Swine epithelium
Summary
Contact with swine epithelium or derived proteins occurs mainly during swine farming. Animal rehabilitation facilities, veterinary practice, owning pigs as pets, and contact with wild boars also allow contact with S. scrofa epithelium. Swine farming is frequently associated with adverse respiratory effects including rhinoconjunctivitis, asthma, decreased lung function, however, IgE sensitization to swine epithelium is infrequent. Similarly, hypersensitivity pneumonitis associated with swine farming is seldom associated with swine epithelial antigens. IgE sensitization to swine epithelium has been proposed as a marker of endocarditis on cardiac valve bioprosthesis.
Epidemiology
Risk factors
Unlike cat, dog, or horse, S. scrofa is infrequently kept as a family pet [2]. Therefore, contact with swine epithelium occurs mainly as a result of occupational exposure: swine farming, veterinarians, other agricultural workers [3]. The increase in unconventional pet keeping may also result in increased contact with S. scrofa epithelium [4]. Conversely, despite wild boar hunting being practiced worldwide and boar farming receiving increasing interest [1], no reported allergy to boar epithelium has been reported yet. Porcine bioprosthesis for heart valve replacement has been associated with IgE sensitization to swine epithelium and in rare cases to noninfectious endocarditis attributed to swine allergy [5, 6].
Route Of Exposure
Main
The main route of exposure to swine epithelium is through inhalation of allergenic molecules [3].
Secondary
Direct skin contact with swine epithelium and surgical implantation of porcine bioprosthetic materials are alternative routes of exposure [3, 5].
Clinical Relevance
Despite swine farming being associated with adverse respiratory conditions, IgE sensitization to swine epithelium is an infrequent finding, the main pathophysiological culprit being IgE-independent mechanisms [3].
Allergic reactions to porcine bioprostheses for valvular replacement have been associated to endocarditis [5, 6].
Cross-Reactivity
There is partial cross-reactivity between swine hair and dander and hair, dander and serum from other domestic animals and pets [9]. Swine epithelium is not involved in the so-called pork-cat syndrome, which is due to allergen cross-reactivity between cat dander and pork meat [8].
References
- Sales, J. and R. Kotrba, Meat from wild boar (Sus scrofa L.): a review. Meat Sci, 2013. 94(2): p. 187-201.
- Curin, M. and C. Hilger, Allergy to pets and new allergies to uncommon pets. Allergol Select, 2017. 1(2): p. 214-221.
- Sigsgaard, T., et al., Respiratory diseases and allergy in farmers working with livestock: a EAACI position paper. Clin Transl Allergy, 2020. 10: p. 29.
- Diaz-Perales, A., et al., Allergy to uncommon pets: new allergies but the same allergens. Front Immunol, 2013. 4: p. 492.
- Loyens, M., et al., Link between endocarditis on porcine bioprosthetic valves and allergy to pork. International Journal of Cardiology, 2013. 167(2): p. 600-602.
- Fournier, P., et al., A deadly aversion to pork. Lancet, 2011. 377(9776): p. 1542-1542.
- IUIS/WHO. IUIS/WHO Chordata. June 12 2022]; Available from: http://allergen.org/search.php?allergenname=&allergensource=cypress&TaxSource=Animalia+Chordata&TaxOrder=&foodallerg=all&bioname=.
- Matricardi, P.M., et al., EAACI Molecular Allergology User's Guide. Pediatr Allergy Immunol, 2016. 27 Suppl 23: p. 1-250.
- Prahl, P., B. Weeke, and H. Lowenstein, Quantitative immunoelectrophoretic analysis of extract from cow hair and dander. Characterization of the antigens and identification of the allergens. Allergy, 1978. 33(5): p. 241-53.