Lettuce anaphylaxis: identification of a lipid transfer protein as the major allergen.
BACKGROUND
Allergy to plant-derived foods is associated with birch pollinosis in central and northern Europe. Symptoms elicited are usually limited to the oropharyngeal system. By contrast, in the Mediterranean area, allergy to the same foods manifests more frequently with systemic reactions caused by nonspecific lipid transfer proteins (nsLTP), independently of an associated pollinosis.


OBJECTIVE
We sought to investigate the pattern of immunoglobulin E (IgE) binding protein bands implicated in lettuce allergy, in particular the presence of an nsLTP.


METHODS
Consecutive lettuce allergic patients were selected. Determination of serum-specific IgE, immunoblot, and inhibition experiments were performed in order to study the pattern of IgE binding proteins and the potential cross-reactivity to pollens. Inhibition studies with recombinant allergens were conducted to identify the lettuce allergens. The major allergen was subjected to N-terminal amino acid sequencing.


RESULTS
Fourteen patients were diagnosed as being allergic to lettuce. All were sensitized to Platanus pollen. Ten of them showed specific IgE to a lettuce protein of 9-kDa. The IgE binding to this protein was completely inhibited by the cherry-LTP and peach extract. The N-terminal sequence of the 9-kDa protein showed a high degree of amino acid sequence identity to other nsLTPs. A clear partial cross-reactivity was observed between lettuce-LTP and Platanus-pollen extract.


CONCLUSIONS
An LTP has been demonstrated to be a major allergen in patients suffering from lettuce allergy.
San Miguel-Moncín
M
M
Allergy Department, Institut Universitari Dexeus, Barcelona, Spain.
Krail
M
M
Scheurer
S
S
Enrique
E
E
Alonso
R
R
Conti
A
A
Cisteró-Bahíma
A
A
Vieths
S
S
D000328:Adult; D000485:Allergens / Q000276:immunology / Q000378:metabolism; D000595:Amino Acid Sequence / Q000235:genetics; D000707:Anaphylaxis / Q000209:etiology*; D052179:Antigens, Plant; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D003429:Cross Reactions; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications*; D006801:Humans; D018545:Lactuca / Q000009:adverse effects* / Q000378:metabolism; D008297:Male; D010940:Plant Proteins; D011058:Pollen / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D014197:Trees / Q000276:immunology
D000485:Allergens; D052179:Antigens, Plant; D002352:Carrier Proteins; D010940:Plant Proteins; C511920:lipid transfer proteins, plant