Why Do We Get Allergies? (And Are They Really Necessary?)

Immune: Yeah, he was like sneezing and had this runny nose like a cause all that, girl.

Hold on.

I'm a call you back?

Okay.

Tina: Thank you for showing up today immune system Immune: What's going on?

Tina: Some of your colleagues here have a few concerns.

Please, join us.

Immune: Is this an intervention?

Nose: You're killing us.

Immune: I don't understand.

I'm just doing what I'm supposed to do.

Eyes: You're making us allergic Immune: To what?

Group: [*group complains about various allergies*] Tina: OK Ok. Everyone, please calm down.

Let's take a breath.

So, Immune System, what I'm hearing here is that everyone thinks you're doing your job very well.

But sometimes your passion for doing your job very well sends you into hyperdrive, and that can have some negative consequences for your colleagues over here.

Immune: It's not my fault.

They can handle it.

I'm just doing my job Eyes: You're not doing your job.

You're completely overreacting over harmless things.

Tina: You're both right.

But let's unpack this.

Why do we have allergies even?

Why are we like this?

Allergies happen when the immune system is a little hypersensitive.

Well, actually, there are four types of immune hypersensitive responses, but we're only going to be focusing on the type that's most commonly associated with allergies.

What sets this type of response apart is that it's mediated by a special antibody called immunoglobulin E, or IgE.

When it's working properly, IgE identifies dangerous triggers such as parasites, and tells the body to release histamine in response.

But sometimes it mistakes a relatively harmless allergen as being dangerous.

When this happens, histamine is released anyway.

Histamine is concentrated in the areas that come into contact with the allergen, and it's what causes those pesky symptoms.

Eyes: Here's the issue.

Every single time I step outside, I just start to cry because I see the beautiful grass and the flowers Skin: Hm Hm.

I don't do grass Eyes: And then I see the cute little bees Skin: I don't do bees either.

Eyes: And then the pollen.

Skin: That'll do it, that'll do it.

You don't have to worry about me you do.

That's how we get rashes.

Eyes: I just can't stop the tears from flowing from my eyes.

Tina: If an allergen gets into our eyes, they'll start to water to wash the allergen out.

Eyes: No, thank you.

Tina: If it's in our nose, it might get runny or we might sneeze to get rid of it Nose: hard pass on that.

Tina: And if it's in our gut, our body might try to expel that threat using any means necessary Gut: Zero out of 10.

Tina: I'll admit that none of these are pleasant.

But they're all your body reacting to the hard work of your immune system to get rid of something that it deemed a threat.

Immune: That's right.

I work hard, eliminating all threats.

Tina: It's just that when the allergen isn't actually a threat, but a normal part of everyday life, the solution becomes the problem.

And our allergic response causes us more trouble than the allergen ever would have.

And for everyone here, that can feel really hard.

Group: Yeah!

So thank you all so much for being vulnerable.

And for being here.

I hold space for you.

And I hear you.

Skin, it looks like you have something to say.

Skin: Yeah, I do.

Look, I don't care if it's immune system, the nervous system, the solar system.

All I know is every time you eat something—rash.

Every time you see something, "oH, tHiS WiLL bE NiCe tO pUt oN,"— I break out!

And every time you get close enough to take a big sniff—I itch.

See, mh mhh, see that's why I don't even do gatherings like this.

I don't step foot out the house.

Because the immune system is always overreacting!

I have to pay the price!

Why can we just stop reacting?

Why does it have to be like this?

Tina: Why does it have to be like this?

Why do we even have allergies in the first place?

Well, imagine you have two options, a an immune system and some unpleasant side effects or B, no unpleasant side effects, but also no immune system, which do you think evolution would pick?

Group: B!

Tina: Okay, good effort.

But no, if we had no immune system, we wouldn't even live long enough to enjoy the lack of allergies because actual threats would slip through.

And we all know what happens then.

Immune: You gotta protect the body from everything.

Constant vigilance.

Skin: Nah mh mhh.

Too vigilant.

Tina: Protecting our body from external threats is something that has been crucial to life since the beginning for almost as long as there have been cells there have been other things trying to get into it and attack those cells.

This is why all organisms today from tiny prokaryotes to humans have built in systems for recognizing and eliminating threats.

In this original, unrefined system.

The method for detecting a threat was fairly simple.

Everything that was part of a cell had a tag that said supposed to be here, and everything that wasn't part of that cell didn't have that tag.

Focusing on the IgE response.

This likely evolved to protect us against worms and parasitic arthropods.

These parasites are too large to be dealt with through or other immune processes.

So the IgE immune response would have been a great way to get rid of them specifically and a great feature for natural selection to keep around on.

Unfortunately, IgE does sometimes misidentify things that are pretty harmless because they share some similarities with things that it evolved to defend us against.

For example, shellfish.

Gut: Love selfish.

Till I like don't.

Cause of you.

Immune: Shellfish is dangerous Tina: Shellfish isn't dangerous but it kind of looks like something that is.

The most common cause of shellfish allergy is our body's response to the protein tropomyosin.

Tropomyosins are a family of proteins that are found in muscle tissues.

They play a role in muscle contraction and relaxation.

Tropomyosins can also be allergens.

When they're recognized in an infection by the parasite Schistosoma Mansoni.

They set off the IgE response.

This is a good thing because it helps people fight off schistosomiasis, the disease caused by this parasitic worms.

However, tropomyosin in other species like shellfish can be misidentified because of their similarity to tropomyosin in parasitic worms.

But obviously not everyone is allergic to shellfish.

So why does this response happen in some but not others?

Shellfish allergies, as well as other food allergies like egg and milk allergies are thought to have a genetic and environmental component.

The genes that cause the allergic response are encoded in our DNA.

However, scientists think that the direct cause of food allergies is related to a person's exposure to allergens.

This includes the timing and amount of exposure to the allergen.

Scientists know that the cause for food allergies isn't purely genetic, because there's been a rise in food allergies around the world.

And this increase haven't been matched by changes in people's genes.

Gut: I got something to say.

You know, I wasn't even bout to come to this thing, for real but, you know, things aren't the same anymore.

I used to be able to eat a whole tub of ice cream, a whole personal pizza, and a six scrambled egg omelet.

But now, nothin's the same.

Immune: You're so full of— [fart noises] It's not my fault that the protein in the milk and the cheese and ice cream and whatever else y'all like to eat sets me off.

I'm just doing my job.

I'm trying to keep us safe.

And all of you being angry at me?

Fine.

I want to my job.

I quit.

Group: No!

Tina: No one is saying not to do your job.

Your job is very important.

We realize that you're probably monitoring a lot of different things.

You've done a lot of growing and evolving and you're still learning while it can be frustrating for everyone here.

It's a good thing that we're expressing our feelings.

But we also want to help you get it right, so that everyone can be happy.

Immune: So what you're saying is that I should protect everyone, but not too much.

Attack threats, but not attack too much.

Defend, but don't defend too much.

What do you want from me?

I'm just trying to my best and I don't know where to start.

Tina: Okay, so let's help you start.

There are a number of ways that we can manage our body's response to allergies.

The first and easiest way is to avoid our allergens wherever we can.

So if you're allergic, maybe avoid shellfish.

And no matter how soft that cat looks, don't pet it.

Eyes: But it looks so fluffy.

Tina: While it can be hard to keep the immune system from Miss identifying allergens, we can help with the response.

Histamine one of the key chemicals released during an allergic response can be calmed down.

Antihistamines can block our body's histamine receptors and prevent histamine from binding and causing an allergic reaction.

So whether over the counter or by prescription antihistamines can calm down the body's response, keeping you from a runny nose and itchy rashes.

Nose: I'll take 10 of those.

Tina: Another option is immunotherapy, which aims to address the immune system directly and teach it to be tolerant to whatever particular allergens bothers you.

Two types of allergy immunotherapy exist: one is injected, and the other is dissolved under the tongue, but both rely on a similar mechanism.

The goal is to change the immune system's response so that it no longer reacts to whatever you're allergic to.

As a result, even when we finish treatment, our immune system should remain calm.

Immune: I can do that.

Eyes: That all sounds pretty doable.

I just want all of us to get along together like the good old days and just go to happy hour and do karaoke.

Skin: Now.

Think about it.

Yeah, remember that time that virus got in and like, shut everything down.

Immune system, you were there for us.

Really held it down.

Nose: One time I got a piercing and it got all infected and stuff.

I wouldn't never known the silver wasn't my color if it weren't for you.

Tina: Okay, I feel like we're really getting somewhere.

Our immune system and the pathways that lead to allergic responses to a lot of good for us and science can help us train those systems so they stay focused on doing the good work that they do.

We just all need to get together and understand how it works, and learn to tackle these allergens as a team.

Thank you all for showing up today and for being so vulnerable.

Eyes: Group hug?

Skin: Oh mh mhm.

I don't do hugs.

Immune: Oh, come on Gut: Nobody use the bathroom for like 30-45 minutes.

Nose: You're killing us.

One time I got my nose pierced— wait, is that right?

I would have known that like silver wasn't my metal my— Tina: schistosoma mansoniiiiiiii Eyes: you're overreacting constantly over just harmful— harmless— harmful?

harmless.

*giggles* You're not doing your job you're completely *giggles* Skin: Taylor come on Taylor.

Come on Taylor!