Since the first use of umbilical cord blood stem cells in 1988, more than 35,000 transplants of this valuable biological material have been performed worldwide. The range of diseases in which umbilical cord blood stem cells are used is constantly expanding, and today includes about 100 nosological units.
The generally accepted protocol for the treatment of malignant and genetically determined diseases of blood and metabolism with hematopoietic stem cell transplant implicates strict immunological compatibility between donor and recipient and the use of high-dose chemotherapy before transplant. The latter is toxic and often accompanied by complications, and the chances of finding a compatible bone marrow donor for some patients are 1 in a million. Umbilical cord blood is known to have lower immunogenicity, which allows it to be used with lower immunological compatibility, but the protocol of high-dose chemotherapy has so far been mandatory as well.
A new, safer approach to hematopoietic stem cell transplant in the treatment of genetically determined metabolic diseases was recently introduced by scientists from a Children’s Hospital in Pittsburgh (USA). The researchers recently reported that they safely and effectively treated 44 children from a variety of serious genetic diseases with the help of umbilical cord blood stem cells. These include sickle cell anemia, thalassemia, Hunter’s syndrome, Crabbe’s disease, metachromatic leukodystrophy, and a number of immunodeficiencies. This is the largest clinical study of its kind using umbilical cord blood conducted to date. The results of the treatment of patients were published in the journal Blood Advances.
Umbilical cord blood stem cells were administered intravenously to patients. Stem cell transplantation was preceded by low-dose chemotherapy and immunosuppressive drugs. Doctors tried to create a therapeutic protocol that would actually be used in different centers at a low cost of treatment. According to this scheme, patients after the first dose of stem cells and their “integration” with the recipient’s body were administered a small subsequent dose. It is important to note that the developed method of treatment did not require strict immunological compatibility between donor and recipient.
The developed method of treatment of genetically determined diseases is especially important for ethnic minorities, because due to the high variability of antigens on the cell surface, children from parents of different nationalities can find it very difficult to find a compatible bone marrow donor.
In treated patients, complications from umbilical cord blood stem cell transplantation were relatively minor. No patient developed an acute form of graft-versus-host disease, and the mortality rate from viral infections was 6%, which is significantly lower than in previous clinical trials.
In all 30 children with genetic metabolic disorders, in which the patient accumulates harmful toxins, a year after treatment, normal levels of enzymes and improvement of neurological symptoms were observed.
The most common disease for which transplantation was performed was leukodystrophy. Patients with this disease usually die within a few years after the first symptoms. Even with umbilical cord blood transplantation, only 60% of children previously lived 3 years after treatment. When using the new protocol described above, more than 90% of patients were alive 3 years after transplant.
None of the previously known treatments has provided such a high level of safety, efficacy and versatility in the treatment of various diseases. This transplant scheme is effective in at least 20 diseases.
The new method of treatment is already being successfully used in adults.