This big sister’s sacrifice cured her brother's sickle cell disease

A 7-year-old boy in Conyers, Georgia, who suffered from a painful disease his whole life is thanking his sister for curing him.

Kyle James was diagnosed with sickle cell disease just two weeks after he was born. The disease forced him to be less active than other kids his age.

>> Read more trending stories

His mother, Tanya James, told ABC News that even a low-grade fever would send Kyle to the emergency room, because it put him at risk for a blood infection.

Kyle regularly had blood transfusions to help him cope with the disease.

"I was explaining to him that people donate blood to help others in the future and to save people who need it," James told ABC News. "He said, 'Oh, they're like superheroes.' Instead of being upset about a blood transfusion, he'd say, 'Today I get to get my superhero blood.' He was excited about it, so it made it a lot easier for the family to walk through the journey with him."

In 2014 Kyle's older sister, Kendall, now 8, was tested to see if she could be a bone marrow donor for Kyle. Turns out, they were a perfect match.

09.30.16 WE MADE IT!! It's our one year anniversary of Kyle's bone marrow transplant ... It's Kendall's one year...

Posted by Tanya S. James on Friday, September 30, 2016

In September 2015, Kyle and Kendall underwent the transplant surgery at Children's Healthcare of Atlanta.

Two months after the surgery, doctors declared Kyle sickle-cell free.

Kyle is loving his new life now. He's currently taking karate lessons and hopes to earn a black belt in the future.

Somebody is over the top excited about turning 7 today. If you ask him about his year 6, he only has AMAZING things to...

Posted by KJ's Hope on Friday, September 9, 2016

About the Author