CHICAGO (WLS) -- Sickle cell disease can cause debilitating fatigue, chronic pain, even death. But now what was once a life sentence may be no more. Doctors in Chicago say they are curing sickle cell disease in adults.The inherited illness affects about one in every 500 African Americans.Felita Sims, a teacher from Waukegan, inherited sickle cell from her father."I actually had a father that passed away from sickle cell, so," she said.She worried the disease might end her life too."Oxygen is being sucked out of you so it stops you from moving, from breathing, sometimes it feels that way," Sims said.The disease causes red blood cells to become crescent-shaped, like a sickle. The distorted cells can't sufficiently deliver oxygen to the body. The result is excruciating pain attacks, organ failure and death."At the end of the day, people die. The average length of life of patients with sickle cell disease in the United State is about 50 years of age," said Dr. Damiano Rondelli, Micheal Reese Endowed Professor in Hematology, UI Health Now a less risky treatment is offering a cure. Sims is part of a clinical trial at UI Hospital in Chicago in which normal stem cells from a sibling are transfused into those with the disease. Sim's donor is her sister.The procedure allows the healthy cells to take over, shutting down the production of the misshapen cells."The immune system of the donor is capable of fighting the immune system of the recipient, which we have lowered with immunosuppressive therapy," Rondelli explained.The end result is no sign of sickle cell disease. The treatment is also easier on the body because it is chemotherapy-free.Kamia Hearns-Quinones had the experimental procedure about three years ago."I feel like I have a new lease on life," she said.She said within two months she knew it was working."I was just sitting at the dinner table with my family and I said, 'I feel good,' and I was like, 'You guys, wanna go for a run?' That's what I told my husband, 'You wanna go for a run?'" Hearns-Quinones said.Twenty people have had the transplant in Chicago so far, and 80 percent remain disease-free."Keep fighting. I always thought I would die from this and I was blessed to have this happen, so don't give up, please,' Hearns-Quinones said.Both Sim and Hearns-Quinones said they are now sickle cell free. Chicago is the first site to try this procedure since it was initially tested by the National Institutes of Health. Next researchers want to find a way to make it work with donors who are not sibling matches.For more information visit http://hospital.uillinois.edu/