Why Does Your Body Declare War on Itself?

The immune system is supposed to protect you. That's the deal. Detect what's foreign, destroy it, move on.

But the weird thing is that the system that protects you can also become the thing that slowly destroys you. In autoimmune diseases the immune system starts targeting your own tissues, it seems that suddenly the distinction between "self" and "enemy" suddenly became blurry.

There are more than 80 of these diseases. And despite decades of research, we still don't really understand why the immune system sometimes flips like that.

Another thing that keeps bothering me: autoimmune diseases are dramatically more common in women, which means there's some huge piece of biology (immune regulation, hormones, genetics, evolution, something) that we clearly still don't understand.

I find that both fascinating and a little unsettling.