Non-Gluten Proteins-A IgA

Function:

Wheat proteins/peptides are commonly categorized as gluten and non-gluten. Non-gluten proteins alpha-amylase and serpin are a very small portion of wheat (2-4% and ~1.6% respectively). Non-gluten proteins are generally soluble in water or aqueous salt solutions and function as storage or enzyme proteins.

Associated With:

- Baker’s asthma

- Wheat allergy

- Chronic urticaria

- Eczema

- Wheat-dependent exercise-induced anaphylaxis

- IgA in Celiac disease

- IgG in Dermatitis herpetiformis

- Crohn’s disease

Known Cross-Reactions:

Alpha-amylase with gamma-gliadin and glutenin, serpin with glutamine rich gluten proteins

Clinical Significance:

Alpha-amylase and serpin can escape digestion and activate toll-like receptor-4 (TLR4). Immune reactivity and clinical manifestations of non-gluten proteins are most often associated with hypersensitivities/allergies. IgG and IgA antibodies to non-gluten proteins may be present due to cross-reactivity between non-gluten and gluten proteins. Homology between g-gliadin and non-gluten proteins has been shown. Furthermore, wheat, barley, rye and corn belong to the same family of a-amylase inhibitors.

References:

1. Sander et al. Multiple wheat flour allergens and cross-reactive carbohydrate determinants bind IgE in baker’s asthma. Allergy,
2011; 66(9):1208-1215.

2. Gomez et al. Members of the a-amylase inhibitors family from wheat endosperm are major allergens associated with baker’s
asthma. FEBS, 1990; 261(1):85-88.

3. Mameri et al. Molecular and immunological characterization of wheat Serpin (Tri a 33). Mol Nutr Food Res, 2012; 0:1-10.

4. Manawil et al. Baker’s respiratory allergy and specific wheat antibodies. J Appl Sci Res, 2013; 9(1):444-450.

5. Oyarzabal et al. Chronic urticaria due to allergy to wheat alpha-amylase inhibitor proteins. Case Rep Clin Med, 2016; 5:130-133.

6. Czaja-Bulsa and Bulsa. The natural history of IgE mediated wheat allergy in children with dominant gastrointestinal symptoms. Allergy Asthma Clin Immunol, 2014; 10:12.

7. Pastorello et al. Wheat IgE-mediated food allergy in European patients: a-amylase inhibitors, lipid transfer proteins and lowmolecular-weight glutenins. Int Arch Allergy Immunol, 2007; 144:10-22.

8. Huebener et al. Specific nongluten proteins of wheat are novel target antigens in Celiac disease humoral response. J Proteome
Res, 2015; 14:503-511.

9. Vojdani and Vojdani. Gluten and non-gluten proteins of wheat as target antigens in autism, Crohn’s and Celiac disease. J Cereal
Sci, 2017; 75:252-260.

10. Takács et al. Immune-analytical detection of the cross-reactive major cereal allergens. Food Agricultural Immunol, 2010;
21(4):317-334.

11. Makharia et al. The overlap between irritable bowel syndrome and non-celiac gluten sensitivity: a clinical dilemma. Nutrients,
2015; 7:10417-10426.

12. García-Olmedo et al. Plant proteinaceous inhibitors of proteinases and a-amylases. Oxford Surveys Plant Mol Cell Biol, 1987;
4:275-334.