Can genetics explain if you are allergic to some pollens or foods?

Genetically determined white blood cell patterns designated as the HLA DQ and DR genes have been identified with an increased risk of allergies to pollen, dust, latex, and food. The intriguing part of this story is that there is an advantage to knowing your HLA DR and DQ type when assessing your risk for pollen allergies and associated food allergies or cross-reactions.

Genetics of reactions to food and allergies

As I explain in more detail in my articles on the genetics of gluten sensitivity, we all have proteins on the surface of our cells that are genetically determined. These patterns are easily detectable by analyzing blood or mouth cells obtained with a Q-tip swab. Specific patterns have been associated with an increased risk of autoimmune diseases, gluten sensitivity, and celiac disease.

HLA DQ genetics and celiac disease or gluten sensitivity

HLA DQ2 is present in more than 90% of people who have celiac disease, while HLADQ8 is present in most of the rest, although not all celiac people have been found to have DQ2 and / or DQ8.

DQ and DR genetic patterns associated with allergies or sensitivities to food and pollen?

It now appears that certain patterns of DQ or DR are also associated with food and pollen allergies. As a Food Doc, I continue to search the literature for more information on genetic links to food allergies and intolerances. My search has led me to a couple of interesting articles in the unusual area of ​​oral allergy syndrome (OAS). The relationship between seasonal and perennial nasal allergies and food allergies is well established, but is generally not known to most doctors or patients. It seems that some of us should avoid eating certain foods if we have hay fever or allergies, especially during hay fever season. This problem also appears to be inherited.

Research documents genetic association with certain food and pollen allergies

Boehncke et al. from the University of Frankfurt reported in 1998 that certain types of white blood cells known as HLA class II genotypes or HLA DQ and DR genetic patterns were found more frequently in people with certain pollen-associated food allergies. HLA-DQB1 * 0301 is present in more people with allergy to grass pollen. Those with HLA-DRB1 * 08, an inherited white blood cell protein pattern linked to an allergy to grass pollen, are at six times the risk of a peanut allergy. Those who have inherited the HLA-DRB1 * 12 white blood cell pattern have a 13 times higher risk of carrot allergy.

Tree pollen allergy to birch pollen appears to be worse

Hazelnut allergy associated with birch pollen is related to HLA-DRB1 * 01, DQA1 * 0101, and DQB1 * 0501. Hazelnut, almond, walnut, and apple are the most common food allergies associated with birch pollen. . Allergies to those foods are commonly associated with birch pollen in other studies.

Weed allergies are also associated with food reactions

In 2004, Wang et al. from China published that the inherited white blood cell type DQA1 * 0302 is found in more people with Artemisia pollen-induced allergic rhinitis, hay fever due to mugwort or mugwort. Mugwort allergy is associated with several food allergies, including apple, celery, hazelnut, pistachio, lettuce, almond, peanut, and carrots.

Where to get genetic testing

I am aware of three commercial labs that offer full HLA DQ typing. They are Quest Laboratories, The Laboratory at Bonfils in Denver, and Enterolab. Bonfils runs Enterolab’s genetic tests. Enterolab offers the functional test on cell samples obtained from a Q-tip swab from the mouth. The test can be obtained directly from Enterolab without a doctor’s order, although it is not covered by insurance. However, it is very reasonable from a genetic testing point of view at $ 149. Bonfils also performs DQ typing on cells obtained from blood samples sent from other laboratories.

The future of genetic testing on pollen and food allergies

In the future, such tests should be very helpful in evaluating food allergies, intolerances, and allergies to pollen. In the meantime, those of us interested in this story look forward to more interesting research findings in this exciting area. Enterolab founder Dr. Fine has previously published the HLA DQ patterns associated with microscopic colitis. It has found that microscopic changes in the colon or large intestine are similar, if not identical, to those seen in the small intestine in celiac disease. Several articles now document that a gluten-free diet works for many people with microscopic, lymphocytic, and collagen colitis. It also helps many people with Crohn’s disease and ulcerative colitis.

A finding of intraepithelial lymphocytosis in the distal small intestine (terminal ileum) is associated with an increased incidence of celiac disease in the proximal small intestine. Now adding to the intrigue are these articles that link certain inherited white blood cell protein genetic patterns to pollen allergy and food allergy cross-reactions that are well recognized but rarely pursued clinically. Oral allergy syndrome (OAS), also called “burning mouth syndrome,” occurs in many people, but is often not diagnosed. Symptoms include a burning sensation, pain, and / or itching in the mouth or throat with or without swelling that occurs almost immediately after eating certain foods. The foods that cause these reactions are commonly associated with allergies to pollen, latex, or dust.

Unusual association of pollen allergies and burning mouth or food reactions

This unusual association of tree, grass and weed pollens, latex, and house dust mite allergies to food reactions, although well documented in the medical literature, is not commonly recognized by physicians or patients. The OAS literature contains numerous reports of food allergy or intolerance reactions that are associated with specific allergies to pollen, dust, mold, or latex. One of the best examples is ragweed pollen allergy. It is associated with an increased risk of allergy or intolerance to some foods. These include foods from the pumpkin family (cucumbers and melons) and bananas. On the other hand, birch pollen allergy is associated with sensitivity to many foods. The list includes foods from the rosacea family (apples, pears), tree nuts (hazelnuts, almonds, walnuts), potatoes, and carrots. Reactions include classic allergic reactions such as skin rashes (atopic dermatitis, urticaria), wheezing (asthma), runny nose (allergic rhinitis), as well as burning mouth, OAS symptoms, and other symptoms of food intolerance.

If you suspect a food allergy, intolerance or sensitivity, have it evaluated by an expert

People who suspect they have a food allergy or intolerance are encouraged to review the connection between food and pollen and undergo appropriate testing for food allergies, intolerances, and sensitivities. Food sensitivity includes sensitivity to gluten and sensitivity to cow’s milk proteins (casein). Food intolerance includes lactose intolerance. Food allergies are independent of and distinct from food sensitivity or intolerance.

Consider getting genetic testing or asking your doctor to do it

This new information on the linkage of white blood cell protein patterns, HLA DQ types, suggests that we should consider genetic testing. After a proper evaluation,

Establish an initial symptom score and start a food symptom diet diary

I encourage everyone to establish a baseline symptom score. A detailed food symptom diary prior to an elimination diet test is also extremely helpful. An elimination diet that excludes major dietary lectins (dairy, cereals, legumes, and nightshades) and any foods on the pollen list to which one is allergic is recommended before accepting diagnoses of IBS, fibromyalgia, neuropathy, or unexplained headaches, and Chronic Fatigue Syndrome. Any symptoms that are not easily explained or improved by other diagnoses and treatments should be considered possibly due to a food reaction until proven otherwise.

Selected bibliography

Boehncke et al. Allergy to Clin Exp. 1998 Apr; 28 (4): 434-41.

Fine KD et al. I am J Gastroenterol. August 2000; 95 (8): 1974-82.

Wang et al. Otolaryngol Head and Neck Surgery Feb; 130 (2): 192-197.