[MUSIC] [PIANO MUSIC] (sneezing)
(coughing) (blowing nose)
(groaning) Ralph Waldo Emerson wrote that “Earth laughs
in flowers” “Ha ha ha ha” Well, you know what? I don’t think it’s
funny. If you’re like me, the coming of spring signals one thing: allergies. [MUSIC] I mean seriously, how much crud can my head
really hold? It’s like Hermione’s purse up in there. Of course it’s not really fair to blame
flowers for most seasonal allergies. While most plants do keep their pollen-covered private
parts right out there in the open, flower pollen is usually too heavy to go airborne,
instead they get bees and other pollinators to help them do the fertilization deed. [FUNKY MUSIC] It’s mainly trees and grasses that let their
genetic material loose on the wind, and they don’t mess around.
I mean really?! Is that necessary? If one tree needs that much pollen to reproduce,
maybe evolution is trying to tell you something. That’s all I’m saying. Maybe this was a mistake…
By my immune system! Allergic reactions are the result of our immune system going haywire,
and doing battle with completely and totally harmless stuff like pollen, dust, or pet dander,
because it clearly has nothing better to do. Your body enlists several types of antibodies
in its immune army. Most are sent out to fight different invaders like viruses and bacteria,
but this one, IgE, seems to have just one purpose: making us miserable a few times a
year… I mean mediating our body’s response to allergens. When we are first exposed to an allergen,
we don’t have much of a reaction… on the outside. But inside our bodies, it’s different.
A special cell in our immune system vacuums up foreign antigens and presents them to other
cells, like “Hey, check this out, this doesn’t belong here.” Mr. T cell sniffs it out,
and says, “I pity the fool who try and invade my mucous membrane”, sending out a chemical
signal that turns on our B cell antibody factories which pump out IgE proteins that bind specifically
to the pollen, cat hair, bee venom, whatever. The IgEs latch on to these mast cells, where
they wait quietly for the NEXT time the allergen shows up, and when that happens, BAM, the
mast cells start pumping out a chemical called histamine. You might know it from all the
anti-histamines you take to beg it, at any cost, to please stop doing its histamine thing. Histamine causes blood vessels in your nose
to dilate and become leaky, it stimulates nerves to make you sneeze, and even increases
inflammation, giving you that nice red-nosed look to set off those bloodshot eyes.
What’s weird is that in developed countries, allergies seem to be getting more common.
In the US, food allergies in children have increased by 50% since 1997, and environmental
allergies are estimated to affect up to one in three people at any time. So, what gives? Allergies do seem to have a genetic basis.
Parents with allergies are more likely to have children with allergies, although they’re
not necessarily to the same thing, but identical twins are likely to share specific allergies. Many scientists think that perhaps we’re
living too clean, that our hygienic lifestyle doesn’t train our immune systems correctly
from a young age. Many allergies and autoimmune diseases are less common in the developing
world, and as nations get richer, they get more allergic. Maybe playing in the mud a
bit more could keep us from sneezing later in life. Some researchers have found that increasing
exposure to an antigen over time, usually in drops placed under the tongue, can desensitize
the body from reacting. And in 2013, Johns Hopkins researchers pinpointed a pathway involving
the protein TGF-beta as a possible culprit for this whole sneezy mess. Our microbiome might have something to do
with it too. A small study done by the BBC found fewer species of bacteria living on
folks with allergies than without, and researchers have seen that when other parts of the immune
system were exposed to and fought off bacteria, it silenced the part of the immune system
that activates IgE. In another study, mice given certain bacteria were cured of a peanut
allergy. It’s likely that, like most things in medicine,
allergies are likely due to more than one cause, our hygiene, our environment, even
our changing lifestyles. But one thing’s for sure. Snot fun. (laughing) Stay curious.