Shannon Boxx had a problem. Even though she was fit and athletic, she couldn’t keep up with the other kids on her sports teams. Plus, one of her fingers kept turning white. At first, she assumed the finger was “dead.” She thought it had gotten hit one too many times while she played catcher in softball. Twenty years have passed since then. Now Ms. Boxx realizes what caused her troubles. As a teenager, she was starting to experience an autoimmune disease called lupus.

Remember those tiny, helpful guys God put into your body as a police force? When a person has an autoimmune disease, those defenders get confused. They think the body’s healthy cells are actually enemies. That means your body starts chowing down—on itself. Yikes!

Like many other autoimmune diseases (and there are lots of them), lupus is ugly. It can cause skin problems. It can make the joints ache and the kidneys stop working. It can even decrease the blood cells in a person’s body. As you can imagine, a person with lupus often feels very weak and tired.

Lupus is a scary disease. But Ms. Boxx hasn’t given up yet. Do you recognize Ms. Boxx’s name at all? She is a famous athlete. She has been working with doctors for years. She has learned how to keep herself as healthy and strong as she can. This year, she played in the fourth Women’s World Cup. In a typical game, she runs about seven miles! Take that, lupus!