Identification of hevein (Hev b 6.02) in Hevea latex as a major cross-reacting allergen with avocado fruit in patients with latex allergy.
BACKGROUND
Recent studies demonstrated that allergy to natural rubber latex is frequently associated with hypersensitivity to avocado fruit. The responsible cross-sensitizing allergen has not been identified.


OBJECTIVE
The purpose of this study was to investigate the cross-reactivity of a latex major allergen, hevein, with avocado proteins.


METHODS
Serum samples from 118 health care workers (HCWs) allergic to latex (HCW group) and 78 patients with spina bifida (SB) allergic to latex (SB group) were included in this study. Anti-hevein and anti-avocado IgE antibodies were measured by enzyme-linked allergosorbent assay. Cross-reactivity of hevein to avocado proteins was assessed by inhibition of the IgE binding in individual patients' sera containing IgE antibodies to both hevein and avocado.


RESULTS
The prevalence of seropositive IgE antibodies to avocado was found to be strongly associated with the presence of hevein-specific IgE antibodies in subjects of both groups (P < .001). Sixty-seven of 91 (73%) subjects from the HCW group and all 19 subjects in the SB group with positive IgE antibodies to hevein also had elevated IgE values to avocado. Competitive RAST inhibition with 42 sera showed that IgE binding to avocado could be completely inhibited in 27 (64%) sera by preincubation with hevein. By contrast, the degrees of inhibition of IgE to hevein by avocado extract ranged from 0% to 36% (n = 16). These results indicate that sensitization to avocado in most patients allergic to latex is caused exclusively by IgE-binding epitopes present in hevein. Results of immunoblots and immunoblot inhibition with 11 serum samples confirmed that a 30-kd protein in avocado was the major IgE-binding component; the IgE-binding reactivity to this protein could be inhibited by hevein in all sera tested.


CONCLUSIONS
Hevein is the major cross-reacting allergen with avocado in subjects with latex allergy.
Research Institute for Occupational Medicine (BGFA), Ruhr-University of Bochum, Germany.
Z
Z
Chen
A
A
Posch
R
R
Cremer
M
M
Raulf-Heimsoth
X
X
Baur
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D019665:Euphorbiaceae / Q000276:immunology; D005260:Female; D005512:Food Hypersensitivity / Q000097:blood / Q000276:immunology*; D005638:Fruit; D006282:Health Personnel; D006801:Humans; D007114:Immunization; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood; D007840:Latex / Q000276:immunology*; D020315:Latex Hypersensitivity / Q000097:blood / Q000276:immunology*; D019770:Lauraceae; D037102:Lectins / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D037121:Plant Lectins; D010940:Plant Proteins / Q000276:immunology*; D017386:Sequence Homology, Amino Acid; D016135:Spinal Dysraphism / Q000097:blood / Q000276:immunology
D000485:Allergens; D023181:Antimicrobial Cationic Peptides; D007840:Latex; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; C045875:hevein; D007073:Immunoglobulin E