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

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

Genetics of food reactions 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 cells from the blood or from the mouth obtained with a swab-type swab. Specific patterns have been associated with an increased risk of autoimmune diseases, gluten sensitivity, and celiac disease.

HLA DQ Genetics and Celiacs 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 people with celiac disease have been found to have DQ2 and/or DQ8.

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

It now appears that certain DQ or DR patterns are also associated with food and pollen allergies. As 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 certainly well established, but is not generally 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 grass pollen allergy. Those with HLA-DRB1*08, a white blood cell protein inheritance pattern linked to grass pollen allergy, have a sixfold increased risk of peanut allergy. Those who have inherited the HLA-DRB1*12 white blood cell pattern have a 13-fold increased 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 mugwort 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 carrot.

Where to get genetic testing

There are three commercial labs that I know of that offer full HLA DQ typing. They are Quest Laboratories, The Laboratory at Bonfils in Denver, and Enterolab. Bonfils performs the genetic tests for Enterolab. Enterolab offers to run the test on cell samples obtained from a mouth swab. 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 standpoint at $149. Bonfils also performs DQ typing on cells obtained from blood samples sent from other laboratories.

The future of genetic testing in pollen and food allergies

In the future, these tests should be very useful in evaluating suspected food allergies, intolerance, and pollen allergies. In the meantime, those of us interested in this interesting story eagerly await further research findings in this exciting area. Dr. Fine, founder of Enterolab, has previously published HLA DQ patterns associated with microscopic colitis. He has found that the 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 collagenous colitis. It also helps many with Crohn’s disease and ulcerative colitis.

A finding of intraepithelial lymphocytosis in the distal small intestine (terminal ileum) is associated with a higher incidence of celiac disease in the proximal small intestine. Now, to add to the intrigue, these papers link certain inherited patterns of white blood cell protein genes 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 often goes undiagnosed. Symptoms include a burning, sore, and/or itchy feeling 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, while well documented in the medical literature, is not commonly recognized by clinicians 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 food allergy or intolerance to only a few 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), the nut family (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 in the mouth, symptoms of OAS and other symptoms of food intolerance.

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

Individuals who suspect a food allergy or intolerance are encouraged to review the food-pollen connection and undergo appropriate evaluations for food allergies, intolerances and sensitivities. Food sensitivities include sensitivity to gluten and sensitivity to cow’s milk protein (casein). Food intolerance includes lactose intolerance. Food allergies are separate and distinct from food sensitivities or food intolerances.

Consider getting genetic testing or asking your doctor to test you

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

Establish a baseline symptom score and start a food symptom diet diary

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

Selected bibliography

Boehncke, et al. ClinExp Allergy. 1998 April; 28(4):434-41.

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

Wang et al. Head neck otorhinolaryngology surgery Feb; 130(2): 192-197.