Any Biologists In The House?

[Matt]

I'm doing this HUGE research project on disease and why we get sick, all from an evolutionary standpoint. Through my research, one thing that has puzzled me is allergies. Allergies, for the most part, are cuase by Immunoglobulin E--a part of the immune system to help fight off parasites.

It is not natural for any person's body to reject substances like pollen, dander, etc. While it is still not understood, the main theory is that allergies develope while Immunogloblin E is in the process of fighting off an actual threat. In the meantime, an "innocent bystander", maybe pollen, was also flagged due to it being an outside intruder. From that point on, this section developed a zero-tollerance cenception of the pollen. Thus, creating the allergic reaction to pollen: once it enters the body, it is emmediately expelled by means of coughing, sneezing, tears, etc.

I understand all that.

What I don't understand is such reactions as a peanut allergy. If someone is suffering a reaction due to a peanut allergy, it appears that the body is doing nothing to rid the body of the substance; but rather, it is making the situation worse by closing off the air passages. But how could such a characteristic within humans be present? By the idea of natural selection, any gene that would code for such a reaction for a foreign substance should have been selected against. AFterall, in the Stone Age, if anyone ever suffered from such an attack, they would shurly die.

Well, thats just a rundown of the allergy part of my research. Any thoughts, ideas, and linkage on the topic is welcome!

Thanks all!

Matt

[flashh4]

Howdy Matt, see if this might help ya !!! http://www.nlm.nih.gov/medlineplus/ency/article/000005.htm

[blim]

Wow! What a project, Matt.

I'm an allergy sufferer myself (molds and "random scents" like Bounce Dryer Sheets) and passed that on to Daughter, BUT she is allergic to Spring Pollen (only when spring flowers are blooming) and oranges. Always wondered why I passed the allergies on to her, but why is she allergic to different things!!

After reading your post, I wonder if the reaction in air-borne/breathed in allergies (like pollen) and "ingested" allergies (ie: peanuts, oranges, strawberries, even bees, seeing as it's "injected into the body" vs. inhaled) has something to do with the type of reaction? In other words, the type of allergic reaction is the result of how the human came in contact to the allergen?

Let us allergy sufferers know what you find out! Sneezing for 20 minutes straight isn't fun!

Liz

[JDoors]

Isn't the body's reaction supposed to protect you from "poisons?" If you were breathing in a poison it would be to your advantage to have your breathing restricted, for mucous production to increase to help dispel the poison along with coughing, sneezing, etc.

Allergies to products that are NOT harmful is a misfunction. There are hundreds of examples of human biology going "wrong," most are not life threatening however. I'd consider those to be 'mutations' that, in time, would either hurt or help human evolution.

Modern medicine essentially protects us from such mutations -- People did used to die from such biological errors, now we work hard to fix them.

I don't know what effect that will eventually have on evolution ...

[Matt]

Isn't the body's reaction supposed to protect you from "poisons?" If you were breathing in a poison it would be to your advantage to have your breathing restricted, for mucous production to increase to help dispel the poison along with coughing, sneezing, etc.

Allergies to products that are NOT harmful is a misfunction. There are hundreds of examples of human biology going "wrong," most are not life threatening however. I'd consider those to be 'mutations' that, in time, would either hurt or help human evolution.

Modern medicine essentially protects us from such mutations -- People did used to die from such biological errors, now we work hard to fix them.

I don't know what effect that will eventually have on evolution ...

(Please keep in mind I'm merely trying to discuss, not attack or agressively dispute ideas)

Hi JDoors. So you are saying that it is reacting to a peanut or shellfish as it would to an airborn toxin? That does make sense. What I don't necessarily aree with is that the attack is a gene mutation. Here's why: If over 25% of the population suffers from a type of allergy, it seems too unlikely that there is that high frequency of a random gene mutation. While I understand that the resoning behind allergies is not fully understood, I don't believe it is genetic. We are pre-built to fight toxins. The fact that we have no tollerance to a harmless substance, as I see, most likely isn't due to a gene mutation. However, it seems that the IgE molecules in the immune system, (which are genes do code for) are attacking the wrong thing; not due to our genes, but for some physiological reason.

This leads me to think that eventually, on the evolutionary path, natural selection may elminate the IgE molecule all together. While this may rid us of allergies, it could also compromise important bodily defenses.

Any thoughts on that idea?

[JDoors]

I'm not sure I understand the distinction between a genetic mutation and *whatever* change occurs that causes one's immune system to attack harmless substances. If the components of a person's immune system consistantly function differently than ... oh, say ... differently than most people/the norm/the way it's supposed to work, wouldn't the fact that it always misbehaves imply that the genes that code for the components in the immune system, in that person, are different than most/normal/supposed to be? That is, mutated?

I guess there could be an outside factor, something that's changing the behavior of the immune system components -- Yeah, OK. I get that now (I'm so slow sometimes). There's no problem with the individual components as they are constructed, it's their behavior once in the system that's "whacky."

You know, a lot of experiments show that a LACK of exposure to pathogens may lead to allergies later. So early exposure may actually be necessary for the immune system to function properly. Thus, a lack of exposure means the immune system works, the parts are there and they do what they are meant to do, but they don't know what is "acceptable" behavior. They haven't been "taught" what's a pathogen and what's harmless (or at least, not dangerous).

I believe though allergies or tendencies toward being allergic do run in families -- But that too could be environmental rather than genetic. When you find out, and after you get the Nobel, be sure to get back to us. OK?

Edited April 28, 2006 by JDoors

[Matt]

I'm not sure I understand the distinction between a genetic mutation and *whatever* change occurs that causes one's immune system to attack harmless substances.

Well, by what I understand, the genes code for the IgE molecules that work in the immune system. For everyone (except some rare mutations) they are all made about the same, the molecules are made to defend against toxins. Then, for some reason, after the genes have done their work and created said part of the immune system, the IgE molecules accidentially flag harmless substances--independant from what the genes coded for. The reasoning behind this is while the immune system is expelling an actually toxin, it also detects something like, pollen as an intruder; and adds it to the blacklist. From this point on, it has no tollerance for the harmless substance.

So, when you sneeze, your body is doing what it would do to a natural toxin: trying to get it out of the body.

Peanuts, shellfish, bee stings, however don't seem to stimulate a sort of expulsion reaction; and this is still what I don't understand. How can it be biologically sound for the body to react to an intruder, whether it be a legitament toxin or a mere peanut; by swelling, cutting off breathing and the other effects?

There's no problem with the individual components as they are constructed, it's their behavior once in the system that's "whacky."

Exactly.

I believe though allergies or tendencies toward being allergic do run in families -- But that too could be environmental rather than genetic.

By the given evidence of the world, yes it does appear to run in the family. What I can't understand is why, if it is genetic, hasn't it been selected against?

When you find out, and after you get the Nobel, be sure to get back to us. OK?

Lol. Well, my big presentation is this monday. I'll let you know how it goes.

Matt

[JDoors]

... What I can't understand is why, if it is genetic, hasn't it been selected against? ...

Why haven't we evolved an immunity to cancer? Partly because you usually live long enough to reproduce. If allergies killed people before they reproduced it would be more likely to be selected against. (Even then, there are diseases and conditions that are always fatal at a young age, so there's more going on than simple evolutionary selection.)

Good luck with the presentation!

[Matt]

Why haven't we evolved an immunity to cancer?

Actually, we have. Tumors occur when there is "unnatural" cell growth in a given tissue. However, it actually is the functions of cells to reproduce. So, when cells reproduce when they aren't supposed to, they are actually doing exactly what they were desgined to do. Our bodies have evolved to do the following:

1. Be able to instruct when cells should and should not grow
   
2. if a cell grows at the wrong time, to terminate it
   

Without those checks, we would grow about 1 billion cancerous cells a day. Since that number is so high (just as gene reporduction is) there is bound to eventually be an error or a missed cell; and that is where cancerous growths occur; just like gene mutations.

Partly because you usually live long enough to reproduce.

That's true now adays. But do you think a child in the Stone Age would have been able to survive a peanut reaction?

(Even then, there are diseases and conditions that are always fatal at a young age, so there's more going on than simple evolutionary selection.)

This is also true. But I do know why fatal childhood diseases still occur. Such diseases can only still be around if the trait that causes them is recessive. Otherwise, everyone that inheted the trait would die before they could pass it on. With that said, if you are only a carrier of the trait, you will live long enough to give it to your child. It is just those who are unlucky enough to inheret 2 coppies of the gene (1 from the mother and one from the father) that will be affected. This is why scientists think natural selection may never be able to leliminate recessive traits.

Good luck with the presentation!

Thanks you very much. Fortuantely, this won't just be a "me talking" kind of thing. I will be able to interact and discuss with the class, and hopefully I will be given some more info on the subject.

[Matt]

Well, I finally gave my presentation. It went very well. While I wasn't able to get all my questions answered, I did have a very good discussion with the class on the various subjects we discussed. I'm guessing it went alright as when I was done, 3 people came up and told me how impressed they were . While my teacher and the others also could not conclude for the reasoning behind the peanut/shellfish reaction we discussed; some interesting ideas were presented. One was that the peanut reaction is the same trigger that reacts when an airborn toxin enters the body. As a defense, breathing is restricted. While it is still not biologically sound to practice such defense (as it can still lead to death), it does work as a sort of 'band-aid' fix. The proposed idea is that perhaps this sort of defense is still a flaw in out genetic makeup and eventually will be coded against. We will continue to evolve, and this is just one change we have not experienced yet.

Thanks again for all the input and ideas for this. It sure is an interesting topic!

Matt

[blim]

So glad it went so well, Matt! Stumping the teacher is a bonus Hoping you get an A+ and someday, I'll be reading about this great scientist named Matt and his cure for allergies!

Liz

[JDoors]

Sounds like it did go well, congrats! Having other students congratulate you is especially satisfying.

So a question: I mowed the lawn and as usual I sneezed several times while doing so. Am I allergic? Or was is a simple reaction to airborn dust & particles?

[Pete_C]

I'm doing this HUGE research project on disease and why we get sick, all from an evolutionary standpoint. Through my research, one thing that has puzzled me is allergies. Allergies, for the most part, are cuase by Immunoglobulin E--a part of the immune system to help fight off parasites.

It is not natural for any person's body to reject substances like pollen, dander, etc. While it is still not understood, the main theory is that allergies develope while Immunogloblin E is in the process of fighting off an actual threat. In the meantime, an "innocent bystander", maybe pollen, was also flagged due to it being an outside intruder. From that point on, this section developed a zero-tollerance cenception of the pollen. Thus, creating the allergic reaction to pollen: once it enters the body, it is emmediately expelled by means of coughing, sneezing, tears, etc.

I understand all that.

What I don't understand is such reactions as a peanut allergy. If someone is suffering a reaction due to a peanut allergy, it appears that the body is doing nothing to rid the body of the substance; but rather, it is making the situation worse by closing off the air passages. But how could such a characteristic within humans be present? By the idea of natural selection, any gene that would code for such a reaction for a foreign substance should have been selected against. AFterall, in the Stone Age, if anyone ever suffered from such an attack, they would shurly die.

Well, thats just a rundown of the allergy part of my research. Any thoughts, ideas, and linkage on the topic is welcome!

Thanks all!

Matt

I like the "innocent bystander" explanation. It makes clear to me how one of the new projects to cure type I diabetes actually works.

Peanut allergy is probably similar; the immune system is in a heightened state and you ingest peanuts and one of the proteins manages to get through the digestive system into the blood unbroken and the result is an immune response to it. This also explains why many people seem to grow out of it if they avoid the peanuts long enough ; most immune responses (as those to vaccinations) fade over the years. But the one generated against islet cells in type I diabetes does not since the body keeps trying to generate them.

(But as the latest mouse research shows if this immune response is cleared the islets regrow and the diabetes is cured).