This is Karli's story, as told by her mom Debbie.Seven-year-old Karli is spunky, friendly and loves Brantley Gilbert. When she fell and hurt her knee, and was still in pain three weeks later, Debbie took her to the doctor. After ruling out a virus that causes arthritis, doctors discovered Karli had leukemia. They immediately began chemotherapy.Karli’s blood counts dropped after receiving chemotherapy, and so she received a blood transfusion. To date, she has received 55 blood products."You can definitely tell a difference. She goes from very weak to getting her energy back."Now, Karli hosts a blood drive in her community to help others like her.“We have received help from so many people,” said Debbie. "It’s important to give back.”