Allergy is an unusual hypersensitivity to various substances, which most people do not cause painful reactions. Typically, the enemies are household dust, plant pollen, mold, pet epithelium, some types of food, etc. These agents become allergens and allergies occur.
In the first years of a child’s life, the development of the disease is provoked primarily by food allergens (cow’s milk, eggs, fish, cereals, orange or red colored fruits and vegetables).
IMMUNOBLOT IN FOOD ALLERGIES
Diagnosis of the state of sensitization in vitro is carried out using test systems to determine the allergen-specific IgE in serum by immunoblotting. The test is a multi-parameter analysis that includes an optimized combination of relevant allergens and allows for simultaneous determination of IgE to these allergens. The so-called “G8” products that most often cause allergies include: cow’s milk, chicken egg, soybeans, peanuts, nuts, wheat, seafood and fish.
Cow’s milk allergens (f2)
True allergy to cow’s milk protein is observed in 2-3% of young children. Antigenic determinants are β-lactoglobulin (f77), α-lactalbumin (f76), bovine serum albumin (e204), α- and β-caseins (f78). Allergy to cow’s milk protein is often combined with a cross-allergic reaction to goat’s milk. At the same time, allergies to goat milk may be a separate disorder and occur in individuals who tolerate cow’s milk. Milk allergens do not lose their properties after boiling, ultra-pasteurization, drying, preserved in the preparation of mixtures for artificial breastfeeding.
Chicken egg allergens (f1)
Chicken eggs contain 13 antigenic determinants, the most important of which are ovomucoid, ovalbumin, konalbumin, lysozyme, ovoglobulin, and levetyn yolk (f75). Some of the antigens of eggs are thermolabile (destroyed by heating), which allows sensitized individuals to eat small amounts of heat treated product. It should be noted that eggs are part of many products, including pasta, sausages, bakery products, ice cream, some semi-finished products.
Soybean allergens (f14)
Antigenic determinants of soybean include glycinin-11S globulin, 7S globulin and conglicin. Soy protein is often found in meat products, semi-finished products, chocolates, sweets, artificial feeding mixtures) and causes severe systemic allergic reactions as well as oral allergic syndrome in sensitized individuals.
Peanut (f13) contains a large number of allergenic proteins, which include vicillin, profilin, conglutin, glycinin, and others. After culinary treatment, the immunogenic properties of peanut antigens are enhanced. Particular care should be taken when eating products that “may contain trace amounts of peanuts” due to the peculiarities of production, since even minimal doses of allergens can cause severe anaphylactic reactions. This category of products includes bakery products, sweets and confectionery products, ice creams and sauces. In 20% of cases of sensitization during the first 2 years of life, tolerance further develops.
Other nuts, in particular hazelnuts (f14), cashews, walnuts, almonds contain spare proteins 7S and 11S globulins, which have strong allergenic properties and lead to cross-reactions.
The greatest clinical significance has wheat gliadin (f4), gluten rye, barley and oats, less often – the proteins of corn, rice (f9), buckwheat. Sensitization to gliadin usually develops in early childhood with the introduction of feed; by the age of 4, 50% of children develop tolerance.
The most allergenic properties are thermostable parvalbumines, in particular M-protein cod (f3), which during thermal treatment can penetrate the respiratory tract with the steam and cause inhalation allergy. Parvalbumins of different fish species cause cross-sensitivity, with age, tolerance usually does not develop. Seafood with pronounced allergenic properties include crustaceans (shrimps, crabs, lobsters) and clams (mussels, scallops, oysters, squid, octopus, etc.).
Nonspecific histaminolyberators (coffee, cocoa, chocolate, citrus, strawberries) may also cause allergies or increase food allergies to other foods.