Cross-allergy

What do we mean by cross-allergy?

This summary draws attention to the occurrence of cross-allergies, which at first glance may give rise to contradictory results.

Occasionally, a reaction to food can be detected even when the patient can prove that they have never eaten the food.
If no ‘hidden’ source can be found when the diet is checked, a cross-allergy or cross-reaction is likely to be the cause.

A cross-allergy occurs when the antibody recognises not only the food protein against which it was produced, but also other very similar antigens.
This may be because some foods and pollen, although not directly related, have the same molecule or the same molecular part.
The part of the molecule recognised by the antibody is called the antigenic epitope.
This phenomenon has long been observed and more and more epitopes are being identified using modern molecular diagnostic tools.

If the homology is above 70%, i.e. the match between different antigens is greater than 70%, a cross-allergy can occur.
Thus, cross-allergy can also occur if the patient has become sensitive to a molecule that is also found in something else with which he or she has come into contact.
Cross reactants include foods and pollens, but also latex and insects.

Other factors that contribute to the clinical manifestation of cross-allergy:

  • the concentration of the allergen;
  • the appearance of the allergen epitope also depends on the maturity level of the molecule;
  • certain antigens are sensitive to temperature and decompose with heat;
  • geographical factors, biodiversity;
  • other contributing factors such as physical exertion, medication.
MIT ÉRTÜNK KERESZTALLERGIA ALATT?

Example of cross-allergy

Many people develop a classic (type I) allergic reaction to tropomyosin, the main allergen in dust mites.
Many patients are desensitised (desensitised) by allergists so that they can overcome their allergies without help.
Others can be cured without medication.

These patients also produce IgG antibodies (more specifically IgG4 antibodies).
High levels of IgG4 antibodies are also detected by FOODTEST 200+.
Normally, the antibodies detected by the test belong to the IgG1 and 2 class, in extreme cases to the IgG3 class.

Tropomyosin, however, is found not only in the dust mite but also in other invertebrates, in varying concentrations.
Commonly consumed invertebrates: mussels, oysters, crabs, shrimps, lobsters.
Thus, if a patient is sensitive to dust mites, he may also react to oysters.
Therefore, the FOODTEST 200+ test will cause oyster positivity even if the patient has never eaten oysters.

keresztallergia-keresztreakcio

The source of the article is from the FOODTEST.hu website

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