Cord blood offers hope for rare diseases and ethnic minorities
Researchers at the University of Pittsburgh Medical Centre may have developed an innovative method of transplanting stem cells, resulting in a safer, universal treatment for a variety of genetic disorders.
Through combining this approach with umbilical cord blood, treatment is also more accessible to ethnic minorities, a demographic that historically has had difficulties accessing bone-marrow transplants.
The study, published in Blood Advances and the largest of its kind to date, used umbilical cord blood to treat 44 children with varying non-cancerous diseases.
Umbilical cord blood is a potent source of hematopoietic stem cells — cells that are able to form red and white blood cells in the patients. Due to their ability to develop into different types of cells, this treatment can be used to address many different types of disorders.
“We wanted to offer a uniform concept to a wide array of diseases,” said Dr. Paul Szabolcs, the Chief of Bone Marrow Transplantation and Cellular Therapies at UPMC Children's Hospital and principal author of the study. “We successfully reduced the intensity of chemotherapy and nevertheless, we were still able to engraft all our patients.”
Typically, before receiving a stem cell graft (either umbilical cord blood or bone marrow) patients undergo an intense round of chemotherapy to kill off the patient's own immune system and allow the new cells to grow.
This method is effective but damaging to the body. For patients who do not have cancer and are pursing this treatment to improve the quality of their life (versus saving their life), the risks may simply be too high.
The approach developed by the team at the Pittsburgh Medical Centre uses a different combination of chemotherapy drugs, which are not as potent to the body. The goal of this approach is not to kill every cell in the patient's bone marrow, but to make enough room for the new cells to flourish.
“We successfully reduced the intensity of chemotherapy and we were still able to engraft all our patients,” Szabolcs says. “Using maximum intensity, you might be inadvertently killing patients and causing irreversible organ disease. (We used) use reduced intensity and have excellent survival (rates).”
This more moderate procedure is promising for conditions where the standard intensity regime poses a barrier to bone marrow or cord blood transfusions. More than half of the patients in the study had a form of leukodystrophy — a genetic disorder that leads to the destruction of the protective coating of the nerves in the brain and spinal cord, according to the National Organization for Rare Disorders.
Three-year survival rate after the standard chemotherapy preparation for umbilical cord blood transfusions for individuals with leukodystrophies ranges from 49 per cent to 77 per cent, depending on their health at the time of the transfusion. The reduced-intensity approach reported a three-year survival rate of 94 per cent.
The stem cells in umbilical cord blood provide a promising treatment as recipients do not have to have a perfect HLA (immune profile) match with the donor.
About 70 per cent of patients who need stem cells or bone marrow transplants have to rely on an unrelated donor to find a match, according to the University of British Columbia Medical Journal.
This can create accessibility concerns for ethnic minorities. A 2012 study calculated that match rates for unrelated donors ranges from two per cent for POC to 46 per cent for Caucasians.
Since 2012, Canadian Blood Services has extended campaigns to communities with low match rates to increase the presence of donors. The concern still remains, however. Cord blood offers a hopeful alternative.
“It's really applicable for ethnic minorities where the perfect HLA match might be elusive in the living donor population,” Szabolcs says. “And cord blood is readily available.”