Hardcore Research

Cross-reactivity in mite allergy

In allergy, cross reactivity is fairly common. An allergy to birch tree pollen may signal an allergy to apples; an allergy to bananas can indicate an allergy to latex. These are examples of different sources of proteins, but chemically they are similar. The chemical similarity can cause the body's defence system to read them as one. Cross-reactivity is common in dust mite and storage mite allergens.

Other examples of possible cross-reactive allergens are bird feathers and egg yolks, shrimp and mites, or grass pollen, with wheat or rye flour. It has been known for some time that allergens of the dust mites (European and American) cross-react with allergens of storage mites. House dust mites have evolved to live on discarded skin scales, mould and general organic debris, while its close relative, the storage mite can be found in barns, stored grains and mouldy environments. The storage mite, living mainly on plants, moulds and micro-organisms, is a vegetarian in comparison with the skin-eating house dust mite. In spite of their different diets both mites, just like humans, have to break down digested fats in order to absorb nutrients. The house dust mite has evolved to digest animal fats while the storage mite digests fat from plants. Although these mites have different diets, they are thought to share the same enzymes (allergens) designed to dissolve fats in food. A 'fact' is still disputed or discussed by researchers.

The lesson here is important. People who are allergic to house dust mites may also be allergic to storage mites commonly found living in poorly stored grain. Some scientists prefer to call all these mites 'domestic mites' as they can be found in our homes and work places if the conditions are right. It's best to be safe and not encourage domestic mites in food or the home environment.

References

'The Biology of Allergenic Domestic Mites, An Update', Barbara J. Hart,1995 Clinical Reviews in Allergy and Immunology Vol.13, pages 115 to 133. Humana Press Inc.

Differences between the allergen repertoires of house dust mites and stored products mites; M Colloff, 'Clin. Immunol'. 1993;16:2

Quantification of IgE both as Total Immunoglobulin and as Allergen Specific Antibodies, T.G. Merritt, 'Allergy and Allergic Diseases',1997, Chapter 62, Editor AB Kay, Blackwell Publishing, ISBN 978-1-4951-570-9

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