exercise induced food allergy caused by parasites?
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From: Kofi on 20 Mar 2008 21:36 In article <4754551f$0$14782$bf4948fe(a)news.tele2.nl>, WA <WA(a)nsopampeelen.com> wrote: > Hi, > > Question: anyone know of scientific research on exercise induced food > allergy in relationship to parasites like giardia? > > Or, more general: allergy and parasites? > > Regards, > WA Believe it or not, the relationship between multi-cellular parasites (helminths) and allergies is *inverse*. The parasites secrete signals that quell the immune system. there is an inverse relationship between parasitic infection (especially worms/helminths) and allergy; as parasitic infections dropped on the Pacific island of Mauke, allergies increased proportionately; one theory is that when freed of parasitic targets, the immune system has time on its hands and turns on innocuous allergens; the body�s Y-shaped IgG antibodies usually target bacteria and viruses by latching directly on to target proteins and recruiting immune cells; parasites activate a different mechanism - Y-shaped IgE antibodies - which attach their tails to the surface of mast cells; mast cells are found wherever the body comes into contact with the outside world and thus multicellular parasites - mucous membranes of the eyes, nose, and throat, and in the lining of the lungs and gut; once the initial IgE response is complete, each mast cell has 100,000 to 500,000 Y-shaped antibodies protruding from its surface with outstretched arms; usually within two weeks of worm infestation, the immune system is primed and each mast cell contains a thousand or more large, globular granules; a worm protein sticks to the arms of two adjacent IgE antibodies and sets off a reaction causing the mast cell to burst and spew its granules (mast cell degranulation) of histamines and other inflammatory chemicals that infiltrate local tissues; this causes itching; blood vessels dilate and leak; tissues swell and mucus production increases; this response may prevent worms from infiltrating further through the skin; other cells are attracted to dump toxins on the parasites; intestinal worms, on the other hand, come in through the mouth and attack the GI tract; in this case, an inflamed gut producing fluid and mucus causes in diarrheamaybe to flush out worms before they can attach; some worms can also spend part of their life cycle in the human lung (like schistosomiasis); this may trigger coughing and sneezing; this responses are all more acute to newcomers in the tropics when first exposed to parasites; some worms do get through though mostly the system works to protect people; in the absence of helminths, IgE antibodies can zero in on airborne allergens (causing asthma or hayfever) or ingested foods instead; worm infested rats have weak allergy responsesl their IgE antibodies are tied up fighting worms; however, in rural New Guinea, worm infestation doesn�t lessen the asthma rate; there�s an IgG antibody that competes with IgE; this G antibody (IgG4) grabs the worm protein before it bumps into the E antibody attached to a mast cell and this prevents the mast cell degranulation; IgG4 (1-2%) is the rarest of the IgG�s; IgG1 targets viruses and bacteria and is the most common; in people with parasites; IgG4 jumpts to 18% <http://www.discover.com/issues/sep-93/features/ofparasitesandpo264/> the hygiene hypothesis was advanced in 1989 by David Strachan of the London School of Hygiene and Tropical Medicine; the immune system expects a dirty environment and when it isn�t living in on it becomes hyperactive; Gabonese children with worm infestations have fewer allergies (and more IL-10, which blocks inflammatory signals among immune cells); children treated for worms became much more sensitive to dust mites; Alan Brown of Britain's University of Nottingham has treated his hayfever with intestinal hookworms; they cause anemia and require overeating; Joel Weinstock (once at the University of Iowa, now Tufts) used pig whipworms (Trichuris suis; TSO from Ovamed) to treat ulcerative colitis <http://www.cosmosmagazine.com/node/695> |