B cells activate T cells in the blood to cause inflammation and brain lesions in patients with multiple sclerosis.
While T cells have been known to play a role in the pathogenesis of multiple sclerosis (MS), new research indicates that T cell interactions with B cells may drive inflammation and brain lesions in the disease, according to a new study published in Cell.
In patients with MS, disrupted T cells attack and damage the body’s myelin sheaths that surround nerve cells in the brain and spinal cord, affecting their ability to communicate with each other. The new findings suggest that B cells, the cells that produce antibodies, also play a key role in causing the onset of MS by activating the specific T cells that cause inflammation in the brain and nerve cell lesions.
The findings provide an explanation for how new MS drugs take effect, according to researchers from the University of Zurich. Certain drugs used to treat MS, such as Rituximab and Ocrelizumab, eliminate B cells to effectively inhibit brain inflammation and flare-ups. This novel approach led the researchers to believe that B cell interaction with T cells may be a key factor in the development of the disease, an understanding that could lead to new approaches in the treatment of MS.
“This means that we can now explain the previously unclear mechanism of these MS drugs,” Roland Martin, MD, director of Clinical Research Priority Program Multiple Sclerosis at University of Zurich, said in a press release.
By using an experimental in-vitro system, the researchers analyzed blood samples of patients with MS to establish the B cells’ role. When the B cells interacted with the T cells, the blood of patients with MS showed increased levels of activation and cellular division among T cells attacking the body’s myelin sheaths that surround nerve cells. The researchers found that when the B cells were eliminated, the proliferation of T cells was effectively inhibited.
Additionally, the activated T cells found in the blood included those that also occur in the brain in patients during flare-ups of the disease. Once the T cells are activated in the peripheral blood, they migrate to the brain.
“These findings will be instrumental to address important questions regarding pathogenic B-T cells interactions in multiple sclerosis and possibly also to develop novel therapies,” the researchers concluded in the study.
Jelcic I, Nimer FA, Wang J, et al. Memory B cells activate brain-homing, autoreactive CD4+ T cells in multiple sclerosis. Cell. 2018. Doi: https://doi.org/10.1016/j.cell.2018.08.011
B Cells Among Factors Leading to Brain Lesions in Multiple Sclerosis [news release]. University of Zurich’s website. http://www.media.uzh.ch/en/Press-Releases/2018/Multiple-Sclerosis.html. Accessed September 5, 2018.