E; D012408:Rubber