Package "Allergy to eggs" (ovomucoid, Egg nGal d 1, f233; ovalbumin, Egg nGal d 2, f232; lysozyme, Egg nGal d 4, k208; conalbumin eggs nGal d 3, f323)
Analyses included in the package:
Egg ovomucoid nGal d 1, f233
Egg ovalbumin nGal d 2 IgE, f232
Egg lysozyme nGal d 4, k208
Egg conalbumin nGal d 3 IgE, f323
Egg white contains about 24 protein fractions and is considered highly allergenic.
Allergy component diagnosis is based on the detection of sensitization to allergens at the molecular level using natural highly purified and recombinant allergen molecules, i.e. their individual allergy components.
There are 2 main advantages of performing this analysis:
- Allergy component diagnostics gives the ability to differentiate true sensitization from sensitization due to cross-reactivity. This data will help to identify the sources of allergy which can be a single allergy, several closely related allergies or many different allergies.
- Molecular allergodiagnosis eliminates the need for provocation tests and allows for clearer recommendations regarding the elimination of contact with allergens.
An allergenic substance contains not one but several protein components that can act as allergens as follows:
Major allergic components are the major allergenic molecules, antibodies to which are found in more than half to 50% of patients in the population reacting to a given source. They are heat stable and more immunogenic. Major are large in size and are found in greater quantities in a given allergen.
Minor allergens are minor, smaller in size and less immunogenic allergenic molecules that are usually contained in smaller quantities within an allergen but are present in many different allergens, sometimes not closely related, providing cross-allergy. That is, allergens with a prevalence of more than 50% are called major allergens and less than 10% are called minor allergens.
Eggs are considered one of the most common sources of food allergy, especially in infants and children, with prevalence rates ranging from 1.3% to 1.6%. However, the prevalence of egg allergy in adults is less than 0.25%. People with suspected egg allergy may experience allergic reactions such as anaphylaxis, gastrointestinal symptoms, skin reactions, and respiratory illness after consuming egg white.
Egg ovomucoid (nGal d 1) is the predominant egg allergen, highly allergenic and resistant to heat. Significant levels of specific IgE antibodies to Gal d 1 indicate a risk of developing clinical reactions to raw and cooked egg. Low or undetectable levels of IgE antibodies to Gal d 1 indicate tolerance to heat-treated eggs, such as in cakes or pastries. Component studies are helpful in identifying children who are likely to outgrow their egg allergy as monitoring sIgE levels to Gal d 1 later can help determine it when tolerance develops.
Ovalbumin (nGal d 2) is a thermolabile protein and is even amenable to enzymatic cleavage. It has been found that the process of heating or enzymatic cleavage of Gal d 2 reduces its allergenicity. Thus, allergy to Gal d 2 is usually associated with raw eggs rather than boiled eggs. Patients with egg allergy who are sensitive to Gal d 2 may have allergic reactions to influenza or yellow fever vaccine.
Egg lysozyme (nGal d 4) makes up about 3-3.4% of the total protein content of egg white and has antibacterial properties. Lysozyme is a thermolabile protein and is even amenable to enzymatic cleavage. The process of heating or enzymatic cleavage of Gal d 4 has been found to reduce its allergenicity. Lysozyme is used in the food (cheese, wine, etc.) and pharmaceutical (e.g., eye drops) industries as a preservative because of its antibacterial properties. Egg allergic patients with sIgE to Gal d 4 may react unexpectedly to the latent form of egg lysozyme in pharmaceutical and food products.
Egg conalbumin (nGal d 3) is thermolabile and may show a risk of clinical reaction to raw or slightly heated egg