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Sarah Faller 12/5/2016 Professor Hubert Bray Paper 3: Allergies Immune System The immune system’s job is to defend the body and keep microorganisms, such as certain bacteria, viruses and fungi out of the body and destroy the ones that do invade the body. The organs involved with the immune system are called the lymphoid organs (Commins). They are responsible for development and release of lymphocytes, a type of white blood cell that defends the body against potentially harmful invading molecules such as allergens. Allergies and Food Intolerance Allergies are a consequence of the immune system overreacting to certain kinds of molecules. However, sometimes what someone might think is a food allergy is really a food Intolerance. When someone is intolerant to a type of food, it’s most likely because their body lacks an enzyme necessary to break down the component in that food. For example, if someone is lactose intolerant they are missing the enzyme lactase that breaks down the sugar in milk (Shreffler). One can also be sensitive to a chemical in the additive food. For example, one may experience headaches, palpitations, or numbness after eating foods that are favored with monosodium glutamate (MSG) (Shreffler). A true food allergy involves one’s immune system. Simply put, one’s body mistakes a normally innocuous food as a “harmful foreign invader”; the substance triggering an allergic response is labeled an allergen. Once the body recognizes the allergen, the body goes into defense mode and produces high levels of antibodies, which are proteins, called immunoglobulins. The human blood contains five types of immunoglobulin: IgA, IgD, IgE, IgG, and IgM (Shreffler). Each antibody is programmed to recognize a unique foreign molecule. The majority of allergic reactions are caused by IgE antibodies. IgE antibodies link up with receptors on other specialized immune cells called mast cells. Mast cells are found in abundance in places that are an entry into the body. When a harmless allergen is recognized by the IgE and is docked on a mast cell, the mast cells instigate the “allergic reaction by releasing histamine, tryptase, and other chemicals,” (Shreffler). These antibodies travel to cells that release chemicals, causing the allergic reaction. Mast cells also release proteases, a chemical that can cause tissue damage. Once the mas cell is activated, they also produce their own cytokines, a chemical messenger that signals B cells, a type of white blood cell, to produce more IgE, which leads to more IgE antibodies docked on the mast cell, increasing the opportunity for inflammation to occur. Concurrently, other cytokines attract whole blood cells to the site of the allergic response, causing local inflammation. If left alone, this cycle can cause lasting tissue damage (Shreffler). Allergies can develop for many different reasons. A person can be either genetically predisposed to be allergic, or factors in one’s environment can make one more susceptible. Many times, it is a combination of both. A child who has one parent who has allergies has a 50% risk of developing allergies and a child who has both parents who have allergies has a 70% chance of developing allergies (Shreffler). A child is said to be atopic if they are genetically predisposed to allergies. However, genes alone are not enough to cause allergies. There are also environmental factors that can cause allergies. Researchers have found a positive relationship between older siblings and allergies since the late 1900’s (Jacewicz). One study that followed a group of British children for 23 years found that “the more older siblings a child has, the less likely he or she will be allergic to airborne particles like dust and pollen” (Jacewicz). Some scientists, such as Brix Pedersen, believe that the reason for this is that the younger siblings are exposed to a wider array of germs; kids are dirtiest when they’re the youngest and they help build their younger siblings immune system (Jacewicz). This is consistent with the study that children in day care, who are exposed to more germs, are less likely to develop asthma. However, some scientists believe in another theory. Danish researchers studied 571 1 month old babies’ snot. The researchers found that infants whose mothers had already been pregnant had a much higher level of signal proteins associated with trigger immune response (Jacewicz). Susanne Brix Pedersen, a biologist at the Technical University of Denmark, believes that because these proteins are not “Type 2” immune chemicals that tripper allergic reactions, it causes cells to react to foreign microorganism in a way different than the way a body acts to an allergy (Jacewicze). The researchers also found that the more time that passed between pregnancies, the lower the levels of protein the child has. This suggests that previous pregnancies can later change the chemistry inside the womb and that these changes can revert after a long period. Meat Allergy In recent years, a group of people started developing severe allergies to meat for no apparent reason. Allergists rejected the theory that the allergic reactions were caused by meat because it was unheard of that adults could develop allergies to food that they have eaten for years. Thomas Platts-Mills, a professor at the University of Virginia and who works for an allergy clinic, had been hearing about this supposed allergy as early as 2004. During the same time Thomas PlattsMills was asked to investigate the cancer drug cetuximab because it was causing some people who were injected with this drug to go into anaphylactic shock. Their immune system started to overreact to anything that was new. Mills was able to narrow down the culprit to a particular sugar molecule, galactose-alpha-1,3-galactose, also known as alpha-gal, a complex carbohydrate molecule (Shreffler). This same sugar is also found in non-primate animals. Mills and his team couldn’t figure out why after years of eating meat, some people were only recently developing an allergy. After extensive research Mills realized that the people who were developing a meat allergy were widespread in the southeast, Mid-Atlantic, and Northeast regions of the United States, places where there were also a lot of people with rocky mountain spotted fever caused by a lone star tick. The allergy was first formally identified by Sheryl van Nunen in her paper in 2009, as originating from tick bites. It wasn’t until Mills intentionally got bitten by a tick and developed the same allergies that his team came to this surprising conclusion (McEwen). Although it is not 100% clear what exactly the tick gives a person that makes them severely allergic, Sheryl Can Nunen and her team have a theory (McEwen). When the tick sticks onto someone, it injects its saliva into its victims. The spit the tick injects has anti-clotting factor, antiinflammatory factor, and many others things including alpha-gal from when it fed off other animals (McEwen). When the body is exposed to alpha-gal, covered by all the other harmful substances in the spit, the immune system goes into defense, and the alpha-gal gets mislabeled as a potential threat and the body remembers that ("Alpha-gal Allergy). Then, the next time that person eats meat, the body unleashes wave upon waves upon IgE antibodies to fight the alphagal. The abundance of antibodies can make the person feel horrible. They have the potential to break out into hives, angioedema, itching, or even experience anaphylaxis ("Alpha-gal Allergy). This allergy is different than most because most food allergies have been associated with proteins. However, alpha-gal is a sugar. Another unique aspect of this meet allergy is that it is not immediate. Most allergies to food are immediate, but a person experiencing alpha-gal allergy doesn’t react until four to six hours after ingesting. Alpha-gal is a sugar that attaches itself to fat molecules and the body can take about eight hours to completely absorb dietary fat from an average meal (St. John). Before fat can be broken down and absorbed, it must undergo processing in the stomach and pass into the small intestine. Stomach emptying, depending on the ratio of fats, proteins and carbohydrates, can take roughly five hours (St. John). Possible Ways of Prevention Allergies are becoming increasingly prevalent. Currently about one in five American children have a respiratory allergy like hay fever, and one in ten have asthma. Everyday nine people die due to asthma attacks. While the increase in respiratory allergies seem to be plateauing, food and skin allergies are continuing to rise (Velasquez-manoff). In the last 15-years the percentage of children allergic to peanuts, milk and other foods has doubled. In addition, each new generation seems to have more severe, life-threatening allergic reactions than the last (Velasquez-manoff). The reasons for this can’t all be genetic. For example, the Amish, who in the northern region of Indiana are remarkably free of allergies and asthma. The Amish originally came to America from the German-speaking religion of Switzerland, and currently Swiss children, a genetically similar population, are about as allergic as the average American (Velasquez-manoff). 92% of the Amish children were either living on a farm or visited a farm frequently; this could be the secret of the Amish (Velasquez-manoff). In addition, 80% of the Amish that the scientists studied consumed unpasteurized milk (raw milk). These children had more regulatory T-cells. The more T-cells one had, the less likely these children were to be diagnosed with asthma (Velasquezmanoff). Scientists believe that the problem is the increasing sensitivity to whatever allergens are already present in the environment. This could suggest that little exposure to potential allergens is critical for strengthening the immune system. Another experiment that supports this claim is an experiment done with peanuts. Peanuts can cause a severe and possibly deadly allergic reaction. In fact, peanuts are the top food allergens in America. However, according to The New England Journal of Medicine, there is one hope for people who have peanut allergies: peanuts. For this study, a group of international researchers gathered infants who had an allergic reaction that affects the skin such as an egg allergy or eczema. Both can be indicators that the child is prone to a peanut allergy (Shreffler). Then the children who divided into two random groups. One group of children didn’t consume any peanuts or any peanut-based product until the age five. The other group of infants were fed a peanut-based snack called Bamba or peanut butter three times a week until the age of five. The results were outstanding. Only 1.9% of children who were exposed to peanuts developed a peanut allergy, while 13.7% of the kids who weren’t exposed to peanuts developed a peanut allergy (Shreffler). It’s clear that the young immune system adapted to the proteins in peanuts so that they didn’t overreact to the innocuous proteins. Israeli children are exposed to peanuts at a much earlier age than British children. Consequently, the risk of peanut allergy was 10 times higher in the British children than in the Israeli children. However, this doesn’t necessarily suggest that at a late age, one should try to expose themselves to everything they are allergic too, encountering it intermittently may push one into overdrive, prompting the misery one is attempting to avoid (Velasquez-manoff). A prospective study from Denmark does suggest that it is never too late no matter what age. Conclusion There is still a lot that is unknown about allergies. However, one thing that most scientists can agree on is that kids should not be overly protected from germs. It is important to let the immune system develop and strengthen. Work Cited "Alpha-gal Allergy." Wikipedia. Wikimedia Foundation, n.d. Web. 06 Dec. 2016. Commins, Scott P., and Thomas A. E. Platts-Mills. "Delayed Anaphylaxis to Red Meat in Patients with IgE Specific for Galactose Alpha-1,3-Galactose (alpha-gal)." Current Allergy and Asthma Reports. U.S. National Library of Medicine, Feb. 2013. Web. 06 Dec. 2016. JACEWICZ, NATALIE. "Asthma-Free With No Hay Fever? Thank Your Older Sibling." NPR. NPR, n.d. Web. 06 Dec. 2016. McEwen, Annie. "Alpha Gal." Radiolab. RadioLab, n.d. Web. 06 Dec. 2016. Shreffler, Wayne, PhD. "Was It Something I Ate? Understanding Food Allergies." (n.d.): n. pag. Harvard Health. Web. St. John, Tina M. "How Long Until Fat Is Absorbed From Food?" LIVESTRONG.COM. Leaf Group, 18 Aug. 2015. Web. 06 Dec. 2016. Velasquez-manoff, Moises. "A Cure for the Allergy Epidemic?" The New York Times. The New York Times, 09 Nov. 2013. Web. 06 Dec. 2016.