SYSK Selects: Gesundheit! How Allergies Work


© Colin Hawkins/cultura/Corbis
© Colin Hawkins/cultura/Corbis

In this week's SYSK Select episode, about 30-40 percent of humans suffer from some sort of allergy. The big joke, though, is that every sufferer is the victim of mistaken identity. Allergies are the result of a hypersensitive immune system mistaking a harmless protein for a foreign invader.

Narrator: Welcome to Stuff You Should Know from howstuffworks.com

Josh: Hi and welcome to the Pod Cast. I'm Josh Clark and there's Charles W. Chuck Bryant, looking particularly smart today, with his glasses. Chuck's the one with the beard by the way. Kind of boggles the mind after making video content, having an entire session of a television show that people still say, wait I thought it was the other one.

Chuck: Yes, it's not like this is the radio days of the 1940s when you really didn't know what people looked like.

Josh: Like Orson Wells is a baby face.

Chuck: He used to beard it up back in the day.

Josh: I think of him as like the - in Citizen Cane early on, he was clean-shaven baby faced. Right?

Chuck: Yes.

Josh: I think so.

Chuck: So what are you saying? How is this like Citizen Cane?

Josh: It's not.

Chuck: Okay.

Josh: Good one, thanks man. How you doing?

Chuck: I'm good, a little under the weather but not because of allergies.

Josh: Are you sure?

Chuck: Well it's funny you said that because Emily was, you may have some allergies because sometimes you think you're getting sick and it could just be allergies.

Josh: It definitely could be.

Chuck: Well she's super allergic.

Josh: To all sorts of stuff?

Chuck: Yes, just really bad allergies. Not like food allergies, seasonal.

Josh: Seasonal, pollen, dust mites?

Chuck: Ragweed and all that stuff.

Josh: Venom?

Chuck: And I grew up with allergies, I think I've mentioned this before, like asthma and all kinds of stuff. And I just grew out of it.

Josh: Because of that faith healer.

Chuck: Yes, I guess so. I got bit by that rattlesnake and everything was all good.

Josh: Venom, it works both ways. Right?

Chuck: Actually it does.

Josh: Because there is anti-venom, remember. Didn't we do one on what's the most venomous or poisonous animal in the world. That was a good one.

Chuck: It was the country of Australia.

Josh: It was a dangerous place. Well, Chuck I specifically remember one time when we were at work and you were attacked by a bee and I had to deliver an epipen shot to your thigh. Remember the whole gang was there. They carted you off in an ambulance. It was really kind of traumatic for us.

Chuck: Scary.

Josh: But I got my Mangum PI plate that day so everything balanced out.

Chuck: All is well that ends well.

Josh: But what's mind boggling is that you don't even have an allergy to bees. So like what happened there?

Chuck: So it was just TV, it was a TV show.

Josh: I'm having trouble distinguishing reality from fiction these days.

Chuck: Other people are too.

Josh: Had you had a bee allergy though, after reading this article, you would know what was going on.

Chuck: Yes, and I think we even covered that in the bee Pod Cast didn't we?

Josh: We covered like anaphylactic shock a little bit, but what we are about to talk about is allergies. The cellular basis of what constitutes an allergy. How they create it. Where they come from. It's pretty cool.

Chuck: Yes, I tried to stump Emily this morning because I thought I was being a smart guy, and even though she has bad allergies, I was like, I bet you don't even know what they really are. She was like, yes, it's an overreaction from your immune system to a perceived invader. Almost exactly like that now, I felt really stupid.

Josh: To a perceived invader. Way to go Emily.

Chuck: She loved it. She called me smart guy and like followed me around the house, brow beating me.

Josh: So she's absolutely right though. An allergy is basically a case of mistaken identity as far as your immune system is concerned. You've got all sorts of foreign invaders coming at you all the time. And we have an immune system to handle these things. But every once in a while, and it depends, they think probably that you are genetically unfulfilled if you have allergies.

Chuck: Oh, it's not an incomplete genetic code or something?

Josh: Yes, like you have a little bit of information missing. Your immune system has a little bit of information missing and so for example in the article they used the example of a shrimp. You can eat shrimp and there's maybe a protein attached to it that your body is like, did he eat this or where did this come from.

Chuck: Are you being attacked by shrimp.

Josh: Exactly. And they think probably all allergies are triggered by proteins. But, it's a case of mistaken identity. So let's talk about this. Let's get into the immune system a little bit. How the immune system handles foreign invaders, perceived or otherwise.

Chuck: That's right. Well I guess we could start with something called lymphocytes and you've probably heard of things like T cells and B cells, those are lymphocytes.

Josh: T cells are - that's how they determine whether you have HIV, I believe. Like if your T cell count is low. Because HIV is an immune deficiency disorder.

Chuck: So are both white blood cells, and they are really important to the immune system. But they make mistakes sometimes. And I love the way this - and who wrote this by the way?

Josh: Steve Beach, freelancer.

Chuck: Never heard of him. I thought he did a great job though because he likened the T and B cells to customs agents. Just like they go anywhere they want in your body and they investigate cells and basically are like let me see your papers, where are you going and what's the purpose of your visit.

Josh: It's like Arizona in your body. They show up anywhere. Like you said they can make it anywhere, they can pass through membranes and blood vessels and just pop up and go, who are you.

Chuck: Lymph nodes?

Josh: Yes.

Chuck: It's very important for them to visit the lymph nodes.

Josh: It is very important because that's where they go back and start producing antibodies. Right?

Chuck: That's right. When they see something and they discover a cell and they go hold on a minute, your papers are not in order sir. Then there is trouble and they launch, basically they start the attack at that point.

Josh: We haven't quite figured this out. Basically what happens when a B cell especially encounters a foreign body. Which is called an antigen because they generate antibodies. They trigger the generation of antibodies in your body, so that's were antigen comes from. The B cell basically takes down all of its data and then goes back up into the lymph nodes and that B cell, that white blood cell, turns into a plasma cell and starts churning out antibodies that are specifically tailored to counteract that antigen, that foreign invader that it encountered.

Chuck: That's right and our bodies have five types of antibodies and they are called immunoglobulins.

Josh: I love that word. It's tough to get out but I love that word.

Chuck: We'll call it the IGs and IGE is the one that's responsible for allergic reactions.

Josh: And the reason that one is responsible for allergic reactions as we understand them, is IGEs, immunoglobulin Es, they attach to mast cells and basophils and those are two different types of cells. A mast cell is found in a connected tissue. A basophil is a type of white blood cell. But they share the commonality that both of them contain histamine. And when they are hijacked by an IGE antibody, they basically become little ticking time bombs.

So think about this, when you come in contact with an antigen and your body goes off, that white blood cell goes off and starts producing antibodies, that first moment of contact creates what's called the sensitizing exposure. Right?

Chuck: Yes, and it's basically a mistake in the case of allergies.

Josh: It is. Because I mean there is nothing inherently dangerous about ragweed pollen and your body can handle bee venom and shell fish right? But there's some protein in each of those that certain peoples bodies, if they don't have the genetic code for their white blood cells to say, oh you pass your fine, there's that case of mistaken identity like you said.

So once you have that sensitizing exposure the first time your body comes across that protein and there's that mistaken identify, it starts producing antibodies. And those antibodies attach, in the case of IGEs to basophils and mast cells and they start circulating throughout your body just waiting for the next time it encounters that antigen that it has been specifically designed to interact with.

Chuck: That's right. And then what happens then, they say, hey I know you. You're not supposed to be here. I'm going to release something called histamine which can be a great thing in your body because that's what's going to - that's basically your arsenal fighting this invader but it can be a bad thing too if too much of it is released as we will see it in a little while.

Josh: So when an antibody and IGE connects to an antigen, it's already connected to a mast cell or a basophil remember. And those things are loaded with histamine.

Chuck: So they are basically taking them along for the party.

Josh: Right. So when it connects, it sends a signal to something called complement proteins, I believe. And those complement proteins comes along and say, cool a chain reaction we can start to fulfill. And they start locking on, and locking on, and locking on. And once a certain amount of them have locked together along into this antibody antigen mast cell basophil joint, the mast cell or the basophil goes kabluey, and all a sudden you have histamine floating through your body.

Chuck: That's right. It basically destroys those original cells such that the histamine is just released and unduly released.

Josh: And this is called the allergic cascade. This is what we think of. So you may have come in contact with shrimp and then ten days later you ate shrimp. It takes seven to ten days for that sensitizing exposure, from that time, to the next time you could have the allergic cascade. Because that's how long it takes your body to produce the antibodies.

But when that allergic cascade is kicked off and the histamine is released, that's when the symptoms that we associate with the type of allergy come about. So, if you inhale it, your mucous membranes are going to flare up.

Chuck: You might get hives.

Josh: Hives, which are basically like histamines, cause your blood vessels in the area to leak which makes it swell. That's a hive.

Chuck: Sneezing, wheezing, and all that. I could wheeze right not if you would let me but it would be really gross.

Josh: Let's hear.

Chuck: I don't want to because people would say, oh man Chuck get to a sanitarium. But I'm sick, I don't have allergies. Josh: A sanitarium?

Chuck: Remember them?

Josh: Yes, like the Kellogg's thing.

Chuck: Nausea, diarrhea, a little vomiting maybe, that's like - I think that's the scale from least reaction to most. If you're vomiting, then you've ingested something that you are really allergic to.

Josh: You can become swollen. Usually the part of your body or the type of reaction you have, if your skin swells, if your arm swells, you probably didn't inhale or ingest that, it probably came in contact with your skin, like a break in your skin.

Chuck: Yes, it depends on how you ingest it and how your body reacts to it because it's different for everyone in severity obviously.

Josh: But, speaking of severity, it can get really bad as you talked about in the bee episode. If this cascade, this allergic cascade is allowed to continue and you have enough of a reaction to it. You have enough antibodies attached to mast cells and basophiles that a ton of histamine is released, you can be in big trouble. You can go into what is called anaphylactic shock.

Chuck: Yes, and proceeding that you can have anaphylaxis which is not quite as bad. It's a bad reaction but it's not the full blown shock. If you are in full blown shock mode then you could die easily and within minutes even if you have let's say a peanut allergy and you accidently eat those peanuts. Unless you get that injection of epinephrine that's going to open those airways and restrict the blood vessels back to their normal levels, then you could be a goner really soon. That's scary.

Josh: That's called a systemic reaction where your whole system is involved in this. If your histamine dilates a blood vessel, your blood pressure can drop. It also causes swelling. If your airway is swollen that tends to close it off and it's tough for you to breath.

Chuck: Yes, you could starve your brain and kidneys of oxygen and organ failure could happen. I think what they say is several hundred people die in the United States alone each year.

Josh: Yes, because we didn't cover this in the TV episode about bees where I delivered that epinephrine pen and saved your life. If you remember. But apparently the effects of the epipen lasts 10 to 20 minutes.

Chuck: I didn't realize it was that short.

Josh: So we should have had you outfitted with a whole belt of those things.

Chuck: I thought you were just good to go once you had the EpiPen shot. So I think it's just like, hey let's save off death until we can get you to a hospital.

Josh: I think so too, but you have to do it early enough so that it can have the effect of counter acting this allergic reaction and if it's longer than ten or 20 minutes to get to the hospital, you should have more than one pen. But even if you survive, your brain and kidneys being starved of oxygen you can suffer long term damage from going into anaphylactic shock.

Chuck: Yes, I would be a freak if I had this possibility existing in my life. I would have an EpiPen in my car, and in each room of my house. I would not take any chances.

Josh: And what about a peanut allergy too. It's got to be so easy to come in contact with that.

Chuck: We mentioned that time on the plane when they said you can't even open peanuts on this flight and we had people write in saying that could seriously happen.

Josh: And I understand that. What's crazy to me is if you fly Delta, they'll give you peanuts all day long.

Chuck: Well not if someone says they're allergic. That's the point. This was a Delta flight and they said, I'm sorry everyone, no peanuts today because the gentlemen in 12E is allergic to peanuts. Everyone was like, oh gosh I want my peanuts, I hate you. I guess I will just eat pretzels and biscotti cookies.

Let's say you think you have allergies and you want to go in and find out for sure. There are a couple of ways they can test this out.

Josh: Smear yourself in honey and run into a beehive.

Chuck: No. You would do what's called the scratch test and I've never had one of these. Emily has had one and she also does immunotherapy which we will get to. But they applied diluted extract of different kinds of allergens to your back or your arm and then they scratch you with a needle and they see what happens. If it becomes swollen and red, they say I think you're allergic to rag weed, because we just put some on your body and scratched it.

Josh: They can also do blood tests and search for specific antigens.

Chuck: Yes, that's better for kids I think.

Josh: Yes, because it can cause a sensitizing event in a kid if you expose them to it. Everybody knows their genes are just stupid.

Chuck: Very susceptible to influence.

Josh: Which is weird to me. So here's the thing. Does that mean it's impossible to die from your first bee sting.

Chuck: That it's what, possible or impossible?

Josh: Possible. Because if there has to be a sensitizing event, how would you come in contact with bee venom other than to be stung. How would you become sensitized. I was looking all over the internet for it and I think one of the things I found while doing additional research for this episode is that we have a pretty good idea of how allergies work, but it's definitely not complete yet.

Chuck: Yes, when you are on the cellular level I'm sure there are still some mysteries to be had. Because one of your questions was, how do they identify that it's a foreign invader. And I was happy to just say, they identify a foreign invader.

Josh: And how do they take down its information and then go back to the lymph node and start producing an antibody.

Chuck: With a pen and pad and they have a little golf cart. That's the way I see it.

Josh: So you've got scratch therapy, blood tests, they both work, they are okay. And then if they say you are allergic to something. There is basically three things they recommend. The first is to avoid that thing, whatever it is.

Chuck: And if that's shell fish or peanuts then you are in pretty good shape because that's pretty easy to avoid in most cases.

Josh: You would think. Have you ever had a shrimp allergy? Shrimp is pretty delicious.

Chuck: It's easier to avoid than pollen let's say. Because pollens are everywhere, especially here in the south.

Josh: So if you are allergic to pollen, there's no avoiding it. All the cars in the Spring in the south are yellow. Every car is painted yellow.

Chuck: The streets run yellow blood.

Josh: Literally. So you would take medication. Corticosteroids, you might walk around with an epinephrine pen depending on what you are allergic to. That kind of thing. And the third one is what you said Emily was doing and what I did before too was immunotherapy.

Chuck: You've done this?

Josh: I think so. I undertook the process of immunotherapy by myself and it seems to have worked.

Chuck: Did a doctor give you injections as some point.

Josh: No. Tell me about Emily's experience.

Chuck: Well, she does the standard immunotherapy where she goes into get her allergy shots once a month, I think, and they start you out on a low dose that's basically a weak dilution of these antigens. They inject it in her body and just build that up over time to increase her immune response I guess.

Josh: Right and then over time - this is what they think happens, over time the body possibly gets its genetic information filled in enough so that it's like, was my face red because this wasn't actually a foreign invader, it's just shrimp protein. And/or they believe that another antibody, IGG, which acts as kind of like a blocking antibody, prevents an allergic reaction and starts to build up as a result of immunotherapy. We should say I think immunotherapy is still fairly controversial.

Chuck: Is it? Josh: I believe so because it's introducing a potentially dangerous thing into a human being and it's not like if you asked somebody if honey is a good immunotherapy. Logically it should make sense. If you use local honey very, very local honey, it's going to contain some of the same pollen that you are exposed to, that you are allergic to in it. So when you eat it, when you ingest, it's like taking that low level and it should be doing the same thing as that taking injections from the doctor but it's more delicious.

Chuck: And, it takes a long time. Emily has been at it for a couple of years without virtually no success. So it takes a while.

Josh: Has it been helping at all?

Chuck: I think so because she still has bad allergies but they used to be way worse. But she has been on these shots now for like - she did it when she was a kid and then again for like five years probably. So, it's been a while.

Josh: I had one serious, it wasn't even serious, but a distinct allergic reaction. It was shrimp once and I ate it and everyone was saying, why are you red and what are those red dots all over you. What's going on? I figured out I was having an allergic reaction to shrimp which I never had before. I tried it the next day, tried a little bite of shrimp, kind of had a similar reaction and was like somethings going on here. So, I decided I was going to get myself over my shrimp allergy. Have you ever had shrimp chips?

Chuck: Yes.

Josh: They are delicious aren't they?

Chuck: They are delicious.

Josh: They are little potato chip french fries, but they are shrimp flavored because they have shrimp dust on them. Actually powered shrimp. So, I started eating little amounts of shrimp chips and over time I would eat more and whole bags of them at a time. And then finally I got to the point where I could eat shrimp again. I don't know if that really cured me or if that was just a fluke. Maybe that shrimp was just a local type of shrimp in the Carolinas or something like that. That's my immunotherapy story.

Chuck: Well you can eat shrimp now like gang busters.

Josh: And I do.

Chuck: Do you really?

Josh: Whenever I can. I like shrimp. I'm trying to make up for lost time because I spent three years, two years without eating shrimp.

Chuck: So beware prawns and shrimps of the world. Josh has got your number.

Josh: I will eat you live.

Chuck: Will you?

Josh: No. That's gross.

Chuck: No it's not. People do that.

Josh: I guess that's it.

Chuck: That is allergies and I bet the reason I quizzed Emily is I think a lot of people who have allergies don't even understand the core concepts and hopefully now you do.

Josh: A case of mistaken identity. That's so awesome.

Chuck: And your DNA is dumb.

Josh: Or incomplete. If you like this you should go check out how allergies work. You can type in the search bar, howstuffworks.com. You can also look up another article I wrote about using honey for immunotherapy which is pretty interesting. Probably honey allergies would be two good words to put in the search bar for that one. And I said search bar twice, which means we are going to have two listener mails.

Chuck: No just one.

Josh: Before we do that, how about a word from our sponsor.

Chuck: Josh, buddy, we believe like most successful partnerships believe that team work is the foundation of success.

Josh: And when we see each other face to face as we are now, we are gang busters. Chuck: Exactly. But, if we are not face to face, or we are spread out over the country, or we want to connect with other people in different parts of the world, we can do that now with, Go To Meetings with HD Phases.

Josh: That's right it's the powerful and simply way to meet and collaborate online where you are, whenever we want to, right? With Go To Meetings it just takes a click. You can share your screen with me. We can collaborate on documents in real-time.

Chuck: You just fire up the little web cam and there you are. And up to six people total at the same time sharing the screen, talking to each other like we are just right there in front of each other.

Josh: And have you left the PCs and laptops in the dust and you are a tablet person now, no sweat. You can use Go To Meetings on your tablet, you IPad even your phone.

Chuck: That's sound pretty great. We actually used it and it was really helpful. So we have a deal for you folks. Try Go To Meetings free for 30 days. Don't wait for this offer. Visit gotomeeting.com. Click on the Try It Free button and then use the promo code stuff. Pretty easy to remember because that's us s-t-u-f-f at gotomeeting.com. Click on that Try It Free button and play around for 30 days if nothing else.

Josh: And I've got the tag on. Are you ready? Go To Meetings, meeting is believing. Time for listener mail.

Chuck: Okay, I'm going to call this in the name of the fire. Guys I just listened to your Pod Cast on stunt men stunt women and I was reminded of a story I thought you might like to hear. My dad is an actor and way back in the '90s he was in a film called In The Name of the Father. Remember that?

Josh: With Daniel Day Lewis right?

Chuck: Great movie.

Josh: Is that his dad?

Chuck: No. He said it stars Abraham Lincoln or Daniel Day Lewis. In the film he played, and this is one of my favorite movies from that year by the way.

Josh: It was about the IRA wasn't it?

Chuck: Yes it was about wrongfully imprisoned group of friends basically that they suspected as being bombers. I don't want to give away too much. But there is a prison. In the film he played a prison guard who gets set on fire by some pretty nasty inmates. What happens next serves as a warning for any actor who decides they are up for performing their own stunts. The director decided my dad could do some flailing and running with his arms on fire and that a stunt professional would do the more intense whole body fire shots.

Josh: Like we said in the stunt person Pod Cast, the fire thing you are always running with your arms going.

Chuck: What do you do when you're on fire. Just stand there and can't someone put me out.

Josh: Some people do. Buddhist Monks just sit there.

Chuck: Well that's different. They wrapped up his arms, covered them in jelly and set them ablaze. But what my dad had failed to realize is that the stunt men do not wait for anyone to say action. As a result he just stood there on fire waiting for someone to say he could go whilst getting hotter and hotter with each passing second. Fortunately the director eventually saw what was happening and hastily yelled, go.

But by this time my dad was way too hot and just kind of side stepped into the shot waving his arms like a half-baked ballerina. If you watch the scene carefully, you can actually see the shots he was really on fire and by the genuine fear and panic in his eyes.

Hope you guys carry on making news for as long as humanly possible. That is Freddy Turner from Oxford, England. And I guess Freddy Sr., well he doesn't say he's a junior, was on fire. And I think Jim Sheridan was the director of that movie if I remember correctly.

Josh: So Jim Sheridan was the one who said, go. That's a pretty great listener mail. What was the dude's name, Freddy?

Chuck: Freddy Turner from Oxford, England.

Josh: Cool. Well if you have a great story associated with something we've talked about. As always we want to hear it. You can tweet to us at syskpodcast. You can join us on facebook.com/stuffyoushouldknow. You can send us an email to stuffpodcast@discovery.com. And check out our website: stuffyoushouldknow.com.

Narrator: For more on this and thousands of other topics, visit howstuffworks.com

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Duration: 27 minutes

Topics in this Podcast: Immune system