Prospective study of sensitization and food allergy to flaxseed in 1317 subjects.
BACKGROUND
Foods containing flaxseed proteins rich inpolyunsaturatedfatty acids are new on the market.


OBJECTIVE
In a population of patients attending the allergology department, we evaluated the frequency of sensitization to flaxseed, characterized allergens and looked for modifications related to industrial processing.


METHODS
Natural, heated and extruded flaxseeds were tested using prick-in-prick tests (PIP using the fresh seed), SDS PAGE, immunoblots, immunoblot inhibition and Fourier Transform Infrared (FTIR) spectroscopy.


RESULTS
PIP tests to natural flaxseed were positive in 5.8% of the 1317 patients. 73 of 77 PIP-positive patients were atopic. There was cross-reactivity with five seeds. peanut, soybean, rapeseed, lupine and wheat, and with rape pollen. Immunoblot inhibition by bromelain confirmed the presence of specific IgE to cross-reactive carbohydrate determinants (CCD). 0.15% of this population presented with food allergy to flaxseed and positive PIP to heated and extruded flaxseed. Two sera showed that clinically relevant allergens in industrial products had MW between 25 and 38 kDa. Sensitization to processed flaxseed characterized only the allergic subjects. FTIR spectroscopy showed major modifications in 3 and alpha structures following industrial processing.


CONCLUSIONS
Positive prick tests to natural flaxseed were mainly due to cross-reactions. Flaxseed allergy is rare and could be detected by PIP to heated extruded flaxseed. Increasing consumption callsfor monitoring of clinical risk.
Fremont
S
S
Laboratoire de Biochimie et Biologie Moléculaire, Hôpital Central, Nancy.
Moneret-Vautrin
D A
DA
Franck
P
P
Morisset
M
M
Croizier
A
A
Codreanu
F
F
Kanny
G
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D015153:Blotting, Western; D002241:Carbohydrates / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D005260:Female; D019597:Flax / Q000276:immunology*; D005512:Food Hypersensitivity / Q000175:diagnosis*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012882:Skin Tests; D017550:Spectroscopy, Fourier Transform Infrared
D002241:Carbohydrates; D007073:Immunoglobulin E