Blood Cell Research Could Improve MS Treatment
By Multiple Sclerosis Connect Staff December 14 2,107
A recent study at the Montreal Neurological Institute and Hospital of McGill University shed new light on the causes of multiple sclerosis, and may point the way to improved treatment. The research, published on the website Science Translational Medicine, offered insights into how B cells, a type of white blood cells, may contribute to MS inflammation and relapses.
What this study means for understanding MS
Another type of white blood cells, T cells, has been generally thought to be the main factor controlling the disease. According to the website The Scientist, research has tended to focus on T cells, rather than B cells, because of their greater numbers in MS lesions, and their importance in a disorder found in mice that is similar to MS.
T cells normally identify and attack bacteria, viruses and parasites. In MS, they target myelin, the fatty material protecting the central nervous system. This leaves the nerves themselves open to damage.
B cells differ from T cells in structure, and are produced in the bone marrow rather than the thymus gland. In a healthy person, B cells work with T cells as part of the adaptive immune system, helping to produce antibodies that defend against invading microorganisms.
Past research has shown that B cell depletion therapy, a form of treatment in which B cells are destroyed in order to fight autoimmune diseases, might restrict new inflammation in MS patients. Recent clinical trials of an anti-B cell humanized antibody called ocrelizumab showed promising results. Precisely how B cells are involved in MS has, however, remained unclear.
The new study set out to learn more about how B cells contribute to MS. Researchers analyzed blood samples from 35 MS patients and 35 healthy volunteers. They found that a subset of B cells, more common in MS patients' blood than in the control group, produces something called the cytokine granulocyte macrophage colony stimulating factor (GM-CSF).
In a properly functioning immune system, GM-CSF is a white blood cell growth factor that helps to fight infection. In someone who has MS, though, this glycoprotein causes inflammation and may also lead to the activation of MS-promoting T cells.
The evidence does not show that GM-CSF-producing B cells actually cause MS. However, it does help explain the part that B cells play in MS symptoms.
Developing more effective treatments
The study's senior author, Dr. Amit Bar-Or, explained what makes these findings meaningful for future MS treatment in a press release.
"The study is significant in discovering a new way by which B cells can contribute to abnormal immune responses in MS, which reinforces the rationale for the use of B cell depletion therapy," Bar-Or said. "Furthermore, better identifying the particular subset of B cells responsible for new disease activity, we can look forward to more selectively targeting the 'bad' B cells while leaving 'good' B cells intact."
Healthy B cells are a vital part of the immune system, and keeping them alive prevents long-term repercussions for a patient's health. Consequently, a more directed approach to B cell depletion could make a tremendous difference in offering improved outcomes for those living with MS.