Allergy misconceptions: Why hay fever may be a good sign

April 25, 2012

(Medical Xpress) -- If you're one of the millions of people coughing, sneezing, sputtering, and cursing your body's hypersensitivity to ragweed, trees, and grass this spring, researchers at Yale have what could be considered positive news: Seasonal allergies may be a sign that your immune system is doing what nature intended it to do -- protect you against environmental toxins that are far more harmful than pollen. The paper appears in Nature.

The body’s defense arsenal consists of different types of immune responses to deal with various classes of pathogens. Type 1 immunity — which battles viruses, bacteria, fungi, and protozoa — relies primarily on directly killing pathogens or infected host cells.

Type 2 immunity, the focus of this Perspectives piece, protects against external environmental challenges by spurring the body’s T cells and antibodies into action to fight the irritant. The problem is, type 2 immunity can go into overdrive when inadvertently activated by environmental antigens such as pollen. Hay fever sufferers know the consequences all too well: The allergens such as pollen trigger an over-production of histamine, resulting in the coughing, sneezing, runny noses, and all-round misery that afflict them most severely in the spring and fall.

Nonetheless, the Yale authors argue that, despite the occasional misfiring, type 2 immunity is beneficial to humans. They write that this particular response of the host defense system evolved over time to protect us from at least four different classes of environmental challenges: helminthes (parasites), noxious chemicals, animal venoms, and environmental irritants.

But if type 2 immunity evolved over time to protect us, what is the purpose of sensing such small amounts of allergen when the levels are far too low to really harm us, and when a misfiring can cause such suffering?

Lead author Ruslan Medzhitov, professor of immunobiology at Yale School of Medicine and a Howard Hughes Medical Institute investigator, said, “We believe that allergic hypersensitivity evolved to survey the environment for the presence of noxious substances. After the first exposure, the gains a memory, and subsequent exposure to even minute amounts will induce an anticipatory response that helps minimize potentially harmful effects.” He added that such responses also encourage avoidance of the environment that contains the noxious substance. “According to this view, hypersensitivity to allergens triggers avoidance of a sub-optimal environment,” Medzhitov explained.

Explore further: What does my child's sneeze mean?

More information: www.nature.com/nature/journal/ … ull/nature11047.html

Related Stories

What does my child's sneeze mean?

April 26, 2011
(Medical Xpress) -- Though much of the beauty of spring is its vivid colors, rosy-red eyes and noses aren’t usually considered a welcome part of the landscape. Runny noses, sneezing and coughing often trumpet spring’s ...

Get ready for spring - hay fever worse in spring than summer

December 21, 2011
Hay fever (runny nose, sneezing, itchy eyes) is caused by an allergy to pollen, and most commonly to grass pollen. These tiny grains bring misery to sufferers through spring and summer and pollen levels are often included ...

Cells use allergic response to protect against cancer-causing damage

December 2, 2011
(Medical Xpress) -- CANCER RESEARCH UK scientists have found that the body’s surveillance for cancer causing damage and its response to allergies share a common pathway, according to research published in Science.

Antibodies are not required for immunity against some viruses

March 1, 2012
A new study turns the well established theory that antibodies are required for antiviral immunity upside down and reveals that an unexpected partnership between the specific and non-specific divisions of the immune system ...

Recommended for you

Gene immunotherapy protects against multiple sclerosis in mice

September 21, 2017
A potent and long-lasting gene immunotherapy approach prevents and reverses symptoms of multiple sclerosis in mice, according to a study published September 21st in the journal Molecular Therapy. Multiple sclerosis is an ...

New academic study reveals true extent of the link between hard water and eczema

September 21, 2017
Hard water damages our protective skin barrier and could contribute to the development of eczema, a new study has shown.

Exposure to pet and pest allergens during infancy linked to reduced asthma risk

September 19, 2017
Children exposed to high indoor levels of pet or pest allergens during infancy have a lower risk of developing asthma by 7 years of age, new research supported by the National Institutes of Health reveals. The findings, published ...

Cholesterol-like molecules switch off the engine in cancer-targeting 'Natural Killer' cells

September 18, 2017
Scientists have just discovered how the engine that powers cancer-killing cells functions. Crucially, their research also highlights how that engine is fuelled and that cholesterol-like molecules, called oxysterols, act as ...

MicroRNA helps cancer evade immune system

September 18, 2017
The immune system automatically destroys dysfunctional cells such as cancer cells, but cancerous tumors often survive nonetheless. A new study by Salk scientists shows one method by which fast-growing tumors evade anti-tumor ...

'Exciting' discovery on path to develop new type of vaccine to treat global viruses

September 15, 2017
Scientists at the University of Southampton have made a significant discovery in efforts to develop a vaccine against Zika, dengue and Hepatitis C viruses that affect millions of people around the world.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

alfie_null
not rated yet Apr 26, 2012
... such responses also encourage avoidance of the environment that contains the noxious substance.

Begs the question.

Antarctica?
Doug_Huffman
not rated yet Apr 26, 2012
Modus ponens, null?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.