The antigen-specific reaction of T-cells working with dendritic cells, which regulate the immune system.
Credit: National Institute of Allergy and Infectious Diseases
SYDNEY: The manipulation of specific immune cells in bone marrow transplants has left a number of patients cancer-free, giving new hope to leukemia and lymphoma sufferers, according to a recent study.
A team lead by Sébastien Maury from the Service d'Hématologie Clinique, France, has shown for the first time that by depleting the regulatory T-cell (or Treg) population in donor tissue, patients suffering from very resistant forms of cancer can achieve complete remission.
By identifying the Tregs’ influence on how a new immune system reacts to foreign elements, it’s hoped that this study will result in more successful cancer treatments using transplantation.
The challenge for new immune systems
Tregs are types of white cells called T lymphocytes, which control the activity of the immune system. When they are less active in a patient, the immune system becomes more activate and can respond better to against foreign antigens.
In the case of cancer patients receiving a donor bone marrow transplant, Tregs in the transplant can kill off cancer in the patients. This is phenomenon is known as alloimmunity, and is often crucial to the success of bone marrow transplantation.
But often when an immune system is grafted to a patient, it won't recognise the cancerous cells as foreign, and instead becomes tolerant.
Anti-tumour effect improved
Maury’s research, published in Science Translational Medicine has provided the first direct evidence that Tregs facilitate this tolerance between the donor immune system and patient cancer cells in the field of transplantation.
“It has been recognised that a principal element in the induction of immune tolerance are regulatory T-cells. We therefore attempted to eliminate them from the graft and demonstrated increased alloimmunity and increased anti-tumour effect,” says Maury.
It is this anti-tumour effect which actively kills off the cancer cells in a patient, and in most successful scenario can render them cancer-free.
