New lease on life for kids with sickle cell anemia

June 9, 2016

Novel therapy grows new immune system from transplanted family stem cells

Cardelia Fox, centre, and her sister Tamika Allen, meet with Dr. Greg Guilcher, an AHS oncologist who leads the sickle cell blood and marrow transplant program at Alberta Children's Hospital.

Story by Greg Harris; Photo by Paul Rotzinger

CALGARY — On her 19th birthday, Cardelia Fox had the words “Set Free” tattooed on the inside of her right forearm. They remind her that the challenges she endured growing up with sickle cell anemia — three strokes, regular visits to the emergency department, and monthly blood transfusions — are a thing of the past.

Today Cardelia is now free of the genetic illness she was born with, thanks to the novel application of a stem cell transplant protocol being used for children and adolescents at Alberta Children’s Hospital in Calgary.

“Before the stem cell transplant I felt like I was trapped,” says Cardelia. “Without this treatment I would likely still be at Foothills getting blood transfusions every month.”

Alberta Children’s Hospital is believed to be the only pediatric centre in the world that is successfully using the non-chemotherapy-based stem cell transplant protocol to cure children of sickle cell anemia.

To date, seven girls and two boys have been cured through a process that first destroys the existing blood system, then grows a new system from the transplanted stem cells of a family member who is an immune match.

“To our knowledge, we have the only experience with this protocol in children with sickle cell anemia,” says Dr. Greg Guilcher, an Alberta Health Services pediatric oncologist who leads the sickle cell blood and marrow transplant program at Alberta Children’s Hospital.

“We’re getting phone calls and emails from around the world from interested parents and other doctors. We think we’re ahead of the curve in offering this curative therapy as a standard of care,” says Dr. Guilcher, who is also an assistant professor in the Departments of Oncology and Pediatrics at the University of Calgary’s Cumming School of Medicine.

Under the transplant protocol, patients are given medications to intensively suppress the immune system in the week leading up to the stem cell transplant. On the day before the infusion of the healthy donor stem cells, they also undergo a low-dose total body irradiation, in final preparation.

Compared to other stem cell transplant procedures, the conditioning protocol has the fewest side effects with high success rates. It has been studied and used with success in adults in the United States.

Sickle cell anemia is a chronic illness in which blood cells can change into a sickle shape and block blood vessels. It varies in severity from patient to patient, but every organ is potentially at risk. Strokes, lung disease, heart strain and damage to the spleen and bones can result.

Even with the most advanced care available, life expectancy is 55-60 years. Many people with sickle cell anemia frequently visit the emergency department.

Genetically, one parent can pass on the mutation that causes sickle anemia without causing illness in their children, but if both parents pass it on, illness results. Sickle cell anemia mainly affects those of African descent, but is occasionally found in other populations.

Cardelia’s older sister, Tamika Allen, proved to be a full match and provided the stem cells for transplant.

The odds of a complete match (unaffected by sickle cell disease) being found within the family are only one in five. Without a family match, the transplant procedure is generally considered too risky to perform.

“When we learned I was a match there was never any question of whether or not I’d do it,” says Tamika, now 22.

“Of course I’m going to do this for my sister. It was such a good feeling to be able to help make her life better — now I call her my mini-me.”