A new allergen family involved in pollen food-associated syndrome: Snakin/gibberellin-regulated proteins

Up to now, the cross-reactive allergen at the basis of this syndrome has not yet been unraveled. Besides the 4 groups of allergens already described in the various Cupressaceae species, an as yet unidentified basic allergen of 14 kDa (BP14), overexpressed in Cupressus sempervirens pollen and different from a lipid transfer protein, was found to sensitize 37% of cypress pollen allergic patients (CPAPs) in Southern France.3 The BP14 IgE epitopes are not related to cross-reactive carbohydrate determinants and are heat resistant but destroyed under reducing conditions. Because Pru p 7 shares more than 80% sequence identity with snakin-1 and more than 95% with other fruit GRP allergens, BP14 should be considered as the cross-reactive allergen in the 2 documented PFAS involving peach and/or citrus.1 Preliminary experiments showed that patients allergic to cypress pollen and citrus expressed IgE against cypress pollen BP14 cross-reactive with a cationic 12-kDa allergen from grapefruit.9 Therefore, snakin/GRP may represent a new diagnostic marker of PFAS in addition to other allergens such as Bet v 1-like proteins involved in the well-studied birch/apple syndrome.10 Whether specific allergenic immunotherapy using a BP14-containing cypress pollen extract can reduce the food-related symptoms remains unknown for the moment and would deserve more investigations. [...]proteins were digested for 3 hours at 37°C in 50 mM NH4HCO3 with trypsin (concentration 12.5 μg/mL, sequencing grade, Pierce, Rockford, Ill). IgE reactivity on Immunosorbent for depletion Snakin-1 Cypress pollen extract 5 Snakin-1 + + BP14 in basic fraction − + 12 Snakin-1 + + BP14 in basic fraction − + Snakin-1 +∗ +† 14 BP14 in total extract − + BP14 in basic fraction −∗ +† 16 Snakin-1 ND ND BP14 in basic fraction − + 19 Snakin-1 + + BP14 in basic fraction − + 1 D. Charpin, C. Pichot, J. Belmonte, J.P. Sutra, J. Zidkova, P. Chanez, Cypress pollinosis: from tree to clinic, Clin Rev Allergy Immunol, April 11, 2017, Epub ahead of print 2 C. Truong van ut, F. Trébuchon, J. Birnbaum, M. Agell, R. Navarro-Rouimi, G. Gentile, Knowledge and behavior of patients with allergic rhinitis during a consultation with primary care in general practitioner, Rev Fr Allerg, Vol. 52, 2012, 429-436 3 Y. Shahali, P. Nicaise, A. Brazdova, D. Charpin, E. Scala, A. Mari, Complementarity between microarray and immunoblot for the comparative evaluation of IgE repertoire of French and Italian Cypress pollen allergic patients, Folia