Cross-allergenicity of peanut and lupine: the risk of lupine allergy in patients allergic to peanuts.
BACKGROUND
Peanut allergy is common, but cross-allergy between legumes is rare. Proteins from Lupinus albus are increasingly eaten in the form of seeds or additives to wheat flour. The risk of cross-allergenicity is still insufficiently known.


OBJECTIVE
We sought to study the risk of cross-allergy to lupine in patients allergic to peanut and to study lupine allergenicity.


METHODS
Twenty-four patients allergic to peanuts were studied by means of skin prick tests with native lupine flour from Lupinus albus. Double-blind oral challenge tests were performed with lupine flour and peanut in 8 of these patients. Specific IgEs were assayed for peanut, lupine flour, and pollen in 6 sera. RAST inhibition tests for lupine pollen by peanut were performed on 4 of these sera. Peanut and lupine flour immunoblots were carried out for 6 sera, and crossed immunoblot inhibitions for peanut by lupine flour and lupine flour by peanut were carried out for 2 sera.


RESULTS
The skin prick test responses with lupine flour were positive in 11 (44%) subjects. The challenge test responses were positive in 7 of 8 subjects at the same doses as with peanut. The major lupine flour allergen (molecular mass, 43 kd) is present in peanuts. The RAST inhibition and immunoblot tests indicated cross-reactivity of peanut with the lupine flour and pollen.


CONCLUSIONS
The risk of crossed peanut-lupine allergy is high, contrary to the risk with other legumes. The inclusion of 10% lupine flour in wheat flour without mandatory labeling makes lupine a hidden allergen, presenting a major risk of cross-reaction in subjects already allergic to peanut products. A high sensitizing potential can also be postulated for this legume.
Moneret-Vautrin
D A
DA
Department of Clinical Immunology and Allergology, Hôpital Central, Nancy, France.
Guérin
L
L
Kanny
G
G
Flabbee
J
J
Frémont
S
S
Morisset
M
M
D000293:Adolescent; D000485:Allergens / Q000276:immunology*; D010367:Arachis / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D007887:Fabaceae / Q000276:immunology*; D005260:Female; D005433:Flour; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007223:Infant; D008297:Male; D010940:Plant Proteins / Q000276:immunology*; D010946:Plants, Medicinal; D011058:Pollen / Q000276:immunology; D012882:Skin Tests; D013025:Glycine max / Q000276:immunology
D000485:Allergens; D010940:Plant Proteins